Catchment-based management of sediment yield using a decision support system: An application to the derived Savanna ecological zone of Nigeria

Abstract

Integrated watershed management is the most sustainable strategy to addressing eco-hydrological problems arising from the siltation of waterways and sedimentation of reservoirs. This work reports the development and application of a simple, interactive, and user-friendly sediment yield management decision support system (SYM-DSS). The tool operates by the adoption of different crop management scenarios (land cover) to ensure that sediment concentration in runoff water from agricultural watersheds is minimized to less than a predetermined threshold (16 Kg/m3). SYM-DSS deploys the Modified Universal Soil Loss Equation (MUSLE) as calibrated for the derived savannah ecological zone of Nigeria in the prediction and management of sediment yield. It was developed using the CLIPS (C Language Integrated Production System) expert system shell. SYM-DSS was tested for the control of sediment yield from a small agricultural watershed typical of the Nigerian derived savannah ecological zone. Nash-Sucliffe’s Efficiency Coefficient test was used to evaluate how effective SYM-DSS was in reproducing observed yields of sediment under a soybean crop management within the study watershed. The test gave an efficiency of 86.3%, hence successfully demonstrating the use of an expert system to implement soil erosion models such as USLE and MUSLE. It was noted that a reasonable knowledge of the agronomy of crops is required in the application of SYM-DSS, as the life cycle of the crop should coincide with the annual rainfall regime at the location of application in order to provide maximum cover during periods of intensive rainfall.