Study of Short-term Longitudinal Profile and Sediment Dynamics of Ikpoba Reservoir

Abstract Complex depositional systems, exemplified by dam reservoirs, pose significant challenges to natural sediment flow in river courses, impacting operational efficiency. This study focuses on the Ikpoba Dam, a critical water source for Benin City, facing functionality issues due to sedimentation. Through repeated bathymetric surveys conducted during wet and dry seasons, the research maps the dam's bed-floor topography. Analysis using empirical formulae and a geospatial approach unveils short-term sediment accumulation dynamics, emphasizing seasonal variations. Results indicate a sediment volume of 400,000 cubic meters in the 2019 survey, translating to 73.33% loss in storage capacity over 44 years, at an estimated rate of 1.66 m^3/year. Verification of bed profile results demonstrates high reliability, with root mean square errors ranging from 90–93%, employing ArcGIS 10.4. Notably, the study identifies a substantial sediment accumulation of 840,127.34 cubic meters. These findings are pivotal for formulating dredging plans essential for dam revamping initiatives, aiming to optimize efficiency while mitigating sedimentation challenges.