Land surface drainage and gully development in Ethiopia
Earth and related Environmental sciences
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Sloping farmland is susceptible to erosion induced by high rainfall, seasonal soil saturation and the construction of drainage ditches. Man-made soil drainage has a range of benefits for the farmer s land, although researchers are still divided about the balance of their positive and negative effects which can be both on-site and off-site. A case study area was chosen around Wanzaye (North Ethiopia), where three different cropland management practices were studied in 75 catchments: (i) the catchment-wide use of stone bunds on the contour, (ii) the use of slightly sloping drainage ditches (feses), and (iii) the combined use of stone bunds and feses. A standardized procedure for topographical threshold analysis was applied to study the impact of different land management practices on gully head development in cropland. Topographical thresholds for gully head development reflect the vulnerability of lands to gullying, i.e. s > kA-b, where s represents slope gradient of the soil surface, A the drainage area at the gully head, b an exponent and k the resistance of the land to gully head development. The lowest k-values are found for feses catchments, which implies that catchments with the exclusive use of drainage ditches are the most vulnerable to gully head development compared to mixed catchments and stone bund catchments. Yet, on-site sheet and rill erosion are reduced by the use of feses as they reduce the runoff gradient.
CitationMonsieurs, E.; Nyssen, J.; Verhoest, N.; Dessie, M.; Adgo, E.; Deckers, J.; Poesen, J. (2014). Land surface drainage and gully development in Ethiopia. , Young Researchers Overseas Day of the Royal Academy for Overseas Sciences,