Groundwater as resource and as archive for environmental change

In this project a model of the Iullemeden basin aquifers in Niger/Nigeria was constructed. It uses all geometric information available in the literature and all pumping test and observation data available in the Ministry of Water and Environment, Niamey. The crucial question looked into is the determination of recharge. Different hypotheses were formulated based on previous research. They concern the relative contributions of plateau areas and “mares” i.e. endhorreic basins to the overall recharge. Environmental tracer data (T, CFC, Cl-) and remotely sensed data were used to approach the problem. A model for the whole aquifer was completed which gives upper and lower limits to recharge rates using a Latin-hypercube sampling scheme in a Monte Carlo approach. In a detailed area the hypothesis is tested using the environmental tracer data and locations of mares found from remote sensing.

Main Publications

Holocher, J., F. Peeters, W. Aeschbach-Hertig, M. Hofer, M. Brennwald, W. Kinzelbach, R. Kipfer, 2002. Experimental investigations on the formation of excess air in quasi-saturated porous media, Geochemica et Cosmochimica Acta, Vpl. 66(23), pp. 4103-4117.

Kinzelbach W., et al., 2002, Groundwater - A survey of methods for analyzing groundwater recharge in arid and semi-arid regions. UNEP Report UNEP/DEWA/RS.02-2.

Contacts

W. Kinzelbach

Agency/Funding

SNF/180 kCHF

Partners

EAWAG, UP Berne, AGRHYMET Niamey, UNEP

Status

To be finished in 2004