Epsilon Open Archive

Abstract

The purpose of this paper is to present the dynamic model for the calculation of cost effective nutrient abatement for a marine sea with heterogeneous coupled marine basins which differ with respect to fast and slow responses to changes in external nutrient loads. A discrete dynamic model with heterogeneous sites – drainage and marine basins – is developed. The application to the Baltic Sea for achievement of the ministerial agreement among the riparian countries on water quality targets (Helsinki Commission Baltic Sea Action Plan) shows expected results; abatement is increasing over time and Poland faces the largest cost burdens. A specific finding is that, in spite of the complex and interlinked nutrient transports, policy design is facilitated by the stringent phosphorus load target on one specific marine basin, Baltic Proper, which is characterised by a relatively slow dynamic process and large interchange with other basins. The achievement of the phosphorus target in this basin then implies fulfilment of nutrient targets in the other basins. It is also shown that total costs under the dynamic cost effective solution can be considerably lower than the nutrient reduction program suggested by the international ministerial agreement, Helcom BSAP.