Development and application of a sustainability index for a lake ecosystem

We modify an existing water quality index of Lake Kinneret to better match the objective of sustaining the ecosystem over time. The Kinneret Sustainability Index (KSI) provides a quantitative indication of how similar the current ecosystem is in relation to a reference state that managers are striving to achieve and sustain once accomplished. As Lake Kinneret is the only freshwater lake in Israel, it is vital to sustain the lake ecosystem over time. The KSI provides lake managers with a means for assessing the state of the lake. The KSI is based on nine ecosystem variables and provides information on each variable and the combined index. We present examples of application of the KSI to lake management and conduct a sensitivity analysis of the underlying assumptions demonstrating its robustness to the assumptions. While the index presented here is specific to Lake Kinneret, it is a general approach that can be readily applied to lakes worldwide and can assist, for example, in achievement of the required good status for European lakes.