77-9 Predicting Groundwater Sustainability – When Irrigated Agricultural Development Meets Population Growth

Session: Groundwater and Sustainability: Integrating Science, Technology, and Policy

Presenting Author:

Authors:

Abstract:

With burgeoning worldwide population, there is an increasing need for food and water supplies, particularly in the economically developing world. In semi-arid and arid areas with limited water, irrigated agriculture is expanding but there is often a balancing act between developing food sources and supplying adequate water resources to the increasing local population.  This is the case in Niger, Africa where about 49% of its current population is 15 years old and younger, with the population projected to double by 2050 reaching approximately 50 million. Niger ranked as the 6^th poorest country in the world in 2024 and is characterized by desertification, limited rainfall, limited access to potable water, malnutrition, and sizable irrigation withdrawals. Agricultural development is planned in Sia Kouzana, a rural area with small villages in the municipality of Tanda in the Department of Gaya, Dosso Region of southwestern Niger. Most present agriculture is at the subsistence level, with some additional rice fields and small orchards that use groundwater. The numerical groundwater model MODFLOW was used with Aquaveo^®’s GMS version 10.5 graphical user interface for prediction of the impacts of different levels of future agricultural development. Information from 78 wells was used to map the groundwater level and provide transmissivity and groundwater storage parameters. A numerical simulation was run for 173 projected pumping agricultural wells in 173 identified development blocks. Pumping rates per month were specified for each well, and projections of water table decline were made for one-year and ten-years of pumping. Most simulated drawdown of the water table in the shallow Sia Kouanza aquifer did not exceed 1.5m of decline. In two locations the predicted response to pumping, Fomo Tounga and Mangué Koira, the predicted drawdown exceeded 2 meters. In these two areas in particular, agricultural development might dry up existing village wells.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10909

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.