Development of irrigated agriculture along the Niger River and in the pastoral zone micro-sites of high marginal productivity produces economic gains, though it may be accompanied by environmental and social costs. Often these costs are hard or impossible to estimate and consequently are excluded from development decisionmaking. To better include environmental and social values in development planning, a computer model has been developed which integrates both quantitative and qualitative values. Using quantitative tools when possible, in conjunction with a qualitative index, different scenarios are simulated. Diversified agricultural production appears to yield the greatest net economic benefits and minimize environmental costs according to indexed analysis. A series of brief case studies is included among the appendices. (Author abstract, modified)
