This paper is concerned with the operation and the control of multi-purpose reservoir systems. The problem involves finding appropriate releases from various reservoirs in the system in order to satisfy multiple conflicting objectives, such as the satisfaction of demands with the required salinity, the minimization of the pumping cost, etc. To solve this problem, we considered two characteristics: multiple objectives and stochastic parameters. The method used is based on the application of stochastic goal programming approach. The implemented model was developed under FORTRAN PowerStation and IMSL library and applied to a multi-reservoir system in the north of Tunisia.