Engineering Assessment of Soil and Water Conservation Works on Agricultural Watersheds in North Central Nigeria

This study conducts an engineering assessment of soil and water conservation works on agricultural watersheds in North Central Nigeria, evaluating the hydraulic performance, structural integrity, and agricultural benefit outcomes of conservation infrastructure. The Middle Belt of Nigeria experiences significant soil erosion and watershed degradation from a combination of deforestation, overgrazing, and intensive cultivation on steep slopes. Soil and water conservation structures including check dams, gully plugs, contour bunds, and bench terraces have been constructed across multiple watersheds in Plateau, Benue, and Kogi States under various government and donor-funded programmes. This study surveys conservation works on 10 agricultural watersheds, assessing hydraulic design adequacy, structural condition, sedimentation performance, and upstream impact on soil moisture and crop yields. Engineering performance is evaluated against SWCS design standards. Beneficiary farmer surveys document perceived benefits and maintenance practices. Findings reveal that 58 percent of surveyed structures show significant structural deterioration requiring maintenance intervention. Check dam sedimentation performance is reducing reservoir capacity at rates above design assumptions due to intensive upstream land use. Farmers in watersheds with functional conservation works report 24 percent higher crop yields and significantly improved dry season water availability. The study concludes that conservation works generate significant agricultural benefits when properly maintained. It recommends a watershed management programme integrating structural rehabilitation with community-based maintenance and upstream land use governance.

Keywords: soil and water conservation, watershed management, North Central Nigeria, check dams, gully erosion.