Weekend Argus (Saturday Edition)
The perils lurking in Milnerton Lagoon
Water quality has decreased steadily, according to report
IF YOU paddle on the Milnerton Lagoon, don’t splash your canoeing companions. And if you tip over, make sure you keep your mouth closed.
That’s the advice for kayakers who, if they take a dip in the lagoon, run the risk of contracting anything from gastrointestinal illnesses to ear, nose and throat infections.
The water quality of the lagoon, according to the latest Inland and Coastal Water Quality Report released by the city, has decreased steadily over the past three years. And, in the year to June this year, it showed a lowly 35 percent compliance rate for recreational use – down from 65 percent between July 2011 and June 2012.
Canoeist Marco Zumpt, who is affiliated to the Milnerton Canoe Club ( MCC), said although he had never contracted any illness as a result of canoeing on the lagoon, he knew of fellow canoeists who had contracted diarrhoea.
“On occasion, they dump a whole lot of sewage which you can actually smell. You can see it in the wildlife too. Alien corals growing are proving to be a problem,” Zumpt said.
Canoe Club coach Gregory van Heerden, who has canoed on the lagoon since 1994, confirmed the concerns: “At the moment we have got Australian coral worm.”
Australian coral worm thrives in nutrient-rich water.
However, Van Heerden conceded that the lagoon was a difficult stretch of water to maintain, as it was fed by the Diep River, which runs through Swartland farmland where it is contaminated by fertilisers, herbicides and animal faeces. It then runs past the Doornbach informal settlement next to Du Noon, where it is further contaminated by human waste.
As a result, Van Heerden said he made sure never to fall out of his canoe. He added that he had noticed changes to the lagoon’s ecosystem. “The sand used to be clean, there were lots of birds and fish, which is not the case now.”
About seven people had left the club to practise their sport on cleaner waters.
Environmentalist Andy Birkinshaw, a long-time Table View resident, said suburban growth contributed to deteriorating water quality as stormwater flowed into the lagoon, including from Montague Gardens industrial area.
He said he had received complaints from canoeists that any cut they got while paddling became infected. Dogs which swam in the lagoon also often ended up at the vet.
The mayoral committee member for roads, transport and stormwater, Brett Herron ,agreed that stormwater from surrounding suburbs and from Doornbach negatively affected water quality.
The Potsdam Wastewater Treatment Works also discharged treated effluent into the river flowing into the lagoon, but “the quality of this effluent is generally good”, he said, adding that water quality often dropped during winter when heavy rains washed pollutants from roads and driveways, and also flushed debris out of drains.
Good news from the report was that water quality was stable or had improved at other popular recreational water bodies around the city, including at Zandvlei in Muizenberg, Zeekoevlei in Grassy Park, and the Rietvlei in Table View.
Zandvlei had a 94 percent compliance rate (up from 88 percent in 2011), while Zeekoevlei was more or less stable at 88 percent (from 91 percent in 2011), and Rietvlei had a 92 percent compliance rate (same as for 2011). For the period January to December last year, Rietvlei was 100 percent compliant.
Another notable inland water system, over which a battle against impending development is being fought, was the Princessvlei, which had a compliance rate of 50 percent – down from 72 percent in 2011.
The worst water system was the Soet River, which flows from the Hottentots Holland through the Lwandle and Nozamo informal settlements, then into the sea at Strand.
It had a 23 percent compliance rate, lower than the Disa River flowing through Imizamo Yethu in Hout Bay, which had a 56 percent compliance rate.
Further, the Big and Little Lotus Canals, and the Diep River and Canals had compliance rates of 26 percent and 45 percent respectively. They both flow into recognised recreational areas, with the Diep River flowing into Rietvlei and the Milnerton Lagoon, while the Big and Little Lotus canals flow into Zeekoevlei.
Overall, however, the longterm results for ecosystem health, measured from a low point in 2008, when the 27 measured systems had an average 50 percent compliance, have improved to levels around 60 percent.
Herron urged residents and visitors to help prevent water pollution.
“Even seemingly insignificant activities like washing out your refuse bin, washing your car in the driveway, hosing your patio and driveway, using pesticides, washing tools and paintbrushes and not picking up your dog waste, actually seriously impact on the environment.
“These pollutants are washed into the stormwater system, and from there into rivers, wetlands and on to beaches,” he warned. – West Cape News