Multi‐objective analysis of boating and fishlife interests in Lake Sommen, Sweden

The conflicts between boating and fishlife interests in Lake Sommen and hydroelectric, irrigation and urban water supply uses in the Svartå river downstream of Lake Sommen are examined using a goal programming model. The desired water levels corresponding to boating and fishlife interests in Lake Sommen are specified as minimum goals. The hydroelectric, irrigation and water supply needs in the Svartå river are specified as minimum levels within the constraint set for the model. The model was applied for a range of levels of the hydroelectric, irrigation and urban water supply uses. During the winter periods the lake level goals for fishing and boating are always fulfilled. However, in the dry periods, in which fishing and boating interests are critical, the goals are not met during the summer. Furthermore there appears to be very little flexibility within the present operating system to improve boating and fishing conditions during these dry summer periods.