GROUND WATER RESOURCE SUSTAINABILITY IN THE BANI AREA OF MALI

In central Mali, water supply programs are providing rural communities with potable water via the installation of hand pumps. The long-term sustainable yield of the aquifers being tapped is not known, but is evaluated. A three-dimensional groundwater flow model is developed for a sub-catchment along the Bani River, a tributary to the Niger River. Data used to develop the Bani model include: well-level measurements, precipitation amounts, surface-water runoff, recharge rates, and extraction rates (pumpage). Mean annual data values are obtained from available published and unpublished studies, and field measurements. The model area covers the southern Segou Region, which is identified as one of the most highly stressed regions of Mali. Stress is based on the region having ecosystem services that are deteriorating, high population densities, and relatively large levels of poverty. Modeling a stressed area provides detailed information on current and future sustainability conditions. Time-series groundwater level data set are used for a transient model to predict several scenarios including increased groundwater extraction rates (for increased population and agricultural use) and/or decreased rainfall due to drought.