Abstract:
The purpose of this study was to understand the spatial variability of climate
change impact in Blue Nile Basin based on hypothetical climate change
scenario and using HBV hydrological model. The assessment was done on
selected 10 catchments of the basin. A hypothetical scenario within the range of
(-30 to +30) for both precipitation arid PET have been investigated .
In terms of hydrological modeling performance, ENs criteria, the 10 catchments
gave generally in the range between 0 . 59 and 0.83 and in the validation
between 0. 56 and 0. 79, which is fair representation of the catchments. Where
as interms of evaluation of water resource change, most of the stations exhibit
more than 18% increase in runoff for PET decrease of 30% but Chacha
catchment has shown extreme increase of runoff above 48.32 %. On contrary,
30% increase in PET showed slightly reduced percentage of reduction in runoff
than the Decreased in PET produced. Meanwhile most of the stations exhibit
more than 50% increase in runoff for rainfall increase of 30% but Chacha
catchment has shown extreme increase of runoff above 100% . On contrary,
30% reduction in rainfall showed slightly reduced percentage reduction in runoff
than the increased rainfall produced. Therefore for both scenarios impact
assessment has shown that Chacha is the most sensitive catchment followed
by catchments Sechi, Birr, Guder, G/Belese,Teme, Muger;Koga, Neshi, and
Little Anger. And from the sensitivity map developed for the whole Basin
Jemma, Dabus, Part of Belese, Woleka, Wonbera and Beshilo are a Special
and overstress sensitive Sub basins, however; Fincha, Anger and Tana Sub
Basins have relaxed water resource change sensitivity.
These sensitivity analyses conducted on watersheds and river basins under a
variety of scenarios may help policy makers to prioritize measures and /or
VI
understanding the effects of climate change for planning and, management
water resources with in the Blue Nile Basin.
