Artificial recharge and Rain water harvesting –Case studies in Kerala

A.Subburaj,Scientist-D

Central Ground Water Board

Kerala Region,Trivandrum

Major causes for scarcity

• Rainfall pattern• Geomorphological set up• Drainage• Sand mining• Hydro geological factors• Over exploitation• Reclamation of land for settlement

Definition• Augmentation of ground water reservoir by man

made structures by using rain water.

• Rain Water Harvesting is deliberate collection and storage of rain water

Methods of Artificial Rechargea.Direct surface techniques

. Flooding

. Basins or percolation tanks

. Stream augmentation

. Ditch and furrow system

. Over irrigation

b.Direct subsurface techniques . Injection wells or Recharge wells

. Recharge pits and shafts

. Dug well recharge

. Bore hole flooding

. Natural openings,cavity filling

c.Combination of Surface-Subsurface techniques . Basin or percolation tanks with pit shaft or wells

d. Indirect Techniques . Induced recharge from surface water source

.Aquifer modification

Rain water Harvestinga.Storage of rain water on surface for future useb.Recharge to ground water- Pits- Trenches- Dug wells- Hand pumps- Recharge wells- Recharge shafts- Lateral shafts with bore wells- Spreading techniques

Benifits• An ideal solution to water problems in areas having

inadequate water resources• The ground water level will rise• Mitigates the effects of drought & achieves drought

proofings• Reduces the runoff which chokes the storm water drains• Flooding of roads and low land areas are reduces• Quality of water improves• Soil erosion will be reduced• Saving of energy per well for lifting of ground water-a one

meter rise in water level saves about 0.40 KWH of electricity.

CostS.No Recharge structure Approximate cost

(in Rs)

1 Recharge pit 2500-5000

2 Recharge trench 5000-10000

3 Recharge through hand pump

1500-2500

4 Recharge through dug well 5000-8000

5 Recharge well 50000-80000

Case studies