This dataset is a map of the surface runoff (mm/year) under observed climate scenario, modelled using Soil and Water Assessment Tool (SWAT), covering the Central Slopes NRM region. It depicts the average amount of surface runoff in mm/year from stream flow from the Hydrologic Response Unit (HRU) using the observed climatic variables (i.e. precipitation, minimum & maximum temperature, and solar radiation) from 2001 to 2010. It is intended for use at catchment scale. This raster dataset has a cell size of 90m x 90m.