Why watersheds are a reasonable planning unit
Schütt, B. and Thiemann, St. 2001
Natural resource management is necessary and has to be done in an integrated manner in order to be successful, i.e. to secure the living conditions of local communities as the overall goal of Integrated Watershed Management. Therefore, a planning unit is required within which most vital resources can be managed effectively, collectively and simultaneously (Tidemann 1996). Administrative planning units are not suitable because use and pollution problems do not halt at political boundaries (GTZ 2007). Additionally, upstream-downstream user conflicts are easier to tackle when the common resource can be understood as natural rather than political (Förch and Schütt 2004 b). Thus, only a natural planning unit comes into consideration. Which natural unit for the management of natural resources is the most appropriate one is explained in the following:
- Management of soils is possible on the basis of a soil series or types or any other convenient unit of land.
- Vegetation can be managed according to forest (sub-)type or similar classifications for trees, grass, etc.
- Water can be managed on the basis of watersheds as units, as these are defined by natural hydrology (Tidemann 1996). On this level the movement of water from precipitation to the outlet of the watershed can be traced as well as the sources of sediment and pollution entry into the water courses.
As soil and vegetation resources can also be managed on the watershed level, the watersheds are the most reasonable planning and management units for natural resources (Tidemann 1996). Watersheds as hydrological unit should not be too large in order that these form also a socio-economic unit (Tiffen and Gichuki 2000).
The principles of Integrated Watershed Management are introduced on the following learning page.