Urban Water Mangament

Urban Water Management Chicu Lokgariwar Gomukh Environmental Trust 92/2 Gangote Path Erandwane, Pune 411 004 Telefax: 020-2567 3324 2565 1434 Email: [email protected] [email protected] Gomukh Environmental Trust

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Debunking Water Conservation „

Too expensive „

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Stored water unfit for use: „

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What about ground water? No intrinsic changes in water over time.

Damages foundations „

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Cost effective, innovative methods available.

Recharge not recommended if ground water levels above level of foundation

What's the need? „

Read the newspapers.

Gomukh Environmental Trust

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Comprehensive Water Management „ „

Rational Water Use Harvesting Water

RECYCLED GREY WATER

RECHARGE TRENCH RECHARGE OF BORE / OPEN WELL

Gomukh Environmental Trust

STORAGE TANK

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Harvesting Surface Runoff „

Passive harvesting „

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Maintaining unpaved areas Installing permeable paved areas (blocks/ bricks without concrete bedding) Not connecting rainwater pipes directly to conduits

Gomukh Environmental Trust

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Active harvesting „

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Rainwater collection and storage Recharge Trenches / pits Use of open/ dug wells. Area treatments to reduce runoff velocity Percolation ponds

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Rooftop Rainwater Harvesting „

Quantities: „ „ „ „

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For a rooftop of 200sqm, in Pune,@ 600mm/year Total quantity = 120 cum or 1,20,000 litres With 70% collection, 84 cum (7m x 6m x 2m ) Will suffice a family of four for 5 months. (@135 lpcd)

Use: Storage (short period between spells) „ Recharge (seasonal rains) „

Gomukh Environmental Trust

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Elements „

Downtakes • Pipes, gutters, spouts,

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Screens / first-flush Collection Storage tank „

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RCC ,Ferrocrete, stone masonry

Recharge pits

Gomukh Environmental Trust

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Recharge „

Pits/ Trenches/Wells „ Existing well may be used „ Settlement tank • Should retain runoff from at least 15 minutes rainfall at peak intensity „

Filtration pit • Graded sand, gravel as filter media

Gomukh Environmental Trust

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Section of a Recharge Pit

Gomukh Environmental Trust

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Capacity of a recharge pit „ „ „ „ „

Take total roof area Multiply by expected rainfall for 15 minutes Assume 80% collection (Multiply by 0.8) Assume 40% voids in the pit (divide by 0.4) Arrived quantity is the volume of the recharge pit

Gomukh Environmental Trust

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Precautions „

Catchment: „ „

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Conduits „

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Keep the catchment clean Use gratings to trap any debris before it enters the conduits Provide first-flush device

Before recharging „ „

Provide Settlement Tank Filter the water

Gomukh Environmental Trust

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Quality Control Line, level, slope „ Sand bed and trenches for underground pipes recommended „ Waterproofing for storage tanks „ Provision of first flush device „ Screen/ mesh at inlet of rainwater downtakes „ Plug bends „

Gomukh Environmental Trust

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Grey Water Recycling „ „ „ „

Grey water – waste water from sinks, bathrooms, etc. ( without fecal matter) Sedimentation and filtration sufficient for non-potable uses. Economical if treated water is used at ground level. Installation of a separate treated water system for domestic use economical for large commercial establishments.

Gomukh Environmental Trust

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References: „

www.rainwaterharvesting.org

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Rainwater Harvesting and Conservation Manual „

Govt of India, Consultancy Services Organisation

Gomukh Environmental Trust

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