Borehole pumps require a constant flow of water in order to keep the motor cool and if the pumps are allowed to 'run dry' the motor can overheat very quickly and burn out. This is costly both in terms of replacing the motor as well as down time for the pumping system.
We have developed the use of pressure sensors to accurately monitor the water levels within multiple wells. This means that we can shut off the pump before the well runs dry and therefore prevent the pump from overheating. The system can be programmed to stop and re-start the pumps at any level within the well and therefore not only is it a good method of preventing over-heating, but can also be used in low permeability soils as an effective alternative to an ejector system. Unlike an ejector system the pumps will only run (and hence consume power) when there is water to be pumped.
We successfully used a system of pressure sensors to limit the drawdown on a site in the centre of Bath where strict planning conditions dictated the maximum drawdown allowed in order to protect the nearby thermal springs. The programmable system allowed high and low water levels to be set for each pumping well and to be adjusted as the site water level was lowered. With sensors in each pumping well and in the monitoring wells we were able to accurately maintain the ground water at the specified level across the site for the 15 months duration of the work.
Borehole Pums in Use At Bath
