Prise en compte du risque environnemental dans les systemes irrigues saheliens: Etude de cas au Senegal.

摘要

Insofar as drought characterises the Sahel climate, irrigation has provided the only alternative in developing a viable agriculture. Faced with the ever increasing and varied needs for water consumption, development of a hydro-agricultural infrastructure is a relevant and appropriate public sector strategy to support the participation of the private sector in increasing agricultural production. Paradoxically, the uncontrolled profusion of irrigation systems constitutes a serious threat to sustainable agricultural production in the Sahel.;Field studies conducted as part of this research permit us to assess the risk of salination in the Village Irrigated Perimeters (VIP) of the Middle valley of the Senegal river. But how is this phenomenon to be taken into account in developing sustainable agriculture? The question posed at the beginning of the research led to the hypothesis that: in the Sahel region, it is the lack of, or insufficient integration of existing knowledge of irrigated systems that constitutes the major constraint in achieving sustainable irrigation.;After developing the problem statement and elaborating the major factors involved in sustainable management of a hydro-agricultural infrastructure in the Sahel, the research demonstrates how a classic management and planning approach does not integrate the risk factors associated with the potential degradation of irrigated areas. A critical analysis of sectorial approaches, provides a relatively precise image of the study area: the upper Ngalenka region in the middle valley of the Senegal river.;Observations revealed that the existing Ngalenka management model was far from ideal, which led to the postulate that: degradation of irrigated areas in this region, is due, in large part, to a lack of accounting for environment risk, both in the construction and planning of irrigation systems.;Based on our experience, but equally, inspired by similar experiences elsewhere, we propose an Approach Through Analytic Criteria (ATAC ). This approach is the product of the research and of personal professional experience. ATAC proceeds by combining sets of knowledge of irrigation systems. It generates a control panel, which can be thought of as a set of specifications that can serve as a planning and management tool and as a monitoring instrument of irrigation systems. The discussion that surrounds our analytic schema suggests the approach is somewhat limited in: (i) integrating the multitude of parameters and (ii) the difficulty in weighing individual risk factors. In addition, the schematic diagrams are strongly dependent on information that is often difficult to obtain. One of the major lessons derived from the research focuses on the strategic management of knowledge of both the bio-physical and socio-economic. The object of the research process is the generation of a model or planning approach for the sustainable management of soil and water resources.;Field studies allow the testing of the technical feasibility of the ATAC that demonstrates that ATAC offers a new alternative and a contribution to the research of irrigation systems. In addition, the ATAC facilitates the modelling of complex systems (that contain multiple components) with multiple potential applications.