| Title: | Sensitivity of SWAT simulated streamflow to climatic changes within the Eastern Nile River basin |
| Authors: | Mengistu, D.T. and A. Sorteberg |
| Year: | 2012 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 16 |
| Pages: | 391-407 |
| Article ID: | |
| DOI: | 10.5194/hess-16-391-2012 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | climate change |
| Secondary Application Category: | hydrologic assessment |
| Watershed Description: | Eastern Nile in northwest Ethiopia (including the Abbay, BaroAkobo and Tekeze river subwatersheds |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | The hydrological model SWAT was run with
daily station based precipitation and temperature data for the
whole Eastern Nile basin including the three subbasins: the
Abbay (Blue Nile), BaroAkobo and Tekeze. The daily and
monthly streamflows were calibrated and validated at six outlets
with station-based streamflow data in the three different
subbasins. The model performed very well in simulating the
monthly variability while the validation against daily data
revealed a more diverse performance. The simulations indicated
that around 60% of the average annual rainfalls of
the subbasins were lost through evaporation while the estimated
runoff coefficients were 0.24, 0.30 and 0.18 for Abbay,
BaroAkobo and Tekeze subbasins, respectively. About
half to two-thirds of the runoff could be attributed to surface
runoff while the other contributions came from groundwater.
Twenty hypothetical climate change scenarios (perturbed
temperatures and precipitation) were conducted to test the
sensitivity of SWAT simulated annual streamflow. The result
revealed that the annual streamflow sensitivity to changes in
precipitation and temperature differed among the basins and
the dependence of the response on the strength of the changes
was not linear. On average the annual streamflow responses
to a change in precipitation with no temperature change
were 19 %, 17 %, and 26% per 10% change in precipitation
while the average annual streamflow responses to a change in
temperature and no precipitation change were −4.4%K−1,
−6.4%K−1, and −1.3%K−1 for Abbay, BaroAkobo and
Tekeze river basins, respectively.
47 temperature and precipitation scenarios from 19
AOGCMs participating inCMIP3 were used to estimate future
changes in streamflow due to climate changes. The climate
models disagreed on both the strength and the direction
of future precipitation changes. Thus, no clear conclusions
could be made about future changes in the Eastern Nile
streamflow. However, such types of assessment are important
as they emphasise the need to use several an ensemble
of AOGCMs as the results strongly dependent on the choice
of climate models. |
| Language: | English |
| Keywords: | |