When it comes to a borehole installation, tests must be carried out to ensure the long-term sustainability of an underground water source. Borehole yield testing allows Aqua Borehole Solutions to establish the potential of an aquifer, ensuring that your alternate water source continues to supply you with water.
With all the benefits that an alternate water source affords businesses and residences alike, Aqua Borehole Solutions would like to take this opportunity to explain the importance of borehole yield testing and the primary types of tests conducted before we complete the installation of your borehole.
Why Do Boreholes Need to be Tested?
With water being a finite resource it is crucial to determine that the aquifer you need to draw water from is sufficient and whether it will produce yields. Borehole yield testing will assist us in determining whether an underground water supply may be depleted or dry out due to constant use. It is also at this point that the quality of the water will be tested to ascertain if it is good enough for its intended use.
How is a Borehole Yield Test Conducted?
Before we delve into the steps of our borehole yield testing, it is important to understand that the time it takes to conduct these tests depends on the amount of water that the borehole will be required to pump. Besides the sustainability of the aquifer, other aspects that need to be tested and recorded include the constant discharge of the aquifer, the quality of the water and the recovery rate of the water levels.
What we do is carry out a step, constant discharge and recovery test before completing the borehole installation, which entails:
- Step test
To determine the effectiveness of the borehole, the pump rate will periodically be increased. It determines the expected yield and should be measured at least three times during this test to ensure that the yield is constant.
- Constant discharge test
In this step, we pump the borehole at a constant discharge rate that can take up to 48 hours. The length of the test is proportional to the expected yield and importance of the borehole. Water levels are recorded and analysed providing useful input in assessing sustainable yields. The constancy of the yield is important otherwise the data cannot be studied.
- Recovery test
Immediately after the discharge test, the pump is switched off to measure the recovery levels of the aquifer. This is extremely useful as it assists us in assessing the effect the pump has and any possible dewatering of the aquifer. The recovery test will indicate the level to which the aquifer is dewatered by measuring the residual drawdown after the borehole is allowed to recover. Recovery is measured until water levels recover to less than 5% of the total drawdown conducted during the discharge test.
Borehole yield testing plays a crucial role in the completion of a borehole project as the results help us to determine the correct sized pump and not to over-pump the borehole.
Important Rules
When Aqua Borehole Solutions determines a sustainable yield we keep these two important rules in mind:
- The amount of water we extract from the borehole will not be less than the natural recharge of the groundwater.
- The borehole will pump in a manner that the water level never reaches that of the main water strike.
The Premier Provider of Water
Aqua Borehole Solutions is a privately owned company that offers full turnkey solutions including water detection, drilling, yield testing, and pump and tank system installations. With a proven track record of detecting an underground water supply 99% of the time, can you afford not to put your borehole installation in our expert hands? Contact us today and we will arrange a free-of-charge on-site visit to discuss your requirements.
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