Eutrophication Management Models

Abstract

In Chapter 3 the relationship between nutrient loads and lake water quality was discussed. The results obtained should now enable us to determine — at least approximately — the load reductions necessary to achieve the required level of water quality (e.g., for the lake to be shifted from a hypertrophic to a eutrophic state). We still do not know, however, how such load reductions can be achieved in practice. What control alternatives are available? How should the lake eutrophication model (LEM) be used in a planning mode? What are the costs, benefits, and constraints associated with such controls? What are the most important trade-offs (e.g., between agriculture, tourism, and environmental objectives)? In other words, we still have to consider the technical and economic implications of various control methods that can be taken within the watershed. A certain level of water quality can be achieved by various management practices. When considering alternative policies the aim is to find the “best” strategy and for this purpose optimization techniques serve as useful tools. Accordingly, most management models involve optimization of some sort, and this is described in this chapter.