Process‐based hydro‐morphometric controls on runoff, erosion, and groundwater recharge in an ungauged tropical crystalline river basin: The Dayi River, Ghana

This study quantifies and interprets the hydro‐morphometric characteristics of the Dayi River Basin to evaluate process‐based controls on runoff generation, erosion susceptibility, and groundwater recharge in an ungauged tropical crystalline river system in Ghana. Using a 30 m resolution ASTER Digital Elevation Model (ASTER DEM), hydro‐morphometric parameters encompassing linear, areal, and relief characteristics were derived. The results revealed an elongated basin with a dendritic drainage pattern, as indicated by a low elongation ratio (0.46), form factor (0.17), and circularity ratio (0.26). The basin further exhibited low drainage density (0.79 km km −2 ), coarse drainage texture (0.32), long length of overland flow (0.63 km), and high infiltration potential, collectively reflecting a structurally controlled hydro‐geomorphic river system with enhanced groundwater recharge. These characteristics regulate runoff distribution, erosion, and groundwater recharge within a dual‐aquifer system, enhancing the basin′s hydro‐geomorphic resilience. The basin‐scale hydrological storage coefficient (1.6) indicates a high storage potential, resulting in attenuated runoff peaks, reduced flow erosivity, and enhanced groundwater recharge through subsurface percolation. Such a storage‐dominated hydrological response indicates that a substantial proportion of rainfall is partitioned into infiltration and subsurface storage, resulting in enhanced groundwater recharge, sustained baseflow contributions, and reduced flash‐flood potential in ungauged tropical crystalline river basins. Watersheds such as Tsatsadu, Tafi, Tsibu, and Tsidje exhibit higher infiltration and reduced erosion, indicating suitability for inland valley rice cultivation, whereas Ahava, Aflabo, Hava, and Koloe show elevated runoff, shorter overland flow, and increased flood and erosion risk. Targeted interventions, including check dams, terraces, afforestation, and sustainable cropping systems, are recommended to mitigate hydrological hazards. By linking DEM‐derived morphometric indices with dual aquifer characteristics, this study provides a transferable framework for watershed assessment and sustainable water management in data‐scarce tropical dual aquifer basins, with applicability to Sub‐Saharan Africa, South Asia, and other tropical regions. The findings contribute to global efforts toward sustainable water management and climate resilience (SDGs 6 and 13), with implications for agricultural water security (SDG 2) in data‐scarce tropical basins.