Water Resources

WATER RESOURCES

WATER CLASSIFICATION and BEST BENEFICIAL USE (DAO 34 Series of 1990)

Water Classification Fresh Surface Waters - rivers - lakes - reservoirs Coastal and Marine Waters

Fresh Surface Waters Class AA – Public Water Supply Class I - Intended primarily for waters having watersheds which are uninhabited and otherwise protected and which require only approved disinfection in order to meet the NSDW of the Philippines

Fresh Surface Waters Class A – Public Water Supply Class II - For sources of water supply that will require complete treatment (coagulation, sedimentation, filtration, and disinfection).

Fresh Surface Waters Class B – Recreational Water Class I - For primary contact recreation such as bathing, swimming, diving, etc. (particularly those designated for tourism purposes.

Fresh Surface Waters Class C Fishery Water - the propagation and growth of fish and other aquatic resources Recreational Water Class II (Boating, etc.) Industrial Water Supply Class I – for manufacturing processes after treatment

Fresh Surface Waters Class D For agriculture, irrigation, livestock watering, etc. Industrial Water Supply Class II (e.g. cooling, etc.) Other inland waters, by their quality, belong to this classification

Coastal and Marine Waters Class SA • Water suitable for propagation, survival and harvesting of shellfish for commercial purposes. • Tourist zones and national marine parks and reserves established under existing laws and/or declared as such by appropriate government agency • Coral reef parks and reserves designated by law and concerned authorities.

Coastal and Marine Waters Class SB • Recreational Water Class I – areas regularly used by the public for bathing, swimming, diving, etc. • Fishery Water Class I – spawning areas for Chanos-chanos of ‘Bangus’ and similar species

Coastal and Marine Waters Class SC • Recreational Water Class II –for boating • Fishery Water Class II – for commercial and sustenance fishing • Marshy and/or mangrove areas declared as fish and wildlife sanctuaries

Coastal and Marine Waters Class SD • Industrial Water Supply Class II (e.g. cooling) • Other coastal and marine waters by their quality belong to this classification

Surface Water • Surface water is water on the ground or in a stream, river, lake, sea or ocean; as opposed to groundwater • Important sources of public water supplies because of the high withdrawal rates they can normally sustain

Seawater • Sea water is water from sea or ocean • On average, sea water in the world's oceans has a salinity of ~3.5% • Seawater can be turned into drinkable (potable) water by one of a number of desalination processes.

Groundwater Water that has percolated downward from the ground surface through the soil pores. • Not as susceptible pollution as surface water but once polluted, restoration is difficult and long term.

Reclaimed Wastewater Water that has been treated sufficiently for direct reuse in industry and agriculture and for limited municipal reclamation.

Water Use Consumptive – renders water unavailable for future use; either because of evaporation, extreme pollution, or seepage underground; until the hydrologic cycle returns as rain. Non-consumptive – leaves the water available (after treatment if necessary) for reuse without going through the hydrologic cycle.

Water Quality Criteria Minimum criteria for surface waters 1. All surface waters shall be free from domestic, industrial, agricultural, or other man-induced nonthermal components of discharges That settle to form putrescent deposit or create nuisance That float as debris That produce color, odor, taste, turbidity That are acutely toxic That are present in concentrations which are carcinogenic, mutagenic, or teratogenic That pose serious danger to public health

Water Quality Criteria Minimum criteria for surface waters 2. Thermal component of discharges which alone, or in combination with other discharges or components of discharges • That produce conditions so as to create nuisance • That increase the temperature of the receiving body of water (RBW) so as to cause substantial damage or harm to the aquatic life or vegetation therein or interfere with the beneficial uses assigned to the RBW.

Water Quality Criteria Minimum criteria for Fresh Waters Conventional and other pollutants affecting aesthetics and oxygen demand Color Temperature pH Dissolved oxygen 5-day BOD Total suspended solids Total dissolved solids Surfactants

Oil and grease Nitrate as nitrogen Phosphate as phosphorous Phenolic substances Total coliforms Fecal colifirms Chloride Copper

Factors Affecting Availability and Quality of Water Erosion Flooding

Drought

Water Supply Problems Unequal distribution of accessible water Rapidly rising demand Pollution of water supplies

Traditional Approaches to Water Shortages • Groundwater withdrawals • Dams and reservoirs

Impacts of Excessive Groundwater Withdrawals Groundwater overdraft leads to saltwater intrusion

Saltwater Intrusion

Impacts of Excessive Groundwater Withdrawals Groundwater overdraft drains swamps and ponds at times drying them up completely.

Impacts of Excessive Groundwater Withdrawals • When water is withdrawn, the soil compacts and sinks, a process called subsidence. • Excessive withdrawal of water threatens the long-term prospects for irrigated agriculture

Impacts of Dams and Reservoirs Positive Effects: • Help prevent recurrent catastrophic floods • Generate electricity • Provide needed water for farms and cities during drought periods • Increase certain forms of recreation

Impacts of Dams and Reservoirs Negative Effects Inundate wildlife habitat, farmland, and towns Reduce stream flow into the ocean resulting in changes in salt concentration of receiving waters Reduction in the flow of nutrient-rich sediment to coastal waters

Meeting Present and Future Demands • Water conservation • Water recycling • Restoration • Education: Learning to use water wisely

How Water is Used in a Typical Household

FLOODING Problems and Solutions

Causes of Flooding • Heavy rainfall • Precipitation that do not evaporate either runoff or percolate into the soil Forest and grasses retard water flow and promote percolation Heavily vegetated watershed s act as sponges. Light vegetation increases surface runoff and, hence flooding.

Causes of Flooding • Stripping of vegetation by farmers, urban planners, and developers • Increasing number of highways, shopping centers, office buildings, and homes, which greatly increase the amount of impermeable surface

Controlling Flooding • Dams • Watershed management • Zoning

EL NIŇO SOUTHERN OSCILLATION (ENSO)

El Niňo • El Niño is an unusual warming of the tropical Pacific Ocean that occurs irregularly at about 3-6 year intervals in response to large scale weakening of the trade winds that normally blow westward from South America toward Asia.

El Niňo • Eastern South Pacific is dominated by an eastern center of high pressure • Lower pressure prevails to the west • Pressure difference causes the trade winds to blow east to west • Southern Oscillation Index (SOI) – pressure difference • Negative SOI - the trade winds may relax or sometimes even reverse

• Relaxation of the trade winds may allow warm water to appear at the surface of South America • This warm water not only kills off marine life, but also affects the atmosphere directly above it causing convection, which can cause intense rainfall in a region that is normally dry.

Teleconnections • Droughts in Central America, Philippines, Southern India, Indonesia, Africa, and Australia. • Large scale bush fires and forest in Australia and Kalimantan (Borneo). • Flooding is more prevalent in the United States, Cuba, Northern Peru, Southern Brazil, Northern Argentina, Eastern Paraguay, Bolivia, and Western Europe.

Impacts of ENSO •

Australia-Drought and devastating brush fires

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Indonesia, Philippines-Crops fail, starvation follows

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India, Sri Lanka-Drought, fresh water shortages

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Tahiti-6 tropical cyclones

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South America – Fish industry devastated

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Decrease in nutrients off Peru- fewer fish

Impacts of ENSO •

Across the Pacific - Coral reefs die

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Colorado River basin-Flooding, mud slides

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Gulf states-Downpours cause death, property damage

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Peru, Ecuador – Floods, landslides

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Southern Africa-Drought, disease, malnutrition