CarmenOlive
Number of posts : 1 Registration date : 2011-09-20
| Subject: Recharge Troughs, Trenches and Pits Wed 28 Sep 2011, 12:59 pm | |
| Recharging bore wells and pits is one of the uses of rain water harvesting. Government is increasingly stressing on the installation of the rain water harvesting system in every Kerala apartment. The rainwater can be used to recharge pits, trenches, troughs etc. A recharge pit is generally 2m to 3m deep and 1.5m to 3m wide. A lining of brick/stone wall with openings called weep-homes are provided at regular intervals of the excavated pit. A perforated cover is used to cover the top area of the pit. One of the easiest and the most effective ways of harvesting rain water is percolation pits. They are generally of the size 60cm*60cm*60cm pits, designed on the basis of expected runoff as described for settlement tanks. The pit is filled with pebbles or brick jelly and river sand. It is then covered with perforated concrete slabs wherever necessary.A continuous trench excavated in the ground and refilled with porous materials like pebbles, boulders and broken bricks is called a recharge trench. It is generally 0.5m to 1m wide and 1m to 1.5m deep. The amount of runoff expected decides the length of the recharge trench. To maintain the intake capacity, the recharge trench should be periodically cleaned of accumulated debris. Recharge trenches are less effective in terms of recharge rates, as the soil strata at the depth of 1.5m is less permeable. Also lesser precautions need to be taken to maintain the quality of the rainfall runoff. Recharge troughs are generally placed at the entrance of a residential complex to collect the runoff from paved and unpaved areas. | |
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