Borehole yield is a pertinent issue. Any new borehole owner wants to enjoy their borehole. However, they also want to do so responsibly.
In order to do this, it’s critical to know how much water your borehole can produce. As a result, you can avoid the borehole running dry.
Borehole yield is affected by factors like:
- The depth of the aquifer
- Over-pumping without enough rainwater to replenish the water supply
WHY IS OVER-PUMPING A BOREHOLE A PROBLEM?
Over-pumping a borehole should be avoided as it causes:
- saline intrusion
- encrustation
- a lowering of the water table
- the borehole to run dry
Borehole yield is established by doing a borehole yield test.
WHAT IS A BOREHOLE YIELD TEST?
A borehole yield test determines how much water can be pumped from a borehole versus the amount of water that flows back from the groundwater.
As a result, it’s an essential tool to help prevent your borehole from running dry. In the same vein, if you stay within your yield capacity your borehole will keep running optimally.
Ensure that the amount of water extracted from the borehole is less than the groundwater charge. Consequently, this will keep your borehole water flowing.
HOW IS THE TEST DONE?
A borehole yield test is done by pumping the water at a measured flow rate from the borehole. As this is done the drawdown of the water level is monitored over time.
It consists of a:
- Step-drawdown test
- Constant discharge test
- Recovery test
You can read more about the steps of the yield test here.
It’s important to note that the water levels must be measured during a yield test. Consequently, you will not get an accurate result by just measuring the yield.
IMPORTANT FACTOR FOR MEASURING BOREHOLE YIELD
- Measure the resting water level before starting the test
- Monitor how the water level changes over time once pumping starts
- Check how long it takes the water level to go back to its original level after the pump stops running
- It is crucial that the pumping rate remains constant during the steps of the yield test
- The pump must have a non-return valve so that water can’t flow back into the borehole
BOREHOLE YIELD TEST DATA TO BE COLLECTED ARE:
- Date and time of the test
- The water level at the beginning of the test
- How deep the borehole is
- Depth of the installed pump
- Borehole diameter
- Rain (If it rains during the test)
- Drawdown of the water level
- Rate of discharge
Constant interruptions to our water supply have simply now become a fact of life for those of us living in South Africa. However, all is not lost! Drill your own borehole and enjoy permanent water security.
In conclusion, it’s important to remember that a borehole ultimately gives you a secure water source. As a result of this, you also have peace of mind. Consequently, it’s so worth the investment!
Water is life and one of our most precious resources!
Contact us today for your free borehole drilling quote, Cape Town!