The most comprehensive water resources assessment for South Africa, commissioned by the Water Research Commission (WRC). WR2012 covers 1,995 quaternary catchments with patched observed streamflow, naturalised streamflow (removing the effects of dams, abstractions, and return flows), and present-day simulated streamflow. Uses the WRSM2000/Pitman rainfall-runoff model with calibrated parameters for each quaternary catchment. Includes catchment rainfall data, Symons pan evaporation, land use information, dam and irrigation data. Provides a web-based interactive platform for data access and visualisation. Key Incomati Basin quaternary catchments include those in the X1, X2, and X3 tertiary drainage regions. WR2012 data is essential for water resource planning, yield analysis, Reserve determinations, and understanding the degree of flow modification in South African rivers.