A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands

The Soil Water Assessment Tool (SWAT) is a watershed model widely used to predict water quantity and quality under varying land use and water use regimes. To determine the respective amounts of infiltration and surface runoff, SWAT uses the popular Curve Number (CN). While being appropriate for engi...

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Main Authors: White, E.D., Easton, Z.M., Fuka, D.R., Collick, A.S., McCartney, Matthew P., Awulachew, Seleshi Bekele, Steenhuis, Tammo S.
Format: Conference Paper
Language:Inglés
Published: 2009
Subjects:
Online Access:https://hdl.handle.net/10568/38178
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author White, E.D.
Easton, Z.M.
Fuka, D.R.
Collick, A.S.
McCartney, Matthew P.
Awulachew, Seleshi Bekele
Steenhuis, Tammo S.
author_browse Awulachew, Seleshi Bekele
Collick, A.S.
Easton, Z.M.
Fuka, D.R.
McCartney, Matthew P.
Steenhuis, Tammo S.
White, E.D.
author_facet White, E.D.
Easton, Z.M.
Fuka, D.R.
Collick, A.S.
McCartney, Matthew P.
Awulachew, Seleshi Bekele
Steenhuis, Tammo S.
author_sort White, E.D.
collection Repository of Agricultural Research Outputs (CGSpace)
description The Soil Water Assessment Tool (SWAT) is a watershed model widely used to predict water quantity and quality under varying land use and water use regimes. To determine the respective amounts of infiltration and surface runoff, SWAT uses the popular Curve Number (CN). While being appropriate for engineering design in temperate climates, the CN is less than ideal when used in monsoonal regions where rainfall is concentrated into distinct time periods. The CN methodology is based on the assumption that Hortonian flow is the driving force behind surface runoff production, a questionable assumption in many regions. In monsoonal climates water balance models generally capture the runoff generation processes and thus the flux water or transport of chemicals and sediments better than CN-based models. In order to use SWAT in monsoonal climates, the CN routine to predict runoff was replaced with a simple water balance routine in the code base. To compare this new water balance-based SWAT (SWAT-WB) to the original CN-based SWAT (SWAT-CN), several watersheds in the headwaters of the Abay Blue Nile in Ethiopia were modeled at a daily time step. While long term, daily data is largely nonexistent for portions of the Abay Blue Nile, data was available for one 1,270 km2 subbasin of the Lake Tana watershed, northeast of Bahir Dar, Ethiopia, which was used to initialize both versions of SWAT. Prior to any calibration of the model, daily Nash-Sutcliffe model efficiencies improved from -0.05 to 0.39 for SWAT-CN and SWAT-WB, respectively. Following calibration of SWAT-WB, daily model efficiency improved to 0.73, indicating that SWAT can accurately model saturation-excess processes without using the Curve Number technique.
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spelling CGSpace381782025-11-07T08:34:47Z A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands White, E.D. Easton, Z.M. Fuka, D.R. Collick, A.S. McCartney, Matthew P. Awulachew, Seleshi Bekele Steenhuis, Tammo S. hydrology simulation models water balance soil water infiltration runoff highlands The Soil Water Assessment Tool (SWAT) is a watershed model widely used to predict water quantity and quality under varying land use and water use regimes. To determine the respective amounts of infiltration and surface runoff, SWAT uses the popular Curve Number (CN). While being appropriate for engineering design in temperate climates, the CN is less than ideal when used in monsoonal regions where rainfall is concentrated into distinct time periods. The CN methodology is based on the assumption that Hortonian flow is the driving force behind surface runoff production, a questionable assumption in many regions. In monsoonal climates water balance models generally capture the runoff generation processes and thus the flux water or transport of chemicals and sediments better than CN-based models. In order to use SWAT in monsoonal climates, the CN routine to predict runoff was replaced with a simple water balance routine in the code base. To compare this new water balance-based SWAT (SWAT-WB) to the original CN-based SWAT (SWAT-CN), several watersheds in the headwaters of the Abay Blue Nile in Ethiopia were modeled at a daily time step. While long term, daily data is largely nonexistent for portions of the Abay Blue Nile, data was available for one 1,270 km2 subbasin of the Lake Tana watershed, northeast of Bahir Dar, Ethiopia, which was used to initialize both versions of SWAT. Prior to any calibration of the model, daily Nash-Sutcliffe model efficiencies improved from -0.05 to 0.39 for SWAT-CN and SWAT-WB, respectively. Following calibration of SWAT-WB, daily model efficiency improved to 0.73, indicating that SWAT can accurately model saturation-excess processes without using the Curve Number technique. 2009 2014-06-13T11:40:52Z 2014-06-13T11:40:52Z Conference Paper https://hdl.handle.net/10568/38178 en Open Access application/pdf White, E. D.; Easton, Z. M.; Fuka, D. R.; Collick, A. S.; McCartney, Matthew; Awulachew, Seleshi Bekele; Steenhuis, T. S. 2009. A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands. In Awulachew, Seleshi Bekele; Erkossa, Teklu; Smakhtin, Vladimir; Fernando, Ashra (Comps.). Improved water and land management in the Ethiopian highlands: its impact on downstream stakeholders dependent on the Blue Nile. Intermediate Results Dissemination Workshop held at the International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia, 5-6 February 2009. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.152-158.
spellingShingle hydrology
simulation models
water balance
soil water
infiltration
runoff
highlands
White, E.D.
Easton, Z.M.
Fuka, D.R.
Collick, A.S.
McCartney, Matthew P.
Awulachew, Seleshi Bekele
Steenhuis, Tammo S.
A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title_full A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title_fullStr A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title_full_unstemmed A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title_short A water balance-based Soil and Water Assessment Tool (SWAT) for improved performance in the Ethiopian highlands
title_sort water balance based soil and water assessment tool swat for improved performance in the ethiopian highlands
topic hydrology
simulation models
water balance
soil water
infiltration
runoff
highlands
url https://hdl.handle.net/10568/38178
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