The impact of altered river structure on the function of selected urban Cape Town rivers

Abstract

Many urban rivers are heavily engineered and no longer function naturally. The City of Cape Town has designed and implemented many stormwater and river management projects. Very little monitoring has occurred as to whether these engineering projects and remediation measures, have had a positive effect on our urban river ecosystem function. The study investigated the influence of specific engineering interventions such as the placement or rocks in stream to create weirs, gabion lining of stream channels, removal of canal walls, establishment of artificial wetlands, and approaches to urban river management, on river ecosystem function of the Keysers River, Little Lotus River, Langevlei Canal, Silvermine River, Moddergat River and Big Lotus River, as measured by specific indices including water chemistry and aquatic community structure (macroinvertebrates and diatoms).