Soil and terrain (SOTER) database for the Upper Tana, Kenya


The Soil and Terrain (SOTER) database for the Upper Tana River catchment, at scale 1:250,000, is the second SOTER database for Kenya, after the first release of Kenya’s national SOTER database at scale 1:1 million.

The SOTER database for the Upper Tana was compiled in the framework of the ‘Green Water Credits’ (GWC) programme by creating a primary database for the hydrologic assesment of the basin. The GWC programme will develop a financial mechanism to reward upstream farmers for protecting their soils from erosion and degradation, thus attaining enhanced water storage. Quantification of water storage and flows is made with hydrologic models. To run such hydrologic models baseline data are required; i.e., soil and landscape attribute data. The Kenya Soil Survey (KSS), a department of the Kenya Agricultural Research Institute (KARI), harmonized the maps and legends of the various studies made in the Upper Tana River catchment, compiled the primary SOTER database by selecting representative soil profiles, and combined the maps of different scales into one digital map. The dataset includes both the original KENSOTER data for the Upper Tana Catchment and new SOTER units and soil profile data taken from soil surveys at 100,000 scale and from other more detailed studies. Gaps in the measured primary data have been filled using a consistent methodology of taxotransfer rules to produce the secondary database (SOTWIS_UT). This data set provides data required for the hydrologic assessment of the catchment, using the Soil and Water Assessment Tool (SWAT). Future Water made this biophysical assessment. The SWAT model projects a.o. the impact of land management on the basin's water balance PDF1, PDF2.

The development of regional and national SOTER databases is part of an ongoing programme of ISRIC – World Soil Information, which is supported by the Food and Agriculture Organisation of the United Nations (FAO) and ISRIC-World Soil Information. The programme is executed under the umbrella of the International Union of Soil Science (IUSS) and aimed at creating a global Soil and Terrain cover and subsequently replace the ‘Soil Map of the World’ (FAO-Unesco 1974).

The SOTER information is presented in shapefile format, while the attribute database is available in tabular Microsoft Access and SQlite format. An overview of the data layers is provided in an ESRI ArcGIS ArcMap document (.mxd) and in a Google Earth file (.kmz).

View the SOTER in Google Earth: click here.

Download SOTER-derived soil property dataset (SOTWIS).