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. 2012. Socioeconomic response to water quality: a first experience in science and policy integration for the Izmit Bay coastal system. ABSTRACT. Deterioration of the Izmit Bay ecosystem, mainly caused by heavy industrialization and urbanization, has significantly impaired its beneficial use and resulted in the surrounding coastal zone losing its attractiveness for the inhabitants. An integrated coastal zone management approach has become an important requirement of future development plans to protect this fragile bay ecosystem. One of the main indicators of deterioration of the Izmit Bay coastal system is the decreasing water quality resulting from increased nutrient loads from the surrounding land.The consensus during the initial stakeholder meeting confirmed the widespread awareness of this phenomenon and "improvement of water quality in Izmit Bay" was determined as the main policy issue at stake. Public perception of and satisfaction with water quality were measured by a willingness to pay (WTP) survey. The WTP for improved water quality was analyzed using the contingent valuation method. According to the questionnaire survey, 55% of the participants are willing to pay to increase the water quality. Impact of water quality on realestate values was evaluated by hedonic pricing method, which is suitable for estimating direct and indirect use values of water resources. These results were used in a simulation model to assess coupled ecosystem, social, and economic system functioning of the Izmit Bay in response to various scenarios, and thus, to permit the necessary actions to be taken proactively. Two scenario simulations, for which domestic and runoff nitrogen loads are reduced independently, showed that hypothetical domestic wastewater treatment resulted in an improvement in simulated water transparency. The results suggest that domestic wastewater treatment should be a first priority for local administrations.

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Benthic macroinvertebrates, macroalgae and phytoplankton constitute the Biological Quality Elements (BQE) proposed in the Water Framework Directive (WFD, 2000/60/EC) to be used for the classification of the ecological status of a water body.Chlorophyll-a is a usefull expression of phytoplankton biomass and this indicator is an effective and relevant BQE for coastal ecosystems which is universally accepted. In the present study, interpretations of the class boundaries according to normative definitions of WFD, are presented for chlorophyll-a in South Eastern (SE) Black Sea. Water quality classification was determined in five different categories as "high, good, moderate, poor and bad". The coastal waters of SE Black Sea were classified in 8 different typologies (K1-K8) based on depth, salinity and substratum types. In this study, types K1 and K2 (>17.5 salinity, >30 m depth) were considered because of availability of time-series data for those typologies. Sinop and Sürmene sites were selected due to the best available long-term chlorophyll-a data set, respectively over the period of 2002-2010 and 2001-2011 for chlorophyll-a respectively. Type specific chlorophyll-a (Chl-a) reference and threshold values were determined based on the 90th percentile of the long-term collected chlorophyll data set. Due to the high seasonal variability of phytoplankton biomass, the annual values were not considered adequate and the classification tool was developed on seasonal basis. The High/Good (H/G) and Good/Moderate (GM) boundaries were defined as seasonal from the long term data sets for Sürmene and Sinop sites. All the boundaries were higher at the Sinop site.Ecological quality ratios distributed between 0-1. It would be necessary to underline the fact that these class boundaries might be higher for waters where depths are below 30 m and salinity values are less than 17.5. However, there is not enough data to support this assumption for the near coast waters of the SE Black Sea. Eventhough Chl-a scaling can not be used as a single tool for the ecological quality classification it is a reliable approach to use the obtained boundaries at temporal and spatial scales for the quality classification of SE Black Sea waters above 30 m depth.