Cape Town - The situation at the Milnerton Lagoon has worsened again.
Residents shared videos of suspected raw sewage and masses of litter flowing into the lagoon over the weekend. They said the fish in the adjacent golf course dam filled with river water had also started to die.
Milnerton Central Residents’ Association environmental head and admin of the RethinkTheStink community group Facebook page, Caroline Marx said: “Despite claims otherwise, there is no observable sense of urgency among City staff, and no apparent accountability either.
“Water from the Diep River entered the golf course dam on Sunday, and was so toxic it seems to have caused a fish die-off within hours. There have been two other major fish die-offs in 2022.”
Residents said a mixture of sewage sludge and plastic rubbish was found at Erica Road, and the sandbags, which formed part of the sandbag weir installed last month to complement the over-pumping and further protect the lagoon from sewage ingress, were either flooded or had fallen over.
The frustration among residents was growing, with sentiments that the City continued to disrespect and disregard the environment, the law and the community by allowing the Milnerton Lagoon situation to reach this level of mismanagement and degradation.
On Monday, Alex Lansdowne, chairperson of the mayoral advisory committee on water quality, hosted a walk along the length of the Lower Diep River to the mouth of the Milnerton Lagoon to assess the state of the river and engaged with residents about their concerns and the City’s progress.
Lansdowne said: “The main tributary starts in the Kasteel Mountain, north of Malmesbury. It is joined by the Mosselbank catchment, which finds its source in Durbanville. It used to discharge into the ocean at three mouths, but now has one fixed mouth at Milnerton Lagoon.”
Lansdowne said there was a lot of work to do in this catchment but the City was not afraid of it.
“We have made significant investments in Erica Road, with more to come. We fitted a litter grid to remove solid waste. We have put in a coffer dam, so that when we pump, we are able to pump the storm water sewage ingress and not the lagoon water.
“We have also increased the frequency of the existing pump. We will be increasing the pumping at Erica Road to ensure it is functioning, essentially for 24 hours.”
He said finer designs for a low-flow diversion were also in the works to divert the Erica Road outfall away from the lagoon permanently.
Ward councillor Fabian Ah-Sing said: “Residents are extremely angry, and rightly so. I share many of their sentiments. However, I understand what is happening behind the scenes, and see the commitment being shown to fix it.
“The City has a fault in this situation, but so do all of us in the situation that permeates here – people dumping into the system, people using it as a toilet, etc.”
Spatial Planning and Environment mayco member Eddie Andrews said: “The City did an inspection of the Milnerton Lagoon and the estuary this afternoon (Monday), and did not observe any signs of a fish die-off.”
Water and Sanitation Mayco member Siseko Mbandezi said heavy rain over the weekend brought down more solid waste than normal and overtopped the sandbags.
During a site visit on Monday, Mbandezi indicated that dark objects in the water near the mouth were crusts of organic sludge lifted from the bottom when gasses formed during anaerobic decomposition of the sludge, causing hardened bits of crust to float to or near the surface.
“The relevant Water and Sanitation departments are working transversally and have determined the root cause of the contaminated stormwater and litter at the Erica Outfall originates from the densely populated Joe Slovo and Phoenix areas.
“The over-pumping activity is a temporary mitigation to intercept the contaminated stormwater coming from nearby areas before it reaches the Milnerton Lagoon.
“Currently over-pumping is being done daily from 05:00 to 21:00 with additional dosing of bio-enzymes. Permission has been granted to over-pump intermittently during the night, and this will be implemented soonest,” Mbandezi said.