Water harvesting structures (small, medium and large size) for laterite soils
The west coast region of India receives abundant rainfall, but the utility of the rain water is limited. The methodology for establishing water harvesting ponds in laterite soils has been standardized with low cost interventions to increase the durability and reduce the cost. After excavation of the pond, high concentration herbicide is sprayed to kill the weeds and unwanted plants. Smoothening of side slopes and bottom are done by using plaster prepared from fine garden soil and about 10-15 cm thick layer of paddy straw is layed along the sides and bottom of pond to provide smooth surface. Both the materials are locally available and, thus reducing the cost, and also to protect the lining material from damage caused by sharp stones. A 300 GSM thickness silpaulin polyfilm is used as a lining material. After laying the polyfilm, it is properly set and fixed in the trench dugout around the pond and covered with soil. The total cost involved in establishing large size (3500 m3 with 3 m depth), medium size (1400 m3 with 2.5 m depth) and small size pond (300 m3 with 1.5 m depth) in laterite soils is about Rs. 6.6 lakhs, 4.7 lakhs and 2.5 lakhs respectively
