The DRMT takes data from multiple rain gauges, surrounding a site of interest or focus, and interpolates to create rainfall ‘surfaces’ for each modeling time step at the centroid of each catchment’s tributary area. This approach is helpful to account for temporal and spatial variability of storm events over a relatively large drainage area and to interpret the observed flow and level data. The interpolation technique currently used is has two options: IDW and Spline Interpolation based on TatukGIS method.