This paper is concerned with the short-term scheduling of the Iguacu river hydroelectric power system, in Southern Brazil. The system comprises four plants with an unusual high coupling, held by two different utilities. Even though government regulations establishes operation guide lines, utilities have their own interests. A multiobjective framework is adopt to study the operation of the system. Dynamic programming is used to find optimal solutions, with an implementation based on the concept of differential dynamic programming. A case study shows the possibility of obtaining energetic gains with the adoption of non-conventional operation rules and the need of negotiation to avoid wasting energy.10417501755