Soil Water Assessment Tool training held in South Africa

Use of the Soil Water Assessment Tool, a comprehensive agricultural and environmental computer modeling tool already employed extensively in the U.S., Europe, Asia and Latin America, is being expanded to South Africa thanks to a collaboration of Texas AgriLife Research entities and others. (Photo courtesy of Texas AgriLife Research)

COLLEGE STATION – The use of an extensive agricultural and environmental computer modeling tool created by Texas A&M University System personnel is expanding to South Africa due to a broad collaborative effort, said project participants.

The Soil Water Assessment Tool is a river-basin scale model developed to quantify the impact of land management practices in large, complex watersheds, according to Dr. Raghavan Srinivasan, professor and director of the Spatial Sciences Laboratory, part of Texas AgriLife Research.

“SWAT is a comprehensive computer modeling tool for addressing landscape processes, watershed channeling processes, plant growth, nutrients, carbon and bacteria – all of which are vital to agricultural and environmental health,” Srinivasan said. “The tool also allows for other inputs for processing real-time data from multiple sources for assessing, maximizing and preserving ‘natural capital’ such as soil and water.”

He noted that more than 800 peer-reviewed articles have been published worldwide by using and applying the model to address water quantity and quality issues.

Bringing this tool to Africa has become increasingly important to studying the various hydrological and environmental processes across that continent, said Dr. Ed Price, director of the Norman Borlaug Institute for International Agriculture, also part of AgriLife Research.

“It can help guide decision making on economic development, land use and agricultural productivity,” Price said. “And while it is being used throughout the world — in the U.S., Europe and across Asia and Latin America — Africa has great need of such informational resources, but so far little has been done to create a SWAT community on the African continent. That is, until now.”

Price said Dr. Tracy Baker, a specialist with the Texas AgriLife Extension Service and research scientist for the Borlaug Institute, recently was invited by Central University of Technology in Bloemfontein, South Africa to deliver the first in what is hoped to be a series of trainings to introduce SWAT modeling to Africa.

The South Africa training was a collaborative effort between the Texas AgriLife Research and Extension Center at Temple, Spatial Sciences Laboratory and Borlaug Institute, he said. The U.S. Department of Agriculture’s Agricultural Research Service in Temple was instrumental in the preparation of training materials.

“The training also was made possible through a new collaborative research partnership in South Africa between the Borlaug Institute and the Howard G. Buffett Foundation,” added Joey King, chief of staff for the Borlaug Institute. “Currently partnership participants are based at a new research station in the Limpopo province, but we expect to build research cooperation with institutions throughout southern Africa.”

King said the South Africa training involved personnel from the Central University of Technology, University of Free State, University of Stellanbosch, Council for Scientific and Industrial Research, and the Western Cape Department of Agriculture.

“SWAT model components include weather, surface runoff, return flow, percolation, evapotranspiration, pond and reservoir storage, crop growth and irrigation, groundwater flow and routing, nutrient and pesticide loading and water transfer,” Srinivasan said. “The training in South Africa was intended to show how the tool can provide an explicit representation of how all incoming water moves through the catchment process in relation to land cover, topography, soil type and vegetative cover.”

Srinivasan said the tool allows the user to study basins of several thousand square miles, divide soil profiles into 10 layers, develop groundwater flow models and show nutrient and pesticide input and output.

“You can also reach modeling language commands to simulate routing and adding flows, including transferring water from channels and reservoirs,” he said. “It also has a graphical user interface using GIS that can accept additional output and measured data and point sources, plus has links for automating inputs.”

He said the modeling system allows the user to estimate water quantities available for extraction at any point and time, and represent the dynamics of soil water, which controls plant growth and chemical cycling.

“The SWAT user can also apply spatially distant controls and consequences to eco-hydrological  modeling that can be quantified and, therefore, valued.”
“Both the Spatial Sciences Laboratory and the Borlaug Institute are committed to partnering with researchers and institutions across Africa to better understand African ecosystems and how that knowledge can be used for the long-term development and conservation of natural resources,” Price said. “It can greatly assist understanding agricultural and environmental issues throughout the African continent.”

For more information on the Spatial Sciences Laboratory and SWAT, go to or .

For more information on the Borlaug Institute and Ukulima Farm, go to and enter the keyword “Ukulima” into the search field.


Editor’s Note: The Soil Water Assessment Tool is a “public domain” model developed by Texas A&M University System personnel at the Texas AgriLife Research and Extension Center in Temple and supported by the U.S. Department of Agriculture’s Agricultural Research Service at the Grassland, Soil and Water Research Laboratory in that city. International SWAT application is coordinated through the Norman Borlaug Institute for International Agriculture and the Spatial Sciences Laboratory of the university’s department of ecological sciences and management. The Borlaug Institute and lab are both entities of Texas AgriLife Research. Some of the agencies, businesses and organizations currently using this tool in the U.S. are: the USDA’s Natural Resources Conservation Service, the U.S. Environmental Protection Agency, environmental consulting firms, Texas river authorities, universities and the National Oceanic and Atmospheric Administration.

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