Implementation of integrated scenario analysis and modelling for the sustainable development of a coastal area in Eastern Mediterranean

Abstract

1 - The gulf of Gera is a semi-enclosed water body located on the island of Lesvos, Greece in Eastern Mediterranean. The main economic activities in the surrounding watershed are related to the primary, secondary and tertiary sectors, among which the former and the latter have increased during the last decade. The primary sector activities include agriculture (mainly oliveculture), fisheries, livestock breeding and aquaculture. The most important industrial activity in the Gera watershed is the elaboration of oil crops, whereas tertiary sector is focused on tourism and services. 2 - Three scenarios of environmental and socio-economic change have been applied in the area: the baseline or reference scenario (Business As Usual, BAU), the policy targeted scenario (Policy Targeted, PT) and the ‘deep green’ scenario (Deep Green, DG). Two versions of each scenario were evaluated, one that considers low and practically non-influential climate change (BAU1, PT1 and DG1) and one that assumes an important influence of climate change (BAU2, PT2 and DG2). A quantitative description of each scenario was developed and simulation was applied for evaluation. Increased nutrient loading was predicted by the model from November to May, especially in winter, during the period of flow of the ephemeral rivers. 3 - The main effect of climatic change in nutrient loading is observed in winter, due to rainfalls of high intensity. The effects of future climatic changes are important since a fourfold increase in surface runoff is predicted by the model. This will increase substantially the frequency of flood events in the watershed, have an important effect on the amount and pattern of the nutrient loads into the gulf and cause problems of erosion. The overall phosphorus loading predicted by the model is higher in the BAU and lower in the DG scenarios, whereas nitrogen loading is almost equal under the BAU and PT scenarios and halved under the DG scenarios.