1. GEF Third Biennial International Waters Conference
Managing Hydrogeological Risks in the Iullemeden Aquifer System IAS (Mali, Niger, Nigeria)
MSP-GEF project
GEF Third Biennial International Waters Conference
Brazil, june, 2005
A. Dodo

2. Situation of IAS in the Niger river basin
Delta Interior ( Km²)
Niger Middle
( km² ):
Niger Superior
( km²)
Niger Inferior ( km²) :

3. Overview of the Iullemeden Aquifer System
Niger
Nigeria
Mali
R. Niger
Mali, Niger, Nigeria
km²
Mali : km² (6%)
Niger : km² (83%)
Nigeria : km² (11%).
Aquifers:
Cretaceaous Continental intercalaire
Tertiary Continental Terminal

4. The Iullemeden Aquifer System is subjected to several real and/or potential risks :
The increase of the water demand because of the growth of the population : 15 millions in 2000, the double in 2025;
A Weak sudden Basin Awareness : groundwater shared;
The Climatic changes;
The mitigation of groundwater recharge rate (because of deforestation: in Niger : weak productivity of the forests (0,1 to 1,5 stere/ha/year) against 87% of the energizing needs between 1,5 and 2 millions tons of firewood per year. In Mali: 90% of the needs of firewood) ;
The silting of the rivers (deforestation, erosion);
The deterioration of water quality because of:
The pollutions: domestic, industrial, mining, artisanal, agricultural;
The groundwater geochemistry of the Continental intercalaire (attendance of Apatite): Bony Fluoroseses.

5. Basin Awareness : Transboundary Shared Water Resources Management

6. Climatic Changes : Annual isoyietal map (mm) in the Sahel part of the SAI: Sliding of isoyietes southwards of about 100 km: decrease of 20% to 30% of the rainfall

7. Mitigation of surface run-off : 20 to 50% to the detriment of the Ecosystem
Mitigation of Niger river run-off at Koulikoro: 23 %
Mitigation of Niger river run-off at Niamey : 36,2%

8. Mitigation of Groundwater Recharge rate :
Dégradation of land forest for firewood
Erosion and silting in Niger river
Installation of sand dunes

9. ● Niger superior in Mali (Pilot experience in152 500 Km²)
Consequences of deforestation, silting : Subsidence of the groundwater table that sustains very weakly or not the run-off
● Niger superior in Mali (Pilot experience in Km²)
(R. Dessouassi et G. Mahé , 1997)

10. Artisanal Pollution : Tannery, Dyeing

11. Excess of Fluoride (6 mg/l) in Continental intercalaire Aquifer
More than 300 victims mainly children irreparably deformed
Bony Fluoroseses
Apatite :
Ca5(PO4)3 (OH, F, Cl)

12. - A state of knowledge of water resources updated in the hole Basin;
- A Common Data base to the 3 countries;
- A Mathematical Models for the establishment of a hydrogeological risks map and for sustainable water resources management;
- An initiation to the Mechanism of Concertation for the joint groundwater resources management and for the monitoring of the relevant indicators of hydrogeological risks
MSP-GEF project gives a good opportunities

13. Thank You