Effects of the short-term regulation of hydro power plants on riverside shoreline recreation use

The short-term regulation of hydropower stations changes the flow and water level situation in the river system. The water level fluctuation influences shoreline recreation use for instance by increasing erosion of river banks and by causing inconvenience on fishing and fastening of boats. Too low water impedes swimming and boating and it can decrease the value of the river landscape. A method to evaluate the effects of short-term regulation on shore line use was developed. Different regulation practices and their effects can be compared. The method is based on the amount on the shift of the shoreline from its preferred position ('optimum zone'), and the daily water level fluctuation. The input data include the slope and the soil quality of the shores and the amount of settlement and recreation usage on the riverside. The input data of the model is collected from field research, maps and literature. The various effects of water level fluctuation are presented both separately and combining different effects. The effects of the shifted shoreline from the optimum zone and water level fluctuation are evaluated separately for each uniform shore section. Various effects are made commensurable and expressed in monetary terms. The assessment model was applied on two areas in the Iijoki river basin and the Oulujoki river basin. The inhabitants and recreation users of the river were interviewed. The results of the interview were compared with the results of the assessment model. The assessment model was found to represent effects in right proportion and it can thus be used to compare different regulation practices. (author)