Agricultural systems and transnational water management in the Senegal River basin

Abstract

Geografisk Tidsskrift, Danish Journal of Geography 99: 59–68, 1999

This paper examines the relationship between hydrology and the functioning of traditional and modern agricultural systems in the Senegal River valley in West Africa. It will be demonstrated that the traditional flood recession agriculture, relying on the natural floodings of the wide river valley, is declining because of a strong reduction of the inundated area. This is due to both the reduction in rainfall since the early seventies and the construction of the Manantali Dam, controlling the discharge in the Bafin branch of the river. The operation of the dam is presently optimized to satisfy the needs of modern irrigated rice cultivation, yet the development of this cultivation has not entirely lived up to expectations, mainly because of economical and management problems. Therefore, farmers still express a preference for flood recession agriculture, whenever the floodings are suffiently large. In the future, water availability for both the flood recession and irrigated agriculture will be influenced by two major projects: Firstly, it is planned that hydro-electric power production will be initiated at Manantali, which will change the principles of dam operation. Secondly, it is planned to dam the Faleme branch of the Senegal River in order to divert water into the dry fossil' valley system in northern-central Senegal, whereby the discharge in the main river is reduced. It will be argued that hydrological modelling coupled with an economic assessment of costs and benefits of all the effects, including the environmental impacts, are necessary in the decision making process concerning major projects that affect water availability and management in major transnational river basins, such as the Senegal River basin.

Keywords:

• Agricultural systems
• flood recession agriculture
• irrigation
• water management
• Senegal