RUNOFF HISTORY

Runoff consists of stormflow plus baseflow from a specific catchment, where stormflow is generated from rain falling on the soil/vegetation surface. The stormflow amount depends on the amount of rain on a given day, how much is intercepted by the vegetation cover, and how moist the topsoil is from previous rainfalls. The baseflow depends on soil drainage characteristics into the groundwater zone and the groundwater store of baseflow, with water from this store released slowly into the stream.

Daily runoff was simulated with the ACRU model under present (mid-1990s) climatic conditions. The climate scenarios were derived from daily climate inputs into the ACRU model from 6 bias-corrected CMIP5 GCMs used in a current (as yet unpublished) WRC Project at the Centre for Water Resources Research at the University of KwaZulu-Natal.