Percolation testDecember 18, 2006
To know how quick water is able to enter into the ground layers of your site there are not thousand and six ways ! But a very efficient one is called Carefull Observation. First while digging a recharge well you can look at the nature of the earth you crop out. Depending on its compactness, its proportions of clay and sand, of stones, you will be able to get an idea of the facility of the water to percolate. You will also be able to determinate the right depth to reach (wich is situated in the weathered zone(see graph above). For a more accurate knowledge of the percolation rate, you will have to
observe the water flowing into the well once it done. Waiting for an heavy rain or filling the well artificially
(as on the pictures) note at regular intervals the level of water in the well. It can take few hours as several
days to empty. According to the results you will know if it is necessary to dig more wells on your site (so
that more water can percolate during heavy rains) and until wich depth croping.
Observation is the key tool in rainwater management. In desert of Rajasthan, when a community decided to build a pond, they started with a small bund and observed during two monsoon how this minor change affected the rain. Only after two years, they felt ready to decide if the site was a good one or not for the pond (below, a pond in desert of Rajasthan).