Modreck Gomo

By Modreck Gomo and Joe Magner

This chapter presents a conceptual discussion of the aquifers that typically occur along river channels and the riparian exchange of water as influenced by valley and channel type and management. Definitions of alluvial and bedrock river channel, based on literature, are provided while highlighting their general attributes and exchange options. Conceptual aquifer models occurring along alluvial and bedrock river channels are then described and presented with respect to groundwater‐surface exchanges and solute fate and transport. There is theoretical reasoning to suggest that channel aquifers and concordant riparian zones can be conceptualized and classified based on valley type and the nature of the river channel hosting the aquifer. The information presented in the conceptual models can be used during desktop studies to strategically plan the optimal management for aquifer and riparian protection and restoration activities subject to anthropogenic risk. Riparian zone management is needed more so today, because basin land use in many parts of the world has advanced to the point of creating both water quantity and quality disequilibrium.

Part of the book: River Basin Management

By Joe Magner and Modreck Gomo

Groundwater comprises about 1.7% of the earth’s total water and over 30% of the total freshwater supply. Is there enough groundwater to meet human, plant, and aquatic life needs? In many parts of the world, yes; however, with changing demographics and concordant land use and climate change, the distribution and availability of groundwater may not be sustainable. This chapter considers some of the current and past stressors of groundwater by using case examples from around the world. We explore hydrogeologic settings where anthropogenic activity has impaired or has the potential to impair human, plant, and aquatic life. Stressors include well pumping, mining, climate change, chemical use, water law/regulation, and manipulation of surface water. These examples serve to inform those concerned about sustainable management and offer insight into the links between groundwater, climate, and land use.

Part of the book: Groundwater

By Kehinde D. Oyeyemi and Modreck Gomo

The research focuses on basement aquifers in crystalline bedrocks, which are vital for groundwater in tropical areas. Geophysical techniques, like geoelectrical resistivity, assess these aquifers’ variability. The study combines geoelectrical soundings with two-dimensional electrical resistivity tomography (2D ERT) to analyze the fractured and weathered zones in Abeokuta basement terrain. This approach delineates the aquifer’s nature, extent, and spatial variability, providing insights into near-surface conditions. Understanding and managing basement aquifers are crucial for ensuring a sustainable and reliable supply of groundwater, environmental preservation, and meeting the water supply of various communities. The hydrogeological conceptual model of the area reveals that the area is underlain by two aquifers system. The shallow water table aquifer system consists of weathered saprolite, while the deeper aquifer system is weathered/fractured basement rock. The vertical electrical sounding (VES) results show the thickness of the shallow aquifer ranges from 5.6 to 9.2 m, and the depths to the top of this aquifer system ranges from 1.6 to 2.3 m. The thickness of the deeper aquifer system ranges from 4.5 to 9.5 m, and the depth of this aquifer system ranges from 8.4 to 18.3 m. The integration of VES and 2D ERT methods enhances the understanding and characterization of basement aquifers, aiding optimal well placement for sustained water yield.

Part of the book: Water Engineering and Sustainability