Spatial evapotranspiration, rainfall and land use data in water accounting – Part 2: Reliability of water acounting results for policy decisions in the Awash Basin
Water Accounting Plus (WA+) is a framework that summarizes complex hydrological processes and water management issues in river basins. The framework is designed to use satellite-based measurements of land and water variables and processes as input data. A general concern associated with the use of s...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-01-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/19/533/2015/hess-19-533-2015.pdf |
| Summary: | Water Accounting Plus (WA+) is a framework that summarizes complex
hydrological processes and water management issues in river basins. The
framework is designed to use satellite-based measurements of land and water
variables and processes as input data. A general concern associated with the
use of satellite measurements is their accuracy. This study focuses on the
impact of the error in remote sensing measurements on water accounting and
information provided to policy makers. The Awash Basin in the central Rift
Valley in Ethiopia is used as a case study to explore the reliability of
WA+ outputs, in the light of input data errors. The Monte Carlo technique
was used for stochastic simulation of WA+ outputs over a period of 3 yr. The results show that the stochastic mean of the majority of WA+
parameters and performance indicators are within 5% deviation from the
original WA+ values based on one single calculation. Stochastic
computation is proposed as a standard procedure for WA+ water accounting
because it provides the uncertainty bandwidth for every WA+ output, which
is essential information for sound decision-making processes. The majority
of WA+ parameters and performance indicators have a coefficient of
variation (CV) of less than 20%, which implies that they are reliable and
provide consistent information on the functioning of the basin. The results
of the Awash Basin also indicate that the utilized flow and basin
closure fraction (the degree to which available water in a basin is
utilized) have a high margin of error and thus a low reliability. As such,
the usefulness of them in formulating important policy decisions for the Awash
Basin is limited. Other river basins will usually have a more accurate
assessment of the discharge in the river mouth. |
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| ISSN: | 1027-5606 1607-7938 |