Farming systems in Lake Tana basin, Ethiopia: land surface management and its impact on runoff response
Earth and related Environmental sciences
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Rainfed farming agriculture is dominant in the Lake Tana basin. Soil loss due to water erosion is a severe threat to the subsistence rainfed agriculture and the national economy of Ethiopia. Agricultural land drainage is widely practiced in the Lake Tana basin to forestall the negative effects of excess of water on crops. Drainage is increasingly recognized as a major factor, determining the off-site environmental impact. A lack of cooperation between land users upstream for safe drainage and gully protection can lead to severe downstream gully erosion. Though, there is a lack of knowledge about the on-site impacts of the use of drainage channels. Poor design and obstruction of the drain are a major causes of gully initiation. Overflowing drains wash out surrounding plots and enhance gully development. Two months of fieldwork have resulted in a detailed mapping of 11 catchments with different farming systems. This study focus on the impacts of these farming systems on hydrological processes (runoff response, infiltration, gully development, etc.), with a special focus on drainage as an initiation factor. The selected catchments have been monitored with regard to vegetal status, rill formation and by putting fixed monitor sticks in the drainage channels. By interviewing the owners of the fields in the catchments information about crop rotation, plowing, reasons of drainage channel construction has been gathered. The runoff response has been measured at the outlet of the 11 catchments by routine flow depth measurement and the construction of rating curves by velocity measurements. Two rain gauges have been used during the measurement period. Conclusions will contribute to management strategies to reduce the negative environmental impacts of farming systems. A good management in the upstream basins of the Ethiopian Highlands will be beneficial for the downstream people, including people in Sudan and Egypt.
CitationMonsieurs, E.; Dessie, M.; Verhoest, N.; Poesen, J.; Deckers, J.; Adgo, E.; Nyssen, J. (2013). Farming systems in Lake Tana basin, Ethiopia: land surface management and its impact on runoff response. , 7th symposium of Ghent Africa Platform,