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We are inundated by bad news stories about deteriorating water quality. Recent events in the Vaal River have shown us that aquatic ecosystems can be rapidly overwhelmed by floating weeds caused by uncontrolled flow of sewage effluent into rivers.
It is true that the value of real estate is impacted by the environment in which the development takes place. Proximity to water is an enhancing feature. Residential homes immediately adjacent to the Onrus River Estuary in Hermanus are at least R1.5 million more valuable than houses built in the second row. Aquatic ecosystems have a material impact on the investment value of both residential and commercial real estate. Nowhere is this more acutely felt than in developments adjacent to distressed aquatic ecosystems. Three examples illustrate this. Hartbeespoort Dam has the most polluted water in Africa, but it also has a density of residential estate development around its banks. Properties riparian to the Vaal River are directly impacted by the deteriorating water quality. Commercial developments around Centurion Lake are negatively impacted by the uncontrolled flow of sewage into what was initially designed as a large water feature that has now become a financial liability and health hazard.
Central to this whole issue is the adoption of a strategy that can protect the commercial value of real estate, while mitigating against the health and aesthetic risks associated with the unintended consequences of sewage flows. Given the magnitude of the sewage crisis, this is a national issue, so different experiments are being conducted by various HOAs that are directly affected by water pollution.
When it comes to strategy, the dominant one is directed to the floating plants – hyacinth and more recently water lettuce – which are either controlled by chemicals or insects, or physically removed. This whole exercise is hotly debated, with HOAs often caught in the middle of the fray, often driven by health concerns arising from the use of herbicides. I am reminded of the COVID-19 pandemic, which was also hotly debated. During that unfortunate event, the initial strategy was to isolate the pathogen by preventing the movement of people. Ultimately the cost of that strategy was just too high, so a new approach was tried. This was centered on learning how to live with the presence of the virus, rather than eradicating it, which was a futile endeavour.
The same thing is happening in the water pollution space, and Pecanwood is leading the way. Their approach has been to create a buffer space between the highly polluted dam and the recreational areas that give the estate its investment appeal. It accepts that the dam water is polluted, but that reality need not negatively impact on the investment value of the real estate. This is remarkable, because Pecanwood is now a beacon of hope in the fight against eutrophication – the enrichment of water by nutrients arising from sewage discharge – which is a national concern.
A small constructed wetland has been created in a natural depression that used to be a problem because it was often waterlogged. By means of clever landscaping, this natural ‘problem’ was converted into a water feature and used as an environmental offset trade against land reclaimed from the dam. In effect, a wetland was constructed by humans, and the regulators accepted the future benefits as a trade-off against the encroachment of different land into the water. This experiment is being repeated in other parts of the world, as a transition towards adaptation rather than eradication is emerging. Adapting to the COVID-19 virus, adapting to the impact of global warming, and now adapting to the presence of pollution in large water bodies collectively constitute a trend. This trend is being called the quest for nature-based solutions, of which constructed wetlands are but a component.
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What makes the Pecanwood experiment so interesting is that the chemistry of the constructed wetland is starting to differ from the chemistry of the dam itself. This is a small but important fact, because an ecological niche emerges that enables different creatures to live there. The dam itself is highly alkaline, with pH values of 9 and 10 at the wall on official record. This is changing slowly, for reasons unknown, but possibly linked to the constant influx of acidic mine water from Mogale City. The constructed wetland is less alkaline, with a pH of 8, and this is a big deal because of the impact on invisible creatures. Most of the living creatures are big things that can easily be seen, like flowers, birds and dragonflies. Yet it’s the small invisible things that really matter because a startling new discovery has been made by a citizen scientist named Gill Ledger. She has been intimately involved in the development of the Pecanwood Estate Wetland Biological Remediation Plan, which is the official regulator-approved document that governs the management of the constructed wetland. This was an offshoot of the Hartbeespoort Dam Integrated Biological Remediation Programme, a controversial project run by DWS, with some questioning its effectiveness.
The Pecanwood HOA has now clearly demonstrated that their biological remediation plan is starting to become a success in adaptation, rather than eradication as noted above. Evidence of this success is in the form of a tiny filter feeder with the grand name of Paradileptus conicus. Think of a basking shark that swims through the ocean with an open mouth, filtering out millions of tiny creatures. Now think of this on a microscopic scale, invisible to the human eye, but a voracious feeder on algae, bacteria and other harmful creatures living in polluted water. However, this little fella punches way above its weight, because it’s an apex predator, capable of changing the ecological balance from a bad to a healthier system. The real significance is that Paradileptus conicus creates clear water. This is in stark contrast to the thick pea soup that occurs when blue-green algae blooms.
A big round of applause is needed for the regulatory authorities, DWS and DACE (the provincial form of DFFE), both of which have authorised the Pecanwood Estate Wetland Biological Remediation Plan. Even bigger applause must go to the HOA, which has endured a lot of criticism as it has tried to find a cost-effective way of protecting investor value in real estate impacted by its proximity to polluted water. Other estates can learn from this policy approach to the management of real estate value through environmental enhancement. The concept of nature-based solutions is likely to grow, with constructed wetlands slowly gaining traction. After all, it makes financial sense to engineer solutions in partnership with nature, because that is often where the biggest bang for the hard-earned buck occurs.
