It is VERY IMPORTANT that the pumping rate is CONSTANT during the individual steps and the constant discharge test.Pump must have suitable power drive and have the correct pumping capacity.Attached spreadsheets show measurement intervals and required info.Rate of discharge (for Steps and constant Tests).Water strike depths (if known from drilling/landowner).The distance from the borehole to observation boreholes (if applicable).The Static Water level at the start of the test.The data that needs to be collected includes: A time equal to the total time taken for the Constant Discharge Test has elapsed.At least three readings taken in succession are identical.Water levels recover to less than 5 % of the total drawdown during the constant discharge test.Immediately after the pump is turned off after the pumping test, start measuring water levels. The water level measurements should be taken and recorded according to the attached spreadsheet.Send Step Test drawdown and yield information to GEOSS for assessment, and we will provide the recommended yield of the Constant Discharge Test.The constancy of the yield is very important, otherwise the data cannot be analyzed.If the water level is drawn down to pump inlet during the test, the pump must be stopped immediately and recovery of the water level monitored.Recovery of the water level after the step test should be monitored till the water level recovers to ~ 1 m hours of the Static water level or for ~ 12 hours. Yield must be measured at least 3 times during the test to ensure it is constant. The planned steps can be adjusted during the test, although the yield during the individual steps must be constant. Step4 – one and a half times the expected yield. Step2 – two-thirds of the expected yield.Step1 – One third of the expected yield.The yield test would need to include: Step-drawdown Test:Ĥ to 6 x 1 hour steps, each at a different rate – incrementally increasing.ĭuring the last step try to draw the water level down to the pump depth. Here is a summary of the specifications for test-pumping of boreholes. This spreadsheet provides a template for the data capture. Remember the Department of Water and Sanitation (DWS) will only authorise groundwater use if the correct (above) method of borehole yield testing is used. The South African National Standard for the test pumping of water boreholes (SANS 10299-4:2003) clearly prescribes how the borehole yield testing is to be carried out. How to correctly follow a borehole yield test?
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