Posted by: Aditi Monday, November 24, 2014
Pump test: Trinity woods and acres

For the past couple of months, our blog has been posting about several activities being conducted as a part of Participative Aquifer Mapping Project. This post goes out as an addition.


In urban areas, to understand the nature of groundwater borewell serve as an important means. Static water level in a borewell acts as a useful proxy. To understand the fluctuations in the static water level few pumping tests were conducted across the sarjapur- bellandur watershed. One such was conducted at Trinity woods and acres near bellandur gate on 7th of November. The activities under pumping test involve measuring SWL before the pumping test starts, taking readings after every 1 min, 5 min and 10 min for total 3 hours or till a steady state is achieved and lastly taking readings after the pumping has stopped for 3 hours to understand the recovery period of SWL.


Trinity woods and acres has one borewell located near the entrance. The capacity of motor is 1.5 hp. An essential condition is that the borewell should not be in use for at least 24 hours before the pumping test. This was followed at trinity. The initial SWL, before pumping was observed to be at 2.9m. The pumping was started and drawdown was observed till 110 min. At this time, a water level had gone down till 19.3 m and stabilized. During pumping, discharge was measured at the start and mid. The discharge was measured by collecting water in a 15 litre bucket and recording the time taken to fill it. The initial discharge was found to be 1036 litres per hour whereas mid discharge was observed to be 374 litres per hour. After 110th min, the pumping was stopped and recovery was started and continued for 180 min/3 hours. The water level had risen up to 3.44 m and stabilized within this time.  


Based on the above readings analysis would be made to understand the rate of discharge, storativity and transmittivity of the underlying aquifer. This would help in understanding our aquifer in a better way.


We would like to thank the manager, the plumbing staff and residents for their co-operation.