Quantifying Ecosystem Service Values of Freshwater Wetlands in the North Central Zone as an Environmental Engineering Planning Tool

This dissertation quantifies the ecosystem service values of freshwater wetlands in Nigeria's North Central zone and develops an original environmental engineering planning framework that integrates these values into water resource infrastructure and land use planning decisions, addressing the systematic undervaluation of wetland ecosystem services that has contributed to their degradation. The North Central zone contains extensive freshwater wetlands along the Niger, Benue, and their tributaries, including the Lokoja confluence floodplains, the Kainji and Jebba reservoir littoral zones, and numerous seasonal valley-bottom wetlands in Benue and Plateau States. These wetlands provide provisioning services including fisheries, water supply, and irrigated agriculture, regulating services including flood attenuation, groundwater recharge, water quality improvement, and carbon sequestration, and cultural services, but these values are rarely quantified in monetary or comparative terms that can inform engineering planning. The dissertation develops and applies a spatially explicit ecosystem service valuation framework using a combination of production function methods for provisioning services, avoided cost methods for regulating services, contingent valuation for cultural services, and InVEST habitat quality modelling for biodiversity support. Field data collection for biophysical service quantification was conducted across twenty-eight wetland sites. Economic valuation employs local market price, replacement cost, and stated preference methods. The original theoretical contribution is an Environmental Engineering Wetland Value Integration Protocol that translates ecosystem service valuations into forms usable in engineering cost-benefit analysis, multi-criteria decision analysis, and environmental impact assessment. Keywords: ecosystem services, freshwater wetlands, North Central Nigeria, valuation, environmental planning.