1. Introduction
Different names has been adopted for the term watershed like Watershed (USA) and drainage basin (USA), catchments
(British), and in some others drainage area. These all would agree that watershed/drainage basin/is an
area drained by a stream of/or a system of connecting streams in such a way that all flow originating in that area
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is discharged through a single outlet. Chow cited by Nigussie [1] stated that the watershed was a divide separating
one drainage basin from another and others have defined it as a geographical unit in which the hydrological
cycle is complete and its components can be analyzed. This geographical unit is one of the possible intervention
points for sustainable land management where monitoring and impact assessment for sustainable land management
could be addressed.
In Ethiopia, there exists an increasing attention toward the improvement of water resources development, integrated
watersheds management, and increasing production and productivity of land resources. Soils erosion
can cause losses of biodiversity, decrease the productivity of land, sedimentation and frequent occurrence of
natural disasters such as floods. Sediments transported from farmlands can bring toxic substances into water reservoirs.
Sediments can also block waterways and cause flood hazards and other associated health problems.
The water carrying capacity of reservoirs can also be lowered dramatically as a result of sedimentation which
will in turn affect the objective and productivity of different investments on reservoirs. Therefore, having a
proper prediction of sediment delivery is an important factor in managing the impacts of sediments for the efficient
utilization of land resources and environmental development efforts. Sedimentation involves soil erosion,
transportation and deposition of sediment processes. Different factors like climate, edaphic factors, land management,
topography, and land cover, human activities etc. are also determinants of sediment delivery [2].
Coarse textured sediments and sediment particles from rill and sheet erosion have a greater likelihood of being
deposited as compared to the fine sediment particles. Therefore, this implies that the transport of sediment
with coarse texture or from sheet and rill erosion is comparatively lesser than the fine sediment or sediment
coming from channel erosion. The concentration of channel within the watershed has a great impact on the
amount of sediment delivery. For instance, a small sized watershed which has a greater number of channels will
have greater sediment delivery ratio as compared to a large sized watershed that has a small amount of channels
in it. In terms of topography too, a watershed with steeply slopes in it will have a greater amount of sediment
transport proportion than a watershed with level and wide topographic orientation. Therefore, in order to overcome
these and other similar challenges and impacts of sedimentation, the integrated watershed management
approach can play a paramount role as it helps to address the different factors in an integral way.
2. Objective
The objective of this paper is to review and explore watershed and sedimentation characteristics in the context of
integrated watershed management approach that will help the promotion of sustained agricultural production.
3. Methodology
For the compilation of this paper, different literatures on integrated watershed management and sedimentation
were reviewed from books, journals and proceedings. Practical field level observations were also captured in the
synthesis of the paper. The paper also identified the major factors that have been observed in the extension of
integrated watershed management approach.