Correlation analysis between the Physical Catchment Descriptors (PCD’s) and the ihacres Rainfall Runoff Model Parameters

The purpose of this study was to analyze the correlation between the physical catchment descriptors (PCD’s) and the IHACRES rainfall Runoff model parameters for the Kasese catchment. Futher researchers can base on the output of this study for regionalisation of Kasese catchments. The model was calibrated for fou(4) catchments to obtain a set of dynamic response characteristics (DRCs) describing the hydrological behaviour within the region. For the four catchments, Mubuku, Rwimi, Nyamugasani and Chambura, IHACRES model calibrated with an R2 of 0.12.0.25.0.38 and 0.51 nrespectively. It was concluded that the poor measures of fit between observed and modelled stream flow (R2) could have been due to lack of good-quality time series of rainfall data representative of the whole basin and influence bof snow melt for especially Mubuku, Rwimi and Nyamugasani. Physical Catchment Desriptors (PCDs) indexing Topography, oil type, land cover, length of main channel, drainage density, and basin area were correlated to the hydrological model parameters, from which a set of DRC-PCD relationship results indicate that strongest correlations were found with the quickflow proportion (Vq). Catchment storage index (1/c), catchment drying constant (TauW) and the temperature modulation factor (f) with the PCD’s. It was then concluded that IHACRES model is applicable to Kasese catchment but further work is necessary to correlate the records from river flow measurement stations and rain gauges to facilitate better modelling results when using this model