Kimberley: Ongoing drought in the western parts of the Karoo have hit every water user hard, but when Middelpos Primary School was landed with an R18,000 water bill in February, a more sustainable plan had to be made.
Located in the small town of Middelpos between Calvinia and Sutherland in the Northern Cape, the school and its hostel were subject to the water restrictions in the Hantam Local Municipality – but clearly could not afford the water it needed. Through a provincial Department of Education programme to alleviate the water crisis in schools, RE Construction was awarded the tender to provide a solution.
Bernie de Jongh of RE Construction approached the leading firm of consulting engineers and scientists, SRK Consulting, to site a water supply borehole within the school property to alleviate the water problem.
“There is an existing borehole at the hostel, but due to numerous sewage pits in the vicinity, the water quality is unsuitable for human consumption,” said De Jongh. “However, the school is upstream of the town and the likelihood of finding potable groundwater in this area was considered to be fairly good.”
SRK principal hydrogeologist Chris Esterhuyse visited the area in March to identify a potential drill site on the school property.
“No prominent geological features linked to the occurrence of groundwater on the school property could be identified from satellite imagery,” said Esterhuyse. “However, detailed surface geological mapping of the area revealed a narrow joint system that intersects the property – and we selected a drill site there.”
A second, backup drill site was selected on another property, adjacent to the town, on a prominent east-west striking dolerite dyke; this was considered the most promising of the two drill targets.
“We began drilling the borehole in the school yard on 16 March 2017 and completed it on the same day,” said Esterhuyse. “We were pleased when fresh groundwater was intersected at 34 metres below ground level (mbgl) with a measured drill stem blowout yield of 2.8 litres per second.”
The borehole was completed to a final depth of 50 mbgl and a water sample submitted to UIS Analytical Services in Kimberley for quality analysis.
“The second borehole was completed to a final depth of 66 mbgl, and also achieved a positive result with a blowout yield of 8.3 litres per second intersected at 63 mbgl,” he said. “Again the water tasted very fresh and samples have been sent for analysis.”
The results from this investigation suggest that groundwater can be a quick, viable solution to improve water supply, especially in drought-stricken areas.
“Finding sustainable drill sites was crucial, so the appointment of a hydrogeologist with the necessary expertise to conduct the investigations and select the borehole sites was invaluable,” said De Jongh.
“We would like to compliment SRK Consulting on the manner in which they conduct their business. They share our commitment to deliver a highly professional service – and without them we wouldn't have been able to achieve the successes we have.”