Development and application of a physically based landscape water balance in the SWAT model

White, Eric; Easton, Zachary M.; Fuka, Daniel R.; Collick, Amy S.; Adgo, Enyew; McCartney, Matthew; Awulachew, Seleshi Bekele; Selassie, Yihenew G.; Steenhuis, Tammo S.

doi:10.1002/hyp.7876

Cited by 110 publications

(100 citation statements)

References 38 publications

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“…Two different SWAT-based modelling concepts are used in the modelling of the Blue Nile basin: the original SWAT model that uses the curve number (SWAT-CN) and a modified version that contains a newly developed water balance concept (SWAT-WB) that uses the topographic index to define the generation processes of the surface runoff (Easton et al, 2010;White et al, 2011).…”

Section: Mass Balance Evaluationmentioning

confidence: 99%

Critical review of SWAT applications in the upper Nile basin countries

Griensven

Ndomba

Yalew

et al. 2012

Hydrol. Earth Syst. Sci.

162

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Abstract. The Soil and Water Assessment Tool (SWAT) isan integrated river basin model that is widely applied within the Nile basin. Up to date, more than 20 peer-reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modelling, land use and climate change impact modelling and water resources management. The majority of the studies are focused on locations in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of geographic information system (GIS) based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straightforward even in data-scarce areas. However, the easy use of SWAT may not always lead to appropriate models which is also a consequence of the quality of the available free databases in these regions. In this paper, we aim at critically reviewing the use of SWAT in the context of the modelling purpose and problem descriptions in the tropical highlands of the Nile basin countries. To evaluate the models that are described in journal papers, a number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported the use of unrealistic parameter values. More worrying is that many papers lack this information. For this reason, most of the reported SWAT models have to be evaluated critically. An important gap is the lack of attention that is given to the vegetation and crop processes. None of the papers reported any adaptation to the crop parameters, or any crop-related output such as leaf area index, biomass or crop yields. A proper simulation of the land cover is important for obtaining correct runoff generation, evapotranspiration and erosion computations. It is also found that a comparison of SWAT applications on the same or similar case study but by different research teams and/or model versions resulted in very different results. It is therefore recommended to find better methods to evaluate the representativeness of the distributed processes and parameters (especially when land use studies are envisaged) or predictions of the future through environmental changes. The main recommendation is that more details on the model set-up, the parameters and outputs should be provided in the journal papers or supplementary materials in order to allow for a more stringent evaluation of these models.

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Section: Mass Balance Evaluationmentioning

confidence: 99%

Critical review of SWAT applications in the upper Nile basin countries

Griensven

Ndomba

Yalew

et al. 2012

Hydrol. Earth Syst. Sci.

162

View full text Add to dashboard Cite

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“…For example, Gregory et al [15] simulated the water balance components at the global scale; and Herrmann et al [16] determined the spatial difference of water balance components at the regional scale. Generally, researchers mainly focused on the water balance at the basin or the watershed scale [3,17,18]. Several studies have discussed the water balance across land cover type, vegetation pattern, and ecosystem scale.…”

Section: Introductionmentioning

confidence: 99%

Assessing Variation in Water Balance Components in Mountainous Inland River Basin Experiencing Climate Change

Yin

Feng

Zou

et al. 2016

Water

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Abstract:Quantification of the changes of water balance components is significant for water resource assessment and management. This paper employed the Soil and Water Assessment Tool (SWAT) model to estimate the water balance in a mountainous watershed in northwest China at different spatial scales over the past half century. The results showed that both Nash-Sutcliffe efficiency (NSE) and determination coefficient (R 2 ) were over 0.90 for the calibration and validation periods. The water balance components presented rising trends at the watershed scale, and the total runoff increased by 30.5% during 1964 to 2013 period. Rising surface runoff and rising groundwater flow contributed 42.7% and 57.3% of the total rising runoff, respectively. The runoff coefficient was sensitive to increasing precipitation and was not significant to the increase of temperature. The alpine meadow was the main landscape which occupied 51.1% of the watershed and contributed 55.5% of the total runoff. Grass land, forest land, bare land, and glacier covered 14.2%, 18.8%, 15.4%, and 0.5% of the watershed and contributed 8.5%, 16.9%, 15.9%, and 3.2% of the total runoff, respectively. The elevation zone from 3500 to 4500 m occupied 66.5% of the watershed area, and contributed the majority of the total runoff (70.7%). The runoff coefficients in the elevation zone from 1637 to 2800 m, 2800 to 3500 m, 3500 to 4000 m, 4000 to 4500 m, and 4500 to 5062 m were 0.20, 0.27, 0.32, 0.43, and 0.78, respectively, which tend to be larger along with the elevation increase. The quantities and change trends of the water balance components at the watershed scale were calculated by the results of the sub-watersheds. Furthermore, we characterized the spatial distribution of quantities and changes in trends of water balance components at the sub-watershed scale analysis. This study provides some references for water resource management and planning in inland river basins.

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“…Models developed in temperate climates such as the Agricultural NonPoint Source (AGNPS) Pollution Model (Haregeweyn and Yohannes, 2003;Mohammed et al, 2004), the Soil and Water Assessment Tool (SWAT) (Setegn et al, 2008(Setegn et al, , 2011, and Water Erosion Prediction Project (WEPP; Zeleke, 2000) can only predict monthly trends well under Ethiopian conditions. To account for Ethiopian conditions, Easton et al (2010) and White et al (2010) modified SWAT and replaced infiltration excess runoff processes by saturation excess and switched erosion controls from upland to channel factors after midAugust. For the Blue Nile at the border of Ethiopia and Sudan, decreasing sediment concentration throughout the season seems to be indicative of what is occurring within individual contributing catchments to the main stem of the river network.…”

Section: Introductionmentioning

confidence: 99%

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

Guzmán

Tilahun

Zegeye

et al. 2013

Hydrol. Earth Syst. Sci.

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Abstract. Loss of top soil and subsequent filling up of reservoirs in much of the lands with variable relief in developing countries degrades environmental resources necessary for subsistence. In the Ethiopia highlands, sediment mobilization from rain-fed agricultural fields is one of the leading factors causing land degradation. Sediment rating curves, produced from long-term sediment concentration and discharge data, attempt to predict suspended sediment concentration variations, which exhibit a distinct shift with the progression of the rainy season. In this paper, we calculate sediment rating curves and examine this shift in concentration for three watersheds in which rain-fed agriculture is practiced to differing extents. High sediment concentrations with low flows are found at the beginning of the rainy season of the semi-monsoonal climate, while high flows and low sediment concentrations occur at the end of the rainy season. Results show that a reasonably unique set of rating curves were obtained by separating biweekly data into early, mid, and late rainfall periods and by making adjustments for the ratio of plowed cropland. The shift from high to low concentrations suggests that diminishing sediment supply and dilution from greater base flow during the end of the rainfall period play important roles in characterizing changing sediment concentrations during the rainy season.

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Development and application of a physically based landscape water balance in the SWAT model

Cited by 110 publications

References 38 publications

Critical review of SWAT applications in the upper Nile basin countries

Critical review of SWAT applications in the upper Nile basin countries

Assessing Variation in Water Balance Components in Mountainous Inland River Basin Experiencing Climate Change

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

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