WE TLANDS
How much is a WETLAND actually worth?
Understanding the economic value of a wetland can positively influence decisions around wetland management. SRK Consulting was appointed to calculate the value of the ecosystem services provided by the Papenkuils Wetland, as well as the potential change in value of these services, if an existing diversion weir were to be raised. By Kirsten Kelly
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ocated 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
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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. “As markets for the water quality amelioration function of wetlands do not exist, in order to value this service, we calculated the replacement costs of the construction and operation of a water treatment plant that provides a similar amelioration function of the Papenkuils Wetland,” adds Law. Other examples of indirect use values provided by the ecosystem services of this wetland include carbon sequestration (calculated from the amount of carbon sequestered by the wetland and the internationally recognised social cost of carbon avoided through the provision of this service), floodwater abatement, and groundwater recharge (both calculated by establishing the replacement cost of a water impoundment or dam of similar capacity).
