RAIN WATER HARVESTING(RWH)

WHAT IS RAIN WATER HARVESTING :

Rain Water Harvesting is the accumulating and storing of precipitation. It is used

to provide water for consumptive and non- consumptive use.

WHY IS RAIN WATER HARVESTING NECESSARY :

There are two main reasons :a) Surface water is inadequate to meet our

demand and we have to depend on ground water.

b) Due to rapid urbanization, infiltration of rain water into the subsoil has decreased drastically and recharging of ground water is diminished.

AVAILABLE CATCHMENTS FOR RAIN WATER COLLECTION :

Rain should be collected from roof top, road top and some specially prepared areas of ground.

Water collection from Roof Top

RAIN WATER HARVESTING TECHNIQUES :

There are two main techniques for RWH:a) Storage of rain water on surface for future use.b) Recharge to ground.

STORAGE OF RAIN WATER : It is a traditional technique. Underground tanks, Ponds, Check dams, Weirs are the

structures used for rain water storage. It is used in rural areas where space is

available for the construction of structure for water storage and where the annual variation in rainfall is less.

RECHARGE TO GROUND :

Recharge to ground water is a new concept of RWH. This technique is frequently adopted in urban areas where space is not available for the construction of structure for rain water storage.Pits, trenches, wells, shaft etc are constructedfor ground water recharge.

FERRO CEMENT TANK

It is used as a rain water storage structure.It is made from wire reinforced mixture of sand, cement and water.Some of its salient features are :a) It is strong, versatile,

long lasting, low cost.b) It is light in weight,

highly tensile and flexible than ordinary concrete structure.

c) Low maintenance cost.

TRENCHES AND BOREWELL FOR GROUND WATER RECHARGE

Bore well

Trench

QUALITY OF RAIN WATER :The physical as well as chemical quality of water Is important to decide its suitability for drinking purpose, cooking purpose etc.

Various standards are formulated by many National and International agencies and all the standards are recommendatory. Rain water must be collected from projected site(s). The parameters analyzed include ph, conductivity, total dissolved solids, hardness, Ca, Na, Mg etc.

BENEFITS OF RAIN WATER HARVESTING :

• Improvement in infiltration and reduction in run-off.

• Improvement in groundwater levels and yields.• Reduces strain on Special Village Panchayats/

Municipal / Municipal Corporation water supply.• Improvement in groundwater quality.• Estimated quantity of additional recharge from

100 sq. m. roof top area is 55.000 litres.

THANK YOU