Modelling potential hydrological returns from investing in ecological infrastructure: Case studies from the Baviaanskloof-Tsitsikamma and uMngeni catchments, South Africa

A shortage of water currently threatens the development of the South African economy and the well-being of its people. Climate change, land degradation and an inherently semi-arid, variable climate are making it increasingly difficult for water service providers to deliver sufficient quantity and quality of water to meet escalating demand. Investments in ecological infrastructure are seldom considered as a way of augmenting water supplies and improving water quality over the long-term. However, hydrological modelling shows that protecting and rehabilitating ecological infrastructure could generate meaningful gains in water quantity in two important South African water supply systems, the Baviaanskloof-Tsitsikamma and uMngeni catchments. The costs of such interventions, as estimated using resource economic techniques, are within the same order of magnitude as built infrastructure solutions. Investments in ecological infrastructure can also have a considerable range of other benefits. These findings make a compelling case for large-scale investment in the rehabilitation and protection of ecological infrastructure, which can be a cost-effective option for achieving water resource planning objectives. The types of rehabilitation activities planned would depend on the needs of local water users. Associated long-term monitoring and research would further improve knowledge of these systems, and provide support for the modelled results.