WATER-A MATRIX

Water is an important natural resource and is the very basis of our life. We use water for drinking, irrigation, industry, transport and for the production of hydro-electricity. Water is a cyclic resource which can be used again and again after cleaning. The best way to conserve water is its judicious use.

 

Rain Water Harvesting:

Rain water harvesting is one of the most effective methods of water management and water conservation. It is the term used to indicate the collection and storage of rain water used for human, animals and plant needs. It involves collection and storage of rain water at surface or in sub-surface aquifer, before it is lost as surface run off. The augmented resource can be harvested in the time of need.

Artificial recharge to ground water is a process by which the ground water reservoir is augmented at a rate exceeding that under natural conditions of replenishment. The collected water is stored and pumped in a separate pipe distribution. This is a very useful method for a developing country like India in reducing the cost and the demand of treated water and also economising the treatment plants operation, maintenance and distribution costs.

WHY DO WE NEED RAIN WATER HARVESTING ?

i. To overcome the inadequacy of surface water to meet our demands.

ii. To arrest decline in ground water levels.

iii. To enhance availability of ground water at specific place and time and utilize rain water for sustainable development.

iv. To increase infiltration of rain water in the subsoil this has decreased drastically in urban areas due to paving of open area.

v. To improve ground water quality by dilution.

vi. To increase agriculture production.

vii. To improve ecology of the area by increase in vegetation cover etc.

Advantages:

i. The cost of recharge to sub-surface reservoir is lower than surface reservoirs.

ii. The aquifer serves as a distribution system also.

iii. No land is wasted for storage purpose and no population displacement is involved.

iv. Ground water is not directly exposed to evaporation and pollution.

v. Storing water under ground is environment friendly.

vi. It increases the productivity of aquifer.

vii. It reduces flood hazards.

viii. Effects rise in ground water levels.

ix. Mitigates effects of drought.

x. Reduces soil erosion.

Methods and Techniques:

The methods of ground water recharge mainly are:

Urban Areas:

Roof top rain water/storm runoff harvesting through

(i) Recharge Pit

(ii) Recharge Trench

(iii) Tubewell

(iv) Recharge Well

Rural Areas:

Rain water harvesting through

(i) Gully Plug

(ii) Contour Bund

(iii) Gabion Structure

(iv) Percolation Tank

(v) Check Dam/Cement Plug/Nala Bund

(vi) Recharge Shaft

(vii) Dugwell Recharge

(viii) Ground Water Dams/Subsurface Dyke

METHOD

Methods of Roof Top Rainwater Harvesting

Storage of Direct use

In this method rain water collected from the roof of the building is diverted to a storage tank. The storage tank has to be designed according to the water requirements, rainfall and catchment availability. Each drainpipe should have mesh filter at mouth and first flush device followed by filtration system before connecting to the storage tank. It is advisable that each tank should have excess water over flow system.

Excess water could be diverted to recharge system. Water from storage tank can be used for secondary purposes such as washing and gardening etc. This is the most cost effective way of rainwater harvesting. The main advantage of collecting and using the rainwater during rainy season is not only to save water from conventional sources, but also to save energy incurred on transportation and distribution of water at the doorstep. This also conserve groundwater, if it is being extracted to meet the demand when rains are on.

Recharging ground water aquifers

Ground water aquifers can be recharged by various kinds of structures to ensure percolation of rainwater in the ground instead of draining away from the surface. 

WATER IS WEALTH - IT IS THE TIME TO SAVE