SWAT+ and SWAT Model Parameters for: Sasumua River Watershed, Kenya; Simiyu River Watershed, Tanzania; and, Murchison Bay Watershed, Uganda.

<p>Surface and ground water availability in East Africa varies substantially with time and climate, and across subregions. Climate, land use, and land management changes are key factors affecting the integrity of water resources in the region. To facilitate hydrologic and water quality modeling and/or other water resources applications, parameters have been developed for three watersheds in the region. The three watersheds of focus—Sasumua River Watershed (Kenya), Simiyu River Watershed (Tanzania), and Murchison Bay Watershed (Uganda)—represent a variety of landscapes from mountainous to coastal; and threats to water security including urbanization, climate change, and land degradation. The similarities and differences across watersheds make them ideal settings for which to develop initial base parameter sets.</p>

<p>The parameters have been developed using and for use with the Soil and Water Assessment Tool, SWAT/SWAT+ models. Some may be applicable to other models or applications as determined by the user.</p>

<p>The following information is included with the parameter sets: component for which the parameter applies (<em>Component</em>); parameter typically used in model calibration (<em>Calibration Parameter</em>); range of values which said parameter can take (<em>Parameter (Full) Range</em>); initial value of parameter as used in the default, i.e. uncalibrated, model (<em>Default Parameter Value</em>); parameter value following calibration (<em>Final Parameter Value</em>); and, procedure used to determine final parameter value (<em>Variation Procedure</em>).</p>

<p style="margin-left:.25in;">Information is included for the following parameters:</p>

<ul style="list-style-type: none;">
<li style="margin-left: 0.25in;">CN2: Curve number for moisture condition II</li>
<li style="margin-left: 0.25in;">ESCO: Soil evaporation compensation factor</li>
<li style="margin-left: 0.25in;">EPCO: Plant uptake compensation factor</li>
<li style="margin-left: 0.25in;">ABF_LTE/ALPHA_BF: Baseflow alpha factor (1/days)</li>
<li style="margin-left: 0.25in;">GW_Delay: Groundwater delay time (days)</li>
<li style="margin-left: 0.25in;">AWC: Available water capacity of the soil layer (mm H2O/mm soil)</li>
<li style="margin-left: 0.25in;">KSAT/K: Saturated hydraulic conductivity (mm/hr)</li>
<li style="margin-left: 0.25in;">SURLAG/surq_lag: Surface runoff lag coefficient (days)</li>
<li style="margin-left: 0.25in;">PETCO/K_LO: K of lowest layer</li>
<li style="margin-left: 0.25in;">CN3_SWF: Soil water factor for cn3 0=fc; 1=saturation</li>
<li style="margin-left: 0.25in;">LATQ_CO/CNCOEF: Plant ET Curve number coefficient</li>
<li style="margin-left: 0.25in;">FLO_MIN/GWQMN: Minimum aquifer storage to allow return flow</li>
<li style="margin-left: 0.25in;">SLPSUBBSN/SLSUBBSN/slp_len: Average slope length (m)</li>
<li style="margin-left: 0.25in;">APM/adj_pkrt: Peak rate adjustment factor for sediment routing in the subbasin (tributary channels)</li>
<li style="margin-left: 0.25in;">USLE_C/usle_c_min: Minimum value of USLE C factor for water erosion applicable to the land cover/plant</li>
<li style="margin-left: 0.25in;">BIOMIX/bio_mix: Biological mixing efficiency</li>
<li style="margin-left: 0.25in;">EFFMIX/mix_eff: Mixing efficiency of tillage operation</li>
<li style="margin-left: 0.25in;">PHOSKD/p_soil: Phosphorus soil partitioning coefficient (m<sup>3</sup> /Mg)</li>
<li style="margin-left: 0.25in;">PSP/p_avail: Phosphorus availability index</li>
</ul>

<p>The following data series contains complementary datasets that can be used alongside the parameter sets: Historical and Future Precipitation and Temperature Data, and Water Data for Select Stations and Watersheds in Kenya, Tanzania, and Uganda. Version 1.0 of November 30, 2022; Released Nov 30, 2022. DOI: <a href="https://doi.org/10.4231/DG18-V225">10.4231/DG18-V225.</a></p>

<p><strong>Funding Acknowledgement</strong></p>

<p>These parameter sets were made possible in part through support provided by the Innovation, Technology and Research Hub of the U.S. Agency for International Development, through the LASER PULSE Program under the terms of Cooperative Agreement No. 7200AA18CA00009. The opinions expressed herein are those of the author(s) and do not necessarily reflect the views of the U.S. Agency for International Development.</p>