Analytical modeling of hydrological processes for effective water governance input: the Nigerian River Basins perspective

Abstract

Climate and economic activities have created gaps between Water Supply and the Users. Effective water governance input; which should fill the gaps, has deteriorated by lack of information associated with water risks. Restoring the governance efficiency was aimed .Specifically; the objective was to harness water hazards from affected ecosystems to the origin by solution-based models. Analytical modeling of hydrological processes showed range of hydrological deficit from −148 to −737 mm/yr around River Basins in Northern Nigeria, while the hydrological excess which ranged from 227 to 807 mm/yr characterized the southern part toward maritime region. In the findings, the River Basins are groundwater importers, whereas the fluvial/surface water bodies are groundwater dependent. Yet, quantity of groundwater depreciates through diminishing Base-flow, following relative decay at level greater than zero as interpreted based on negative values of the Base-flow around riparian regions. These riparian zones have been characterized by woodlands suspected to instigate the groundwater loss via Evapo-Transpiration. The worst case scenarios include Lake Chad and Western Littoral Areas with Base-flow decay indirectly quantified as; −33 mm/yr and −109 mm/yr, respectively. Thus, the entire environmental flow is imminently stressed, indicating possible deterioration of aquatic food chains, as well as revealed why freshwater fish depopulated. Consequently, traditional fishermen among riparian populace resorted to fish breeding in managed ponds, just as others breed in pools at homes. By algebraic/analog model, the study demonstrated that about 50% impact of groundwater loss affects fluvial ecosystem; a need for integrated water resources and land-use management.