Evaluating the desertification risk assessment tool with local experimental results |
|
Author: Victor Jetten
Introduction Cape Verde has been facing to severe environmental problems impact for the people living in the island. In order to control desertification (drought, storm runoff, erosion) the government has been taking actions regarding biodiversity conservation, ecosystem management and better valorisation of water resources. Slanting terraces as a form of conservation are widespread, but in the dry climate vegetation cover is low and the terraces do not always have the desired effect. The experiment aims at improving the system with vegetation barriers.
Desertification indices The desertification risk calculated is water erosion. The calculated risk is moderate (3.23). Introducing slanting terraces and runoff barriers lowers the risk to moderate (2.94) if the angle of the terraces is low (< 2%). When the edge of the terraces are planted this is translated to an increase in cover and runoff control measures the risk is further decreased to moderate (2.51).
Conclusions The desertification risk assessment tool correctly identifies the risk for water erosion in this area but the effect of the terraces is not very clear, a lowering of the slope angle seems to have very little effect.
|