Over 30 schools have been provided with boreholes as part of this programme over the past three years, according to SRK principal hydrogeologist, Leon Groenewald, saving 130,000 m3/a of water that would have had to come from municipal supplies.
"This helps take pressure off the supply of potable water, which of course also needs to go through a costly treatment process before being reticulated to consumers and industry," said Groenewald. "It is much more cost-effective to use borehole water - rather than treated water - for irrigation, making it affordable for schools to create and sustain grassed sports fields and attractive green areas."
SRK has also been monitoring the boreholes, ensuring sustainable levels of pumping to avoid depletion. This is done by placing data loggers in the borehole itself to record water levels on an hourly basis, as well as total flow meters in the delivery line to record the volume of water being pumped.
"Our monitoring over the past couple of years has shown that more water was abstracted than was planned, but this was probably not surprising as many of the schools were starting their green areas from scratch and this required additional water," said Groenewald. Fortunately, the aquifers are behaving as predicted with no signs of depletion.
Before the boreholes were drilled, SRK conducted a hydro census and a detailed geophysical survey so that the yield of the boreholes can be assessed and the optimum drill target determined.
"This process gives the architects and planners the information they need, to plan fields and green areas according to the amount of groundwater available for irrigation," he said. The data gathered by the monitoring is fed back to each school's maintenance contractor to inform their water usage activities.
Groundwater is an increasingly important resource as South Africa's economic growth starts to put a strain on its limited surface water supplies; underground aquifers therefore need to be carefully managed so their natural replenishment can keep up with borehole extraction levels.
