Located within the Western Cape, the vast Papenkuils Wetland is fed primarily by the Breede River, but also the Holsloot River, a smaller tributary of the Breede. A diversion weir redirects a portion of that water into Brandvlei Dam and away from the wetland; raising the weir by 30 cm to improve the supply of irrigation water would further increase the volume of water diverted away from the wetland into Brandvlei Dam.
The Western Cape Department of Environmental Affairs and Development Planning tasked SRK Consulting with establishing the value of ecosystem services provided by the Papenkuils Wetland, in order to inform its policy and management. The first step was to identify the services of the ecosystem.
Services of the Papenkuils Wetland
Wetlands in general sustain unique environments in terms of fauna and flora, and are among the most productive ecosystems in the world. “They provide ecosystem services that have direct use value (these are easier to quantify because they are typically valued in traditional markets) and more discreet indirect and non-use values that are harder to calculate,” explains Matthew Law, principal environmental economist and management consultant, SRK Consulting.
An example of a direct use value is grazing on the wetland itself. The combination of shallow water and high nutrient levels in wetlands creates highly productive agricultural areas; the direct use value of grazing was calculated by establishing the carrying capacity of the wetland and comparing this to the capacity of surrounding dry-land grazing areas. Another example of a direct use value is the waterblommetjies harvested from the wetland and sold by the local community. “We were able to calculate the direct use value of this wetland service per hectare, based on the number of harvesters and waterblommetjies sold,” he continues.
Water quality amelioration is an ecosystem service with indirect use value (as opposed to direct economic benefits), as wetlands remove contaminants and improve water quality. Wetland vegetation can help to trap suspended material, remove nutrients and conduct chemical detoxification. In the absence of these wetland services, farmers downstream will receive poor water quality, adversely affecting agricultural production and causing siltation of irrigation systems, with associated direct costs to farmers.
