Concerned residents have put the spotlight on the metro’s civil works project which has been under way in the Third Avenue/Glenhurd Drive dip in Newton Park for seven months.
Representatives of the Baakens Valley Preservation Trust said the design and implementation of the R13m project were creating problems even as the metro sought to achieve the stated aim of easing traffic flow.
Trust spokesperson Steff Schenk said the organisation backed sensible development.
“But poor management of stormwater and failing to rehabilitate work sites are regressive, undermining the value of the valley and creating huge future problems – and there are glaring examples of that situation happening here.”
Schenk said the gabion stormwater channel running down the south side of Glenhurd Drive had created a “hydraulic ram”.
The box-shaped channel, lined with rock and wire gabion baskets, runs steeply downhill and ends abruptly a short distance above the dip where stormwater has already gouged a hole in the soil.
An underground drain from the new Fairview link road opens into the channel halfway down its length, increasing the volume of water.
Schenk pointed out where rushing stormwater below this outlet pipe had already eroded the ground below the wire and created troughs of erosion.
“This project has created more hard surfaces which means more stormwater runoff and instead of spreading the force of the flow, this structure has created a chute.”
The stormwater should instead be spread horizontally via berms across the slope below Mangold Park, he said.
“The water would be slowed down, reducing erosion and downstream flooding, and at the same time nourishing vegetation and replenishing our water table.”
Schenk also pointed out a thick clump of alien castor oil plants and mounds of rubble and plastic at the bottom of the dip on the north side of Glenhurd Drive.
“The area has been cleared of vegetation and then just left, brutalised.
“There are many examples of this situation in the valley and we’re calling on the metro to compel contractors to clean up and rehabilitate with suitable indigenous vegetation when they’ve finished.”
Barry Patterson, who worked for 34 years in conservation bodies and as a consultant to the transitional local councils in the Western Cape on urban river management plans, echoed the trust’s concerns.
He pointed to where rubbish and rubble had been bulldozed into the river and said the bare slopes above the gabion channel and the link road also needed urgent attention. “They should have been rehabilitated as soon as work there was finished to slow runoff and avoid erosion.”
Metro spokesperson Kupido Baron said the road project created a link from Restitution Avenue west of the William Moffett Expressway to Glenhurd Drive, to improve traffic flow from Fairview to Glenhurd and Newton Park.
Rubbish bulldozed into the river had happened during a separate project to locate a valve that had to be repaired, he said.
“The contractor, SP Excell, will be instructed to return to rectify the matter.”
He confirmed the erosion at the bottom end of the gabion channel but said an outlet structure, which would alleviate it , still had to be built.
An environmental impact assessment had been done, conditions were being implemented and the metro was satisfied with the project.
Provincial environment department manager Dayalan Govender said audits of the project showed it was complying with conditions set down by the department.