In my last article for Drilltalk, I reviewed how the quality of the water in your borehole can be protected. Now we discuss the benefits of knowing how your well is behaving in terms of yield and water level and spotting issues before they cause a problem—particularly relevant where water is being abstracted in high volumes.
Regular measurement of the borehole’s water level—both when pumping and at rest—is one of the most valuable things that can be done in good borehole management. Water level monitoring could even be a condition of your abstraction licence. However, the data that you collect provides far more valuable information than simply for an annual report to the Environment Agency.
A water supply comprises three principal assets: the borehole, the pumping equipment and the water. Flow ceases should any one of these components fail. The amount of water that can be pumped from a borehole is dependent both on the water level in the borehole, and how easy it is for that water to flow into the borehole.
Underground water levels do not remain constant: natural variations, the act of pumping, and the amount of recharge from rainfall affect them. If the water level falls too far, damage can occur to the pump as it draws in air and the cooling efficiency of water is reduced. Regular water level monitoring allows problems to be identified.
The graph illustrates long-term monitoring data: Over the first three years, there is a steadily falling water level. This could be due to over-pumping of the regional aquifer, the borehole screen becoming clogged, or an increase in abstraction.
Its water reached a critical level and dropped suddenly in March 2004. Thereafter the water level stayed relatively constant, although it had fallen to the level of the pump, leading to increased wear and tear and premature pump failure. In this case, although data had been collected, failure to plot the graph and regularly review it, meant that the problem wasn’t picked up early. Had the data had been reviewed, the steadily falling water level would have given concern, the sudden drop warranted investigation and possibly remedial action before the pump failed, and an emergency occurred.
If you have a time-limited licence, regular measurement of levels in pumping and observation boreholes allows the effect of pumping on the groundwater system to be evaluated. Having this data available when the licence is due for renewal demonstrates to the Environment Agency that the abstraction is not having an adverse environmental impact. This in turn helps your case and may be necessary proof for renewal. All new licences are now time limited and there will in the future be pressure to change ‘in perpetuity licences’ into time limited licences. But whether monitoring is a licence condition or not, data can prove invaluable during licence renewal.
Monitoring cannot be carried out retrospectively and the longer the record period, the more confidence you will have in the interpretations. So, if you are not monitoring you should start now and take a weekly measurement accurate to 1cm relative to the same point on the borehole headworks, Taking a measurement is easy and accurate using an electronic dip tape. Keep the data in a notebook or on a spreadsheet and plot it as a graph as you collect it. You’ll see patterns emerging after about three months.
Regular monitoring, proper data recording, and presenting the results as graph helps you protect the assets that provide you with the water that is so important to your home or business.
WB&AD Morgan can provide you with help and advice on setting up and maintaining a monitoring system, and with the aid of our expert hydrogeologists provide interpretation and reporting on the results for you to present to the Environment Agency.

James Dodds, JDIH (Water & Environmental) Limited, 01332 865866 , www.jdih.co.uk.