Stellenbosch Municipality is entering the last phase of removing the sediment spilt into the Eerste River after a municipal exploration borehole was drilled nearby in February 2018.
The municipality will remove two sandbanks by hand which are restricting the flow of the stream.
In addition, they will assess the recovery of worms, snails, springtails and insects which occur naturally in the river. This assessment indicates the quality of the water and how habitable the river is in the effected zone.
The borehole has been capped and sealed as it is not in use. The tracks in the sand caused by the recent rain shows where the silt, clay and biodegradable lubricant would have ran from the borehole to the river. PHOTO: Christi Nortier
The borehole was sunk as part of the municipality’s Groundwater Exploration Drilling project which forms part of its Drought Intervention Programme. However, the borehole hit sediment which spilled into the Eerste River and caused some environmental damage, calling for urgent intervention.
“This borehole was the first on the particular site…The Municipality was able to source sufficient volumes of water from other boreholes in Stellenbosch. No further boreholes will be sunk on the Jonkershoek site at this stage,” says Stuart Grobbelaar, the spokesperson of Stellenbosch Municipality.
The clean-up is being done by the municipality’s Conservation Section under the guidance of CapeNature and an environmental control officer from Cornerstone Environmental Consultants.
“Cornerstone supervised the removal of silt on 9 February 2018, and prepared the Method Statement for removal of the silt, in conjunction with CapeNature,” said Mari de Villiers, the Cornerstone environmental consultant who is leading the project.
“CapeNature provided recommendations that the clean-up should take place as a matter of urgency and that it should be done sensitively, by using less destructive methods (i.e. using shovels, buckets and hands), as this is a highly ecologically sensitive site. The Jonkershoek Expanded Public Works Programme team did some initial silt removal.
“Assessments of the spill was conducted by CapeNature for two weeks after it occurred…” says Loren George, the PR and Digital Manager of CapeNature.
“There was an immediate impact with regards to removal of instream habitat when the spill occurred. There appeared to be some water quality impacts, but the major one picked up was the increase in turbidity of the water with the unnatural increase of fine sediments and silt. This persisted in the impacted zone for more than a month after the borehole malfunction happened,” says George.
Professor Nebojsa Jovanovic, a researcher at the Council for Scientific and Industrial Research, ran initial tests on water samples to determine the immediate effect of the chemicals that were used. “I did chemical inorganic tests… from the tests it didn’t look like there is a major problem, except that there was high turbidity- a lot of suspended solids in the water,” said Jovanovic.
“A Generic Environmental Management Plan has been compiled for all drilling sites throughout the municipality as well as Site Specific Method Statements (both with the input from Cape Nature) for each site that the drillers have to implement. An Environmental Control Officer monitors compliance in this regard,” says Grobbelaar in relation to how the municipality will prevent future borehole spills.
“This isolated incident had no effect on the Municipality’s Blue Drop drinking water quality,” says Grobbelaar.
-Christi Nortier