Hartbeespoort – Magalies Water says it is making progress in removing water hyacinth covering the lake at Hartbeespoort dam.
Magalies Water this week said it was effectively managing the hyacinth regrowth and proliferation.
At the beginning of April 2025, the water hyacinth coverage at the lake at Hartbeespoort Dam 9.9%.
“With the implementation of integrated management strategies, Magalies Water has successfully decreased water hyacinth coverage to 0.2% as of 15 July 2025,” said David Magae, spokesperson for Magalies Water.
“This success highlights the importance of collaborative approaches in the ecological remediation of the dam.
“Magalies Water conducts systematic water sampling and analysis at the dam and multiple upstream sites, collecting data from over 53 monitoring points on a monthly and quarterly basis.”
Magae explained that analysis of data gathered over the past two years reveals that the dam is hypereutrophic, characterised by elevated nutrient concentrations and increased chlorophyll and algal biomass.
“These findings indicate that continuous runoff contamination from upstream activities presents a significant challenge to managing the dam’s water quality,” said Magae.
“To mitigate the amount of solid waste entering the dam, a litter boom has been installed at the Crocodile River inlet.”
However, an exponential increase was observed in the growth of Salvinia, a plant that thrives during the winter months, with coverage rising from 1.6% in April to 5.8% in June 2025.
Salvinia is a small plant, measuring only 0.5 to 4 cm in length, which makes mechanical removal challenging.
“To facilitate the removal of Salvinia, the physical removal team has constructed a net structure that helps collect large amounts of Salvinia and push them toward the shoreline for manual removal,” said Magae.
“As a result of these efforts, Salvinia coverage has decreased to 2.76% as of early July 2025.
“Operations are ongoing to further curb the rapid regrowth of Salvinia.
“Additionally, advanced biological methods utilising nanobubble technology have been implemented at the dam’s inlet for removal.”
Magae said this method enables the diffusion of oxygen-infused nanobubbles, which effectively reduce contaminants through various mechanisms: oxidation processes that target nutrient pollutants such as nitrogen and phosphorus, precipitation methods for metal removal, and the reduction of oxidative stress affecting algal and cyanobacterial populations.
