Alexandra Lutz, Candidate, PhD1, Jim Thomas, PhD
1, Greg Pohll, PhD
1, Mamadou Keita, Hydrogeologist
2, W. Braimah Apambire
3 and W. Alan McKay
1, (1)Desert Research Institute, (2)Mali Rural Water Project, (3)World Vision United States
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 can be evaluated by a sustainability study. In cooperation with Mali Rural Water Project (MRWP), the Desert Research Institute (DRI) is conducting such a study in a small area of central Mali. A three-dimensional groundwater flow model is developed for a sub-catchment along the Bani River, a tributary to the Niger River. The conceptual model is constructed and run using the software package GMS-MODFLOW. Necessary data for building 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 Mean annual data values are obtained from available published and unpublished studies, and field measurements.
Reasons for choosing the Bani area of Mali for a groundwater study include: the presence of community hand-pumps; availability of surface flow data from several stream gauges on the Bani River; ease of access to hand-pump sites; location of a climate monitoring station in the nearby town of San; and availability of time-series groundwater level measurements at five wells. Additionally, the model area covers the southern Segou Region, which is identified as one of the most highly stressed regions of Mali. In this case, 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 should provide detailed information on current and future sustainability conditions. A limited set of time-series groundwater level data set are used for a transient model capable of forward predictions of several scenarios including increased groundwater extraction rates (for increased population and agricultural use) and/or decreased rainfall due to drought.
The 2007 Ground Water Summit
