갯벌 매립사업 환경평가 개선방안에 관한 연구

Abstract

Abstract Improving Environmental Assessment in Tidal Flat Reclamation Tidal flats play many important roles in maintaining coastal environment by eliminating inorganic salts and organic matters from land, by purifying sea water, and by providing enriching microalgae to animals through food chains in tidal flat ecosystem. In addition it is noticed that salt plants in the tidal flat works as ’carbon sink. These values of tidal flat have been recognized for a long time, but ’preservation’ has been a dead word for tidal flat in Korea because of urgent demand for ’development.’ Therefore, how to properly implement environmental assessment on tidal flat reclamation is very important. But current methods of environmental assessment on tidal flat reclamation lack of clear guidelines and do not provide enough information to understand and predict potential impacts of tidal flat development on environment. So far, environmental assessment on tidal flats has been implemented without properly evaluating functions, values, and economic cost-benefit of tidal flats. Lack of thoughtful survey, in turn, contributed to excessive tidal flat development. If the current environmental assessment on tidal flat development continues, it will continue to destroy tidal flat. Therefore, to minimize impacts of tidal flat reclamation on environment, the study researched following alternatives: improving EA on tidal flat ecosystem, tidal flat value assessment and economic assessment, and mitigation measures of tidal flat reclamation. First, the study provided methodology to survey profiles of tidal flat ecosystem. It proposed measures to improve survey planning, identification of environmental characteristics, range of survey site, survey period, map-making of habitats of investigation sites, survey of coastal environmental quality and monitoring based upon examining problems of existing survey. Furthermore, it showed methods to predict impacts in the form of checklists. Second, it showed alternatives to existing value assessment of tidal flat ecosystem by examining existing problems of value assessment of pollution purification and marine biota production. In the case of evaluation of marine biota production, the study estimated an ecosystem model to reflect energy flow among ecosystem constituents and examine food chains in tidal flat ecosystem. In the case of value assessment of pollution purification, existing problems were identified as follows; 1) Most of studies rely on BOD removal value of Odum. 2) Attempts to assess value based upon measured function have been not made enough. 3) Most studies based on the field or laboratory are heavy on limited functional groups (mainly microorganisms). 4) Functions of meiobenthos or macrobenthos have been ignored. Particularly, roles of the latter have been underestimated and, high standing crops to other biota and effects of producing crops have been dropped in assessing functions of purification. To solve these problems, this study assessed the value by calculating standing and production crops of biological constituents in tidal flat ecosystem and converting the amount of carbon removed from them according to cost basis of the function of pollution purification of sewage processing terminal. The result shows that the amount reduced by tidal flat ecosystem amounted to about 1000 ton C/㎢/year. This has the value of about 34,000,000(KRW) per ha. In other words, it has 3.3 to 95 times as much as value range (3,600,000 to 12,000,000 (KRW)) of purification set by Ministry of Maritime Affairs and Fisheries. Third, it proposed an alternative to improve economic assessment of tidal flat reclamation. In order to implement effective economic assessment of tidal flat reclamation, the study proposed following improvements; 1) Comprehensive review of diverse functions of tidal flat 2) Development indicators capable of estimating ecological, socio-cultural, and economic functions of tidal flat 3) Development and application of diverse value assessment methods 4) Thoughtful analysis of stakeholder related to tidal flat 5) Establishment of long-term planning for tidal flat management Problem of existing economic assessment of tidal flat development is that economic benefits of development is inflated while environmental and indirect costs are rarely scrutinized. Therefore, there needs to examine the latter more carefully. In addition, diverse alternatives need to be discussed in current economic assessment. Alternatives to develop harbors and industrial complexes in places other than tidal flats should be considered in economic assessment. This study aimed at proposing alternatives to evaluate ecosystem and economic assessment of tidal flat reclamation as to minimize adverse impacts of tidal flat reclamation projects on environment. Eventually, alternatives discussed in the study will contribute to sustainable coastal development through rational environmental impact assessment on tidal flat.