Award Date

5-15-2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geoscience

First Committee Member

David Kreamer

Second Committee Member

Wayne Belcher

Third Committee Member

Gabriel Judkins

Fourth Committee Member

Jeremy Koonce

Fifth Committee Member

Krystyna Stave

Number of Pages

195

Abstract

Groundwater is important in regions where water resources are not abundantly distributed such as arid and semi-arid regions. In many countries in Africa, groundwater serves as the most reliable source of water supply and supports over 50% of the African population. Groundwater is stored in underground water-bearing permeable rocks, rock fractures, or unconsolidated materials known as aquifers. Groundwater can be transboundary, meaning it crosses international political boundaries between two or more sovereign states. Transboundary aquifers are prone to overexploitation that depletes the groundwater resource and can cause a lowering of the water table and possible ground subsidence. Overexploitation in transboundary aquifers can also cause saline water intrusion, that is, the flow of seawater (in coastal areas) or brines into the aquifer. Saline water intrusion contaminates the groundwater and leads to the degradation of the groundwater quality.

The Iullemeden Aquifer System is a transboundary aquifer shared by Algeria, Benin, Mali, Niger, and Nigeria. It covers an area of 620,000 km2 (490,000 km2 in Niger and 64,000 km2 in Nigeria) and supports a population of more than 40 million. In this research, the transboundary aquifer between Niger and Nigeria is studied. A conceptual model, 3D hydrogeological framework (HFM), numerical model with MODFLOW-NWT, a predictive climate change model, drought model, and particle tracking model using MODPATH is used in this dissertation. The goal is to characterize the aquifer system between Nigeria and Niger, assess the groundwater-flow properties for each country, explore the effects of climate change to the aquifer system, assess the sustainability of groundwater resources for human activities during an extended period of drought, and evaluate potential transboundary contaminant pathways.

This dissertation research is in three parts (3 research). The first research focuses on the development of a steady-state numerical model that characterizes the aquifer and is used as initial condition for predictive modelling. The results of the first research showed that recharge from precipitation is the main source of water to the aquifer, groundwater flows generally from the west to the east, and there is flow of groundwater across the boundary of the two countries in both directions. The second research uses a predictive model to explore the effects of climate change on the aquifer system. The results showed that climate change and population growth posed a major threat to the Maradi and Niamey regions as the greatest declines in groundwater were in these locations. The third research assesses the sustainability of the aquifer system in an extended period of drought and evaluates potential contaminant pathways between Nigeria and Niger. The results showed declines in water levels, leading to the drying up of wells and water availability concerns for Maradi and Niamey. The results also indicated that groundwater particles move across boundaries and could possibly originate from outside the study area.

Keywords

Africa; Climate Change; Groundwater; MODFLOW; Numerical Modelling; Transboundary

Disciplines

Earth Sciences | Geology | Hydrology

File Format

PDF

File Size

4600 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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