The pressures on ecosystems in combination with the expected effects of CC, as described above, make it necessary for a water manager to develop adaptation strategies to maintain the quality of the ecosystems. In this research the emphasis lies on water-related changes and impacts, so the issues are approached through the perspective of a water manager.
Enhancing the quality of the environment is one of the goals of the water manager, as described in Chapter 1. The other goals are to enhance human welfare, enhance industrial capacity and to enhance food capacity and security. For reaching these goals, the AMR framework (Chapter 1) is developed to structure the development and evaluation of adaptation measures that address policy objectives and the physical state of the water resources system. This section describes the framework, with the emphasis on the environment.
To link the objectives to water quantity and quality, a set of indicators is used, as shown in Fig. 1.10 (p. 18). On the right, state indicators (SIs) represent the state of the water resources system. On the left, objectives are refined in decision indicators (DIs). Note that the objective 'Quality of nature' is elaborated in two intermediate objectives, 'habitat' and 'water quality'. This elaboration is based on a literature survey of concepts such as ecosystem health, ecological integrity and biodiversity (Lorenz, 1999). The quality of nature in a river system depends heavily on habitat (expressed in structure, area and biodiversity) and water quality. The DI describes the state of the (intermediate) objectives. Values of the DIs reflect whether the goals of a decision maker are reached.
There are many different DIs and the managers and decision makers involved have to choose the ones that are representative for goals in their basin. In Fig. 1.10, the DIs that are used in the ADAPT project are described. They enable the evaluation of the performance of measures taken by the water manager.
The state indicators characterize the state of the water resources system (WRS) of a basin in terms of water quantity and quality. Out of the effects of CC on the environment, as described earlier, indicators can be deduced. The environmental SIs based on these effects are: number of floods (environmental high flow), droughts (environmental low flow), temperature of the water and concentration of NaCl and BOD. During the project, other SIs suitable for describing the state of the WRS were developed. These are concentration of PCB, N and P and annual discharge. These indicators can be found in Fig. 1.10 and are described in Box 4.1.
The state and decision indicators are related to each other. If a state indicator changes (thus the water system of a river changes), the decision indicator will also change, and hence can imply that a certain objective cannot be met. Or, the other way around. When, for example, the goal is to bring a certain fish species like the salmon back into the river, the following steps have to be taken. First the current state of the water resources system has to be assessed. For instance, the concentration of fertilizer in the water and the absence of spring floods are the limiting factors for the return of the salmon. These limiting factors can be found through the indicators we assigned to measure the state of the WRS. The next step is to design and implement measures to improve the status of water resources. Such measures could be to reduce cropland near the river and to change reservoir management by allowing more spring floods. The effectiveness of such measure is evaluated through the changing values of the DIs.
With this framework it is possible to show the effects of interventions in the water resources system. It is, however, important to note that only the indicators that are applicable to the regional circumstances in a river basin can be chosen.
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