Can Land Use Decisions Alter the Water Cycle? The Case of the Ouémé River Basin, Benin

Abstract

The impact of LULC change on hydrological processes (water balance) including surface runoff, lateral flow, baseflow, aquifer recharge and evapotranspiration on land is not fully understood in data-scarce regions such as the Ouémé River Basin, yet is crucial for water availability, flood management and infrastructure design. This study examines how LULC changes affect hydrological processes across multiple temporal periods. Key findings show that: • Forest and Savanna areas have decreased by 4 % and 24 %, respectively, while Agricultural and Settlements/bare land have increased by 1 % and 28 %, respectively from 1986-2023. • These LULC changes increased surface runoff by 32 mm/y from 1986-2023, reducing baseflow (5 mm/y), lateral (6 mm/y) and groundwater recharge (22 mm/y). • Settlements/bare land expansion and Forest loss are strongly linked with increased surface runoff, intensifying flood risks due to higher volumes of water from reduced infiltration, and limiting groundwater availability for domestic, farming and industrial activities. To address these challenges, it is recommended that: • The Ministry of Living Environment and Sustainable Development in collaboration with communities embark on the reforestation of degraded Forests with clear demarcation of the Forest areas and laws to handle encroachment. In addition, training on the benefits of Forests and the effects of deforestation should be provided to communities to improve their knowledge of sustainable Forest management. • Also, the Ministry of Agriculture, Livestock and Fisheries (as part of the Government Action Plan (PAG 2021- 2026) and the Strategic Plan for Agricultural Sector Development (PSDSA 2017-2025) build the capacity of farmers in sustainable agriculture intensification, and conservation agriculture practices (such as plant cover, crop rotation, minimum tillage, etc.), and support those implementing them. The study underscores the crucial need for sustainable farming and urban planning to improve sustainable water resources management.