Integrated Water Mangement in the Seven Cities Basin

Abstract

The Sete Cidades lake in the Azores, is located in a volcanic crater. Increased frequency of logging (380 hectares of production forests) and the use of fertilizers on pastures and forages (450 hectares) that sustain 750 cows, provide direct employment to 67 farmers and induce employment to more 50 actives, but also increases the eutrophycation and sedimentation of the lake. To address the issue an integrated model generates efficient land use scenarios for different degrees of phosphorus emissions with related effects in the water quality. The model is used to obtain various indicators for each scenario that feed a multi-objective program able to find the dominant solutions. The final solution is chosen by the politicians: 600 cows that produce 3.0 millions of milk, provide direct employment to 55 farmers and induce employment to more 41 actives. This, jointly with a partial stream deviation, allows a reduction of 63% of the phosphorus load to the lake. Compensatory measures pay the farmers their losses and compensate the community for the lost employment. Keywords: integrated water management; decision support system; Azores