Integrated management of the scarce river water of the Upper Niger basin
BackgroundThe Inner Delta of the Niger River in Mali is one of the largest riverine floodplains in the world. Since the area is situated at the southern edge of the Sahara, where local rainfall is very limited, its flooding fully depends on the supply by the river. The Niger originates in the rain forest of Guinea-Conakry where the annual rainfall amounts to 2500 mm per year. However, the annual rainfall in the catchment differs from year to year. This causes variation in the annual peak discharge between 2000 and 10000 m3/s. Due to this variation, the water level in the Inner Delta rises some years up to 7 m while in others it may not reach more than 4.5 m, resulting in a variation of total inundated area between 10.000 and 45.000 km2.
 |
Nearly one million people try to make their living in the Inner Delta as fishermen, cattle breeders or farmers. They fully depend on the natural resources found within an area of 50.000 km2. The annual production of fish and rice is determined by the river discharge and is insufficient to feed the local people in the drier years.
  |
Years with a peak discharge below 4000 m3/s occurred only twice between 1900 and 1980, but it has rarely been above this level during the last 20 years. This decrease is partly due to a reduced rainfall in the catchment area of the Niger, but can also be attributed to two dams in the river, upstream of the Inner Delta. At the Markala dam, an amount of 2.5 km3 water is taken each year since 1950 to irrigate 40.000 ha. 2.5 km3 is only 3% of the total river discharge if there is much water, but a similar amount in a poor year is equivalent to 16% of the total river discharge. The Selingué dam is used since 1982 to produce electricity for the capital, Bamako. Due to this dam, a similar amount of the peak river discharge might be withheld in the constructed lake. Both dams together therefore have a considerable impact on the water levels and total area of inundation, particularly in the drier years.
 |
Aim
The aim is the development of a decision-support system for river management in the Upper Niger, in which ecological and social-economical impacts and benefits of dams can be analysed in relation to different water management scenarios.
| Partners Mali Direction National de l’Hydraulique Direction National de la Conservation de la Nature Institut d’Economie Rurale Ministère de l’Environnement Office de Niger Operation Pêche Mopti Operation Riz Mopti Operation Riz Segou Wetlands International - Mali The Netherlands RIZA (lead) Wetlands International (lead) Altenburg & Wymenga Alterra, Wageningen-UR Instituut voor Milieuvraagstukken WL | Delft Hydraulics |
Short project description
Involve in the decision process social-economic factors at the regional and national level, and ecological factors at the international level. The model will clarify the often conflicting interests and will provide the necessary analysis that will help to balance them:
• power generation
• food production in the irrigated areas
• food production in the seasonal floodplains
• international biodiversity values of the river basin.
Output
A decision support system for integrated river management, based on a sound hydrological, socio/economic and ecological data set, supported by the Malian governmental partners.
| For further information, please, contact: Mr. Leo Zwarts RIZA P.O. Box 17, 8200 AA, Wageningen, The Netherlands  + 31 320 298411 l.zwarts@riza.rws.minvenw.nl www.riza.nl |
|
  |
