Assessment and evaluation of surface water potential and demands in Baro-Akobo river basin, Ethiopia
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Date
2016-06
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Addis Ababa University
Abstract
Baro- Akobo river basin is located in the southwest part of Ethiopia. The objective of this
paper is to assess surface water potential using SWAT model and estimation of water
demands using the Water Evaluation and Planning (WEAP) model in the Baro-Akobo Basin.
According to the result obtained from SWAT model, the basin receives a mean annual
rainfall of 1701.6 mm, which is 115.6BM3. The mean annual actual evapotranspiration is
30.8BM3 or 27% of the mean annual rainfall of the basin. The mean annual surface runoff
that leaves from the basin is 19BM3 that corresponds to 279.68 mm. Out of the mean annual
rainfall of 115.6BM3 and the other 18.6BM3 that is 273.71mm flows as lateral flow. The
remaining 2.4BM3 is lost due to percolation for the recharging of the deep aquifer and
42.17BM3 revap from the shallow aquifer and flows as return flow.
For calibration, the model was run for a period of six years and the monthly calibration
results for R2 and NS were 0.83 and 0.56 respectively that are acceptable by the given ranges.
For model validation, the model was run for a period of six years and the model validation
results on monthly time step shows the results of R² and NS values were 0.81 and 0.67
respectively which is acceptable by the given ranges too.
The water demand estimation portion of this study was done for six water supply, three
hydropower and seven irrigation projects in the basin. The water demand result shows there
is no shortage of water supply for scenario year 2015 to 2030. The annual overall demand is
4.085BMC. The annual demand for irrigation projects is 4.077BMC. The water demand
found by this analysis is about 21.5% of the total surface water potential of 19BMC of
surface water potential per year.
The SWAT model is very sensitive and needs accurate input data. Using sufficient time and
input data the model can simulate good result, which fits the observed stream flow data. In
addition to this up to date land use and management data is essential for SWAT model. More
efforts required to find best estimation of the surface water potential using SWAT model.
The water demands in the basin is very small so further investigation is essential to use the
available surface water potential of the basin.
Key words: SWAT model, WEAP model, SWAT-CUP, surface runoff and water demands
Description
Keywords
SWAT model, WEAP model, SWAT-CUP, Surface runoff and water demands