News Water Doc Permit Support Document May2006

MEMORANDUM TO:

RIVANNA WATER & SEWER AUTHORITY BOARD OF DIRECTORS

FROM:

THOMAS L. FREDERICK, EXECUTIVE DIRECTOR

SUBJECT:

COMMUNITY WATER SUPPLY PLAN – JOINT PERMIT SUPPORT DOCUMENTS

DATE:

MAY 22, 2006

For the past several years, the RWSA staff has been working to develop and permit a future water supply for the Charlottesville and Albemarle County community. Today we present to the Board for consideration the Community Water Supply Plan, Joint Permit Support Document as prepared by our engineering consultant team of Gannett Fleming and VHB, Inc. This plan is the synthesis of significant technical evaluation, regulatory coordination and community input. On April 18, 2006, RWSA conducted a Community Outreach Meeting to announce that the preferred future community water supply is the Ragged Mountain Dam Alternative. At the meeting, the public was given the opportunity to ask questions and provide feedback. I am pleased to announce that there was broad support for this alternative and encouragement from the community to continue in the permitting process. To that end, staff has requested that Gannett Fleming provide a brief overview of the document before you today. This Joint Permit Support Document will serve as the background and basis for a future permit submittal. At this time, the conceptual environmental mitigation plan has not been included in the document. As the mitigation plan becomes more fully developed, RWSA will provide an opportunity for public discussion and approval. With the consent of the Board, RWSA staff will be presenting the preferred alternative, for approval, to each of the regional governing bodies as follows: Charlottesville City Council Albemarle County Board of Supervisors Albemarle County Service Authority Board of Directors Rivanna Water and Sewer Authority Board of Directors

June 5, 2006 June 7, 2006 June 15, 2006 June 26, 2006

Upon the support of the preferred alternative, by the regional governing bodies, RWSA staff anticipates a Community Water Supply Permit submission by July 4, 2006. Attachment

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Rivanna Water & Sewer Authority

Community Water Supply Project City of Charlottesville and Albemarle County, Virginia

PermitSupport SupportDoscument Document Permit

Prepared by:

May 17, 2006

Rivanna Water & Sewer Authority Community Water Supply Project

Permit Support Document

Prepared For

Prepared By

May 17, 2006

Table of Contents Section I – Introduction .................................................................................. 1 Section II – Statement of Purpose and Need................................................ 2 A. B. C. D.

Demand Analysis ............................................................................................... 2 Supply Analysis.................................................................................................. 3 Supply Deficit ..................................................................................................... 3 Purpose............................................................................................................... 5

Section III – Existing System Description..................................................... 5 A. Raw Water Sources............................................................................................ 5 South Fork Rivanna Reservoir (SFRR)................................................................ 5 Sugar Hollow Reservoir (SHR) ............................................................................ 6 Ragged Mountain Reservoirs (RMR) ................................................................... 7 North Fork Rivanna River .................................................................................... 8 B. Water Treatment Plants ..................................................................................... 9 South Fork Rivanna Water Treatment Plant ........................................................ 9 Observatory Water Treatment Plant .................................................................... 9 North Fork Rivanna Water Treatment Plant......................................................... 9 C. Operations ........................................................................................................ 10 Normal Conditions ............................................................................................. 10 Drought Conditions ............................................................................................ 10

Section IV – Alternatives Identification and Screening ............................. 10 A. B. C. D. E.

Background ...................................................................................................... 10 Water Supply (Raw Water) Component Identification................................... 11 Treatment Plant Components ......................................................................... 12 Alternatives Development ............................................................................... 13 Evaluation Factors ........................................................................................... 13 Estimated Total Project Cost ............................................................................. 13 Impacts to Aquatic Ecosystems and Wetlands Impacts..................................... 14 Stream Impacts.................................................................................................. 15 Threatened or Endangered Species .................................................................. 15 Other Environmental Impacts ............................................................................ 16 Logistical Issues................................................................................................. 16 Cultural Resources ............................................................................................ 16 F. Results .............................................................................................................. 17

Section V – Short Listed Concepts Evaluation .......................................... 22

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A. South Fork Rivanna Reservoir – 4 Foot Crest Gate Expansion Concept.... 22 Concept Description........................................................................................... 22 Safe Yield .......................................................................................................... 23 Cost ................................................................................................................... 23 Concept Impacts ................................................................................................ 23 Wetlands. .................................................................................................... 23 Streams....................................................................................................... 24 Threatened and Endangered Species......................................................... 25 Cultural Resources...................................................................................... 25 Other Impacts. ............................................................................................ 25 Land Acquisition.......................................................................................... 25 B. Dredging South Fork Rivanna Reservoir Concept ........................................ 26 Concept Description........................................................................................... 26 Safe Yield .......................................................................................................... 27 Cost ................................................................................................................... 27 Impacts .............................................................................................................. 29 Wetland/Stream/Cultural Resources and Threatened and Endangered Species ....................................................................................................... 29 Benthic Community and Secondary Impacts .............................................. 30 Upland Impacts ........................................................................................... 30 C. James River Intake and Pipeline Concept ..................................................... 31 Concept Description........................................................................................... 31 Raw Water Quantity. ................................................................................... 31 Raw Water Quality ...................................................................................... 31 Potential Intake Site Locations.................................................................... 31 Pipeline from Scottsville to Charlottesville................................................... 32 Property Acquisition .................................................................................... 34 System Capacity/Yield ................................................................................ 34 Cost ................................................................................................................... 34 Project Impacts .................................................................................................. 35 Stream Impacts: James River Intake .......................................................... 35 Stream Impacts........................................................................................... 36 Wetlands. .................................................................................................... 36 Threatened and Endangered Species ........................................................ 37 Cultural Resources...................................................................................... 38 Property Acquisition .................................................................................... 39 D. Ragged Mountain Reservoir Expansion and Pipeline................................... 39 Concept Description........................................................................................... 39 Safe Yield .......................................................................................................... 40

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Costs.................................................................................................................. 40 Project Impacts .................................................................................................. 41 Wetlands ..................................................................................................... 42 Streams....................................................................................................... 42 Threatened and Endangered Species ........................................................ 43 Cultural Resources...................................................................................... 43 Other Project Impacts ................................................................................. 44 Property Acquisition. ................................................................................... 44 E. Summary........................................................................................................... 45 Four Foot Crest Gates at SFRR......................................................................... 45 Dredging SFRR.................................................................................................. 45 James River Intake and Pipeline........................................................................ 45 Raising Ragged Mountain Reservoir. ................................................................ 46 Conclusion ......................................................................................................... 46

Section VI - Selection of Preferred Alternative........................................... 47 A. Concepts That Are Not Preferred.................................................................... 47 South Fork Rivanna Reservoir – 4-Foot Crest Gate .......................................... 47 Dredging South Fork Rivanna Reservoir ........................................................... 47 B. Further Evaluation of Candidate Concepts.................................................... 48 James River Intake and Pipeline........................................................................ 48 Operating Conditions: .............................................................................................. 50 Normal Operating Conditions:................................................................................. 50 Drought Operating Conditions:................................................................................ 50 Ragged Mountain Expansion............................................................................. 51 Operating Guidelines ............................................................................................... 54 C. Evaluation of Candidate Alternatives ............................................................... 55 Project Purpose ................................................................................................. 55 Cost ................................................................................................................... 55 Logistics............................................................................................................. 56 Environmental Impacts ...................................................................................... 62 Value for Habitat, Wildlife and Recreation ............................................................. 62 Moormans River ...................................................................................................... 63 Mechums River ........................................................................................................ 64 South Fork Rivanna River........................................................................................ 65 James River .............................................................................................................. 65 D. Agency Coordination ....................................................................................... 66 E. Public Involvement........................................................................................... 67 F. Preferred Alternative........................................................................................ 69

Section VII – Mitigation ................................................................................. 70 iii

A. Avoidance and Minimization Measures............................................................ 70 Avoidance .......................................................................................................... 70 Minimization ....................................................................................................... 71 Mitigation ........................................................................................................... 71

Section VIII – Conclusion ............................................................................. 71 Bibliography .................................................................................................. 73 Appendix A Supporting Documentation

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List of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14

Statistics for South Fork Rivanna Reservoir....................................... 6 Statistics for Sugar Hollow Reservoir ................................................. 7 Statistics for Upper and Lower Ragged Mountain Reservoirs .......... 8 Statistics for North Fork Rivanna River Intake ................................... 8 Analysis of Selected Alternatives (Page 1 of 2) ................................ 19 Analysis of Selected Alternatives (Page 2 of 2) ................................ 20 Key Determining Factors for Selected Alternatives ......................... 21 Cost Estimate for Installing 4-foot Crest Gates on SFRR ................ 23 Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with 50% Reuse of Dredged Material ................. 28 Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with 20% Reuse of Dredged Material ................. 28 Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with No Reuse of Dredged Material ................... 29 James River Intake and Pipeline Concept Cost Estimate ................ 35 Ragged Mountain Reservoir Expansion and Pipeline Concept Cost Estimate ...................................................................... 41 Estimated Costs .................................................................................. 56 Existing and Proposed Flows in the Moormans River Immediately Downstream of Sugar Hollow Dam .............................. 64

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List of Figures Follows Page Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15

Vicinity and Service Area Map.............................................................. 1 Existing Urban Service Area System Map........................................... 1 Projected Daily Demand and Supply .................................... on page 4 Existing System Schematic .................................................................. 5 South Fork Rivanna Reservoir – 4 foot Crest Gate Expansion Concept ............................................................................. 23 South Fork Rivanna Reservoir – 4 foot Crest Gate Expansion Potential Resource Impacts................................................................ 23 Low Points of SFRR Cross Sections (Data from 2002 Bathymetric Survey) ................................. on page 26 Potential Parcels for Purchase and Construction of River Intake................................................ on page 32 Generic Raw Water Transmission Pipeline from James River to Observatory WTP ....................................... on page 33 Ragged Mountain Reservoir ............................................................... 39 Ragged Mountain Reservoir Concept – 686-foot Pool .................... 40 Ragged Mountain Reservoir Concept Impacts ................................. 42 James River Alternative...................................................................... 48 Ragged Mountain Alternative ............................................................. 51 Ragged Mountain Alternative – Pipeline Stream Crossings............ 66

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Section I – Introduction Since 1973, Rivanna Water and Sewer Authority (RWSA) has been responsible for providing a safe and dependable water supply to its wholesale customers in the City of Charlottesville and surrounding Albemarle County, (Figure 1). Acting as a wholesale distributor, RWSA sells finished water to the Albemarle County Service Authority (ACSA) and the City of Charlottesville Public Works Department; that then distribute retail water to residential, commercial and industrial users within a geographic area known as the “Urban Service Area”. The Urban Service Area encompasses all of the City of Charlottesville (including the University of Virginia) and some of the more densely populated areas of Albemarle County surrounding Charlottesville (Figure 2). According to RWSA, present raw water demand within the Urban Service Area typically ranges from 9 to 12 million gallons per day (MGD) throughout the year. Although not part of this study, Crozet and Scottsville are also served by RWSA. The Urban Service Area is supplied by several sources of raw water which include: the South Fork Rivanna River Reservoir (SFRR), the Sugar Hollow Reservoir (SHR), the adjoining “Upper” and “Lower” Ragged Mountain Reservoir system (RMR), and a river withdrawal on the North Fork Rivanna River (see Figure 2). The water is treated and supplied as potable water to the Urban Service Area. Raw water from the South Fork Rivanna River Reservoir is treated at the South Fork Rivanna Water Treatment Plant (WTP). Raw water from the Sugar Hollow Reservoir can be diverted into the Ragged Mountain Reservoirs through an 18-inch gravity fed transmission main approximately 13 miles in length. Water can also be directly diverted to the Observatory Water Treatment Plant. Water from the SHR that is not diverted to RMR or the Observatory WTP can be released to the Moormans River by flow over the spillway, or as a voluntary release through an orifice on the 18-inch RMR pipeline located just below the Sugar Hollow Dam. Considered as one interconnected system, raw water from Sugar Hollow/Ragged Mountain is treated at the Observatory WTP. Raw water from the North Fork Rivanna River is treated at the North Fork Rivanna WTP. The total raw water safe yield of this water supply system is currently 12.8 MGD. For a more detailed description of the water supply system, see the Safe Yield Study and Safe Yield Study Supplement No. 1 (Gannett Fleming, 2004). Over the course of many years, RWSA has been evaluating water supply conditions and community needs. As a result, it is evident that the existing raw water sources will be inadequate to handle the growing needs of the community. The capacity of the existing system is also gradually declining due to siltation. Consequently, RWSA has evaluated numerous potential water supply alternatives. Many of these alternatives have the potential to affect resources under the jurisdiction of the U.S. Army Corps of Engineers (USACE), the Virginia Department of Environmental Quality (DEQ) and other state and federal agencies. After conducting a rigorous evaluation of alternatives in accordance with the Clean Water Act Section 404 (b)-(1) Guidelines, and after extensive coordination with all relevant state and federal regulatory agencies, and numerous public meetings, RWSA has determined that an expansion project of the Ragged Mountain Reservoir and construction of a pipeline between

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Figure 1

Vicinity and Service Area Map

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18,000 feet Piney Mountain Water Tank

Existing Service Area Sugar Hollow 18” Raw Water Line Ragged Mountain 18” Raw Water Line Water Treatment Plant

North Fork Rivanna WTP

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South Fork Rivanna WTP

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Figure 2

Existing Urban Service Area System Map

South Fork Rivanna Reservoir and Ragged Mountain Reservoir is the least environmentally damaging, practicable alternative available for expanding the safe and reliable water supply to the Urban Service Area. Conceptual planning indicates that the reservoir expansion will affect stream and wetland resources under USCOE and DEQ jurisdiction. Accordingly, this document has been prepared to present the necessary and relevant information to interested state and federal regulatory agencies and assist their consideration of accompanying permit applications. The following sections of this Permit Support Document include a statement of project purpose and need, an evaluation of alternatives (including associated environmental impacts and means to avoid or minimize them), the rationale for selection of the preferred alternative and a detailed description of the environmental impacts that are expected from the preferred alternative. Finally, a description of the proposed actions to mitigate unavoidable impacts to aquatic resources is provided.

Section II – Statement of Purpose and Need The Commonwealth of Virginia Waterworks Regulations state that “At such time as the water production of a community waterworks reaches 80% of the rated capacity of the waterworks for any consecutive three-month period, the owner shall cause plans and specifications to be developed for expansion of the waterworks to include a schedule for construction…” RWSA urban water system demands regularly exceed 80% of water supply capacity in summer months. Further, in the Commonwealth of Virginia Guidance for Conducting a Comprehensive Public Drinking Water Supply Needs Assessment, DEQ indicates that a 50-year water supply planning horizon is appropriate. Accordingly, RWSA initiated the planning process and has established a 50-year planning period for this analysis. This complies with standard industry practice, pursuant to Virginia Department of Environmental Quality policy and federal policy pursuant to the National Environmental Policy Act, 42 U.S.C. § 4321 et seq. Use of a long-term planning window is environmentally sound as it helps to assure that projects with short-term advantages are not preferred over those with more durable and lasting value. To assist RWSA in their long range planning, a detailed analysis of existing and future water demand and water supply was completed in November of 1997 and updated in May 2004. The Demand Analysis for the Urban Service Area (Gannett Fleming, 2004) and the Safe Yield Study and Safe Yield Study Supplement No. 1 (Gannett Fleming, 2004) document the methodologies and results of these analyses and serve as the basis for determining the RWSA’s future raw water supply needs. These documents were distributed to state and federal regulatory agencies and discussed at coordination meetings during the summer of 2004. A summary of the key findings is presented in the following paragraphs.

A.

Demand Analysis

The future raw water needs of RWSA were projected on the basis of historical demand and population projections. Future demands of each component of water use were projected using

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four different methods. The results of these methods were averaged to arrive at a gross projected demand for 2025 (20-year interim horizon) and 2055 (50-year horizon), which are 15.3 MGD and 19.6 MGD, respectively. Another important factor in projecting demand is water conservation. The ACSA and the City of Charlottesville have vigorous water conservation programs that are expected to produce increasing results as the planning period unfolds. With this in mind, the gross projected demand values were adjusted downward by a factor of 5% to account for active water conservation measures that may be implemented during the planning period. The 5% water conservation factor is considered appropriate given the current and projected water conservation measures in place by the City of Charlottesville, the ACSA, and after consideration of other municipal programs around the country. The resulting net projected demands are 14.5 MGD in 2025 and 18.7 MGD in 2055.

B.

Supply Analysis

In the supply analysis, the safe yields of the three water supplies currently available to the RWSA were studied: 1) South Fork Rivanna River Reservoir, 2) Sugar Hollow/Ragged Mountain Reservoir system, and 3) North Fork Rivanna River Intake. The most salient fact emerging from the safe yield analysis is that the safe yield of the system is diminishing at a steady pace due to siltation and consequent loss of water storage capacity at South Fork Rivanna River Reservoir. This storage loss was predicted at the time the reservoir was originally proposed, and has been quantified over time. Due primarily to this factor, the combined safe yield of the existing sources supplying the Urban Service Area are expected to fall from approximately 12.8 MGD (2004) to 8.8 MGD by 2055. Also affecting the water supply situation is the current regulatory status of Ragged Mountain Reservoir in the Virginia Dam Safety program. Specifically, both the upper and lower dams were deemed to be seriously inadequate. As a result the dams are currently being operated under “conditional” operation and maintenance certificates provided by the Virginia Department of Conservation and Recreation, Division of Dam Safety. Over the years, Virginia Dam Safety has granted several extensions to the conditional operating permit. RWSA is working with Dam Safety towards resolution of these issues.

C.

Supply Deficit

The supply deficit or surplus is determined for a water system containing reservoirs by comparing the average daily demand of the area served with the safe yield of existing water supply facilities. Water demands and supplies within the Urban Service Area have been projected over the 50-year planning period and are presented in Figure 3. As this figure indicates, it is expected that the average daily demands will exceed the safe yield by approximately 2008. Each year after 2008, increasing demand and shrinking supplies will increase the probability that a drought may cause service reductions unless steps are taken to alter the situation. By 2055, projected demand will total 18.7 MGD (approximately twice the safe yield of the system today), exceeding the safe yield by 9.9 MGD.

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Figure 3 Projected Daily Demand vs. Safe Yield 20

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Supply Deficit

Demand/Safe Yield (MGD)

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Year Safe Yield with Existing Facilities Average Daily Demand (Approx.)

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D.

Purpose

A thorough analysis of water supply and demand in the RWSA Service Area suggests that system demand will exceed safe yield by 2008. By 2025, the projected demand will total 14.5 MGD and the available safe yield will decline to 11.2 MGD resulting in a projected deficit of 3.3 MGD. By 2055, the projected demand will total 18.7 MGD and the available safe yield will decline to 8.8 MGD, resulting in a projected deficit of 9.9 MGD. Furthermore, merely to maintain this deficit situation, the present impounding structure at Ragged Mountain Reservoir must be repaired or replaced. Accordingly, the RWSA must expand its water system capacity and manage demand to assure that water supplies are adequate to meet demand throughout the planning period. This includes addition of new raw water sources, as well as the necessary improvements in treatment and distribution to meet the projected water demands.

Section III – Existing System Description The Urban Service Area is comprised of raw water sources, treatment plants, transmission and storage facilities. It includes the following three water treatment plants (WTP): (1) South Fork Rivanna WTP, (2) Observatory WTP, and (3) North Fork Rivanna WTP. These WTPs receive raw water from four reservoirs and one river intake. The South Fork Rivanna WTP is supplied by the SFRR. Although not currently configured to do so, water from Sugar Hollow Reservoir (SHR) could be released into the South Fork Rivanna River via the Moormans River, a tributary to the South Fork Rivanna River. The Observatory WTP is supplied by the Upper and Lower Ragged Mountain Reservoirs (two adjacent dams in series) via an 18-inch diameter pipeline and from SHR via another 18-inch diameter pipeline. Water can also be transferred to Ragged Mountain Reservoirs (RMR) from SHR. The North Fork Rivanna WTP supplied by an intake on the North Fork Rivanna River. A map of the RWSA Urban Service Area raw water sources and treatment system is presented in Figure 2. A schematic showing facility connectivity is also presented in Figure 4. Major raw water source and WTP features are described below to provide a basis for future discussion of water supply alternatives.

A.

Raw Water Sources

South Fork Rivanna Reservoir (SFRR) SFRR is located on the South Fork Rivanna River and was constructed in 1966. It currently serves as the primary source of raw water for the Urban Service Area. Sugar Hollow Reservoir, Beaver Creek Reservoir (a multi-use facility that provides water supply to the Town of Crozet), and Lake Albemarle (a recreation reservoir) are also located within the watershed. Although not currently used, the Mechums River Pumping Station built in 1965, is also located in the watershed. SHR, discussed below, is the only facility of these mentioned that contributes directly to the RWSA Urban Service Area raw water source system.

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Figure 4

Existing System Schematic

The original storage capacity of South Fork Rivanna Reservoir, with a normal pool at Elevation 382.0 feet, was approximately 1,700 million gallons. The lowest water supply intake level is set at Elevation 367 feet. The storage volume below this elevation (dead storage) was 492 million gallons at the time of construction. The storage available for water supply is the difference between the total storage capacity and the dead storage. The designers of the dam expected that reservoir sedimentation would be significant. The most recent bathymetric survey conducted in March 2002 determined that the total reservoir storage capacity at that time was 1,155 million gallons. The corresponding dead storage below elevation 367 feet was 355 million gallons. This equates to an average annual loss of total reservoir storage of 15.1 million gallons per year. This storage loss will continue significantly to reduce the safe yield of the SFRR over time. There is no regulatory minimum release from SFRR because it functions essentially as a runof-the-river impoundment except during substantial drought. Nevertheless, the RWSA has made a voluntary commitment to release a minimum flow of 8.0 MGD from South Fork Rivanna Reservoir except during unusually severe drought conditions when such a release would threaten the ability to meet public water supply needs. When the reservoir inflow is less than 8.0 MGD, release from the reservoir would equal the natural inflow to the reservoir. In other words, the streamflow downstream of the dam would be at its natural level rather than being artificially augmented by reservoir storage. Streamflow records indicate that the natural flows into the reservoir are less than 8.0 MGD approximately 3 percent of the time, and that extended periods of no flow occurred during the 2002 drought. According to the 1978 Phase I Inspection Report for the dam, no seepage was observed. Important statistics for the facility are summarized in Table 1. Table 1

Statistics for South Fork Rivanna Reservoir

Feature/Parameter

Value 259.1 mi2 60 feet 382 feet 366 acres 1,155 Million Gallons

Drainage Area Dam Height Normal Pool Elevation Surface Area of Permanent Pool Volume of Permanent Pool (2002 Survey) Existing Voluntary Conservation Release Seepage at Dam

The Lesser of 8.0 MGD or the Natural Inflow None observed

Mi2 = Square Miles

Sugar Hollow Reservoir (SHR) Sugar Hollow Dam was constructed in 1947 on the Moormans River to expand the public water supply system. An inflatable bladder was added to the spillway crest in 1999 to increase spillway capacity while maintaining original storage capacity. The normal pool with the inflatable bladder in the raised position is at Elevation 975 feet. At this normal pool condition, the existing reservoir storage is approximately 360 million gallons. This storage volume is 6

based on a bathymetric survey performed in September 1995 following a landslide in the reservoir. The June 1995 event resulted from severe rainfall and approximately 70 million gallons of storage was lost. There are presently three ways that water in the SHR can be released: (1) by overflow from the spillway to the Moormans River; (2) by release of 400,000 gallons per day to the Moormans River through a tap on an 18-inch diameter transfer pipeline; or (3) by transfer of water through the 18-inch diameter transfer pipeline approximately 13 miles to the Ragged Mountain Reservoir or Observatory Water Treatment Plant. The spillway includes a bladder that can raise the spillway elevation by 5 feet when raised, but this is the only control device available for spillway control. Operating practice is to keep the bladder inflated except for necessary maintenance or when flood conditions are predicted or are occurring. Although there is no minimum release regulatory requirement from the reservoir, the RWSA has made a voluntary commitment to release at least 400,000 gallons per day to the Moormans River unless total available reservoir storage falls below 80 percent. Current analysis of streamflow records indicate that the natural flows at the dam are less than 400,000 gallons per day approximately 5 percent of the time and during extreme drought events there are brief periods of no river flow. Important statistics for the facility are summarized in Table 2. Table 2

Statistics for Sugar Hollow Reservoir

Feature/Parameter

Value 17.51 mi2 77 feet 975 feet 51.2 acres 360 Million Gallons 0.40 MGD whenever reservoir storage exceeds 80 percent of total Unquantified

Drainage Area Dam Height Normal Pool Elevation Surface Area of Permanent Pool Volume of Permanent Pool (1995 Survey) Existing Voluntary Conservation Release Seepage at Dam Mi2 = Square Miles

Ragged Mountain Reservoirs (RMR) Ragged Mountain Reservoirs are comprised of two dams located in the Ragged Mountain region immediately west of Charlottesville. The two reservoirs, Upper Ragged Mountain Reservoir (URMR) and Lower Raged Mountain Reservoir (LRMR), are formed by dams in series on an unnamed tributary to Moores Creek. Together, these dams form the Ragged Mountain Reservoir System (RMR). The URMR dam was constructed in 1885 and originally had a normal pool elevation of 654.7 feet (Gannett Fleming 2002 datum). LRMR was constructed in 1908 and has a normal pool elevation of 641.0 feet (Gannett Fleming 2002 datum). Currently, the reservoirs are connected by a 10-inch diameter pipeline. During lowflow conditions, the normal pool level in URMR equalizes and is controlled by the LRMR pool level. Modifications to the spillway, which were prompted by dam safety, were 7

completed in the 1980s. These modifications, combined with a break in the 10-inch diameter pipe have resulted in a lower pool level in the Upper Reservoir than was originally intended. RMR can be filled via an 18-inch transmission line from SHR, approximately 13 miles in length. The relatively small contributing drainage does provide some natural runoff. For the purposes of this study, Upper and Lower Ragged Mountain Reservoirs are deemed to act as one system. The current combined storage capacity of the reservoirs with normal pools at an elevation of 641.0 feet (Gannett Fleming 2002 datum) is 513.6 million gallons. No known bathymetric surveys have been performed on the reservoirs since their construction. Reservoir sedimentation does not appear to be an issue due to the relatively small size and undisturbed condition of the watershed. There is no regulatory minimum release requirement for the RMR system. There may be some minor seepage from the Lower Ragged Mountain dam, but it appears to be insignificant.. Although the watershed is ungaged, evaluation of nearby streamflow data indicates that there is little to no natural inflow into the reservoirs during drought events. Important statistics for the facility are summarized in Table 3. Table 3

Statistics for Upper and Lower Ragged Mountain Reservoirs

Feature/Parameter

Value 1.81 mi2 67 feet 640.5 feet 70.4 acres 513.6 Million Gallons 0.0 MGD Unknown

Drainage Area Dam Height (Lower Dam) Normal Pool Elevation Surface Area of Permanent Pool Volume of Permanent Pool (Current) Existing Conservation Release Requirement Seepage at Dam (Lower Dam) Mi2 = Square Miles

North Fork Rivanna River The RWSA operates a river intake and pumping station on the North Fork Rivanna River just downstream of the confluence with Jacobs Run. The effective pumping capacity of the river intake is 2.0 MGD, which is transferred directly to the North Fork Rivanna WTP for distribution. There is currently no flowby requirement at the river intake. Important statistics for the facility are summarized in Table 4. Table 4

Statistics for North Fork Rivanna River Intake

Feature/Parameter

Value 115.0 mi2 0.0 MGD 2.0 MGD

Drainage Area Existing Conservation Flowby Water Treatment Plant Capacity Mi2 = Square Miles

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B.

Water Treatment Plants

South Fork Rivanna Water Treatment Plant The South Fork WTP is a conventional process water treatment plant located just north of the City of Charlottesville. It was originally constructed in the mid 1960’s and has a permitted capacity of 12 million gallons per day (MGD) average. It is well run and generally in good condition. It is currently operated at about 8 MGD and peaks periodically at 11.5 MGD. South Fork Rivanna WTP is supplied by raw water from an intake located adjacent to the SFRR dam. There are 3 levels of intakes that can be used depending on water quality issues and reservoir pool level. Normally water is withdrawn from the highest intake. Currently, raw water from SFRR can only be treated at the South Fork Rivanna WTP. SHR water can be transferred to the SFRR, and thus be treated by at South Fork Rivanna WTP. RMR raw water cannot be transferred to the South Fork Rivanna WTP.

Observatory Water Treatment Plant The Observatory WTP is a conventional process water treatment plant located in the southwest portion of Charlottesville on the University of Virginia property. The original facility was significantly rebuilt in 1953 and is permitted at 7.77 million gallons per day (MGD). Although well run by RWSA staff, the facility is in need of major improvements. Current water supply pipeline capacity limits the sustainable WTP output to about 4 MGD, although the WTP can be operated at approximately 5.5 MGD. Observatory WTP is supplied raw water from RMR and SHR. Raw water can be supplied from either source. Separate 18-inch-diameter pipelines transfer water from RMR and SHR. These raw water pipelines are also interconnected for flexible source use. Currently, raw water from RMR can only be treated at Observatory WTP. SHR water can be transferred to Observatory WTP. SFRR raw water cannot be transferred to Observatory WTP.

North Fork Rivanna Water Treatment Plant The North Fork WTP is a small conventional process water treatment plant located at the north end of Albemarle County. It was originally constructed in the early 1970’s and is permitted at 2.0 million gallons per day (MGD). Although well run by RWSA staff, the facility is in need of improvements. It is currently operated at approximately 0.25 MGD average and peaks periodically near 1.4 MGD. North Fork WTP is supplied raw water from an intake located on the North Fork Rivanna River. Water is transferred to the nearby North Fork WTP and pumped into the northern portion of the Urban Service Area. Although not currently capable of transferring water south to the central portion of the distribution service area, RWSA plans to obtain this ability in the near future through a new pump station and pipeline along U.S. Route 29. There is no raw water storage to supply the North Fork WTP, nor is there a means to transfer raw water from SFRR, SHR or RMR. The North Fork WTP can only be supplied by flowing surface water in the North Fork Rivanna River.

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C.

Operations

Normal Conditions Water is normally plentiful in the RWSA raw water system, and the location and proportion of water production at each WTP is not critical. Finished water is typically produced at all three WTPs. There are hydraulic limitations in the distribution systems that influence the production proportions and therefore affect how the water is used within the system. Planned improvements in the transmission system will eventually remove these restrictions thus improving operational flexibility by allowing most or all of the finished water to be pumped into the distribution system from any location. RWSA varies normal production based on time of year, water quality, and staffing issues to produce high quality drinking water in an efficient and economical manner.

Drought Conditions RWSA has experienced severe and very severe droughts in the 1930s, 1960s, and in 2002. During such periods, RWSA’s wholesale customers implement water conservation measures in phases to reduce system demands and modify the management of source water use to preserve storage and maximize available water as much as possible within the constraints of existing physical facilities. Use of the South Fork Rivanna River source is prioritized during these periods to make use of water from the largest drainage area that would otherwise be lost (spilled). In addition, as the drought advances and water no longer spills at SFRR, the opportunity to capture any runoff within the reservoir is maintained. These operations are maintained until sufficient rainfall occurs and reservoirs recover.

Section IV – Alternatives Identification and Screening In evaluating potential actions to decrease the water supply deficit over the study period, RWSA has considered individual actions that would offset the supply deficit as well as multiple actions that, when combined, provide the projected yield requirements. Before discussing the details of these alternatives, it is helpful to understand the history and process of this effort.

A.

Background

As early as the 1970’s, RWSA began long term planning to meet the water demands of a growing Charlottesville community. Initial efforts focused on the acquisition of land for a new raw water reservoir. However, as environmental regulations pertaining to wetlands, streams and other natural resources were developed by federal and state agencies it became apparent to RWSA that a broader approach to identifying water supply alternatives would be required to implement (permit) a new water supply project. In 1999, RWSA retained Vanasse Hangen Brustlin, Inc. (VHB) and O’Brien and Gere, Inc. (OBG) to identify potentially feasible alternatives, including a new reservoir, that might successfully meet projected raw water deficits. VHB and OBG identified 33 alternatives to

10

reduce the water supply deficit including both new structural facilities and demand management options. In 2004, Gannett Fleming, Inc.(GF) and VHB built on these earlier studies, by identifying “components” that provide additional safe yield. These “components” may meet the entire deficit and be considered a viable water supply “alternative” project or could be combined to create a water supply “alternative”, if the component cannot satisfy the entire deficit on its own. Each “alternative” was coupled with “water treatment components” to form an alternative that provides a basis for accurate cost comparison. The results of this work are summarized below.

B.

Water Supply (Raw Water) Component Identification

In 2000, VHB and O’Brien & Gere completed the Water Supply Project Analysis of Alternatives (VHB, 2000). Thirty-three (33) alternatives were identified, including the “No Action” alternative. Some of the alternatives satisfied the entire supply deficit; others provided only a portion of the deficit and had to be considered in combination. As part of the current analysis, the 33 alternatives were assessed and reformulated into raw water components (again, a component is defined as a project that may alleviate the water supply deficit as a stand-alone measure, or may require use in combination with other components). Twelve of the VHB 2000 “alternatives” were selected for additional evaluation: 1.

Dredge South Fork Reservoir;

2.

Reduce Sediment Load into South Fork Rivanna Reservoir (SFRR);

3.

Add 4-foot crest controls on South Fork Rivanna Dam;

4.

Add 8-foot crest controls on South Fork Rivanna Dam;

5.

Up to 5-foot drawdown of Chris Greene Lake;

6.

Use Beaver Creek Reservoir to Supplement Flows in Mechums River;

7.

Conversion of Ragged Mountain to Pumped Storage Reservoir;

8.

Pumpback to Mechums River;

9.

Construct Dam on Buck Mountain Creek;

10.

James River Withdrawal at Scottsville;

11.

Rivanna River Withdrawal; and

12.

No-Action.

Gannett Fleming identified six additional components, including: 13.

Add crest controls at South Fork Rivanna Dam to meet full deficit;

14.

Use available storage in Lake Albemarle;

15.

Raise Ragged Mountain Reservoir;

16.

Construct new pumped storage facility at Rocky Creek;

11

17.

Expand Sugar Hollow Reservoir; and

18.

Enlist Regional Cooperation with Fluvanna and Louisa Counties for a James River Withdrawal.

In total, this reformulation resulted in eighteen (18) raw water components which were evaluated. Eight were not evaluated further after it became clear they could not reliably contribute to solving the deficit, either alone or in combination, and that failing to meet this water supply need would have unacceptable adverse consequences on the community and public interest. For additional details on this evaluation, see the Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004). The 8 components which were dropped from the evaluation are: •

Reduce Sediment Load into South Fork Rivanna Reservoir (SFRR);

•

Up to 5-foot drawdown of Chris Greene Lake;

•

Conversion of Ragged Mountain to Pumped Storage Reservoir;

•

Pumpback to Mechums River;

•

Rivanna River Withdrawal;

•

No-Action;

•

Use available storage in Lake Albemarle; and

•

Construct new pumped storage facility at Rocky Creek.

C.

Treatment Plant Components

In addition to expanding the raw water capacity available to the Urban Service Area system, it is also necessary to improve the raw water transmission system and water treatment capacity of the system at appropriate locations and confirm the usefulness of the expanded water supply. The costs and feasibility of the additional treatment capacity could vary with the raw water supply options. For the purposes of this study, Treatment Plant Components are important because they may affect the relative costs of the alternative. Accordingly, the costs associated with treatment plant expansions, rehabilitation or new construction have been considered in subsequent cost estimating presented in Chapter V. It was also determined that none of the treatment plant components would have impacts within areas sensitive to aquatic ecosystems or other jurisdictional areas. There are few reasonable options for increasing the water treatment capacity of the Urban Service Area. The Observatory Water Treatment Plant is in need of rehabilitation and will require extensive work in order to keep it operational over the long term. Therefore, alternatives must address the possibilities of rehabilitation or expansion of the Observatory Water Treatment Plant. The South Fork Water Treatment Plant is the largest WTP in the Urban system and is in good condition. Rehabilitation and expansion alternatives will be

12

considered at this location. Raw water availability and site conditions restrict the ability to expand the North Fork Rivanna Water Treatment Plant. Rehabilitating this WTP and providing 2 MGD treatment capacity would be common to all alternatives. Further discussion on Water Treatment Options is provided in the Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004).

D.

Alternatives Development

Alternatives were formed by a logical step process. The first step identified feasible water supply components previously discussed in Section IV.B. In addition to the stand-alone components, other components were considered in combination to produce “alternatives” that could provide the required 9.9 MGD safe yield. In identifying combinations of components, combinations using multiple reservoirs were found to result in increased project costs as well as environmental impacts. To focus on reasonable alternatives that have less environmental impacts to aquatic ecosystems, only the existing Beaver Creek Reservoir was considered further for use in combination with another expanded or new reservoir. Based on these analyses, water supply components were combined with appropriate water treatment components that met the associated peak day demands to form 22 alternatives. Additional discussion of each of the combination of components is included in the Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004).

E.

Evaluation Factors

After formulating the 22 alternatives, each was evaluated on criteria that will identify those that are practicable and least environmentally damaging. This evaluation resulted in a “short list” of alternatives for more detailed analysis. The following sections will discuss the criteria utilized for the initial evaluation of the 22 alternatives.

Estimated Total Project Cost An alternative’s cost is a relevant and important consideration in assessing whether a project is feasible and practicable. All costs are capital costs and the electrical costs for various alternatives consider average 50-year pumping costs for water from the raw water source to a treatment plant located in the Urban Service Area. The following is a list of the cost estimating items identified for the alternatives:

1. 2. 3. 4. 5. 6. 7.

Land Acquisition Easements Clearing Road Allocation / Relocation Bridge Replacement Utility Relocation Electrical Extension

8. 9. 10. 11. 12. 13.

13

New Dam Construction New Pumped Storage Facility Construction Raise Dam Elevation Beaver Creek Flow Controls WWTP Treatment Process Upgrade New WTP Construction

14. 15. 16. 17. 18. 19.

WTP Expansion Pump Station Electrical Costs Pipeline Intake Structure Rehabilitation of Ragged Mountain Dam 20. Demolition of Pipeline from SHR to RMR 21. Rehabilitation of Observatory WTP 22. Replace Pipeline from SHR to RMR

23. 24. 25. 26. 27. 28. 29. 30.

Engineering, Permitting and Construction Management Rehabilitation of Mechums River Pump Station and Intake Demolition of Observatory WTP Environmental Mitigation Dredging Access Road Culvert Embankment Stabilization

A detailed breakdown of the estimated project costs can be found in Appendix A, Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004).

Impacts to Aquatic Ecosystems and Wetlands Impacts USACE has regulatory authority over waters of the United States including adjacent wetlands. Within the Commonwealth of Virginia, the State Water Control Board assisted by the DEQ has jurisdiction over state waters, including wetlands. For regulatory purposes, wetlands are defined as “those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas” (33CFR328.3b). In order to be considered jurisdictional, a wetland must exhibit all three of the following: the presence of hydrophytic vegetation, hydrologic indicators, and hydric soils, although these parameters alone may not necessarily constitute a jurisdictional wetland. Several methods were used to establish approximate wetland areas within the potential limits of impact associated with a particular alternative. First, the previous impact analysis was reviewed for those alternatives that were being assessed further. The previous effort employed limited field reconnaissance and review of existing mapping sources to produce mapped wetland and stream boundaries in a Geographic Information Systems (GIS) platform. This approach produces a more accurate determination than would rely solely on National Wetland Inventory (NWI) mapping. The data sources included: •

NWI maps – U.S. Fish and Wildlife Service

•

Aerial infrared photographs, 1994 – U.S. Department of Agriculture, Farm Service Agency

•

Albemarle County soils mapping – U.S. Soil Conservation Service

•

Topographic maps – U.S. Geographic Survey (USGS)

14

Second, updated NWI maps were consulted for all alternatives. This allowed the study team to incorporate more recent information into the previous analysis, as well as to determine estimated impacts for alternatives not previously considered. This analysis included distinguishing among various types of wetlands (e.g., forested, scrub-shrub, or emergent) where such data were available, thereby allowing a more accurate estimation of impacts and potential mitigation measures. Finally, more detailed analysis was performed regarding potential impacts of raising the SFRR. Specifically, the study team performed field analysis to verify and supplement the information on impacts identified in 2003 wetland investigations conducted by Malcolm Pirnie. This involved a combination of photo-interpretation and actual wetland delineation and flagging consistent with the USACE Manual. Results were field mapped, and a wetland report was produced to document findings that are summarized in the following paragraphs.

Stream Impacts As with wetlands, the USACE has jurisdiction over discharges to “waters of the United States” pursuant to the provisions of the Clean Water Act and the Rivers and Harbors Act. The State Water Control Board, assisted by the DEQ, has broader jurisdiction over state waters pursuant to the State Water Control Law. Stream impacts occur where new or increased reservoir pool levels result in a replacement of riverine characteristics by lacustrine characteristics. Stream impacts can also occur from disturbance associated with facility construction. Regulatory practices for assessing stream impacts methodology have changed somewhat since the previous analysis, and stream impacts now are identified separately from wetland acreage. The current analysis, consistent with prevailing regulatory practices, has produced separate categories for wetland impacts and linear feet of stream impacts. For consistency, this methodology has been applied to all alternatives in the current study. As a result, stream impact figures in previous reports may appear substantially larger than in the current analysis. However, the actual impacts remain essentially the same; they are simply categorized differently. The implications for permitting remain unchanged, while estimated mitigation costs have increased substantially. Stream impacts were calculated using NWI maps, USGS Quad Sheets, aerial photography, and data from the previous analyses.

Threatened or Endangered Species Plant, animal, or insect species officially classified as “threatened” or “endangered” are protected at the state and federal levels. Agencies with regulatory authority regarding these issues in Virginia include the U.S. Fish and Wildlife Service, the Virginia Department of Game and Inland Fisheries (VDGIF) and the Virginia Department of Agriculture and Consumer Services. A comprehensive database containing known occurrences of rare, threatened, and/or endangered plant and animal species in Virginia is maintained by the Virginia Department of Conservation and Recreation’s Natural Heritage Program and is updated regularly.

15

To evaluate potential impacts to these resources, requests for inventory information were made to the Natural Heritage Program in spring 2004. Evaluation of the preliminary alternatives was performed based upon available information contained in the database at the time of the request. In addition to the database information, specific surveys for the presence of freshwater mussel species were reviewed. The report documents field surveys of the upper Rivanna River watershed and the upper James River tributaries, for the presence of freshwater mussel species, some of which are listed as threatened and/or endangered. Furthermore, a mussel survey of Buck Mountain Creek was completed in October 1996 by Phil Stevenson under contract with VHB, Inc. The VDGIF also conducted a survey in Ivy Creek and determined that the 4-foot crest controls at SFRR would not impact the James spinymussel. Each alternative was evaluated based on the results of those surveys.

Other Environmental Impacts Other impacts relate to any issues unique to the study area, such as designated trout waters, pristine habitats or systems, and groundwater recharge or aquifer systems.

Logistical Issues Logistical issues deal with any matters that will have an impact on the practical implementation of the alternative in question. These include the following: •

Roadway relocation – alternatives that require relocation or realignment of a roadway can incur substantial cost and time delay.

•

Residential displacements – Albemarle County’s GIS database, which includes the most up-to-date information on residential development, was used to count the residences that would be displaced by a particular alternative. In the City of Charlottesville, no displacements are anticipated.

•

Bridge replacement – the study team used topographic mapping, existing bridge plans, inspection reports, and proposed water elevations to assess the potential need for replacement of the Ivy Creek Bridge at SFRR.

•

Utility relocation – alternatives that require relocation or realignment of major utilities can incur substantial cost and time delay.

Cultural Resources Federal authorities are required to evaluate the potential impact of their actions (e.g., issuance of permits) on historic sites and properties either listed or eligible for listing on the National Register of Historic Places as defined by the National Historic Preservation Act. This may include consultation with the State Historic Preservation Officer. A file search was conducted at the Virginia Department of Historic Resources (DHR) to identify previously recorded architectural properties and archaeological sites that might be affected by each alternative as appropriate. Records on file at DHR for each site/property were consulted for additional information when available. No field reconnaissance was

16

conducted except as described below for SFRR. Potential impacts are therefore based solely on available information. Data are presented at this stage to provide preliminary information about the types of resources that could potentially be impacted. Detailed additional analysis will be required regardless of which alternative is selected for implementation. Based on prior studies, a Phase I Cultural Resources Survey was performed in the proposed areas of inundation for the SFRR alternatives. The survey identified several sites for which follow-up efforts may be necessary. The views of the community, as determined through a number of public meetings, were considered carefully in evaluating these criteria.

F.

Results

Each of the alternatives was analyzed to assess cost, environmental impacts, and other relevant information, per the criteria defined in Section IV.E. The results of these analyses are explained below, and summarized in Table 5. In addition, Table 6 provides an abbreviated summary of the results, including the key factors in determining whether further study was warranted. Additional information regarding alternatives screening is found in the Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004). This evaluation demonstrated that there are four basic water supply concepts that have potential to meet the project purpose in a practicable and least environmentally damaging way. In addition, it demonstrated that the costs and environmental impacts of treatment plant components do not preclude any alternatives from further consideration. Consequently, treatment plant components were not used further as evaluation criteria. The four basic “concepts” warranting further evaluation are: •

Use of Crest Gates at SFRR o would have to be used in combination with other components

•

Dredging o would have to be used in combination with other components

•

An Intake on the James River o could be developed as a RWSA stand alone project or a regional project with Fluvanna and Louisa Counties

•

Raising the Dam at Ragged Mountain Reservoir o may or may not require other components

At the conclusion of the Water Supply Alternatives Supplemental Evaluation in July 2004, a number of uncertainties associated with the possible use of Beaver Creek reservoir to supply the Urban Service Area were identified and these indicated additional study of that possibility was necessary. Gannett Fleming produced two additional technical documents which resulted in the following conclusions (Gannett Fleming September 9, 2004 and Gannett Fleming March 17, 2005):

17

1.

Beaver Creek is a dual purpose reservoir providing water supply and flood control for the Crozet service area. Given the projected long term demands for the Crozet area, it was determined that, at the normal pool elevation, Beaver Creek could provide a maximum of 0.8 MGD of water to supplement the Urban Service Area as a long-term option, and such supplemental supply could be less than 0.8 MGD if evapotranspiration or “bed losses” in the Mechums River between the Beaver Creek Reservoir and SFRR further limited supply.

2.

Raising the permanent pool of Beaver Creek Reservoir to maintain flood storage and increase surplus safe yield for the Urban Service Area would be very costly, and would produce additional environmental impacts that, in combination with any other raw water components, would not produce an environmentally superior preferred alternative.

Based on these conclusions, the use of the Beaver Creek Reservoir as a concept toward satisfying the 9.9 MGD deficit in 2055 for the Urban System would not be reliable. Accordingly, the Beaver Creek Reservoir as a long term supply for the Urban System was removed from further consideration. RWSA did also conclude, however, that while pursuing a long-term supply, since the Crozet service area has not yet reached its projected future needs, the Beaver Creek Reservoir can supplement the Urban Service Area during drought events on a short-term, interim basis.

18

Table 5

Analysis of Selected Alternatives (Page 1 of 2)

Potential Alternative

Estimated Total Project Cost (Millions)

Wetlands Impacts (ac) Forested

Emergent

Scrub

Total 0

Stream Impacts (LF)

Logistical Issues Doesn’t satisfy water deficit

Potential Impacts to Previously Identified Cultural Resources Structures 0

Arch. 0

Previously Identified Threatened or Endangered Species in Vicinity ****

1. No Action

$31.2

2. Construct New Dam at Buck Mountain

$109.7

UA

UA

UA

25

40,000

9240 l.f. - roadway 1320 l.f. – bridge 3 buildings

4

1!

James spinymussel

3. Construct New Dam at Buck Mountain + Beaver Creek Reservoir

$105.0

UA

UA

UA

<25

32,000

9240 l.f. – roadway 1320 l.f. – bridge 3 buildings

4

1!

James spinymussel

4. Construct New Pumped Storage Facility at Rocky Creek

$105.5

0

0

0

0

7,400

1 building

0

0

James spinymussel

5. Construct New Pumped Storage Facility at Rocky Creek + Beaver Creek Reservoir

$98.1

0

0

0

0

6,300

1 building

2

0

Bewick’s wren, Loggerhead shrike

6. James River Intake

$109.5

UA

UA

UA

5

+/- 32 streams crossings

None

10**

1

James spinymussel

7. James River Intake + Beaver Creek Reservoir

$102.7

UA

UA

UA

5

+/- 32 streams crossings

None

10**

1

Bewick’s wren, Loggerhead shrike

8. Regional Cooperation with Fluvanna/Louisa Counties

N/A

UA

UA

UA

UA

?

None

unknown

unknown

Unknown

9. Regional Cooperation with Fluvanna/Louisa Counties + Beaver Creek Reservoir

N/A

UA

UA

UA

UA

?

None

2

unknown

Unknown

10. Raise Ragged Mountain Dam with Pumped Storage

$81.7

1

4

0

5

2,300

I-64 issues

0***

11. Raise Ragged Mountain Dam + Beaver Creek Reservoir

$69.0

1

4

0

5

None

12. Raise Ragged Mountain Dam with Pumped Storage + Beaver Creek Reservoir

$78.7

1

4

0

5

<2,300

13. Raise Ragged Mountain Dam + Beaver Creek Reservoir + Add 4 ft. Crest Gates on SFRR

$82.1

6

14

18

38

14. Raise Ragged Mountain Dam with Pumped Storage + Beaver Creek Reservoir + Add 4 ft. Crest Gates on SFRR

$91.6

6

14

18

38

Other Considerations

Land Acquisition Requirement (acres) 0 664

Crozet demand

330

135 Crozet demand

116

30 Crozet demand

30 Unknown

Crozet demand

Unknown

0

I-64 issues

120

2***

0

I-64 issues

102

None

2***

0

Peregrine falcon, Loggerhead shrike

I-64 issues Crozet demand

102

18,200

688 l.f. – roadway 420 l.f. - bridge

2***

10*

James spinymussel, 1 Peregrine falcon, Loggerhead shrike

I-64 issues Lengthy fill time Crozet demand

190

<18,200

688 l.f. – roadway 420 l.f. - bridge

2***

10*

James spinymussel, Peregrine falcon, Loggerhead shrike

I-64 issues Possible phasing: low short term $ Crozet demand

190

19

Table 5

Analysis of Selected Alternatives (Page 2 of 2)

Potential Alternative

Estimated Total Project Cost (Millions)

Wetlands Impacts (ac) Emergent 11

Scrub 25

Total 47

Stream Impacts (LF)

Logistical Issues

35,700

834 l.f. – roadway 420 l.f. - bridge

Potential Impacts to Previously Identified Cultural Resources Structures 0

Arch. 10*

Previously Identified Threatened or Endangered Species in Vicinity ****

Other Considerations

Land Acquisition Requirement (acres)

15. Raise SFRR high enough to provide all required additional storage

$99.3

Forested 11

16. Raise SFRR + Beaver Creek Reservoir

$98.6

< 11

< 11

< 25

< 47

< 35,700

792 l.f. – roadway 420 l.f. - bridge

0

10*

James spinymussel

17. Pumpback from Moores Creek WWTP to SFRR Tributary

$91.2

UA

UA

UA

2

+/- 20 streams crossings

None

unknown

unknown

James spinymussel

18. Pumpback from Moores Creek WWTP to SFRR Tributary + Beaver Creek Reservoir

$91.6

UA

UA

UA

2

+/- 20 streams crossings

None

unknown

unknown

James spinymussel

Crozet demand

5

19. Pumpback from Moores Creek WWTP to SFRR Tributary + Beaver Creek Reservoir + Add 4 ft. Crest Gates on SFRR

$110.6

7

10

18

35

+/- 20 streams crossings + 16,000 LF

688 l.f. – roadway 420 l.f. - bridge

unknown

unknown

James spinymussel 1

Crozet demand

120

20. Expand Sugar Hollow Reservoir + Beaver Creek Reservoir

$125.6

0

0

0

0

4,900

None

4

0

Trout stream, federal property Crozet demand

75

21. Expand Sugar Hollow Reservoir + Beaver Creek Reservoir + Add 4 ft. Crest Gates on SFRR

$127.9

5

10

18

33

18,700

688 l.f. – roadway 420 l.f. - bridge

4

10*

James spinymussel 1

Trout stream, federal property Crozet demand

170

22. Dredging SFRR + Beaver Creek Reservoir + Add 4 ft. Crest Gates on SFRR

N/A

5

15

18

38

16,000

None

0

0

James spinymussel 1

James spinymussel

300

Crozet demand

5

* The number of archaeological sites associated with SFRR is artificially high in comparison to the others because this reservoir was surveyed recently for the project. Intensive survey of the other alternatives would likely results in similar numbers of archaeological resources. ** The James River pumped storage route is within two historic districts that are on the National Register of Historic Places. Multiple individual properties are along this route. *** RWSA has reported 2 structures of potential concern at Ragged Mountain, but these are not recorded with the VDHR. ****The Buck Mountain Reservoir alternative has at least 1 unrecorded archaeological site identified during the SFRR survey by Gray & Pape. ***The Bewick’s wren, loggerhead shrike, and peregrine falcon are bird species with wide ranging habitat preferences. Listings in the table indicate historical sightings in the vicinity, although the preferred habitat may not be impacted by the alternative. !! Online database indicates presence. DGIF survey determined absence. UA – Unavailable 1

Online database indicates presence. DGIS survey determined absence.

Note: All data were based on preliminary investigations as of May 2004.

20

300

N/A

Table 6

Key Determining Factors for Selected Alternatives

Potential Alternative 1. No Action

Estimated Cost (millions)

Wetlands Impacts (acres)

$31.2

N/A

Stream Impacts (linear feet)

Threatened or Endangered Species

N/A

1

Other Issues Does not satisfy water deficit

2. New Dam at Buck Mountain Creek

$109.7

25

40,037

2

3. New Dam at Buck Mountain Creek + Beaver Creek Reservoir

$105.0

<25

31,624

2

4. Pumped Storage at Rocky Creek

$105.5

03

7,355

1

5. Pumped Storage at Rocky Creek + Beaver Creek Reservoir

$98.1

03

6,343

1

6. James River Intake

$109.5

5

32 stream crossings

Unknown

7. James River Intake + Beaver Creek Reservoir)

$102.7

5

32 stream crossings

Unknown

8. James River (Regional Cooperation)

N/A

Unknown

Unknown

Unknown

Unknown

9. James River (Regional Cooperation + Beaver Creek Reservoir)

N/A

Unknown

Unknown

Unknown

Unknown

2,284

1

Inundates I-64 culvert

>2,284

1

Inundates I-64 culvert

<2,284

1

Inundates I-64 culvert Inundates I-64 culvert Inundates I-64 culvert

10. Raise Ragged Mountain Dam with Pumped Storage 11. Raise Ragged Mountain Dam (No Pumped Storage) + Beaver Creek Reservoir 12. Raise Ragged Mountain Dam with Pumped Storage + Beaver Creek Reservoir

$81.7

4.8

$69.0

>4.8

$78.7

<4.8

13. Raise Ragged Mountain Dam (No Pumped Storage) + Beaver Creek Reservoir + 4-foot Crest Gates SFRR

$82.1

38

18,151

1

14. Raise Ragged Mountain Dam with Pumped Storage + Beaver Creek Reservoir + 4-foot Crest Gates SFRR

$91.6

<38

<18,151

1

15. Raise SFRR to Provide All Required Additional Storage

$99.3

46.7

35,712

1

16. Raise SFRR + Beaver Creek Reservoir

$98.6

<46.7

<35,712

1

17. Pumpback from Moores Creek WWTP to SFRR Tributary

$91.2

2

20 stream crossings

1

18. Pumpback from Moores Creek WWTP to SFRR Tributary + Beaver Creek Reservoir

$91.6

2

20 stream crossings

1

19. Pumpback from Moores Creek WWTP to SFRR Tributary + Beaver Creek Reservoir + 4-foot Crest Gates at SFRR

$110.6

35.21

16,022 + 20 stream crossings

1

20. Expand Sugar Hollow Reservoir + Beaver Creek Reservoir

$125.6

03

4,913

21. Expand Sugar Hollow Reservoir + Beaver Creek Reservoir + 4-foot Crest Gates SFRR 22. Dredging SFRR + Beaver Creek Reservoir + 4-foot Crest Gates on SFRR

$127.9

33.21

18,735

Inundates federal property 1 1

N/A

1

Listed species have been identified in the project vicinity

2

Listed species have been identified in the project footprint

3

Available mapping does not show wetlands (other than stream channel) in the project footprint. It is likely that field-based analysis would indicate presence of wetlands.

Note: All data were based on preliminary investigations as of May 2004.

21

Inundates federal property

Section V – Short Listed Concepts Evaluation Section IV explained how water supply components were identified that might either stand alone or be combined with other components to produce a solution to the projected water supply deficit. These components were later used to build 22 potential “alternatives.” The 22 potential “alternatives” were then screened using the preliminary information that was available at this point in the investigation. When sufficient, reliable information was available to conclude that an “alternative”, when compared to the others, could not become the “least environmentally damaging, practicable alternative” as defined by the regulations, an “alternative” was removed from further consideration. The remaining “alternatives” consisted of either one or a combination of four project concepts. These four remaining water supply concepts came to be known in public discussion as the “short list” and became the focus of further investigations in greater detail. These concepts are: •

SFRR – 4-foot Crest Gate Expansion

•

Dredging SFRR

•

James River Intake & Pipeline

•

Ragged Mountain Reservoir Expansion & Pipeline

Further evaluations of each short listed concept were documented in four Technical Memoranda (one for each concept). Each concept also was presented for community input at public hearings (4) held throughout 2004 and 2005. This section of the Permit Support Document provides a summary of these technical memoranda and other relevant information developed concerning the four water supply concepts.

A.

South Fork Rivanna Reservoir – 4 Foot Crest Gate Expansion Concept

Concept Description Increasing the usable storage volume of SFRR by raising the reservoir’s normal pool level would increase the safe yield of this facility. This would be accomplished by installing a moveable gate on the existing spillway’s fixed crest. Moveable crest gates on the existing fixed spillway crest would allow the normal pool level to be raised during normal river flows while maintaining the original spillway discharge capacity. This is important during flood events. During significant flood events, the moveable gate would be lowered to return the spillway to its original capacity. Additional detail is included in a technical memorandum published by Gannett Fleming on January 20, 2005 (Appendix A). The July 2004 Water Supply Alternatives Supplemental Evaluation investigated the safe yield and environmental impacts associated with reservoir pool increases and determined that environmental impacts increase dramatically when the crest gate height is increased above 4 feet. Heights of less than 4 feet produced inconsequential increases in safe yield; therefore, a

22

crest gate height of 4 feet is defined for this concept. The resulting area of inundation is depicted in Figure 5.

Safe Yield Based on 2002 one-foot contour mapping of the SFRR, increasing the normal pool of the reservoir by 4 feet to Elevation 386 feet would increase the volume of the permanent pool by about 550 MG. The July 2004 Water Supply Alternatives Supplemental Evaluation reports an associated 2055 safe yield increase of 3.3 MGD. The sustainability of this safe yield in the future, beyond 2055, will depend on sedimentation rates and deposition patterns. Presently, it would appear that the safe yield would continue to decline after 2055. It should be noted that this alternative provides only about 1/3 of the projected water supply deficit and must be combined with one or more other concepts to meet the project purpose.

Cost The cost of this concept is summarized in Table 7 below, in 2004 dollars. Detailed cost assumptions and methodology can be found in Appendix A. Table 7

Cost Estimate for Installing 4-foot Crest Gates on SFRR

Item

Cost

Installation of 4-foot Crest Gates

$1,060,000

Upgrades to Existing Dam

$1,000,000

Bridge Replacement (420 l.f. @ $2,400/l.f.)

$1,010,000

Road Relocation (688 l.f. @ $240/l.f.)

$165,000

Environmental Mitigation

$9,974,000

Subtotal

$13,209,000

Engineering/Permitting and CM (20%)

$2,642,000

Cultural Resources Investigations

$80,000

Land Acquisition (150% of Assessed Value)

$1,200,000

Subtotal

$17,131,000

Project Contingencies (25%)

$4,283,000

Total Project Cost

$21,414,000

Average Cost Per GPD of Safe Yield (provides 3.3 MGD)

$6.49

Note: Cost estimates as reported in Concept Development – South Fork Rivanna Reservoir Expansion (Gannett Fleming, January 1, 2005)

Concept Impacts Wetlands. Wetland habitat types (i.e., emergent, scrub-shrub, forested) around the perimeter of SFRR were mapped based on topographic information, color infrared and natural color aerial photographs, and field investigations to verify vegetative signatures (Figure 6). Lacustrine and palustrine wetlands occur in various landscape positions around the SFRR and are supported by a number of different hydrologic regimes. Lacustrine emergent wetlands 23

\\vawill\projects\31671.01\graphics\figures

0

approx. 3,000 feet Scale - 1:38,000

South Fork Rivanna Reservoir

(382 ft. existing pool elevation)

4-foot Crest Pool (386 ft. contour)

Bridge

Dam

South Fork Rivanna River

Bridges

Figure 5

South Fork Rivanna Reservoir 4 foot Crest Gate Expansion Concept

\\vawill\projects\31671.01\graphics\figures

0

approx. 3,000 feet Scale - 1:38,000

4-foot Crest Pool (386’ elev. inundation) PFO Wetlands PSS Wetlands PEM Wetlands Streams James Spinymussel Cultural Resources

Bridge

Dam

South Fork Rivanna River

Bridges

Figure 6

South Fork Rivanna Reservoir 4 foot Gate Expansion Potential Resource Impacts

(those wetlands that occur below the normal pool elevation of 382 feet) are sparsely found in shallow water areas near shorelines to a maximum water depth of about 3 feet. These systems are dominated principally by three-way sedge (Dulichium arundinaceum), and tend to shift ephemerally as conditions of the reservoir change. Palustrine wetlands are found along the fringe of the reservoir as well as in stream seeps and ponds above the normal pool level. These are the most common wetland type. Some of these palustrine wetlands occur because the ground water table is near the normal pool elevation of the reservoir. These wetlands are generically described as “fringe” wetlands. Most of the fringe wetlands are emergent and scrub-shrub habitats that occasionally flood as the reservoir stages up during storm events. Fringe wetlands comprise approximately half of all palustrine wetlands in the project area. The remaining palustrine wetland systems are supported by hydrology other than the reservoir, such as stream inputs and seeps. Most of these systems are affiliated with stream bottoms, headwater seeps, and/or beaver ponds adjacent to Ivy Creek, Fishing Creek, and the South Fork Rivanna River. Several emergent wetlands rely on groundwater seepage slopes that occur just above the normal pool level. Other than lacustrine wetlands, the four general wetland types around the SFRR that would be affected by a 4-foot increase in water depth include palustrine emergent wetlands (PEM), palustrine scrub-shrub wetlands (PSS), palustrine forested wetlands (PFO), and open water associated with beaver ponds above the normal pool elevation (POW). The general distribution of these wetlands around the reservoir is depicted in Figure 6. An assessment was performed to determine the acreage of palustrine vegetated wetlands that would become inundated with the placement of a 4-foot crest (i.e., between the normal pool elevation of 382 feet to an elevation of 386 feet). The results of the assessment showed a total of 30.6 acres of impacted wetlands, as indicated below: Forested Wetlands………………………4.3 acres Scrub-shrub Wetlands………………….18.2 acres Emergent Wetlands……………………..8.1 acres Open water habitat associated with beaver ponds was not considered to be affected by the 4foot crest since no change would occur in the habitat type (see Figure 6). Streams. In addition to Ivy Creek and the South Fork Rivanna River, a total of 48 streams drain directly into the SFRR (see Figure 6). An assessment of existing conditions included a cursory inspection of each stream channel to qualitatively determine stream stability, character, and potentially affected resources. Three of the 48 streams within the study area occur on steep, rocky slopes that would incur virtually no back flooding with a 4-foot crest increase. The other 45 stream channels, in addition to Ivy Creek and the South Fork Rivanna River, would sustain an estimated total of 18,000 linear feet of stream impact caused by the 4-foot increase, with some streams having impacts of more than 2,000 linear feet (see Figure 6).

24

More important than the overall length of impact, is the order of the channels that will be affected by inundation. Determining stream order is a means of classifying the relative size of streams and providing some indication of its position in the watershed (Strahler 1952). Headwater streams with no tributaries are called first-order streams. The intersection of two such streams – streams with identical orders – produces a stream order one higher (second order). The intersection of dissimilar orders does not result in an increase in order (e.g. the junction of a first and second-order stream yield a second order stream). As one moves lower in the watershed, streams coalesce and the channels tend to support increasing higher and more diverse ecosystems, including fin fish, reptiles and amphibians. The 48 stream channels potentially affected by the four-foot crest increase include thirty-four (34) first-order channels, eight (8) second-order channels, six (6) third-order, one (1) forthorder and two (2) channels of fifth order or higher. Similarly, the constancy of water flow within the channel also provides insight into the aquatic organisms that can be supported by the stream system. Threatened and Endangered Species. The U.S. Fish and Wildlife Service (USFWS) and Virginia Game and Inland Fisheries (VGIF) have identified the endangered James spinymussel (Pleurobema collina) as potentially affected by the 4-foot crest increase. A survey for this species was performed by the Virginia Cooperative Fish and Wildlife Unit, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University (2004). The results of the survey found one individual James spinymussel in the lower reach of Buck Mountain Creek immediately upstream from the confluence with the South Fork Rivanna River. This location represents the northern-most reach of influence by the 4-foot crest increase (see Figure 6). Cultural Resources. As reported in the Water Supply Alternatives Supplemental Evaluation (July 2004), a Phase I Cultural Resources Survey was conducted by Gray & Pape in the proposed areas of inundation. The survey identified potentially eight (8) sites for further study of impacts, should this concept be advanced. (see Figure 6). Other Impacts. An assessment of potential project effects on existing infrastructure, utilities and recreational facilities revealed that the Route 676 Bridge would have to be raised to accommodate the four foot water surface increase. Minor impacts would also occur as sections of a recreational trail around the reservoir would be inundated. Land Acquisition. In addition to impacting the resources discussed above, an increase of the normal pool elevation from 382 feet to 386 feet will have an impact on land use surrounding the SFRR. All land at Elevation 386 feet and below will normally be submerged. The shaded areas in Figure 5 and 6 present the newly submerged land. The total area expected to be submerged is approximately 116 acres. It will be necessary for RWSA to purchase the land from the current property owners. Upland habitats that would be inundated include: 68 acres of mixed deciduous and pine forest, 6 acres of open field and pasture, and 7 acres of woody shrub lands.

25

B.

Dredging South Fork Rivanna Reservoir Concept

Concept Description The second raw water supply concept under consideration involves dredging of the South Fork Rivanna Reservoir. The following paragraphs describe the concept, associated costs, current reservoir conditions, and potential impacts of this concept. As previously stated, the RWSA Urban Service Area safe yield will decrease from the current 12.8 MGD to approximately 8.8 MGD in 2055. The 4 MGD reduction in safe yield is due primarily to the projected sedimentation that will occur in the SFRR. According to previous bathymetric studies, it appears that the majority of the sedimentation of the SFRR has occurred in its upper two-thirds. Data was assembled in 2002 and the lowest points from each of the 47 SFRR cross sections were determined as shown in Figure 7 below. 385

380

Elevation (feet MSL)

375

370

365

360

355

350

345

340 0

5000

10000

15000

20000

25000

30000

Distance Along SFRR (feet) SFRR X -Sect ion Low Point s

Lowest SFRR Int ake Elevat ion = 367 f eet

Figure 7. Low Points of SFRR Cross Sections (Data from 2002 Bathymetric Survey)

Figure 7 suggests there are significant sediment deposits within the useable storage of the upper reaches of the SFRR. Estimates of dredge material quantities or water storage volumes are based on the best information available at this time. Assuming a sedimentation rate of 15.14 MG/yr, by the year 2055 there will be approximately 1,302 MG of accumulated sediment in the reservoir, leaving 398 MG of total storage. Based on the assumption that a portion of the sediment will settle in both the useable and dead storage of the reservoir, it is estimated that 200 MG of useable storage will be remaining in the year 2055. The dredging concept consists of physically removing the accumulated sediment from the useable storage portion of the SFRR. A maximum benefit would occur if the original 1966 SFRR volume was restored. Once the previously-lost volume was restored, regular and periodic maintenance dredging would be necessary to continue to retain this restored volume. 26

The total dredging volume can be estimated based upon the original useable storage volume (1,250 MG) less the projected useable volume in 2055 with no dredging (200 MG). Therefore, 1,050 MG of sediment would have to be removed during the restoration phase of the program to fully restore the original useable storage. Allowances regarding sediment removal efficiency and dredging operations, result in an estimated 5 million cubic yards (CY) of material that must be removed to accomplish the volume restoration. This amounts to removal of approximately 100,000 CY of sediment each year for 50 years. Beyond the 50-year planning horizon of this study, further dredging would have to continue in order to maintain the useable storage volume in the SFRR. If the sedimentation rate of 15.14 MG/year continues beyond the 50-year planning period, the same amount of sediment will need to be removed annually to maintain the useable storage of the reservoir. This is a dredging volume of approximately 75,000 CY of sediment, which would need to be removed in each and every year after the 50 year planning period to sustain the described project. Hydraulic dredging was considered the most practical method for sediment removal. A hydraulic dredging operation would consist of the following components: •

Floating hydraulic dredge to remove material;

•

Pumps and pipeline to transfer the slurry to an upland containment area;

•

Single dewatering and materials handling site adjacent to the SFRR;

•

Permanent disposal sites for dewatered sediment.

Since the topography surrounding the SFRR is rugged, it is not feasible to dewater and dispose of the material on adjacent land. Dewatering facilities would be constructed on adjacent land and the dried material would have to be transported by truck to remote disposal sites. A significant portion of the overall cost of this concept is associated with the material handling, treatment and disposal. The potential for economic value for the removed sediment was considered. Although there may be some value to a portion of the material, Gannett Fleming concluded that this concept nevertheless is logistically difficult and remains very expensive when compared to other concepts. Additional detail is included in a June 15, 2005 letter report published by Gannett Fleming.

Safe Yield Based on best-case removal of sediment from SFRR and a resulting useable storage of 1,100 MG at SFRR, the Safe Yield of the RWSA Urban System would be 14.3 MGD if the dredging concept were implemented. This is an increase of 5.5 MGD over the predicted Safe Yield of the RWSA Urban System in 2055 (8.8 MGD) with no dredging program. Although a safe yield increase could be realized, only about ½ of the project deficit could be provided and this concept must be combined with one or more other concepts to achieve the project purpose.

Cost An analysis of potential dredging costs is provided in Appendix A. Tables 8 through 10 summarize the cost estimates for three different dredged spoil reuse assumptions. The costs are in 27

2004 dollars and provide the total cost for dredging and disposal or reuse of all 5,000,000 cubic yards of material. Table 8

Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with 50% Reuse of Dredged Material

Item Land Acquisition for Dewatering Facility (40 acres @ $16,500/acre) Dewatering Basins Construction Environmental Mitigation and Permitting Hydraulic Dredging ($5/CY) Land Acquisition for Disposal (4.5 acres per year, 225 acres total over 50 years @ $16,500/acre) Hauling Costs for Reused Dredged Material ($12/CY) Disposal Costs for Unusable Dredged Material ($16/CY) Mobilization/Demobilization ($40,000/year) Engineering/Permitting and CM (25% of Dewatering Basin Construction only) Subtotal Project Contingencies (25%) Total Project Cost Average Cost per MGD of Safe Yield (provides 5.5 MGD)

Cost $660,000 $450,000 $150,000 $25,000,000 $3,712,500 $30,000,000 $40,000,000 $2,000,000 $112,500 $102,085,000 $25,521,250 $127,606,250 $23.2

Note: Cost Estimates as reported in Concept Development – Dredging South Fork Rivanna Reservoir (Gannett Fleming, December 1, 2004)

Table 9

Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with 20% Reuse of Dredged Material

Item Land Acquisition for Dewatering Facility (40 acres @ $16,500/acre) Dewatering Basins Construction Environmental Mitigation and Permitting Hydraulic Dredging ($5/CY) Land Acquisition for Disposal (7.2 acres per year, 360 acres total over 50 years @ $16,500/acre) Hauling Costs for Reused Dredged Material ($12/CY) Disposal Costs for Unusable Dredged Material ($16/CY) Mobilization/Demobilization ($40,000/year) Engineering/Permitting and CM (25% of Dewatering Basin Construction only) Subtotal Project Contingencies (25%) Total Project Cost Average Cost per MGD of Safe Yield (provides 5.5 MGD)

Cost $660,000 $450,000 $150,000 $25,000,000 $5,940,000 $12,000,000 $64,000,000 $2,000,000 $112,500 $110,312,500 $27,578,125 $137,890,625 $25.1

Note: Cost Estimates as reported in Concept Development – Dredging South Fork Rivanna Reservoir (Gannett Fleming, December 1, 2004)

28

Table 10

Cost Estimate for Dredging a 50/50% Mixture of Sand and Silt/Clay with No Reuse of Dredged Material

Item

Cost

Land Acquisition for Dewatering Facility (40 acres @ $16,500/acre)

$660,000

Dewatering Basins Construction

$450,000

Environmental Mitigation and Permitting

$150,000

Hydraulic Dredging ($5/CY)

$25,000,000

Land Acquisition for Disposal (9 acres per year, 450 acres total over 50 years @ $16,500/acre) Disposal Costs for Unusable Dredged Material ($16/CY) Mobilization/Demobilization ($40,000/year)

$7,425,000 $80,000,000 $2,000,000

Engineering/Permitting and CM (25% of Dewatering Basin Construction only)

$112,500 $115,797,500

Subtotal Project Contingencies (25%)

$28,949,375

Total Project Cost

$144,746,875

Average Cost per MGD of Safe Yield (provides 5.5 MGD)

$26.3

Note: Cost Estimates as reported in Concept Development – Dredging South Fork Rivanna Reservoir (Gannett Fleming, December 1, 2004)

Impacts Implementation of the dredging concept would constitute a major long-term effort, with environmental impacts resulting from specific components of the operations such as establishing construction and haul road access, building dewatering and disposal areas, and the actual dredging process itself. The potential effects of these activities are discussed in the following paragraphs in general terms, as specific access, dewatering and disposal sites have not been identified. It has been assumed, however, that these project components would be optimally located to minimize impacts to aquatic resources. Wetland/Stream/Cultural Resources and Threatened and Endangered Species. Based on the description of dredging operations outlined in the previous paragraphs, it is assumed that dewatering and disposal of dredged material could be accomplished at an upland site, without direct impacts to wetlands or streams. Consequently, impacts resulting from clearing or placement of fill in these aquatic systems is assumed to be limited to stream crossings for access roads, portions of staging areas or booster pump sites, ramp construction, and pipeline installation. Such impacts are estimated at a total of 1.13 acres and 168 linear feet of stream channel. Launch areas, pipeline routes, and dewater and disposal areas would be selected to avoid cultural resources or threatened and endangered species. Similarly, costs associated

29

with compensatory mitigation were assumed to be an insignificant fraction of the overall program costs. Benthic Community and Secondary Impacts. The actual dredging process has the potential to produce direct and indirect environmental effects. Direct impacts to benthic organisms living in the substrate of the reservoir will occur as the dredge cuts and removes the accumulated sediments. It is generally accepted that benthic communities disturbed by dredging recover relatively quickly. Secondary effects may occur due to turbidity in the water column resulting from disturbance of fine sediments on the bed of the reservoir. Because of the suction action associated with hydraulic dredging, turbidity effects are generally minimal and can be further controlled through the use of a turbidity curtain installed around the perimeter of the work area to limit suspended sediment movement away from the cutterhead. Discharges from the dewatering site can also have an effect on receiving waters if the channel is inadequate to receive outflow from the basin, or if there is a discharge of turbid waters. These issues are addressed through careful engineering design of the outflow channel and by sizing and configuring the basin to allow fine sediments to settle out of suspension prior to discharge. A system of baffles is often used to increase the travel distance between the point of entry of dredged material and the outfall pipe, allowing more complete settling before release. Upland Impacts. Land area requirements for dewatering would be based on the specific physical characteristics of the dredged sediments. It is assumed that gravity settling would be sufficient for the sediments removed. Sediments containing primarily sand will require less area because they will dewater faster and sediments containing primarily silt/clay will require more area because they will dewater slower. The required dewatering site size to adequately handle 100,000 CY of (50/50) sediment is 40 acres. This land area has been used for the cost estimates presented in this document. If the actual sediment composition were other than the stated content, the required dewatering site size would vary. A range of between 20 acres (for 100% sand) and 65 acres (for 100% silt/clay) would be required. The land areas indicated here include sufficient room for cell construction, embankments, material spreading, and material removal. The number of cells would be dependent on the characteristics of the dredged material, dewatering period needed, and topography of the available dewatering area. Additional land may be required for access roads, parking, and administration areas depending on the site selected. It is possible that some dredged material can be reused. Given the uncertainties associated with post-dewatering reuse, a range of reuse portions was established for cost estimating purposes. For the purposes of estimating land requirements, disposal has been estimated based on no reuse, 20% reuse and 50% reuse of the dredged materials. Further, the depth of disposed material has been assumed to be a relatively uniform 8 feet. Using these assumptions, the annual land requirement for disposal for no reuse, 20%, and 50% reuse of material are 9 acres, 7.2 acres, and 4.5 acres respectively (including area for sloping and workspace). The precise amount of land area required for disposal of dredged materials is dependent on the volume of material that can be reused, the depth of the disposal piles, existing topography at the disposal site, stability of the dredged material and proximity to natural drainage or forest features. 30

C.

James River Intake and Pipeline Concept

Concept Description The James River intake and pipeline concept includes a withdrawal intake on the James River near Scottsville, in southern Albemarle County and a pipeline that would generally run along Route 20 into the Urban Service Area. The James River drainage area at Scottsville is approximately 4,584 mi2 and includes portions of Albemarle County, Buckingham County, Nelson County, Appomattox County, Amherst County, Campbell County and Bedford County. Numerous central Virginia communities located upstream and downstream from Scottsville utilize the James River as a source for community drinking water. Sizable communities include Lynchburg (upstream), and Richmond and Henrico County (downstream). Cumberland County and Henrico County are jointly evaluating the feasibility of an off stream pumped storage reservoir using the James River above Richmond as a source. Raw Water Quantity. As reported in Rivanna Water and Sewer Authority Water Supply Project – Analysis of Alternatives (VHB, February 2000), the James River at Scottsville has a 1Q30 flow of approximately 338 MGD. The 1Q30 is the lowest one-day average flow expected to occur once in thirty years based on the available period of record and is a common expression of low surface water flows in Virginia. Assuming a maximum RWSA withdrawal rate of approximately 15 MGD (discussed below), 4% of the 1Q30 flow in the James at this location would be withdrawn. The majority of the water withdrawn would be returned to the Rivanna River, and through it to the James River, by means of treated wastewater discharges. Because treated wastewater from the RWSA system would be returned to the Rivanna River, the James River flow would be impacted from the withdrawal point near Scottsville downstream to the confluence with the Rivanna River, a distance of approximately 25 miles. Raw Water Quality. Raw water quality is a crucial factor in providing acceptable drinking water to consumers. The James River is used as a raw water source for numerous communities both upstream and downstream from the Scottsville area. Since water quality generally degrades downstream, the experiences of two communities downstream from Scottsville were considered. Based on these experiences, conventional water treatment processes would likely provide appropriate treatment of this source and satisfy federal and state safe drinking water requirements. RWSA has indicated that the location of treatment facilities for raw water from the James River would be near the City of Charlottesville and that nearly all of the pipeline would transport raw water. Potential Intake Site Locations. A river intake structure would need to be constructed in order to withdraw water from the James River. The shortest reasonable route suggests that the intake structure would be located near the town of Scottsville, which is approximately 20 miles south of Charlottesville. Figure 8 identifies various potential properties that could be purchased in order to construct the river intake structure along the northern bank of the James River. About 5 acres would be necessary for the intake and raw water pump station.

31

Figure 8 - Potential Parcels for Purchase and Construction of River Intake

Pipeline from Scottsville to Charlottesville. A pipeline would generally follow VA Route 20 from Scottsville to the Urban Service Area with the discharge location at the Observatory WTP. Figure 9 illustrates the potential pipeline routing. This pipeline route would be approximately 22.9 miles in length. Considering the additional dynamic head, the elevation differences dictate the use of at least three pump stations including the intake pump station. Evaluations indicate that a nominal 30-inch diameter pipe would be needed for this application. A route study would be completed during the early stages of design if this concept is advanced as the preferred alternative. The pipeline route would be finalized at that time. It is anticipated that any modifications made would reduce cost and minimize environmental impacts. Nevertheless, this general route is considered to provide a relevant approximation of the costs and impacts that would attend any final design. Generally, water transmission piping is installed below grade (under ground) by “open-cut” method which means a trench is excavated from the ground surface to the depth required, the pipe is installed, and the trench is backfilled to the original ground surface. Along most of its length, the pipeline would be installed either within or adjacent to existing roadways. Numerous stream crossings would be encountered along the pipeline route and to minimize environmental impacts directional drilling methods could be employed. To establish the least impacting alignment, the east side of Rt. 20 was found to have fewer streams/wetlands, and as such, this side was chosen for the alignment and impact analysis. 32

Figure 9 - Generic Raw Water Transmission Pipeline from James River to Observatory WTP

33

Property Acquisition. It is preferable to construct subsurface pipelines within existing public rights-of-way or adjacent to existing rights-of-way to minimize impacts to nearby property owners. In this case, there are no existing rights-of-way between Scottsville and Charlottesville on Route 20, which occupies a prescriptive easement. In order for the pipeline to follow this route, RWSA would have to purchase easements along the majority of Route 20. Following the eastern side of Route 20 would minimize property acquisition. Following the eastern side (northbound lane) of Route 20 would require obtaining easements over approximately 150 properties. The width of the easements would depend on several factors. However, the most important would be the size of the pipe and the depth of cover over the pipe. In this case, a 30” diameter pipe with a depth of cover of 36” to 42” would require a permanent access easement width of approximately 20 feet and a temporary construction easement width of approximately additional 20 feet. These widths will vary depending on stream crossings, road crossings, construction access requirements, depth to rock, utility crossings and other factors. System Capacity/Yield. The projected 2055 average daily water supply deficit, presented in the Water Supply Alternatives Supplemental Evaluation, dated July 2004, is 9.9 MGD assuming the projected SFRR, Ragged Mountain Reservoir, and Sugar Hollow Reservoir yield capabilities are maintained. Intake and transmission features of community water supply systems are typically sized based on a peak day factor (peak daily demand divided by average daily demand). The Urban Area system peaking factor, presented in the above referenced report, is 1.5; therefore, the design capacity for the intake and transmission main would have to be 14.85 (rounded to 15 MGD). This concept would provide for all of the needed water to overcome the projected water supply deficit.

Cost A cost estimate for a James River intake and pipeline was included in Water Supply Alternatives Supplemental Evaluation (GF – July 2004). For comparison purposes with other raw water concepts, only costs associated with raw water supply and transmission will be included in this analysis. For more details regarding the assumptions and methods applied in the cost estimates, please refer to Concept Development-James River Withdrawal (GF – February 2005). The cost estimate has been modified to address only the raw water conveyance requirements (eliminating any reference to water treatment) and to reflect additional findings presented in this technical memorandum. Table 11 presents the cost estimate for the James River Intake and Pipeline concept.

34

Table 11

James River Intake and Pipeline Concept Cost Estimate

Item

Cost (2004$)

Intake Structure and Pump Station

$2,500,000

Pump Stations (2 pump stations @ $2,000,000 each)

$4,000,000

Electrical Costs

$2,927,000

Pipeline (121,000 l.f. of 30" Diameter @ $180/l.f.)

$21,780,000

Road, Stream & Railroad Crossings (2,000 lf @ $200/lf)

$400,000

Environmental Mitigation

$201,000

Engineering, Permitting, and CM (20%)

$6,362,000

Land Acquisition (Intake Structure and intermediate pump stations – 15 acres @ $10,000/acre) Easement Acquisition (150 properties and 121,000 linear feet) Subtotal

$150,000 $1,585,000 $39,905,000

Project Contingencies (25%)

$9,976,000

TOTAL PROJECT COST

$49,881,000

Average Cost Per GPD of Safe Yield (Provides 9.9 MGD)

$5.04

Note: Cost estimates as reported in Concept Development – James River Withdrawal (Gannett Fleming, February 2, 2005)

Project Impacts Stream Impacts: James River Intake. Typically, impacts to stream systems are discussed with respect to the “footprint” associated with installation or construction of the permitted facilities. However, more important in this case are the potential impacts associated with cumulative withdrawals of water from the James River, particularly during dry periods when river flows would be diminished. An important consideration in this regard is the complexity of the James River and associated wetland systems, the higher trophic level organisms such as anadromous fish species that inhabit the James and the uncertainty of cumulative impacts associated with multiple withdrawals by other municipalities and irrigation facilities located along the James. As discussed in assessing the impacts resulting from raising the SFRR dam, stream order provides more insight into the character of the channels that may be affected by the alternative. Specifically, stream order is a means of classifying the relative size of streams and providing some indication of its position in the watershed (Strahler, 1952). Headwater streams with no tributaries are called first-order streams and tend to support lower trophic level organisms such as a variety of macro-invertebrates. As one moves lower in the watershed, streams coalesce and the channels tend to support increasing higher and more diverse ecosystems, including fin fish, reptiles and amphibians. Similarly, the constancy of water flow within the channel also provides insight into the aquatic organisms that can be supported by the stream system. The James River constitutes the highest order stream that would be affected by any of the core concepts (>5). Virtually thousands of tributary channels flow to the James upstream of its

35

confluence with the Rivanna River. These channels not only contribute to the flow volume of the river, but also provide essential biological and chemical components that produce a far more complex and diverse ecosystem with the ability to sustain higher trophic level organisms. For example, the Virginia Department of Game and Inland Fisheries reports more than 92 species of aquatic organisms that occur or are likely to occur within this 25 mile reach of the river. The list includes three species of bass, 9 species of shiner, shad, gar sea lamprey, walleye, chain pickerel, multiple species of darters, mussels and floaters, many of which are listed as federal species of concern or are listed as threatened at the state level. This concept would reduce flows within the James River for an approximate 25 mile reach between Scottsville and its downstream confluence with the Rivanna River, where treated waste water from the Urban Service Area would be returned to the James. Applying general assumptions, the area of the river affected includes approximately 3,000 acres of aquatic and edge habitat. Because of the sensitivity of this habitat and the potential for future cumulative impacts, the EPA has stated that detailed analysis of potential cumulative impacts may be required should this concept be advanced for further consideration. Stream Impacts: Pipeline Route. Stream channels along the pipeline corridor were mapped in the office using a combination of aerial photographs and USGS quadrangle mapping. These preliminary maps were then used in the field to verify the presence of stream channels. Follow-up field work was conducted to assess the general condition of the streams. A James River pipeline route would affect a total of 30 perennial streams and 8 intermittent streams. Of these, 25 are first order channels, 7 are second order channels, 2 are third order channels, 3 are fourth order channels and the Hardware River is classified as a fifth order channel. Approximately 6,930 linear feet of channel from 38 streams will incur some form of encroachment by the pipeline and easement. Of these 38 streams, approximately 10 stream channels comprising 910 linear feet currently maintain riparian buffers consisting of pasture (i.e. grass) or impervious structures, which will result in no change in riparian habitat values after the pipe is installed. An estimated 34 channels with shrub/forested riparian buffers totaling 6,020 linear feet will incur permanent changes to riparian buffers as part of the easement. Wetlands. Scientists assessed the presence of wetland areas utilizing the three parameter approach outlined in the 1987 Corps of Engineers Wetland Delineation Manual, as modified by subsequent regulatory guidance. The area of coverage included various locations along the James River as a potential site for a future pump station and approximately 100 feet from both sides of Route 20, Interstate 64, Old Lynchburg Road, and other neighborhood roads in Charlottesville leading to the Observatory WTP. Wetland boundaries were mapped in the field using 1994 color infrared aerial photographs at a 1 inch to 200-foot scale and topographic information. Field investigations were then conducted to verify the photographic signatures and confirm the presence of hydric soils, hydrophytic vegetation and wetland hydrology. Wetland habitat types (i.e., emergent, scrubshrub, forested) were mapped during the field inspections.

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A total of twelve (12) individual wetlands were observed adjacent to both sides of the roadways along the proposed pipeline route. Five (5) of the wetlands are forested systems and seven (7) are emergent. All wetlands are relatively small pockets ranging in size from approximately 0.75 acre to as small as 0.01 acre. In addition to the wetlands, a total of three (3) man-made ponds were observed along the pipeline route. An evaluation of potential wetland impacts was performed based on a generic alignment of the pipeline along the east side of Route 20 and north side of Interstate 64. The impacts analysis makes four assumptions which are believed to be reasonable – 1) no loss of wetlands resulting from the pump station near Scottsville (i.e., it is assumed a location for the pump station can be found that avoids impacts to wetlands); 2) impacts are limited to the 20foot wide permanent easement paralleling the east side of Route 20; 3) impacts to emergent systems will be temporary and restored to their full functioning character resulting in no net loss of wetland functions and values, and 4) impacts to forested systems within the 20-foot wide permanent easement will be restricted to conversion of forested habitat to emergent habitat. Impacts to wetlands would occur at 4 different locations, with 2 of these impacts being temporary disturbances to emergent wetlands, and 2 of the impacts resulting in the conversion of forested wetlands to emergent wetlands. The total amount of temporary wetland disturbance is estimated to be approximately 0.23 acre. The location and description of the wetland impacts are provided below. •

Just north of Interstate 64 lies a forested system between Biscuit Run and the Holiday Inn just east of the Route 631 interchange. The area of conversion would be approximately 0.11 acres.

•

Approximately 2.2 miles south of Interstate 64 along Route 20 is an emergent wetland seep that occurs near the drive entrance to several houses. Temporary impacts to this system would equate to 0.04 acre.

•

A very small emergent wetland occurs approximately 1.3 miles south of Carters Bridge. Temporary impacts to this system would equate to 0.01 acre

•

Approximately 2 miles north of Scottsville lies a small forested wetland immediately adjacent to Route 20. The 20-foot wide permanent easement would result in approximately 0.07 acre of conversion impacts.

•

The total area of temporary disturbance is summarized as follows: Temporary disturbance with no conversion – 0.05 acre; Temporary disturbance and a conversion of habitat – 0.18 acre.

Threatened and Endangered Species The U.S. Fish and Wildlife Service (USFWS) and Virginia Department of Game and Inland Fisheries (VDGIF) identify the endangered James spinymussel as a potential listed species in the area of the pipeline corridor. Surveys performed on the Hardware River at the Route 622 bridge in Fluvanna County did reveal the presence of the spinymussel, which confirms that the species is present in the river watershed. The VDGIF has advised that it would require an intensive search for the James spinymussel at

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the Route 20 Hardware River bridge location if this concept plan were to be selected as the preferred alternative. In addition, VDGIF records indicate the historical presence of the James spinymussel within the James River near the Scottsville area; however, recent scientific studies have not shown its presence within the James River. The recent studies indicate the habitat now occurs primarily in the James River headwater streams. No other survey information is available for other stream reaches bisected by the pipeline corridor, and additional surveys may be required for such other stream reaches if this concept is selected as the preferred alternative. Cultural Resources. There are two historic districts located within the Area of Potential Effect (APE) of the James River Intake and Pipeline alternative: the Scottsville Historic District (VDHR No. 298-0024) and the Southern Albemarle Rural Historic District (VDHR No. 002-5045). The Scottsville Historic District is listed on the National Register of Historic Places (NRHP), and the Southern Albemarle Rural Historic District has been determined eligible for the NRHP. Both of these districts possess a high degree of integrity with few modern intrusions. Additional architecturally significant districts may be impacted, although no property-specific impacts are anticipated at those locations. The project area also contains a high concentration of eighteenth century to early twentieth century architectural resources that have been surveyed but have not been evaluated for eligibility for the NRHP. An architectural survey would be needed for any of the previouslyidentified structures within view of a proposed pump station location. Likewise, any structures that are at least 50 years old that have not been previously surveyed, and are within view of a proposed pump station location would need to be surveyed at the reconnaissance level to determine if they may be eligible for the NRHP, and if they are, these may require more intensive study. Numerous archaeological sites have been identified along the James River within all of the properties under consideration for the construction of the River Intake and Pump Station facility. Three of these sites are quite large and were identified after a large flood in 1985 that scoured the river bank. These include Sites 44AB0286 (69-acre tract), 44AB0287 (18acre/69-acre tracts), and 44AB0288 (5-acre/18-acre tracts). Due to their size, it is likely that at least one of these resources would be encountered during construction of the Intake and Pump Station. Several additional archaeological resources have been recorded within the other tracts under consideration as well, but they are much smaller and may be avoided. Generally, the floodplain of the James River should be considered to have a high potential for containing archaeological resources that are eligible for the NRHP due to the preference of such settings by Piedmont Virginia Native Americans for large, permanent prehistoric villages and the potential for archaeological deposits to be deeply buried below alluvial deposition. Numerous sites exist in downtown Scottsville, however the pipeline would be carefully routed around the town proper to avoid any sensitive resources. The construction of a below-ground facility, such as that proposed with the James River Intake and Pipeline Concept, would involve only a temporary effect to the previously

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identified structures during construction. These resources may not be adversely affected by the project, and additional cultural resources studies may not be necessary. These have not been included in the summary table, because they may not be affected depending on how the project is aligned. The construction of any above-ground permanent facilities such as the two proposed pump stations along the pipeline route would represent a potential adverse effect to any historic properties within view of those structures. Construction at all stream crossings along the route has the potential to encounter archaeological resources because prehistoric and historic archaeological resources are commonly found within proximity to perennial water sources and because construction at these locations will require additional excavations. Phase I archaeological survey at such locations may be necessary depending on the extent of such activities. Similarly, the presence of an architectural resource often indicates the presence of an adjacent historic archaeological resource of similar age and is an indication of a high probability area for archaeological resources. Phase I archaeological survey may be necessary in proximity to such resources where the pipeline will be excavated within undisturbed soils. Property Acquisition. Installation of the pipeline along Route 20 would require the acquisition of easements across approximately 150 private properties and would result in permanent and temporary disturbance to approximately 115 acres of upland and riparian habitat.

D.

Ragged Mountain Reservoir Expansion and Pipeline

Concept Description The current conditions of the Ragged Mountain Reservoir are detailed in several reports, including the most recent Technical Memorandum (Gannet Fleming, 2004). As outlined in these documents, the Ragged Mountain Reservoir System consists of two dams (Figure 10). The Upper Dam was constructed around 1880 and the Lower Dam was constructed in 1908. As part of the federally-sponsored National Dam Safety Program, inspections were conducted during the late 1970’s and early 1980’s to evaluate their design adequacy in terms of potential hazards to public safety associated with passing the Probable Maximum Flood (PMF) event. The 1978 Phase I Inspection Report concluded, “…the dam would be overtopped for all storms exceeding approximately 25 percent of the Probable Maximum Flood. The spillway is, therefore, judged as seriously inadequate, and the dam is assessed as unsafe, non-emergency.” The inspection report also suggested that investigations into the effect of seepage on the stability of the steep earth buttress slope were warranted. The dams are currently being operated under “conditional” operation and maintenance certificates provided by VDCR Division of Dam Safety. The conditions stated for the operation and maintenance certificates for each dam are given below: 1.

Resolve and/or rectify the existing inadequate spillway capacity of the Upper Ragged Mountain Dam and the Lower Ragged Mountain Dam

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Lower Ragged Mountain Reservoir

Upper Ragged Mountain Reservoir Dams

0

approx. 1,200 feet Scale - 1:14,400

Figure 10

Ragged Mountain Reservoir

2.

Resolve and/or rectify the stability analysis requirement identified in the Phase I Report for the Lower Ragged Mountain Dam

Accordingly, RWSA retained Gannet Fleming to prepare a ”Feasibility Study for Upgrading the Ragged Mountain Dams,” (Gannett Fleming, 2003). The purpose of the study was to reevaluate the design adequacy of the Lower Dam using state of the art engineering analysis methods developed since the 1978 Phase I inspections. The scope of this study also included the conceptual-level development of remedial or upgrade alternatives to address the design deficiencies. The report provided recommendations which included partial breeching of the Upper Dam and raising the normal pool of the lower dam by 3.2 feet to recover capacity that would be lost by breaching the upper dam. The recommended remediation project would result in removal and replacing the lower earthen dam with a roller-compacted concrete buttress. Given the scope of this remediation project and the necessity for action due to dam safety concerns, it is appropriate to consider whether the dam could be re-constructed at a significantly higher elevation to provide the needed water supply deficit, rather than merely maintain the existing safe yield. Raising Ragged Mountain Reservoir is thus presented as the fourth concept that has potential to meet the project purpose. As noted, the Ragged Mountain Reservoir is situated relatively high in the watershed, resulting in a limited drainage area for refilling the reservoir during dry periods or following a drought. Therefore, an important component of this concept is an overland pipeline that would re-fill the expanded reservoir more quickly, restoring the normal pool for use in the event of back to back drought events. The pipeline would run from the SFRR to the expanded Ragged Mountain Reservoir, over a distance of approximately nine (9) miles.

Safe Yield Increasing the usable storage volume of the Ragged Mountain Reservoir System could be accomplished by raising the reservoir’s normal pool level either by raising the spillway crest of the existing Lower Dam or by constructing a new dam just downstream of the existing dam. Any such project would also include addressing the dam safety deficiencies at the Lower Ragged Mountain Dam and removing the Upper Ragged Mountain Dam from service. Due to the design and construction methods of the nearly 100-year-old existing Lower Dam, any proposed spillway raising greater than approximately 10-15 feet would best be accomplished by construction of a new dam immediately downstream. Construction of a new dam would have the benefit of allowing the existing dam and reservoir to remain in service during construction of the new dam. The Ragged Mountain Reservoir could be expanded to provide the entire projected water supply deficit by constructing the new dam with the spillway crest at an elevation of 686, which equates to a 45’ increase in the pool elevation (Figure 11).

Costs During the evaluation of the four “short list” concepts, the Ragged Mountain Expansion Reservoir Concept was built around refilling the reservoir through the replacement of the pipeline between SHR and RMR and the refurbishment of the Mechums River Pump Station. The cost estimates below are based on this configuration. As is described in Section VI of

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Lower Ragged Mountain Reservoir

Upper Ragged Mountain Reservoir

Proposed New Dam

Dams

0

approx. 1,200 feet Scale - 1:14,400

Existing Ragged Mountain Reservoir Proposed 686 foot Pool Elevation

Figure 11

Ragged Mountain Reservoir Concept 686-foot Pool

this report, this concept was later revised to refill the RMR through a pipeline from the SFRR, eliminating the need to replace the SHR to RMR pipeline and the Mechums River Pump Station. Table 12 summarizes the cost estimate for the expansion of the Ragged Mountain Reservoir to Elevation 686 feet. The costs are in 2004 dollars. Additional descriptions and references for cost estimates can be found in Appendix A of this report. Table 12

Ragged Mountain Reservoir Expansion and Pipeline Concept Cost Estimate

Item

Cost

Construction of New Dam (Normal pool elevation = 686 feet) Breaching of Upper Ragged Mountain Dam Breaching of Lower Ragged Mountain Dam Clearing (133.5 acres @ $5,000/acre) Culvert Under I-64 (740 l.f. @ $931/l.f.) Embankment Stabilization (1,000 l.f. @ $521/l.f.) Rehabilitate Mechums Pump Station & Intake Construct Fish Ladder at Mechums Pump Station Road Reconstruction (5,280 l.f. @ $74.80/l.f.) Ivy Creek Trail Replacement (19,000 l.f. @ $6/l.f.) Electrical Extension to Mechums PS (3,750 l.f. @ $196/l.f.) 18” Pipeline from Sugar Hollow to Ragged Mountain – Parallel to Existing Pipeline ($195/l.f. for 66,000 l.f.) Environmental Mitigation Subtotal Engineering/Permitting and CM (20%) Land Acquisition (133.5 acres @ $4,114/acre) Electrical Costs Subtotal Project Contingencies (25%) Total Project Cost Average Cost Per GPD of Safe Yield (provides 9.9 MGD)

$15,745,000 $360,000 $809,000 $668,000 $689,000 $521,000 $1,000,000 $90,000 $395,000 $114,000 $735,000 $12,870,000 $5,146,000 $39,142,000 $7,828,000 $549,000 $99,000 $47,618,000 $11,905,000 $59,524,000 $6.01

Note: Cost estimates as reported in Concept Development – Ragged Mountain Reservoir Expansion (Gannett Fleming, February 16, 2005)

Project Impacts The upper reservoir was originally constructed to maintain a normal pool level of 654.7 feet (~655 feet). Modifications to the spillway were prompted by dam safety concerns and were completed in the 1980s. There is a break in the 10-inch diameter pipe beneath the Upper Reservoir, resulting in a lower pool level in the Upper Reservoir than was originally intended. Today, the reservoir pool of the upper reservoir matches that of the lower reservoir, Elevation 641 feet. The following discussion provides an assessment of the impacts to natural resources 41

found between an elevation of 641 feet and the proposed elevation of 686 feet, the anticipated elevation after the 45-foot increase. Wetlands. Fringe wetlands around the Ragged Mountain Reservoirs primarily occur in the form of palustrine systems located just landward of the existing pool (Figure 12). These systems are supported hydrologically by inputs such as stream bottomlands and seeps in cove areas where they connect to the reservoirs. The largest system is associated with the main unnamed channel that approaches the upper reservoir from underneath Interstate 64. Between the reservoir pool and the interstate lies a series of interconnected forested and emergent seeps, a portion of which are occupied and manipulated by beavers. The main channel presently contains three beaver dams within this reach, the dams occurring approximately 500 feet apart. The beaver dam closest to the reservoir is the largest of the three observed, and currently floods an area approximately ¼ acre in size. The other two dams occur within the incised portion of the channel, and are not large enough to cause the water to overtop the channel banks. An assessment was performed to determine the acreage of palustrine vegetated wetlands that occur between the current reservoir elevation of 641 and the proposed elevation of 686. The wetland areas that would be impacted by the proposed reservoir project are provided below and presented in Figure 12. Forested Wetlands………………………1.43 acres Scrub-shrub Wetlands…………………. 0.07 acres Emergent Wetlands……………………..1.08 acres Total…………………......2.58 acres The location of these wetland areas around the reservoir is directly related to the history of the dams and management of the water levels for safety purposes. Specifically, approximately 2.5 acres of wetlands developed after the upper pool was lowered from 655 feet to the pool level of the lower reservoir at 641 feet in response to directives of the Virginia Department of Conservation. Thus, the majority of the wetland impacts would occur if RWSA were to simply restore the reservoirs to their original design conditions, and only about 0.1 acres of wetland impact would be attributed to the expansion project driven by the need for an increased water supply. Another 0.03 acres of scrub-shrub wetlands will be temporarily affected by the pipeline installation. Although these wetland areas around the existing reservoir would be inundated by the proposed project, it is highly likely that a new wetland fringe will become established around the new reservoir pool, partially offsetting these wetland impacts. Streams. Biologists inspected each stream reach between the proposed 686-foot elevation and the existing pool elevations of 641. An assessment of existing conditions included a detailed inspection of each stream channel to determine perenniality, stream stability and general biological activity in order to better define the nature of project impacts. A total of 21 streams flow into the existing Ragged Mountain Reservoir. Fifteen of these are first order channels originating from the adjacent hillside seeps. Five are considered second order streams and one is classified as a third order stream. Due to the seepages and springs

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Lower Ragged Mountain Reservoir

Upper Ragged Mountain Reservoir

Proposed New Dam

Dams

0

approx. 1,200 feet Scale - 1:14,400

686 foot Elevation Inundation PEM Wetlands PSS Wetlands PFO Wetlands Streams

Potential Cultural Resources

Figure 12

Ragged Mountain Reservoir Concept Potential Resource Impacts

found in the upper watershed, 16 of the channels were determined to be perennial and 5 were classified as intermittent. Even with the higher order channels, these streams are very small threads in the extreme upper reaches of the watershed, with an average bankfull width of 6 feet and an average bankfull depth of only 6 inches. With the exception of some minnows near the reservoir pool, the only organisms observed in the channels were various macroinvertabrates (worms and insects). Higher trophic level organisms were generally lacking from the contributing drainages, although occasional evidence of frogs and other amphibians was observed. More important in the case of Ragged Mountain is the fact that these channels are part of a closed ecological system. That is, the natural down-gradient stream continuum has been truncated by the existing Ragged Mountain dams. The main dam essentially eliminates any downstream movement of detritus and organisms that normally contribute to the ecologic diversity of the down gradient channels. Consequently, the ecological value of these steam channels was impacted over 100 years ago, when the first dam was installed. Since that time the primary function of these channels has been to convey runoff from the steep hillsides to the reservoir. The length of any one individual stream within the elevation boundaries defined above, typically ranges between 400 to 1,300 linear feet, with the lowest reach being 120 feet and the longest being over 2,500 feet. In total, approximately 13,400 linear feet of streams occur below the maximum study elevation of 686’ (see Figure 12). Approximately 2,000 linear feet of this impact could be attributed to repair or rehabilitation for safety purposes, while the remaining 11,400 feet would result from the water supply expansion. Threatened and Endangered Species. According to the U.S. Fish and Wildlife Service and the Virginia Department of Game and Inland Fisheries, species of potential concern in the project area include the Peregrine falcon and the Loggerhead shrike. In addition, the potential for the presence of James spinymussel habitat downstream from the dam was assessed during an on-site visit with DGIF and FWS. The stream channel was deemed inadequate spinymussel habitat. FWS has also noted that a habitat for the Indiana Bat (Myotis sodalis) may occur within the upland forest adjacent to the reservoir. Cultural Resources. There is one recorded architectural resource within the vicinity of the Ragged Mountain Reservoir System: the Jim Newell Farm, ca. 1770 (VDHR No. 002-1170); however, this resource is outside the anticipated project Area of Potential Effect (APE) and would not be directly or indirectly affected by the project. The field investigations identified two unrecorded early-twentieth century architectural resources within the APE of this alternative discovered during fieldwork, the former Gate House of the dam and the caretaker’s house. There are no previously recorded archaeological resources within the project vicinity; however, there are two former house sites and one quarry within the anticipated APE of the Ragged Mountain Reservoir System. These potential resources are shown in Figure 12. The two house sites are represented by standing chimneys and archaeological sites surrounding them, and are either associated with a former caretaker’s residence or residences that were abandoned after the reservoir was created.

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Additionally, the field investigations identified three potential archaeological resource locations based on their topographic setting. These are relatively flat, preserved terraces less than 20 feet above the current reservoir pool. Prior to construction of the reservoir, they would have been first or second terraces above the stream and suitable locations for prehistoric or historic occupation. Each of these areas is less than 10 acres (see Figure 12). Follow-up work conducted by Gray & Pape indicates that none of the identified sites are eligible for the National Register of Historic Places and no further work is warranted. The details of the study and findings are included in Appendix A of this document. Other Project Impacts. Initial hydrologic analyses indicate that for a 45-foot raise in reservoir level, the I-64 highway profile remains more than 110 feet above the maximum reservoir level in the area upstream (worst case location) of the I-64 embankment for the 100year flood event (see Figure 12). Initial analyses indicate that this is also true for the more extreme flood event used as the design criteria for the proposed dam, the Probable Maximum Flood (PMF). Therefore, a proposed increase in reservoir level by 45 feet would not pose a potential flooding hazard to the I-64 corridor, even for extreme flood events. Another potential adverse impact to the I-64 embankment relates to the stability of the engineered highway embankment slopes both on the northern and southern sides. Regardless of the type of embankment material and whether or not the slope would be susceptible to failure in its present configuration, generally accepted methods have been successfully used to stabilize earthen or rock-fill embankment slopes either submerged or adjacent to a reservoir. It is reasonable to assume that if the I-64 embankment is determined to be unstable under certain proposed loading conditions one of these accepted methods would satisfactorily remedy any deficiencies. The most likely remedy would involve placing an earthen berm against the highway embankment to provide a free-draining buttress that would increase the resisting forces. The concrete box culvert would be extended on both sides of the highway embankment. Further detailed geotechnical investigations will be required for design purposes, if an expanded Ragged Mountain Reservoir is selected as part of the preferred alternative. Preliminary and final design investigations would fully address the needed culvert modifications and the associated hydraulic capacity in conjunction with the design of the necessary embankment stabilization measures. A permanent pool elevation change would likely have no detrimental impacts on the recreation-related activities identified in the previous section. However, a raise of 45 feet would result in a pool elevation of 686 feet, which would inundate a large portion of the looped trails currently located around the reservoirs. All trails that are inundated could be replaced. The overall length of trails located within the Ragged Mountain Natural Area would likely be increased due to the increase in surface area of the reservoir. For the purposes of this investigation, one-half of the approximately 7 miles of existing trails are assumed to be impacted. This results in approximately 19,000 linear feet of new trail that would be constructed as part of this alternative. Property Acquisition. The entire area that would be impacted by this project is owned by the City of Charlottesville and no private property acquisition would be necessary.

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E.

Summary

Four Foot Crest Gates at SFRR. This concept could increase existing safe yield by about 3.3 MGD and therefore would not satisfy the basic project purpose on its own. To do so, it would have to be combined with one or more additional concepts. The concept would result in the greatest physical alteration of wetlands and stream habitats. Primary environmental impacts resulting from the increased pool are estimated to be 30.6 acres of wetlands and 18,000 linear feet of stream channel. While the majority of the inundation would affect first-order streams, eight (8) second-order, six (6) third-order, one (1) forth-order and 2 channels of fifth-order or higher would be impacted by the project. An endangered species (James spinymussel) has also been documented very near, if not in, this affected aquatic habitat. It has approximately 25 times the number of wetland acres per MGD safe yield provided than the concept with the next highest impact (as shown in Table 1). It has approximately 6 times the linear feet of permanent stream impacts per MGD safe yield provided than the concept with the next highest stream impacts (as shown in Table 2). When paired with other concepts to provide the required yield, additional impacts result. All alternatives that include the Four Foot Crest Gate concept are significantly more environmentally damaging to the aquatic ecosystem than other alternatives. When coupled with other concepts, excluding dredging, alternatives that are cost competitive may be formed. There are no other known issues that would render the project technically infeasible or logistically impracticable.

Dredging South Fork Rivanna Reservoir This concept could increase existing safe yield by at most about 5.5 MGD and therefore would not satisfy the basic project purpose on its own. To do so, it would have to be combined with one or more additional concepts. Dredging by itself is estimated to result in approximately 2.0 acres of wetland impacts and approximately 200 linear feet of stream channel impacts due to construction access and activities associated with spoil disposal. When combined with other concepts to provide the required yield, additional impacts result. No endangered species are known to be affected by the project. It is assumed that the effects of the dredging itself on the aquatic ecosystem in South Fork Rivanna River Reservoir would be slight. It is the most costly concept on a current day cost per MGD safe yield provided basis by approximately 4 times the next most costly concept (as shown in Table 3). This high cost is driven in part by the difficult logistics of handling, drying, transporting, and disposing of dredged material. The possible effects of marketing dredged spoil on these costs has been considered, but can not be quantified within any reasonable degree of probability.

James River Intake and Pipeline. This concept could supply the needed safe yield and therefore would satisfy the project purpose on its own. In contrast to other core concepts, environmental impacts of this standalone alternative include “footprint” impacts resulting from physical construction, as well as other direct impacts that may result from the withdrawal of water from the James River, particularly during times of drought. The affected stream reach is approximately 25 miles which is habitat for anadromous fish and affect other trophic species. Permanent wetland impacts associated with this concept are limited to 0.2 acres of wetlands, however another 4 45

acres of forested wetlands would be converted to emergent or scrub shrub habitat within the permanent right-of-way. Temporary construction impacts would occur to 6,930 linear feet of stream channel, while only 720 feet of stream channel would be permanently impacted. No endangered species are known to be affected by the project, although additional study may be required. There are no other known issues that would render the project technically infeasible or logistically impracticable. However, it is noted that the long term or cumulative impacts to the aquatic systems of the James River resulting directly from RWSA withdrawals and in combination with other community needs within the watershed have yet to be quantified. Such withdrawals have the potential to affect the complex ecological system of the James, adversely affecting higher trophic level species such as anadromous fish. In addition, due to the broad geographic extent of this concept and the location of the withdrawal facilities on the banks of the James River, this alternative has the highest potential for effects to cultural resources.

Raising Ragged Mountain Reservoir. This concept could supply the needed safe yield and therefore would satisfy the project purpose on its own. The primary environmental impacts of this stand-alone concept would include about 0.1 acres of wetlands and 11,400 linear feet of stream channel assuming the effects below the existing Upper Ragged Mountain Dam crest are excluded. Should some or all of these impacts be considered, wetlands impacts would still be limited to 2.6 acres of “closed system” wetland above an existing impoundment. Stream channel impacts would occur to 13,400 linear feet of stream supporting only lower trophic species (e.g. worms and insects). No endangered species are known to be affected by the project. When coupled with other concepts, excluding dredging, alternatives that are cost competitive may be formed. There are no other known issues that would render the project technically infeasible or logistically impracticable. Furthermore, the Raising Ragged Mountain Reservoir concept allows the use of stored water rather than direct withdrawal of surface water during drought events, a potential environmental benefit. Implementation of this project would also solve existing dam safety issues at Ragged Mountain Reservoirs.

Conclusion Based on the foregoing information, the concept of raising South Fork Rivanna River Reservoir by four feet would entail the greatest adverse effects to aquatic ecosystems, a key consideration in the regulatory review process. Similarly, any alternative that might employ the concept of Dredging South Fork Rivanna River Reservoir is disproportionately expensive and impracticable when compared with other practicable and environmentally-acceptable alternatives. Stated in the context of the Clean Water Act Section 404 (b)(1) Guidelines, alternatives incorporating the Four Foot Crest Gate concept will not be the “least environmentally damaging”. Similarly, alternatives incorporating dredging SFRR for purposes of increasing water supply will not be “practicable” owing to logistical issues that cause disproportionate costs, and uncertainties that cannot be eliminated with any reasonable level of investigation. In contrast, the environmental effects of the James River Intake and Pipeline concept and the Raising Ragged Mountain Reservoir and Pipeline concept are both relatively low when

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compared with the Four Foot Crest Gate concept. Both concepts also appear to be feasible after consideration of cost and logistics. As a result, these two concepts will be evaluated in greater detail in the following section.

Section VI - Selection of Preferred Alternative A.

Concepts That Are Not Preferred

South Fork Rivanna Reservoir – 4-Foot Crest Gate The 4-foot crest gate expansion concept at the South Fork Rivanna Reservoir would result in the greatest physical alteration of wetlands and stream habitats. It would impact approximately 30.6 acres of wetlands and 18,000 linear feet of streams as a result of inundation. Many of the impacted streams in the South Fork Rivanna River watershed are high order streams, supporting diverse ecosystems. Since this concept would have to be combined with one or more additional projects to achieve the required yield, impacts would be even greater as a result of the complimentary project impacts. Impacts from the 4-foot crest gate expansion are substantially greater than the wetland and stream impacts associated with the other core concepts as summarized in Table 5. In comparison, the Ragged Mountain concept would only impact 2.6 acres. Stream impacts would also be less with the Ragged Mountain concept, which would affect only about 13,000 linear feet of streams, and the vast majority of these streams are shallow, narrow low order streams with little species diversity. Furthermore, the endangered James spinymussel and several archaeological sites may potentially be affected by the 4-foot increase in pool elevation at SFRR. Based on the magnitude of impacts to environmental resources, the SFRR crest gate expansion concept is not preferred because it is not the least environmentally damaging and cannot be combined with other concepts to produce an alternative that would be the least environmentally damaging.

Dredging South Fork Rivanna Reservoir Although impacts to wetlands and streams associated with this concept by itself would be low, dredging of the South Fork Rivanna Reservoir is not practicable due to many uncertainties that cannot be resolved. These include issues such as re-use and sale of dredged material, acquisition of suitable adequate dewatering and disposal sites and associated travel distances, that could result in very high costs driven in large part by the difficult logistics. The details of this alternative and the cost assumptions are described completely in the Gannett Fleming technical memorandum entitled Concept Development – Dredging of South Fork Rivanna (December 2004) Since this concept would have to be combined with one or more additional concepts in order to achieve the required yield, environmental impacts would actually be similar to those of the Ragged Mountain expansion or James River Pipeline, while the costs would be raised even higher as a result of the complimentary concept.

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Dredging is estimated to be the most expensive of all concepts, costing as much as approximately four (4) times more than other concepts on a unit safe yield basis. In addition to the cost of removing the accumulated sediment through the dredging itself, a large portion of the overall cost is associated with dewatering, transporting and disposing of the material. Due to the steep topography around the SFRR, dewatering facilities would have to be constructed on nearby land, and then the dewatered material would have to be loaded onto trucks and transported to remote permanent disposal sites. In addition, the dredging process would not be a one-time event; it would require regular and periodic maintenance dredging that would continue throughout and beyond the fifty-year planning period encompassed in this study. Based on the substantial uncertainties that cannot be resolved, and also on the magnitude of costs and logistical difficulties as compared to other core concepts, dredging of the South Fork Rivanna Reservoir is not a preferred water supply option, as it is not practicable and cannot be made both practicable and least environmentally damaging through combination with another water supply concept.

B.

Further Evaluation of Candidate Concepts

The remaining concepts, James River Intake and Pipeline and the Ragged Mountain Expansion are examined further in this section with respect to operational logistics and environmental considerations.

James River Intake and Pipeline Major Components: The major components associated with this alternative include: 1.

a new raw water intake and low lift pump station at the James River in the vicinity of Scottsville;

2.

a pre-treatment facility located near the river intake;

3.

a raw water transmission system consisting of a pipeline and high lift pumping stations to deliver raw water from the James River to the RMR and Observatory WTP;

4.

a new pumping station at the RMR; and

5.

an expansion of the Observatory WTP facility.

These facilities can be seen in Figure 13. The pre-treatment facility located near the raw water intake and pump station will be capable of treating all water withdrawn for a total capacity of 15 MGD. This facility is intended to provide primarily sediment removal and turbidity reduction, with the added benefit of nutrient reduction. This will reduce wear on the high lift pumps delivering water to RMR or Observatory WTP, decrease operation and maintenance expense for the pipeline, and improve raw water quality transferred to RMR.

48

\\vawill\projects\31671.01\graphics\figures

1 4

2

3

South Fork Rivanna WTP

5

1. Expansion of Obs WTP (18 MGD) 2. Replace RM Pump Station 3. Pipeline from RM to Obs WTP 4. Rehab Ragged Mountain Dam 5. Pipeline from James River

Observatory WTP

James River Alternative Pipeline

1. Intake Structure and PS (15 MGD) 2. Pretreatment facility (20 MGB) 3. Booster PS 4. Pipeline 30”

4 3 2

1 0

10,000 feet

Figure 13

James River Alternative

The James River to RMR pipeline would be located along VA Route 20 between Scottsville and Charlottesville, and eventually along portions of Interstate 64 and Route 780 in order to connect to the Observatory WTP. As the new pipeline approaches the Observatory WTP, a portion of it would branch off and follow the existing pipelines to RMR. This configuration would allow water from the James River to be delivered to Observatory WTP or RMR. It is estimated that two (2) booster pump stations would be required along the pipeline route. The booster pump stations would be capable of supplying water to Observatory WTP and/or RMR. A new pump station serving the RMR would be added to allow water to be transferred to Observatory WTP during drought periods. This pump station would replace two existing facilities. Observatory WTP would be expanded to a treatment capacity of 18 MGD. This is based on the maximum raw water transfer of 15 MGD from the James River with balance coming from RMR. At the end of the 50-year planning horizon, the majority of treated water delivered to the Urban Service Area would be treated at Observatory WTP as opposed to SFRR WTP. During a drought period, flow from the James River might be limited to the average day deficit of 9.9 MGD according to conversations with regulatory personnel. During such periods, the balance of the demand (up to 8 MGD) would be transferred from RMR to Observatory WTP. In addition, drought conservation measures would be employed as necessary in such an emergency. Facility sizes were selected based on the following criteria and assumptions: 1.

The 2055 average daily demand (ADD) of the entire Urban system is 18.7 MGD.

2.

Peak day demand (PDD) is 1.5 times the ADD and equals 28.0 MGD.

3.

The North Fork source is limited to 2 MGD and the North Fork WTP would be expanded to 2 MGD.

4.

Observatory WTP will be expanded to 18 MGD.

5.

SFRR WTP will remain at its current capacity of 12 MGD.

6.

The new raw water intake and low lift pump station will have a 15 MGD capacity. The capacity of these systems is selected to satisfy the peak day demand at the end of the 50 year planning horizon (1.5 X 9.9 MGD). The intake and pump station will be in the vicinity of Scottsville, where the James River is closest to the Urban Service Area thereby minimizing the transmission pipeline length.

7.

The pretreatment facility is sized for 15 MGD so that all of the raw water going into RMR and/or Observatory WTP can be pretreated for turbidity reduction and perhaps some nutrients.

8.

The raw water pipeline must be 30-inch diameter based on the established 15 MGD capacity

49

9.

Two 15 MGD booster pump stations are required to lift the water from the James River to RMR and/or Observatory WTP.

10.

Approximately 14 acres of property will need to be acquired for this alternative. It is assumed that the raw water intake structure and low lift pump station will require 5 acres, while the pre-treatment facility will require an additional 5 acres. The 2 booster pump stations will require approximately 2 acres each.

11.

RMR dam will be replaced/repaired to provide the originally envisioned storage for this facility.

12.

An 8 MGD booster pump station will be required to transfer water from RMR to Observatory WTP for lake turnover and water supply during drought conditions.

Operating Conditions: All existing storage facilities generally would be operated according to the guidelines originally established for them. These guidelines include using the SFRR storage first during a drought, then SHR storage, and finally RMR storage. There would be two alterations required: 1) RMR would have to be used sooner such that RMR and SHR would empty at the same time; and 2) the James River would have to be used during both normal and drought periods. These guidelines are required to ensure that the SFRR/SHR system does not run out of water before the end of a drought, and that stored water is not used too soon, which would reduce the system safe yield.

Normal Operating Conditions: Normal operating conditions apply to those periods of time outside of a drought. During normal operations, it is assumed that the Urban Service Area demands would be primarily met by surface water runoff from the North Fork and South Fork Rivanna River sources. As demands increase over time, the additional raw water would need to be provided by the James River. It is imperative that RWSA maintain the reservoirs at their normal pool elevations during normal conditions so that the reservoirs are full at the beginning of a drought period. The projected 2055 average daily demand is 18.7 MGD. The projected 2055 peak daily demand is 28.0 MGD. Average day demands would be limited by WTP capacities. North Fork WTP will be able to produce 2 MGD and SFRR WTP will be able to produce an expected 12 MGD. Therefore, at least 4.7 MGD would have to be produced at Observatory WTP (supplied by the James River). On peak days, up to 14.0 MGD would have to be produced at Observatory WTP (supplied by James River). The peak capacity of the James River supply is 15 MGD. RWSA may elect to vary production based on economy, efficiency, water quality and time of year.

Drought Operating Conditions: During drought periods, SFRR storage would be used first, followed by SHR storage. As SHR storage is drawn down, RMR water would also be used. SHR and RMR pool levels should be proportionally drawn down so that the two reservoirs would empty at the same time (which would theoretically be at the end of the current statistical drought of record).

50

Normal operating conditions dictate that the James River supply would be used at a rate of at least 4.7 MGD and not more than 15.0 MGD. The projected 2055 water supply deficit is 9.9 MGD on an average day basis. At the beginning of a drought, and continuing throughout the entire drought, water would have to be withdrawn from the James River at least 9.9 MGD to preserve system storage. If water is withdrawn at less than 9.9 MGD during the drought, water stored in SFRR, SHR, and RMR would have to be used too soon, and would not be available in storage at the end of the drought. In short, system safe yield would be reduced below the projected need. Is it noted that the James River is subject to algae blooms during low flow periods, exactly the time that the community would depend on this source to make up the 9.9 MGD deficit.

Ragged Mountain Expansion Major Components: The major components associated with this alternative include: 1.

replacing the dam at Ragged Mountain Reservoir with a new dam at higher elevation;

2.

a pipeline connecting the RMR and the South Fork Rivanna Reservoir (SFRR) and SFRR Water Treatment Plant (WTP);

3.

pumping stations at the RMR and SFRR;

4.

a new pipeline connecting RMR and Observatory WTP;

5.

a new raw water intake and low lift pump station at SFRR;

6.

a pre-treatment facility located at the SFRR; and

7.

an expansion of the water treatment facilities at SFRR WTP.

8.

A release structure to meter flows and release water to the streams.

These facilities can be seen in Figure 14. Following substantial public outreach comments related to the stream flow needs of the Moormans River and a Pre-Application Meeting with the regulatory agencies on June 22, 2005, the Ragged Mountain Reservoir Expansion Alternative was modified with respect to the refilling of the reservoir. Instead of replacing the SHR to RMR pipeline and refurbishing the Mechums River Pump Station as described in Section V of this report, the revised alternative reflect refilling the reservoir through a new pipeline from SFRR. Raising the normal pool elevation of the RMR by 45 feet to an elevation of 686 feet would provide the necessary increase in the Urban System safe yield to provide an adequate drinking water supply over the 50-year planning horizon. This would be accomplished by constructing a new dam immediately downstream from the existing Lower RM Dam and the subsequent breaching of both the Upper and Lower RM Dams once the new dam is completed. Clearing of approximately 180 acres would be required for the expanded RM Reservoir based on the area required for access roads, staging areas, and clearing one vertical foot above the proposed normal pool elevation. Approximately 29,000 feet of either temporary or permanent 51

\\vawill\projects\31671.01\graphics\figures

0

1. Pipeline from SFRR to RM (36”) 2. SFRR Intake Structures and PS 41 MGD 3. WTP Expansion (SFRR WTP to 16 MGD) 4. Pre-Treatment Facility (30 MGD Capacity)

60,000 feet

Existing Urban Service Area System

2

Sugar Hollow 18” Raw Water Line Ragged Mountain 18” Raw Water Line

3

4

Proposed Pipeline Water Treatment Plants

12

”

24”

1

South Fork Rivanna WTP

2

3

”

12

5

Observatory WTP

1

4 6

1. Dam 3 Raise = 45’, Pool Elevation = 686’ 2. Pipeline from SFRR to RM (36”) 3. Pipeline from SFRR/RM to Obs WTP (30”) 4. Replace RM Pump Station to Obs WTP 5. Rehab of Obs WTP to 10 MGD 6. RM to SFRR Pump Station

Figure 14

Ragged Mountain Alternative

access roads would need to be constructed and maintained over the course of the dam construction. Raising the normal pool elevation of the reservoir would cause it to expand to the south side of Interstate 64 (I-64) via an existing 8-foot square culvert under the highway. It is anticipated that embankment may need to be stabilized to accommodate these changed conditions. The embankment stabilization would include stripping, filling, and seeding/mulching as well as constructing extensions of the box culvert with new head walls. In order to gain access to this portion of the expanded RMR, approximately 2,650 feet of permanent access road would be constructed. This road can be unpaved in order to appropriately maintain the wooded, high quality environment of this area. A pipeline connecting the RMR to Observatory WTP and the SFRR would be constructed. The pipeline would provide water supply from the SFRR to the Observatory WTP under normal operating conditions and would be used to refill RMR from the SFRR when RMR is drawn down. This pipeline would also be used during severe drought conditions to provide water from RMR to both SFRR WTP and Observatory WTP in any proportions as system conditions dictate. Preliminary pipeline corridors have been selected, reviewed in the field, and presented to the public for comment. Much of the RMR-to-SFRR pipeline crosses large parcels and has been discussed with property owners. The RMR-to-Observatory route is assumed to parallel an existing pipeline. Acquisitions of 20’ easements over approximately 25,200 and 11,000 linear feet would be required along the RMR-to-SFRR and RMR-toObservatory WTP pipelines, respectively. New pump stations would be constructed at both of the reservoirs to allow the transfer of water through the pipeline in either direction. The pump station at RMR would be located at or below the dam and would serve as a dual-purpose pump station with the ability to send water to either the SFRR or the Observatory WTP. The SFRR pump station would be a high lift pump station that would be used to transfer water to the RMR and the Observatory WTP. A new raw water intake and low lift pump station would be constructed at the SFRR that would deliver the raw water to the existing SFRR WTP and the proposed pre-treatment facility located on the SFRR WTP site. The pretreatment facility is designed to provide primarily sediment removal, turbidity reduction, and nutrient reduction. This will reduce wear on the high lift pumps delivering water to RMR or Observatory WTP, decrease operation and maintenance expense for the pipeline, and improve raw water quality transferred to RMR. Facility sizes were selected based on the following criteria and assumptions: 1.

The average daily demand (ADD) of the entire Urban system is 18.7 MGD.

2.

Peak day demand (PDD) is 1.5 times the ADD and equals 28.0 MGD.

3.

The North Fork source is limited to 2 MGD and the North Fork WTP would be expanded to 2 MGD.

4.

Observatory WTP would be expanded to about 10 MGD.

52

5.

SFRR WTP would be expanded to about 16 MGD so that the total Urban system WTP capacity meets the projected PDD.

6.

The SFRR to RMR pipeline would be able to transfer a maximum of 20 MGD peak flow for refilling RMR. It must, in addition, have capacity to provide flows to Observatory WTP for continuous operation. When RMR is initially being refilled after a drought, it is likely that water conservation measures will still be in place and that the calculated PDD will not occur. Therefore, an additional allowance of one-half of the Observatory capacity of 10 MGD (which is 5 MGD) is projected to be adequate. This results in a maximum design flow of 25 MGD for the RMR to SFRR pipeline. The pipeline must also be able to convey up to 16 MGD in the opposite direction (from RMR to the SFRR WTP) when storage in SFRR and SHR is depleted at the end of a drought.

7.

The pretreatment facility is also sized for 25 MGD so that all of the raw water pumped from SFRR to RMR can be pretreated for turbidity reduction and nutrient reduction.

8.

The total capacity of the SFRR intake and low lift pump station for delivering water either to the SFRR WTP, or to the pretreatment facility for pumping to RMR or the Observatory WTP, is 41 MGD. This is the total of the peak day pumping rate to RMR and Observatory WTP (25 MGD) and the anticipated capacity of the SFRR WTP of 16 MGD.

Operating Guidelines Operating guidelines were established to simulate future operating conditions for the RWSA Urban system including the proposed RMR Expansion and related features to: 1.

Confirm that reasonable operating guidelines could be established;

2.

Determine the size and configuration of the expanded RMR that will provide the projected water supply demand;

3.

Understand potential changes in stream flow patterns, reservoirs operating statistics; and

4.

Establish pumping guidelines for refilling RMR from SFRR.

The guidelines discussed below were applied to the computerized raw water model originally developed to analyze the existing system and referenced in Section II of this report. These guidelines are established for the 2055 conditions and generally apply to times of drought, since these are critical for determining RMR reservoir size and other key operating parameters. During other times when water is plentiful, RWSA will use raw water to meet its demand conditions in any proportion with respect to its individual reservoirs and treat water in any proportion at its water treatment plants, subject to facility limitations. The release conditions discussed in operating guideline number 6 (below) and RMR refill conditions discussed in note 1 (below) will be followed at all times.

53

Operating Guidelines 1.

RWSA will be able to treat water in any proportion at its treatment plants, subject to facility capacity limitations, once the SFRR to RMR pipeline is constructed.

2.

When necessary to maximize safe yield, use the maximum available from North Fork up to the established 2 MGD water treatment plant permit and withdraw remainder of demand at SFRR.

3.

When flow past the SFRR stops, use the water from SFRR and SHR first, reserving RMR for last.

4.

As the SFRR is drawn down, transfer water from SHR to SFRR as appropriate. SFRR should be sufficiently drawn down to avoid “losing” any runoff that may occur.

5.

Assume 25% of water released from SHR is lost to stream baseflow during transfer. Note, actual performance should be monitored over time and appropriate adjustments made.

6.

In addition to water demands, withdraw water from SFRR and pump to refill RMR when necessary according to the following schedule:

SFRR Flow Past the Dam (MGD) 0 to 18

Maximum Allowable RMR Refill Pumping Rate (MGD) 0

18 to 40

10

> 40

Unregulated

Notes: 1.

Assume that a minimum release at SFRR is the lesser of 8 MGD or the natural inflow to the reservoir. Until the SFRR to RMR pipeline is completed, minimum releases at Sugar Hollow are 0.4 MGD when storage exceeds 80 percent of SHR total storage. After the SFRR to RMR pipeline is completed, SHR will remain full and flow past the dam will mimic natural conditions except during drought periods when releases are authorized as expressed in these Operating Guidelines, or for conditions stated in Note 7. There are no minimum releases from RM; however RM is assumed to have constant seepage loss.

2.

Dead storage in RMR is assumed to be 15 percent of total storage.

3.

2055 Average Day Demand is 18.7 MGD. Peak Daily Demand is 28.0 MGD.

4.

Reservoirs are full at the beginning of the drought.

5.

When SFRR flow past the dam exceeds 40 MGD, the maximum allowable RMR refill rate is not regulated and is limited only by the capacity of the pumping system as indicated in Operating Guideline 6. Hydraulic modeling concludes that following a

54

severe drought, the actual refill rate under these SFRR flow conditions may need to be at least 20 MGD to refill RMR before the next dry season. 6.

All water demands will be withdrawn from the SFRR during RMR refill. Peak daily demands will be satisfied as necessary.

7.

None of the guidelines for any dam or reservoir are intended to prohibit short-term deviations in dam operation or downstream releases that may result from maintenance requirements, or in the interest of public safety under forecasts of severe weather events, such as a flash flood watch or warning or other similar circumstances.

C. Evaluation of Candidate Alternatives In order to determine the preferred water supply alternative, the James River Pipeline and Ragged Mountain expansion options are discussed with respect to the key evaluation criteria established by federal and state regulations (See Section IV-E). Because both alternatives already have been shown to be technically feasible, they will be evaluated below with respect to the following, remaining criteria: ability to meet the overall project purpose, logistics, cost, availability and environmental impacts.

Project Purpose Based on the 2004 demand analysis and safe yield study, the projected 2055 supply deficit in the RWSA Urban Service Area is 9.9 MGD. Both the James River pipeline alternative and the Ragged Mountain Reservoir expansion alternative could supply the needed safe yield independently of other water supply options.

Cost The candidate alternatives are comparable in cost. On the basis of project cost estimates updated in April 2006, the James River Intake and Pipeline Alternative (JRIP) would cost approximately $122.6 million on a current capital cost basis, and the Ragged Mountain Reservoir expansion alternative would cost approximately $130.5 million on a current capital cost basis. Since these two alternatives would require very different raw water pumping conditions, which would substantially affect electrical operating costs over the planning period, life-cycle electrical operating costs for raw water pumping are also compared. The 50year life cycle electrical raw water pumping costs are estimated as $28.3 million for the James River alternative and $12.3 million for the Ragged Mountain alternative. When these estimated electrical costs are added to the estimated capital cost, the complete comparison is $150.9 million for the James River alternative and $142.8 million for the Ragged Mountain alternative. For the purpose of this report, the conclusion is that neither alternative is disproportionately expensive with respect to the other. A summary of these estimated costs is shown in Table 13.

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Table 13

Estimated Costs

Ragged Mountain Reservoir Alternative

Cost

Ragged Mountain Dam

$24,300,000

SFRR to RMR Pipeline

$34,900,000

RMR to Observatory Pipeline

$7,700,000

Observatory WTP Upgrade

$14,200,000

Future WTP Upgrades

$6,000,000 Subtotal

$87,100,000

Engineering

$17,300,000

Contingency (25%)

$26,100,000 Total Capital Cost

$130,500,000

50-Year Raw Water Pumping Cost (Electricity)

$12,300,000

Total Project Cost (for Alternative Comparison)

$142,800,000

Cost

James River Pipeline Alternative James River Intake, Pipeline & Pumping

$46,300,000

Rehabilitate RMR at current size

$3,700,000

RMR to Observatory Pipeline

$5,900,000

Observatory WTP Upgrade

$14,200,000

Future WTP Upgrades

$12,000,000 Subtotal

$82,100,000

Engineering

$16,000,000

Contingency (25%)

$24,500,000 Total Capital Cost

$122,600,00

50-Year Raw Water Pumping Cost (Electricity)

$28,300,000

Total Project Cost (for Alternative Comparison)

$150,900,000

Logistics For the purposes of this analysis, logistical considerations include: dam safety, property acquisition, operational flexibility, phasing potential, water supply contamination potential and use of existing assets. Each is discussed in the following paragraphs. Dam Safety The condition of the Ragged Mountain dams has been well documented in this report. It is imperative that RWSA implement a plan to improve, replace or eliminate these structures as

56

soon as possible. If water were to overtop the crest of either dam, causing embankment failure leading to an uncontrolled release of the reservoir pool, losses to life and property are probable. For many years, the normal pool in the upper reservoir has been significantly drawn down to reduce risk. RWSA also operates the lower reservoir at a reduced pool level during hurricane season. While this strategy is prudent for flood control and risk management, it reduces long term water supply and is not desirable in a system that currently has a water supply deficit even if all facilities were fully operational. Dam safety issues must be addressed regardless of which water supply alternative is selected. The ‘existing’ safe yield discussed in this report includes the RMR contribution. If the JRIP Alternative were to be implemented, the RMR would still have to be repaired or replaced in a manner that at least maintains its existing safe yield. Property Acquisition Property acquisition for large municipal projects is time consuming, costly, and challenging. Negotiations with property owners for easements and rights of way can be difficult and often result in project delays. Minimizing the number of parcels impacted greatly enhances the likelihood of successful and timely project implementation. The existing RMR dams and the entire watershed are currently owned by the City of Charlottesville and operated by RWSA. The intake and pump station at SFRR is mostly either City property or RWSA property. Water treatment plant upgrades and pump stations are planned at existing sites. The RMR Alternative therefore could be readily implemented with minimal property acquisition needs. Easements or right of way would be needed only for the approximately 61,000 linear feet of supply pipeline from SFRR. It is estimated that approximately 63 parcels would be crossed. Many of these are large parcels owned by VDOT, the University of Virginia Foundation, or local municipal entities. Of the total pipeline length, approximately 77% is on municipal land and 23% is on private property. Some of the municipal properties may not require easements. If the JRIP Alternative is implemented, property acquisition would be required for the intake, pre-treatment plant, and raw water pump station located adjacent to the James River near Scottsville. Two more pump stations are required to lift the water from the lower elevations near the James River up to Charlottesville. Property for each of these pump stations would also need to be acquired. Easements for the approximately 121,000 linear feet of pipeline would also need to be acquired. It is estimated that approximately 200 parcels would be crossed. In contrast to the RMR alternative, nearly double the length of pipeline requires easement and over 3 times as many property acquisitions are necessary. When the number of municipal parcels required for the RMR Alternative is considered, the JRIP alternative would require nearly 4 times as many private property acquisitions. Operational Flexibility The JRIP Alternative would result in a fragmented RWSA water supply and treatment system serving the Urban Service Area. Once the SHR to RMR pipeline is phased out, the SHR and SFRR reservoirs would supply water to the SFRR WTP. The James River Intake and Pump Station would supply water to the Observatory WTP and RMR. Raw water could not be

57

transferred from one part of the system to the other. Water treatment plant production must be constantly monitored and revised based on observed reservoir levels, river stage, precipitation history, and potential weather events. It is imperative, to fully realize system safe yield, that reservoirs be drawn down proportionally and that storage in SHR and RMR be used last. In the latter stages of the planning horizon, average water demands are projected to be 18.7 MGD. The James River would be used regularly at that time. While it is probable that the James River withdrawal would be limited to the average day deficit of 9.9 MGD, during peak periods of demands (up to 28 MGD) withdrawals could be as much as 15 MGD. Overall hydrogeological conditions would need to be closely monitored and water conservation measures coordinated and implemented at appropriate times to reduce overall system demands to meet permit requirements. In any case, under current operating guidelines, the 9.9 MGD would be constantly withdrawn from the river each and every time the SFRR stops spilling, indicating that a drought could be starting. The RMR Alterative would result in an integrated system with greater operational flexibility. All of the major raw water sources (SFRR, RMR, and SHR) would be linked. Raw water could be supplied from any source to either of the major WTPs. Even though stored water would have to be used in a prescribed order to maximize safe yield, it would not be critical where the water is treated (as it would be with the JRIP Alternative), since the reservoirs are linked. As an example, the Operating Guidelines suggest that the stored water in RMR be reserved until late in a drought to maximize safe yield. Under this condition, the pipeline from SFRR normally used to keep RMR full would then be used in reverse to supply water from RMR to the SFRR WTP. Thus, the WTP capacity at SFRR could continue to be used even when raw water from RMR must be used. Whether raw water is being withdrawn from SFRR directly, indirectly from RMR, or a combination thereof, it could be treated by the WTPs in any proportion. Phasing Potential Phasing is the ability of an alternative to be implemented in logical and cost-effective increments, rather than all at once, in order to improve efficiency, conserve resources, and minimize costs and mitigate the impact on customer rate increases. In general, the RMR Alternative offers greater phasing potential than the JRIP Alternative. In either case, the early phases of the project must accomplish two goals: 1.

Eliminate the dam safety issue at the existing Ragged Mountain dams; and

2.

Provide adequate safe yield at a manageable cost for a reasonable initial period.

If the RMR Alternative is implemented, the first element of the project could be to construct a replacement dam to an initial height that would significantly increase existing yield, but that would be short of the ultimate 45-foot increase. This would accomplish both stated objectives. Construction of the dam's first phase would produce adequate yield to cover an interim period while avoiding the greater capital cost associated with future needs. The dam would be raised to its full height in the future when more users create additional demand and those additional ratepayers can share the cost. While the pipeline from SFRR to RMR and associated pumping would also have to be constructed in one phase, this pipeline project is less than one-half of

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the length of the JRIP Alternative pipeline making it easier to afford. Pretreatment facilities would be similar for either alternative. Furthermore, the water treatment plant improvements that would be needed at the Observatory WTP would be smaller capacity and therefore less expensive with the RMR Expansion Alternative. That is because raw water could easily be transferred from RMR in any proportion to the Observatory WTP or the SFRR WTP, whereas the JRIP Alternative would supply raw water only to Observatory WTP, necessitating greater capacity there. If the JRIP Alternative is implemented, the first elements of the project must include rehabilitation or replacement of the existing Ragged Mountain dams to solve dam safety problems and maintain existing safe yield. The pipeline from the James River to Charlottesville and associated pumping must also be constructed to provide increased water supply. This pipeline is over twice as long as the RMR pipeline and more pump stations are needed since the James River is significantly below the City of Charlottesville in elevation. Essentially, the entire project would have to be constructed at the outset as its full capacity cannot effectively be constructed in increments. In summary, RMR can be divided into two phased capital projects spanning the planning horizon and can be built when needed to match demands over time. The entire JRIP would have to be built to the ultimate 50 year capacity immediately and cannot be built economically in phases to match demands over time. Water Supply Contamination Potential The RMR and JRIP Alternatives are very different in terms of water supply contamination potential. RMR is located in the upper portion of watershed that encompasses less than 2 square miles. The contributing drainage area above the reservoir where Interstate 64 (I-64) crosses is less than 1 square mile. In contrast, the James River at Scottsville has a contributing drainage area of over 4,500 square miles. The potential for contamination, the types of potential pollutants, their possible sources and extents also vary accordingly. This discussion focuses on accidental events. Intentional contamination is unpredictable. The entire RMR watershed is municipally owned with no public roads and is completely undeveloped with the exception of I-64. The largest contamination threat to RMR would be trucks carrying hazardous materials along this interstate highway. Hazardous material could leak from transport vehicles and be carried to the reservoir by surface water runoff. While the chances are very low, the largest threat is a traffic accident involving a truck carrying hazardous liquid in the immediate vicinity of the reservoir. Fortunately, most of the hazardous liquids typically transported by truck would float on water and therefore could be separated and removed with relative ease. Because the threat to RMR is localized and specific, it is possible to construct physical improvements that would isolate and contain hazardous spills and to implement emergency training and action plans. Advance planning for emergency response would include purchasing spill mitigation equipment in advance to shorten reaction time and training emergency personnel to react to likely scenarios and understand how to protect the reservoir 59

water quality. Physical improvements could include Best Management Practice (BMP) stormwater type facilities, containment berms, absorbent booms, and similar holding and filtering facilities. Although the chances of RMR contamination are extremely small, the impact could render the source unusable until the contamination is mitigated. If this event occurred in a drought period, the results could be significant. During the vast majority of time, however, water is plentiful within the South Fork Rivanna watershed and the RMR Alternative is configured so that SFRR water can be transferred to both SFRR WTP and Observatory WTP. This would allow normal water operations to continue until the contaminated reservoir was mitigated. The JRIP Alternative includes a water supply intake on the James River near Scottsville. The potential type and severity of potential contamination at this location is difficult to predict since the upstream drainage area is quite large and includes residential, commercial and industrial development. It also includes hundreds of miles of roads, railroads and other high risk activities that increase the chance of hazardous materials reaching the James River. Because the risk of contamination to the James River is more widespread and varied, physical improvements and emergency planning to mitigate the risk are more problematic. It is important that owners of water intakes along the James River establish communication links and pass information to downstream intake owners to aid reaction time. Although reaction time can be enhanced, the amount of time would be significantly less than the RMR Alternative. Some smaller contamination events may be mitigated by emergency response methods described above. However, it is likely that larger events would require stopping withdrawal until the contaminated plume passes by the intake. Physical improvements to direct floating contaminants away from the intake could be constructed but may not be useful in large scale events. The JRIP Alternative relies on the James River both as a normal and drought water supply. At the end of the planning period, at least 4 MGD normally must be withdrawn from the James River and 9.9 MGD must be withdrawn during a drought. Should the James River become contaminated during a drought, it is likely that withdrawals from the river would have to be curtailed or stopped until the contamination passed. The Observatory WTP would need to be fed by the RMR during a contamination event. Once the supply in RMR was depleted, Observatory WTP would need to shut down until the James River supply was again available. This would be particularly burdensome during drought periods. To summarize, the risk of a significant contamination event causing water supply disruption to the Urban Service Area appears to be lower for the RMR Alternative than the JRIP Alternative. Furthermore, for the RMR Alternative there would be a greater ability to prepare for, react to, and mitigate the effects of any such event. Use of Existing Assets The JRIP Alternative requires construction of a new intake, pump station and pre-treatment facilities near Scottsville and an approximate 25 mile pipeline with booster pump leading to RMR and the Observatory Water Treatment Plant. In contrast, implementation of the RMR expansion alternative would maximize usage of the existing RMR and the associated 60

watershed that was originally acquired by the community in the early 1900’s. It also expands the utility of the SFRR by transferring water during high flows to the RMR, thereby allowing use of this stored water during drought conditions rather than withdrawing water from flowing streams during such events. Further, dam safety issues will require RWSA to expend funds on replacement of repair of the existing dam at RM and the expansion alternative allows maximum return on the investment by producing an increase in safe yield as well. Availability The existing Ragged Mountain Reservoir dam and the entire watershed is already publicly owned, ensuring that this alternative is available. In contrast, there is some uncertainty that the JRIP Alternative may be able to supply the projected 9.9 MGD average to the RWSA, especially during droughts, given the uncertainty of additional withdrawals by other municipalities and the potential for withdrawal limitations at the state level in the future. Regulatory polices may dictate that RWSA be subjected to reduce allocations from the James River as a result of future competing regional agreements pertaining to use of the James River as a water supply. Currently, many communities located upstream and downstream from Scottsville use the James River for drinking water supply. These include Lynchburg, the City of Richmond, and Henrico County making the James River the primary water supply for central Virginia. Cumberland and Henrico County are jointly evaluating a water supply concept that potentially uses the James River above Richmond as a source. Other localities that are looking at the James River for water supply purposes are Fluvanna and Louisa Counties. Over the long term, and particularly as more localities use the James River for water supply, limitations may be imposed on RWSA for withdrawals from the James River during times of drought as a result of a growing number of competing local interests. Another factor that potentially may affect the availability of the JRIP Alternative to RWSA is public opposition. A majority of those participating in the public meetings to date has repeatedly expressed concern over and opposition to the alternative. Some of the concerns expressed by the public include the potential for increased development in southern Albemarle County, water quality, contamination potential, environmental risks, and impacts to historic resources and the ecosystem of the James River (see Public Involvement, below). Public opposition could cause delays in the permit process as well as delays in the acquisition of properties and easements necessary for the intake and pipeline. Similarly the acquisition of County permits maybe problematic. Finally, the availability of the James River as a water supply source is subject to additional analyses of the potential for cumulative impacts with other water supply projects as more localities look to the James River as a source of drinking water. The EPA has stated that a detailed analysis of potential cumulative impacts may be required should the JRIP Alternative be selected by RWSA as the preferred alternative. Completing this analysis and the review process following the analysis would cause further delays in the permit process, and both risk and expense for RWSA.

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Environmental Impacts Wetlands The Ragged Mountain Reservoir expansion alternative would result in impacts to 2.6 acres of wetlands as a result of inundation, the majority of which (1.43 acres) are palustrine forested, 1.08 acres are emergent and 0.07 acres are scrub-shrub wetland habitats. Almost all of these wetlands are found just landward of the existing normal pool elevation of the Upper Reservoir, between an elevation of 641 feet (current normal pool) and 655 feet (the historic normal pool). Thus, the wetlands being impacted would be affected even if the RMR expansion project is not selected as the preferred water supply alternative due to the necessity for dam rehabilitation/replacement for dam safety purposes. No wetlands would be impacted between the historic pool elevations and the proposed pool elevation of 686 feet. The proposed SFRR-to-RM pipeline would temporarily impact 0.03 acres of scrub-shrub wetlands associated with stream crossings. However, this disturbance area would be restored to grade and allowed to re-establish a scrub-shrub community. In comparison, implementation of the James River intake and pipeline alternative would impact 0.18 acres of wetlands as a result of the pipeline construction, as well as 2.6 acres of wetlands as a result of the Ragged Mountain Reservoir dam safety project. The wetlands impacted as a result of the James River pipeline construction are a conversion of forested wetlands to emergent wetland systems at two locations. One is a small forested wetland two miles north of Scottsville, immediately adjacent to Route 20. The 20-foot wide permanent easement needed for the pipeline would result in approximately 0.07 acres of conversion impacts. The other is a forested system between Biscuit Run and the Holiday Inn just east of the I-64/Route 631 interchange. The area of conversion would be approximately 0.11 acres. Streams Comparison of the impacts to streams from water supply projects involves consideration of a wide variety of factors. These include the relative values of the existing stream segments being impacted for habitat, support of wildlife resources and recreation, consideration of potential changes in flow, evaluation of the nature and extent of potential changes to the entire wetted perimeter of each stream segment, and the value of any newly created aquatic habitat.

Value for Habitat, Wildlife and Recreation Stream order was considered as an indicator of a stream’s ability to support aquatic wildlife and habitat. The vast majority (15 of the 21 streams draining into Ragged Mountain Reservoir) are very small, first order channels originating from adjacent hillside seeps. None of the streams are fourth or fifth order streams. Even the few second and third order streams present were small. The average width for these streams is only 6 feet and the average depth is only 6 inches. These narrow, shallow stream channels support predominantly macroinvertebrates; insect orders Ephemeroptera, Plecoptera, and Trichoptera were most abundant. The most commonly found insect was the larval stage of case maker caddisflies (Order Tricoptera). Higher trophic organisms were not observed. Evidence of amphibians was observed in two locations, but was not observed near the existing reservoir interface. More importantly, these small channels are part of a small, closed aquatic ecological system,

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truncated by the existing Ragged Mountain dams almost 100 years ago. The ecological value of this system is very limited, with the primary function of these small channels being the conveyance of runoff from the steep hillsides to the reservoir. The upper portions of these channels will continue to provide these functions after the expanded reservoir is in place. As a result, the Ragged Mountain Reservoir expansion alternative is not expected to substantially impact aquatic wildlife or habitat. On the contrary, the increase in pool elevation would increase the volume and surface area of the lake, providing approximately 135 acres of additional aquatic habitat and edge habitat. In comparison, the JRIP alternative also would impact mostly first order streams. However, this alternative would also impact three-fourth order stream channels as well as the Hardware River, which is classified as a fifth order channel. These higher order streams, not found in the Ragged Mountain Reservoir watershed, support higher and more diverse ecosystems including fin fish, reptiles and amphibians. The James River constitutes the highest order stream that would be affected. Unlike the small, closed ecological system of the Ragged Mountain Reservoir watershed, the James River watershed is a large and complex ecosystem, supporting many species of aquatic organisms within the 25-mile reach of the river that would be affected by the potential withdrawal at Scottsville. The potential for impacts to aquatic wildlife and habitat is therefore greater with the James River intake and pipeline alternative. Stream Flows

Moormans River The Moormans River is a tributary of the South Fork Rivanna River. The Sugar Hollow Reservoir (SHR) is a water supply impoundment located in the headwaters of the Moormans River watershed. Flow in the Moormans River is currently dictated by natural inflow from the watershed, the amount of water that is manually released (by RWSA staff) from SHR through the pipeline to Ragged Mountain Reservoir (RMR) or released directly to the Moormans River, and the amount that spills over the Sugar Hollow Dam. Although there are no regulatory release requirements, RWSA voluntarily releases a minimum of 0.4 MGD as long as the reservoir is at least 80% full. Currently, approximately 3 MGD is regularly transferred to Ragged Mountain Reservoir and/or Observatory WTP via a pipeline. Both the Ragged Mountain Reservoir expansion alternative and the James River intake and pipeline alternative were developed assuming the current voluntary release policy would be maintained. With the RMR alternative, the SHR to RMR pipeline would eventually be phased out and replaced with a pipeline from South Fork Rivanna Reservoir (SFRR) to RMR. With the James River alternative, the SHR to RMR pipeline would be phased out as soon as the James River Pipeline is completed. For both alternatives, following completion of respective pipelines, all water flowing into SHR, would flow into the Moormans River. This would result in additional flows in the Moormans and South Fork Rivanna Rivers. Most of the time, SHR would be full and spilling.

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To look at changes in the Moormans River flows as a result of the Ragged Mountain alternative, average monthly flows are presented for existing and proposed conditions based on computer simulation over the entire period of record, along with pertinent statistics (Table 14). Existing Moormans River flows currently average 5.0 MGD to 32.2 MGD. Proposed flows are projected to increase to 7.8 MGD to 34.5 MGD. On average, flow rates would increase by about 2.5 MGD. During high flow periods, the additional flow is not significant. However, during drier months flows are more significant. In the driest month (July), flow in the Moormans River is statistically projected to increase by 56%. The increased dry-weather flows more closely conform to natural (i.e., pre-impoundment) Moormans River conditions.

Table 14

Existing and Proposed Flows in the Moormans River Immediately Downstream of Sugar Hollow Dam

Month January February March April May June July August September October November December

Average Existing Flow MGD 19.7 23.8 32.2 29.9 16.1 11.4 5.0 11.0 9.1 11.7 12.9 15.5

Average Proposed Flow MGD 22.3 26.2 34.5 32.3 18.5 13.8 7.8 13.5 11.4 14.0 15.6 18.3

Average Flow Increase MGD 2.7 2.5 2.3 2.3 2.4 2.5 2.8 2.6 2.3 2.3 2.7 2.8

Percent Increase % 14% 10% 7% 8% 15% 22% 56% 23% 25% 20% 21% 18%

Mechums River The Mechums River is a tributary of the South Fork Rivanna River. Beaver Creek is a tributary of the Mechums River. There are several impoundments located within this watershed that are not used for water supply in the Urban system. The Mechums River flow would not be affected by either water supply expansion alternative considered in this document once fully implemented. RWSA currently has a permit to withdraw raw water from the Mechums River at the Mechums River Pump Station located along the SHR to RMR pipeline route. This permit allows RWSA to pump water from the Mechums River to the existing RMR. Neither the RMR alternative nor the James River alternative would make use of this facility and no withdrawals are planned for either alternative. This significant change in RWSA approach

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would preserve current flows and result in more water in the Mechums River than otherwise would have been there.

South Fork Rivanna River The South Fork Rivanna River is a tributary of the Rivanna River. South Fork Rivanna Reservoir (SFRR) is a water supply impoundment located about 3 miles upstream from the confluence with the Rivanna River. This reservoir, along with the South Fork Rivanna River watershed, is the main source of supply for the RWSA Urban system. Flow in the South Fork Rivanna River downstream from the SFRR is currently dictated by natural inflow from the watershed, withdrawals from the SHR and Beaver Creek Reservoir, and the amount of water that is withdrawn by RWSA through its intake at the SFRR dam or released directly to the South Fork Rivanna River. Although there are no regulatory release requirements, current RWSA voluntary release policy indicates a minimum of the lesser of 8.0 MGD or natural inflow would be released. From the historical record, SFRR is spilling and providing a downstream flow in excess of 8 MGD over 97% of the time. RWSA also owns and operates a community wastewater system. Most of the potable water used in the Urban system is eventually treated at the Moore’s Creek Wastewater Treatment Plant (WWTP). Thus, water from all raw water sources serving the Urban Service Area is returned to the Rivanna River via Moores Creek at a point approximately 5 miles downstream from the South Fork Rivanna River/Rivanna River confluence. Only the fraction not returned as wastewater by Urban system customers is “lost”. This “lost” water is itself returned to the hydrologic cycle via groundwater recharge from irrigation uses, evaporation, and related natural functions. Between SFRR and Moores Creek, about 8 miles of river length is currently impacted by water withdrawals. Since the SHR and SFRR facilities and watersheds are maximized in either the JRIP or RMR alternatives, the impact on the South Fork Rivanna River is similar. The RMR expansion alternative was developed with the current release policy regarding flow in the South Fork Rivanna River downstream of the SFRR when the reservoir is drawn down and with a restrictive policy for pumpover to RMR when the reservoir is spilling. The operating guidelines used to develop the RMR alternative require roughly one-half of all flows exceeding 8 MGD to also be released rather than used to fill the RMR. In essence, water withdrawn to refill RMR is “skimmed” during high flow periods to avoid impacts to the aquatic ecosystem. This water is pumped to RMR and used later during drought periods. This skimming of high flows from the South Fork Rivanna River is used in place of low flow withdrawals on the James River when impacts to the aquatic ecosystem are expected to be much greater.

James River The RMR expansion alternative would result in no adverse impact to the James River flow regime. In contrast, the primary permanent impact of the JRIP alternative is an almost constant withdrawal of water from the James, during both high flow and drought conditions. Withdrawal rates in 2055 range from a minimum of 4.7 MGD (average daily demand basis) to a maximum of 15 MGD (peak daily demand basis). The reduced flows would affect the

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approximately 25-mile reach of the River between Scottsville and the confluence of the Rivanna and the James Rivers at Columbia. During drought conditions this withdrawal amounts to approximately 4% of flow. Linear Feet of Stream Directly Altered The Ragged Mountain Reservoir expansion alternative would impact approximately 14,500 linear feet of stream channel as a result of inundation. Some of these impacts, approximately 1,000 linear feet, are a result of the necessity for dam rehabilitation/replacement for dam safety purposes, and would occur regardless of which water supply alternative is selected. Of the 21 impacted streams, roughly 1/4 are intermittent (5 total), and 3/4 are perennial (16 total). The pipeline component of this alternative will cross 24 stream channels, resulting in temporary impacts to 1,108 linear feet of construction related disturbance (Figure 15). In all channels the pre-construction conditions would be restored. In comparison, approximately 5,990 linear feet of channel from 38 streams would incur some form of encroachment by the James River intake and pipeline alternative, as well as the 1,000 linear feet of impact that would occur as a result of the dam safety project at Ragged Mountain Reservoir. Of the 38 streams impacted by the pipeline, 30 are perennial and 8 are intermittent. None of these streams would be lost completely; where encroachments occur, the pipe would be installed using cut and backfill techniques, with the exception of the Hardware River and Biscuit Run where underground directional drilling would be used to install the pipeline. An estimated 34 channels with shrub/forested buffers would incur permanent changes to riparian buffers as part of the easement.

D.

Agency Coordination

Coordination with state and federal regulatory agencies has been a keystone of the alternatives development and selection process, with more than six pre-application meetings being held over the planning period, three of which were held since August 2004. On June 22, 2005, RWSA conducted a joint interagency meeting with all concerned state and federal regulatory agencies. The purpose of the meeting was to present the findings of the alternatives analysis, outline RWSA’s assessment of the alternatives and receive agency feedback before selecting a preferred alternative. During the presentation, RWSA concluded that the South Fork Rivanna Reservoir 4-Foot Crest alternative and dredging the South Fork Rivanna Reservoir were not viable options due to environmental impacts and disproportional cost, respectively. This position was supported by the COE, DEQ and VMRC, as well as the advisory agencies. Specifically, with respect to the Four Foot Crest alternative, the agencies stated that this alternative was a “nonstarter”, with the EPA commenting that there was no way to show the alternative as the least environmentally damaging. Similarly, while permitting and advisory agencies did not object to the dredging alternative, as it has minimal environmental impact, they confirmed that they would not require RWSA to pursue dredging as a viable water supply alternative. The COE stated, specifically, that they did not consider it to be a practicable alternative.

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0

60,000 feet

Existing Urban Service Area System Sugar Hollow 18” Raw Water Line Ragged Mountain 18” Raw Water Line Proposed Pipeline

South Fork Rivanna WTP

Water Treatment Plants Pipeline Stream Crossings

Observatory WTP

Figure 15

Ragged Mountain Alternative Pipeline Stream Crossings

Discussion of the James River Intake and Ragged Mountain Expansion alternatives were not as definitive, however, the agencies did provide assessments based on their knowledge at the time as well as guidance on more detailed investigations. An important point of discussion was the fact that, because the Ragged Mountain Reservoir had been in place for almost 100 years, the stream channels that would be impacted by the expansion alternative were already disconnected from the watershed system and therefore had diminished ecological value. DGIF noted that, given the size of the affected channels and the fact that they flow to an existing reservoir, if impacts were to occur, this was the place for them and not in a new, currently undisturbed location. These observations were echoed by FWS and DEQ. With respect to the James River Intake, the primary point of discussion was the potential for cumulative impacts that may result from multiple municipalities withdrawing water from the James. This point was emphasized by EPA, noting that, if RWSA were to pursue the James River Intake as its preferred alternative, a basin-wide Environmental Impact Statement may be required to more fully evaluate long term effects. The COE supported this concern by stating that the cumulative impacts were the primary issue it was concerned with, should the James River Intake become the preferred alternative. In order to better assess impacts, agency representatives requested more detailed investigations of the stream channels that would be affected by the Ragged Mountain Expansion alternative. Further field studies were conducted and an interagency field inspection was held in fall 2005. The results of the additional studies, documented in the Ragged Mountain Stream Assessment (VHB 2005) and agency comments during field review, supported earlier assumptions regarding the status of potentially impacted streams, suggesting that the Ragged Mountain Expansion alternative could be advanced as the least environmentally damaging practicable alternative.

E.

Public Involvement

A common theme throughout the various phases of RWSA’s water supply planning is openness and communication with the interested community. Most recently, a series of nine public meetings were held over a thirteen month period to keep the public informed at each phase of the evaluation process: •

September 21, 2004 – Alternatives Overview

•

November 18, 2004 – SFRR Dredging Alternative Review

•

December 2, 2004 – SFRR Expansion (4-Foot Crest) Alternative Review

•

January 6, 2005 – James River Concept Review

•

January 20, 2005 – Ragged Mountain Expansion Concept Review

•

February 17, 2005 – Concept Comparison

•

March 3, 2005 – Joint Meeting and Work Session

•

April 18, 2005 – Joint Meeting and Work Session

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•

June 22, 2005 Pre-Application Meeting

•

October 27, 2005 – Project Update and New Ragged Mountain Alternative Review

•

April 18, 2006 – Discussion of Preferred Alternative and Mitigation Planning

Each meeting reported the status of the planning studies, and four sessions were dedicated to the four core concepts. On many occasions presentations by the project team were followed by breakout groups where small informal discussions were held and public comments were recorded. Comments were also taken during open-microphone sessions at each of the meetings. The public meetings were all well attended, with average attendance of each meeting ranging between 60 to 90 people. A complete record of these meetings is available through RWSA. The sequence of public meetings revealed broad public interest in the water supply project, with several key points emerging as common community concerns. First, it became clear that SFRR is considered an important recreational amenity and a valued community resource. Vocal support for maintaining the reservoir through whatever means available was noted at both the 4-Foot Crest and Dredging meetings. Through the presentations, the public was advised of the criteria used to determine the “least environmentally damaging practicable alternative,” and that neither of the SFRR concepts met this test. Nevertheless, RWSA acknowledged the significant citizen interest in SFRR and advised that long term management initiatives would be considered outside the water supply planning process. Second, while a few participants at the James River Pipeline hearings voiced support for this concept, a vast majority expressed opposition, citing concerns about water quality, potential adverse affects on the James River ecosystem, and a general sense that this option would be viewed as a virtually unlimited source of water that might foster wide-spread development in more rural areas of the county. In addition, there was widespread preference among interested community citizens for a self-sustaining water supply located within the community, where the quality of the water supply could be under local management and control. Several citizens from the Town of Scottsville were particularly vocal in their opposition to the James River Pipeline alternative, and in order to hear their concerns as well as share information, RWSA conducted a special meeting within that community where the opposition was expressed. The October 27, 2005 meeting provided the public with new information regarding potential routing of the SFRR-to-RMR pipeline and its importance to the RMR expansion alternative. In addition, discussions centered on the relative benefits and detriments of the James River Intake and Pipeline and the RMR Expansion candidate concepts. Community input during small break-out sessions and during the open-microphone forum revealed broad acceptance and support for expanding Ragged Mountain Reservoir as the preferred water supply alternative. Commentary acknowledged that maintaining and expanding an existing element of the existing water supply system at equal cost and with minimal environmental impact, was preferable to constructing a new element of the water supply system, with unclear long term consequences.

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Throughout the process, RWSA maintained a speaker’s bureau to speak to smaller community groups about the water supply process. Ten such programs were presented during 2005.

F.

Preferred Alternative

Through the alternatives evaluation process outlined in the preceding sections of this document, the expansion of the Ragged Mountain Reservoir has emerged as the preferred alternative. Expansion of the existing Ragged Mountain Reservoir achieves the project purpose by providing the required water supply (9.9 MGD) over the fifty year planning period and can be implemented at a cost equal to or less than the next viable option, the James River Intake and Pipeline concept. A comparison between the two options reveals the following benefits of implementing the RM expansion: 1.

Resolves the on-going dam safety issue and maintains RM as an element of the water supply system

2.

Requires minimal additional property acquisition, thereby limiting impacts to citizens

3.

Allows for greater phasing and operational flexibility and efficiency

4.

Maximizes use of existing facilities rather than constructing new distribution and treatment facilities

5.

Remote location leads to lower contamination potential

6.

Relies on local watersheds as source of water and therefore retains management control at the local level

7.

Results in definable, predictable and minimal effects to aquatic habitats that were previously impacted by initial reservoir construction almost 100 years ago

8.

Produces no adverse impacts to cultural resources or threatened and endangered species

9.

Allows for use of stored water during drought conditions, rather than withdrawing from a live stream system

10.

Allows for increased releases from existing reservoirs to stream systems within the community

11.

Provides an expanded recreational amenity for the Charlottesville community

12.

Is supported by the community

13.

Is the least environmentally damaging practicable alternative.

Based on the foregoing, expansion of the Ragged Mountain Reservoir as a long term water supply project was approved by the City of Charlottesville, Albemarle County, the Albemarle County Service Authority and the RWSA Board at public meetings held throughout the months of May and June, 2006. Accordingly, a joint permit application describing the

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proposed project has been prepared for review and approval by local state and federal regulatory agencies as the first step toward project implementation.

Section VII – Mitigation A.

Avoidance and Minimization Measures

Avoidance The search for an additional source of water to meet long-term water demand in the Urban service area began as far back as the early 1970’s. Two studies completed for RWSA in the 1970’s (Malcolm Pirnie, 1972 and Camp Dresser McKee, 1977) developed and evaluated a number of primarily structural alternatives including various new impoundments, a new river intake, and expansion of the South Fork Rivanna Reservoir. Based on the factors that were considered at the time, construction of a new impoundment on Buck Mountain Creek was determined to be the best option for a new water supply. And, based on this conclusion, RWSA initiated the process of acquiring property on Buck Mountain in anticipation of building a new reservoir in this location. Subsequent studies in the 1980’s focused in greater detail on design aspects associated with the proposed Buck Mountain Reservoir, looking at various dam locations and dam heights. RWSA proceeded with the planning and design of Buck Mountain Reservoir through the mid 1990’s and by that time had acquired all of the land necessary to build the proposed reservoir. In 1996, RWSA retained Vanasse Hangen Brustlin, Inc. (VHB) and O’Brien and Gere, Inc. (OBG) to prepare and submit the necessary permit application for Buck Mountain Reservoir. As part of that effort, a wide range of potentially feasible alternatives were developed, including alternatives that avoided impacts to Buck Mountain Creek and tributaries totaling more than 60,000 linear feet of stream channels including habitat for the James Spinymussel. In order to take a comprehensive look at avoidance measures, the alternatives analysis process that began in the 1970’s was re-opened. In 2000, a new alternatives analysis report was issued (VHB, 2000) that evaluated over 30 concepts. These alternatives included both structural and non-structural options including water conservation, regional cooperation, growth management and demand management, dredging of existing reservoirs, crest controls on South Fork Rivanna Reservoir, re-use, various reservoirs, and surface water withdrawals. The alternatives analysis and screening process continued in the early 2000’s, with Gannett Fleming, Inc. (GF) and VHB building upon the earlier studies, the results of which have been summarized earlier in this report. In short, the 33 concepts identified in 2000 were subject to a detailed screening process that included an analysis of environmental impacts. The most recent Water Supply Alternatives Supplemental Evaluation (Gannett Fleming, 2004) narrowed the alternatives down to four concepts: dredging the SFRR, 4-foot crest gates on the SFRR, the James River intake and pipeline, and the RMR expansion. All other options and combinations of options were eliminated for a variety of reasons including environmental impacts. Since less environmentally damaging and practicable alternatives were identified, all new reservoir options (including Buck Mountain Creek Reservoir) were not considered the preferred alternative. 70

Based on the information contained in this report, the preferred alternative is considered to be the least environmentally damaging, practicable alternative and avoids impacts to the aquatic ecosystem.

Minimization To minimize impacts to the environment, the Ragged Mountain Reservoir expansion alternative has been sized to just meet the 2055 water deficit, and no larger. At the dam height proposed for this alternative, the safe yield of the expanded reservoir would be 9.9 MGD. Furthermore, by solving both dam safety concerns and water supply augmentation with one project, impacts to aquatic ecosystems that might result from two separate projects are minimized and avoided. With respect to the SFRR-to-RM pipeline, the proposed alignment was established along high ground, away from primary wetland systems, limiting impacts to 24 perpendicular crossings of narrow stream channels. Impacts to these channels are temporary and limited to the construction phase of the project.

Mitigation Implementation of the Ragged Mountain Expansion project will produce unavoidable impacts to approximately 2.6 acres of wetland habitat including 1.43 acres of palustrine forested, 0.07 acres of scrub shrub and 1.08 acres of emergent communities. Similarly, a 45’ increase in the dam will inundate approximately 14,500 linear feet of narrow, shallow headwater stream channels. RWSA has initiated an expansive planning process to identify an acceptable compensatory mitigation strategy. Through letters, public meetings and community bulletin boards, RWSA has solicited candidate wetland and stream mitigation sites from the public, state and federal regulatory agencies and special interest groups. This effort has produced a large pool of potential candidate sites that included urban stream channel improvements, dam removal, sensitive restoration of floodplain areas and preservation and enhancement of riparian corridors. Of particular interest is watershed-scale preservation and enhancement within RWSA’s Buck Mountain Creek property. Consisting of more than 1,800 acres with 60,000 linear feet of tributary stream channels, this concept is considered to have the important benefit of enhancing, protecting and preserving known habitat for the James spinymussel, a federally listed endangered species. RWSA is currently evaluating these and other potential mitigation alternatives and is committed to developing a comprehensive mitigation plan that will adequately offset the relatively small remaining unavoidable project impacts to streams and wetlands. A final plan will be developed and submitted in support of the Ragged Mountain Expansion joint permit application for state and federal agency approval.

Section VIII – Conclusion The Rivanna Water and Sewer Authority, on behalf of Albemarle County, Albemarle County Service Authority, and the City of Charlottesville, has conducted an extensive planning process to ensure that the community’s water supply needs can be met over a fifty year period. After consideration of more than thirty-three potential alternatives and rigorous

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analysis of four primary concepts, expansion of the Ragged Mountain Reservoir has been identified as the least environmentally damaging practicable alternative for meeting the community’s long-term water demands. Through the foregoing analysis, the project has been determined to have minimal and acceptable environmental impacts that can be mitigated through stream and wetland restoration or enhancement and preservation efforts implemented throughout local watersheds. Accordingly, the RWSA respectfully requests issuance of the required federal and state permits for the Ragged Mountain Expansion Project so that design and implementation efforts can commence, bringing additional water supply on-line and solving dam safety issues in a timely fashion.

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Bibliography Camp, Dresser & McKee. July 1977. Report on Alternative Water Supply Sources. Gannett Fleming, Inc. July 2004. Water Supply Alternatives Supplemental Evaluation. . September 2004. Evaluation of Fluctuations in Beaver Creek Reservoir Pool Level. Technical Memorandum. . October 2004. A Survey for Freshwater Mussel Fauna Within Tributaries of the Ragged Mountain Reservoir. . December 2004. Concept Development – Dredging the South Fork Rivanna Reservoir (SFRR). Technical Memorandum. . January 2005. Concept Development – South Fork Rivanna Reservoir Expansion Technical Memorandum. January 2005. . February 2005. Concept Development – James River Withdrawal. Technical Memorandum. . February 2005. Concept Development – Ragged Mountain Reservoir Expansion Technical Memorandum. Gray & Pape, Inc. May 2005. Draft Report – Phase Ia Reconnaissance Cultural Resources Survey of the James River Intake and the Ragged Mountain Alternatives for the Rivanna Water Authority. . February 2005. Draft Report - Archaeological Investigations at the Charlottesville Reservoir at Ragged Mountain on Behalf of the Rivanna Water Authority, Albemarle County, Virginia Malcolm Pirnie, Inc. April 1972. Feasibility Report on Regional Water Supply and Wastewater Disposal. Strahler, A. N. 1952. Dynamic basis of geomorphology. Geological Society of America Bulletin, 63, 923-938.

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