Abstract:
The purpose of this study was to estimate the major components of the
hydrologic cycle of Meki River basin using physically based hydrologic water
balance simulation model WaSiM-ETH. The model was calibrated for two years
of record of daily flow data (2000 - 2 001) measured at the outlet of Meki
watershed. The model was then validated using three years (1997 - 1999) and
five years (1997 - 2001) of measured river flow records. The calibrated model is
generally found to be capable of reproducing the historically recorded flow of
Meki River with R
2
of 78% in calibration and 71 % and 68 % in validation.
However, it was also seen that the model was unable to capture extreme flow
conditions during rainy season. According to the water balance calculation, out
of the total aerial precipitation around 75.7% is lost by evapotranspiration, 14 . 9%
is total runoff, and 9.7% is interception loss. Similarly, the partitioning of the flow
of Meki Ri ver showed that 62. 3% is lnterflow, 23.1 % is surface runoff and 13 . 8%
is base flow. The result of the water balance was found comparable with other
previous studies of similar nature done in the study area and proved the model
can be used in any future studies in Meki watershed. Grid outputs of the model
for major water balance components showed that the model was able to capture
the catchment heterogeneities. This capability of the model becomes very
essential for developing relationships between hydrologic components with
deferent environmental variables at grid cell level.
