The Significance of Water Quality Parameters for Decision-Making in Water Pollution Control – A Case Study: Lake Päijänne in Finland

Abstract

Estimation of water quality impacts plays an important role in the planning of water pollution control. In this paper the connection of water quality aspects with the rest of the planning procedure is examined in the light of a case study area, Lake Päijänne in Finland. For this area an integrated water resource development plan was made by the Finnish water authorities. In order to diminish the adverse effects resulting from effluents of pulp and paper mills and municipalities, different pollution control alternatives were drawn up. Next, forecasts about the development of water quality in different alternatives were made. The most important parameters from the point of view of the different modes of water utilization were taken into account. These parameters were oxygen, phosphorus, COD, lignin and colour. In addition, in assessing the impacts, toxity of effluents was taken into consideration. The impacts of these parameters on the usability and utilization of water areas were analyzed. The forecasts of impacts on vacation settlement, water supply and fisheries were made. In the comparison of the alternatives, numerous intangible factors were involved. In the assessment of the alternatives the costs of water pollution control measures, the benefits and the adverse effects were taken into consideration. The impacts of intangible factors were assessed in each alternative by comparing the water use possibilities with the goals that had been set.