Pump Flow Testing

Pump Flow Testing

After drilling your borehole it is very important to carry out a test pump to monitor and record the flow of water from the borehole. This also determines the pumping requirements and quality of the water available.

Test pumping of the borehole is carried out to gather the following information:

  1. Flow rate
  2. Recovery rate
  3. Water quality

This enables us to select the correct size pump to maximise the efficiency of the borehole and to gather water samples to check the quality of the water produced. The water samples are tested by a UKAS accredited lab to establish the purity of the water. From the results we can specify a water treatment system to comply with UK regulations and provide you with a safe and pure water supply.

Using a submersible pump the test is normally carried out for a total of eight hours for boreholes abstracting up to 20m cubed. However depending upon the performance this may need to be increased to a longer period. For boreholes exceeding 20m cubed the test is determined and carried out in accordance with Environment Agency guidelines.

There are three main types of borehole yield tests we commonly use:

  1. Step Test – During this test, the pump flow rate is increased in steps at regular intervals. This type is particularly useful for us to determine the effectiveness of the borehole.
  2. Constant Rate Test – The borehole is pumped at a constant rate over a period ranging from 8 to 48 hours. The discharge is kept constant for the duration of the test, and water levels are recorded in the borehole. This test provides useful information to assess the sustainable yield of the borehole and its performance and potential.
  3. Recovery Test – The recovery of the water level is measured whilst the borehole is pumping immediately after the Constant Rate Test and when the pump has been switched off. This recovery test is very useful in assessing the effects of pumping and the possibility of dewatering of aquifers that may result due to the limited extent of an aquifer. The recovery test will also tell us at level the aquifer is dewatered by measuring the residual drawdown after the borehole was allowed to recover. It gives an indication of the longevity of borehole supply.

Please contact us for further information and advice.