The City of Cape Town is aiming to restore the environment at Milnerton Lagoon in the shortest possible timeframe, and is taking the next step forward with the appointment of environmental consultants to help investigate and assess possible short-term interventions. The consultants will assess a range of short-term measures to improve water quality and odour at the lagoon, as well as options for the dredging of sediment to remove decades-long build-up of urban pollution in the water body. Specialists in estuarine science and remediation will contribute to this plan.
‘Restoring the health of the Milnerton Lagoon is not optional. It’s a must. In the coming years, we aim to generate a compounding positive effect via multi-billion rand sewerage and stormwater infrastructure upgrades coupled with on-the-ground pollution mitigation measures. The aim is to steadily close off pollution sources to the lagoon over time, building up to the ultimate goal of dredging the water body and removing the sediment containing decades-long build-up of pollution. This is complex environmental and engineering work, and professional consultants will help us time and cost our interventions to get this done in the shortest possible time. In the meantime, we must consider what short-term interventions are feasible, efficacious, and environmentally defensible. Many people have flooded us with proposed “solutions”. It is not possible for us to know which of these is serious, and which is wishful thinking. This will be the work of this specialist consulting team,’ said Cape Town Mayor, Geordin Hill-Lewis.
Consultants have been tasked to quantify the costs and timeframes of the various environmental remedial interventions.
‘The City will be monitoring the consulting work via a dedicated team of officials from the Environmental Management Department and Water and Sanitation Directorate. We will also be sharing information with community and civil society stakeholders along the way. I want to assure the public we are committed and working with all urgency to mitigate the multiple sources of urban pollution in our waterways. We appreciate the assistance from local communities who are working with us and showing their passion for finding solutions,’ said the City’s Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment, Alderman Eddie Andrews.
The scope of consulting work broadly entails assessing the following options for restoring the lagoon:
Short-term water quality and odour mitigation of the lagoon, including bioremediation of sediments through microbial inoculation
Costs for dredging of the lagoon and river channel to various depths; and removing nutrient rich sediment that has accumulated in the system
Feasibility of pumping seawater into the lagoon to increase salinity and dissolve oxygen levels
Diffusion aerator to improve oxygenation in the estuary
Construction of reed beds or low-flow vegetated channels in the upper river channel
Engaging relevant environmental authorities to identify applicable legislative provisions and the most efficient processes to allow for prompt decisions
Preparing terms of reference for any required assessment and licensing processes
‘The sources of pollution in the Diep River and the catchment, including Milnerton Lagoon, vary and emanate from a wide geographical area which also spans multiple local municipal boundaries. One thing remains clear: our interventions will be limited unless the sources of pollution are addressed within the city and beyond, as part of a wider and systemic approach. All of us are affected, and we share the responsibility for cleaning up and preventing further pollution,’ said Alderman Andrews.

Source: City Of Cape Town