Rainfall-runoff Modelling

Subbasins of the Gina River catchment (17)
Subbasins of the Gina River catchment (17)
Image Credit: adopted from Beck et al., 4

For rainfall-runoff modeling applying the HEC-1 tool the Gina River catchment was subdivided into 17 sub-basins (see figure). The Curve Number was calculated for each sub-basin. The generation of simulation hydrographs for each sub-basin shows the progression of the flood wave. In sub-basin number 17 runoff is concentrated during a short period of time.

The runoff-precipitation quotient was computed for each sub-basin. Spatial variations of the runoff-precipitation quotient within the Gina River catchment are quite remarkable in contrast to the detected low variation between two different rainfall events.

The comparison of the rainfall-runoff quotient with the average slope of each sub-basin does not show any distinct trend. But in some sub-basins (e.g., sub-basin 10), the quotient is much higher than in basins with smoother slopes. In contrast, in sub-basin 1 the quotient is lower than in basins with steeper slopes (Beck et al. 2004, 45-51).

The presented results are discussed briefly in the next step.