지속가능한 하구역 관리방안(Ⅲ-1)

Abstract

Development of Sustainable Estuary Management Strategy in Korea Ⅲ(Current Status of Esturies and Estuary Management) Abstract In this first report for the Sustainable Estuary Management Strategy Project, the aim is to understand environmental problems in the major estuaries in Korea, as well as strategies and measures to solve them. In this study, we investigated the current general status of 17 estuaries. More in-depth studies were conducted in this study, and specific management strategies are suggested for four major estuaries, the Han, Youngsan, Sumjin, and Nakdong River estuaries. The human population density of the 17 Korean typical estuaries is 1,324 people per ㎢, which is 2.8 times the average population density in Korea. In addition, the population growth rate in estuarine regions increased more than the national growth rate of 2.8% to about 3.6% from 1997 to 2002, further suggesting that Korean estuaries are under high pressure from development. The First and Second ’Reclamation Plans to Publicly-Owned Water Surfaces’ (1991~2011) indicate that 22.6% (146 sites) of all planned reclamation areas are located in estuaries, and reclamation in estuaries accounts for 42.8% (427㎢) of all reclamation land. If reclamation projects are conducted as planned through 2011, 30% more remaining wetland be destroyed relative to the amount in 2002. More than 300,000 enterprises including 77 industrial and rural industrial parks are located on estuaries. The cargo volume of ports located in estuaries is 426,600 revenue tons, accounting for 46% of the total national cargo volume, and during the last decade this volume had an annual growth rate of 6.8%. High development pressure has led to common environmental problems in most of estuaries in Korea, including restricted water circulation, estuarine wetland destruction, decreased biological diversity and natural resources, and water quality deterioration. Most of the major Korean estuaries have estuary barrages that block water circulation and ecological pathways of fish travelling upstream and downstream. The water enclosed by the barrages is of very low quality, with level III and over. Levels of heavy metals in fish and shellfish in the Geum, Mankyoung, and Dongjin River estuaries exceeded the standards for marine products. In addition, some estuaries with steel mills or shipyards, such as the Han, Sumjin, Taehwa, and Hyoungsan River estuaries, are polluted with hazardous organic substances and tributyltin. The geomorphological and biological diversity of estuaries in Korea are lower than others worldwide; in particular, the biodiversity indices of estuaries heavily disturbed by river-mouth barrage are below 10 endangered species present, and geomorphological diversity is so low that fewer than three geomorphological components among 19 components. In addition to these common environmental issues, other problems such as solid waste inputs from stormwater and damage from salt water intrusion also urgently require solution. However, no policy exists to manage these environmental problems, and definition of "estuary" and estuarine management concept are absent from the more than 50 environmental laws in Korea. The administrative division of environmental management in Korea between the Ministry of Environment (MOE) for lands and the Ministry of Maritime Affairs and Fisheries (MOMAF) for sea has complicated Korean estuarine management. This Fragmented management system has been an obstacle to developing comprehensive national strategies to control unnecessary development of estuaries and mechanisms to solve conflicts related to the multi-purpose uses of estuaries. The lack of a strong knowledge base to support the development of policies for estuary management are also fundamental obstacles to effective estuary management. Research to date has only focused on determining the present status of estuarine ecosystems; therefore there are insufficient data, such as physical aspects of estuarine circulation and the characteristics, ecological functions, and structures of habitats in estuaries, for solving pending estuarine problems. We conducted more in-depth research in the Han, Youngsan, Sumjin, and Nakdong River estuaries, and provide indications on how to sustainably manage environmental problems in these areas. The Han River estuary has been well preserved because of political reason such as an establishment of demilitarized zone (DMZ), and we define the management objective of this estuary as "Preservation of the Unique Estuarine Ecosystem and Restoration of Abundant Natural Resources". The action goals of this management plan may include the designation of a wetland protection zone, environmental improvements to help the recovery of marine resources such as yellow puffer, and proper land-use management for sustainable estuarine uses. Specifically, to accomplish the above goals, five management strategies and 27 core projects are suggested. They include the designation and wise management of a Wetland Protection Area (inland wetland on the Han River, tidal flat on the south part of Ganghwa county); the implementation of a total pollution load management system to improve water quality; strict land-use regulations in sensitive areas such as riparian zones; the introduction of a development rights transfer system to compensate for stricter land-use regulations; and the implementation of an integrated estuary management program to strengthen the base of estuary management. The management objective for the Youngsan River estuary is defined as "Improvement of Youngsan Reservoir Water Quality and Restoration of Ecosystems and Culture", given the water quality problems and recent projects to recover endemic culture and associated historic sites in the area. Action goals for this objective include improving the water quality of the Youngsan Reservoir to better than level II, modifying the estuary barrage structure as a landmark for sustainable development and local identity, and reviving historical and cultural assets around the Youngsan River. To implement these goals, 28 core projects in five areas are suggested. The projects include modifying the estuary barrage structure to improve water quality and to provide for multi-purpose uses of the estuary, introducing a ’No Net Loss of Natural Shoreline" policy to establish a coastal eco-belt for tourism, designating Environmental Management Zones, and implementing land-use management. The Sumjin River estuary is one of the few natural estuaries remaining in Korea and has typical estuarine environmental problems, such as salt water intrusion to Corbicula habitat and variation in the range of salt water intrusion probably because of the excessive extraction of groundwater. The Sumjin River has been well preserved upstream; however, Gwangyang Bay near the downstream in the River is one of the most deteriorated coastal bodies of water in Korea. Considering these unique characteristics of the Sumjin River estuary, we suggest the management objective of "Maintaining Sound Estuary Circulation and Improving Ecosystem Health". Specific action goals include solving conflicts between stakeholders caused by increasing seawater intrusion, recovering specialized marine products such as Corbicula and sweetfish, and improving water quality in Gwangyang Bay for sustainable estuary use. We suggest 27 core projects based on five management strategies. Examples of core projects include modifying stream weirs to maintain and preserve the estuarine ecosystem, installing fish passages in weirs, redefining dry season streamwater flow, adjusting the amount of effluent water in the upstream dam, introducing a total pollution load management system in Gwangyang Bay, reconsidering development demands arising competitively between central and local governmental agencies, reconsidering the validity of a reclamation plan as part of the environmentally-friendly development of a free economic zone, and developing an integrated estuary management modeling system for building an estuary management base. The Nakdong River estuary, which provides habitat for migratory birds and is a highly valuable natural environment, has many designated protection zones, and relatively large amount of research has been conducted on this system. However, since the free economic zone was designated around Busan, large-scale development projects have initiated high development pressure on the estuary. Therefore, preventative and integrated management strategies solving pending environmental problems and accepting a reasonable development pressure while preserving the estuarine ecosystem should be established. The management objective for the Nakdong River estuary is "Creating an Estuary with Abundant Natural Resources and Promoting Harmony between Humans and Nature". To accomplish this objective, 26 projects have been outlined, such as the management of valuable ecosystems and habitats, comprehensive management considering human life and estuarine ecosystems, environmentally-friendly small-scale development and support for local residents, and implementation of a comprehensive estuary management scheme. The projects also include management of stream islands, the conversion of agricultural lands to wetlands, improvement of water quality in West Nakdong River, implementation of a land-use system through the establishment of a land-use plan, the integrated application of estuary maintenance plans, and implementation and operation of the Nakdong River Estuary Program. Development of Sustainable Estuary Management Strategy in Korea Ⅲ(Estuarine Wetland Loss and the Economic Value of Estuary) Abstract Despite intense debate concerning ecologically sound estuary management, strong foundations and progress in estuary management have been rare in Korea, probably because most people do not recognize the importance and ecological value of estuary function. Studies conducted in Korea and worldwide have shown the necessity of estuary conservation plans and management strategies. However, domestic Korean research on estuarine value is in the early phase. To effectively manage and conserve estuarine wetlands, this research has attempted to quantify estuarine wetland loss during the period from the 1910s to the present decade and to evaluate the environmental values of the representative estuaries. Different types of wetlands located in an estuary are considered important factors affecting the estuary ecosystem and its environmental value; however, analysis of topographic maps from the 1910s to the 2000s indicates that the diversity and amount of this wetland has decreased. The ratio of estuary wetland to entire estuary area was nearly 8.81% in the 1910s, but decreased to 7.96% in the 1970s and in the present decade is no more than 2.73%; most wetland loss has been caused by large-scale reclamation during the 1970s-1980s. The estuaries with relatively higher percentages of wetlands in the 2000s are the Gahwa(5.96%), Han(3.94%), and Tamjin(3.20%). The Sumjin and Youngsan estuaries have been developed intensively in the past few decades, with 0.71 and 1.00% wetlands remained in the 2000s, respectively. To promote environmental policies and management plans, it is necessary to evaluate the economic value of estuarine wetlands. Here we first attempted to understand the factors affecting wetland value using a meta-regression analysis. Analysis of existing data showed that the wetland value per unit area is not greatly influenced by wetland function but valuation method. Moreover, there was a close positive correlation between wetland size and ecological value. This research suggests that the benefit-transfer method, which was used in the second year of the this study, is consistent for evaluating the economic value of estuarine environments in Korea. Although the value of the whole estuarine environment depends on estimation methods, the national economic environmental value of the Sumjin River estuary is 28.95 billion won per year, using the contingent valuation method. That of the Nakdong River estuary is 51.34 billion won per year. Interestingly, most people who think that either the Sumjin or the Nakdong River estuary is valuable have not actually been there, indicating that estuary conservation and management is meaningful to the public in aspects of non-use values, such as existence itself or conservation for future generations. The estimated emergy (renewable emergy+nonrenewable emergy) of the estuary environments based on an emergy model is as follows; Han estuary, 5 trillion 260 billion Em; Youngsan estuary, 930 billion Em; and Sumjin estuary, 2 trillion 70 billion Em. To extract the relative importance of a wetland using comparative analysis of emergy per unit area (ha) of estuary, the environmental value of emergy represents the contribution to the region’s economy; that of the Han estuary is 11.85 million Em. and the Youngsan estuary is 5.97 million Em. The value for the Sumjin estuary is 17.63 million Em., i.e., higher than that of the other two estuaries. Therefore, based on this comparative analysis, the Sumjin estuary has the greatest conservation potential. Benefit transfer through meta-analysis, the contingent valuation method, emergy models, and other methods used in this study to quantify the environmental value of estuaries should be applied differently according to the goals, assumptions, and uncertainty of each method, as there are limits to the quantitative abilities of each method. However, more effective estuarine environment management and policies will be possible with increased knowledge of estuarine wetlands and environmental value. Development of Sustainable Estuary Management Strategy in Korea Ⅲ(Estuary Management Plans and Programs) Abstract The Problems with managing estuaries include the following; the lack of definition or geographic boundary of estuaries, a lack of integrated management of terrestrial- and aquatic-estuarine ecosystems, inadequate management systems for dealing with complex tradeoffs between environmental quality and economic development, a superficial knowledge of estuary management, and not incorporating local opinion in estuary management systems to resolve existing issues. This goal of this study was to develop estuary policy to effectively overcome these problems. Estuaries are expected to be treated as management units, and the management strategies should be developed rationally in this study. Moreover, the quality of life of local residents should be improved by the conservation of estuarine ecological value. First, to embody a concept of sustainable estuary management, we envision estuaries as bountiful residential zones, and the target of estuary policy will be an effective use of estuary resources. The development system based on local opinion and current estuary status can result in an ecologically healthy estuary. To achieve these goals, five major management strategies are suggested: estuary preservation, estuary enhancement, estuary restoration, fundamental knowledge expansion, and development of estuary management systems. An estuary conservation policy is proposed to raise the effectiveness of estuary ecosystem management through effective management plans for protected areas. This nationwide estuary management strategy consists of 13 factors: the additional delineation of protected areas near small- or medium- scale estuaries, the construction of a National Institute for Integrated Coast and Ocean Protected Areas to obtain the management goals, the adoption of new guidelines to maintain natural coastlines to protect estuary ecosystems through ’set-back’ systems, and the proposed zoning of a buffer area 500 or 1,000m from the coastline. In addition, to limit misuse of nearby rice paddies within estuaries, strict regulation and eco-friendly agricultural systems are encouraged both at the national and local levels. We also examined introduction of a Transferable Development Rights (TDR) in land purchase system. These systems do raise the effectiveness of estuary habitat management, especially can be used to rationally manage land use and land ownership around protected areas. The development of special management programs is proposed to solve environmental problems by considering the type and degree of problem. Four socio-economic programs and 108 projects are included: in the Han estuary, an estuary ecosystem preservation and natural resources restoration program; in the Youngsan estuary, a water quality improvement and water circulation restoration program; in the Sumjin estuary, a program to protect estuary against salt water intrusion and to restore estuary resources; and in the Nakdong estuary, a utilization and development model program. Each program and each estuary is ssociated with different objectives, management targets, policy directions, action plans, and projects. A national policy for two aspects of estuarine restoration is proposed, i.e., the restoration of degraded estuarine wetlands and the restoration of estuary circulation interrupted by artificial constructions such as weirs, dams, and estuary dikes. Habitat restoration to create floodplains is required to comply with recent flood control policy changes. The restoration of water circulation in estuaries is proposed through the improvement of existing estuarine structures. Estuary facilities and operations should be modified to achieve various goals such as floodwater storage, water quality, ecological corridor, stream flow, and environmental education. In particular, management to restore water circulation in estuaries involves the removal of estuary dikes/weirs and changes to the operation of estuary facilities. Management improvements should proceed gradually and in steps, such as estuary facility function estimation, development of an estuary circulation restoration model project, and an estuary dike structure improvement project. In this study, we recommend the Sapgyo and Youngsan Reservoirs as targets for estuary dike structural improvement projects. Because of the various kinds of knowledge required to effectively manage estuaries, we propose a monitoring program and systematic support for estuarine research related to estuary management. Included in estuary-related studies are techniques for the cutting-edge implementation of wetland creation and restoration. Both the Ministry of Environment (MOE) and the Ministry of Maritime Affairs and Fisheries (MOMAF) should cooperate with estuarine investigations and research, detailed investigations of small- and medium-scale estuaries, the construction and operation of estuary monitoring systems, and the establishment of estuary research groups. To support systematic progress in estuary management, 10-year milestones should be developed for field-based surveys, research projects, and restoration techniques. To more effectively support estuary management, we propose an estuary management system integrating the management plans of the MOE and the MOMAF. The goal of this plan, the Estuary Management Master Plan, is to improve communication and coordination between central ministries and agencies, and to manage funds for estuarine research, surveys, and awareness programs. For this purpose, an estuary management committee will be organized at the local level to coordinate environmental conflicts and develop estuarine management plans. Also, the estuary management advisory committee can play an important role in building estuary programs and policies, such as establishment and estimation of estuary management action plans for the control of complex problems, as well as estuary investigations, research, and public awareness on estuarine ecosystems. To systematically support estuary management and policy, the following four legislative options are compared and examined. The revision and update of an existing law, the establishment of an estuary management law, the establishment of an estuary restoration law, and the establishment of a ’○○ estuary management special law’ are described as four alternative ways to solve estuarine management problems. The enactment of an estuary restoration law is needed for the organization of an estuary restoration plan. Executive office at the national level, called ’an estuary restoration task force team’, should be created for effective communication among stakeholders. A task force team for estuarine water circulation and another for wetland restoration should be organized. Continuous discussion between government agencies and non-governmental organizations is desirable for the most effective determination of estuary management policy.