| 摘要 |
This report presents the results from the first year of the ongoing three-years study on development of the national environment management policies and strategies to support sustainable estuarine development in Korea. Objectives of the first year study are - to define management area boundaries of 17 major estuaries, to classify estuarine types in the management perspective, and to develop policy directions of the individual management types. Diverse approaches including field survey, existing data review, case analysis, workshops, interviews and questionnaires were employed to collect a wide range of data and stakeholder’s opinions.
Management boundaries were delineated mainly by the physical, geographical, and land use characteristics of the estuaries. Landward boundaries were commonly determined by the tidal head, but seaward boundaries were defined case by case based on the geographical characteristics and land use patterns of the individual estuaries. It was also included in the management area to support watershed- based management of the main and tributary watersheds lying between the tidal head and seaward boundary. Among the 17 major estuaries, we defined 15 management areas because Ansung and Sapgeu estuaries, Mangeong and Dongjin esturies could be respectively treated as one estuarine system as Asanman estuary and Saemangeum estuary according to their common reponses on the river-mouth barrages.
Socio-economic data indicates that estuaries have been excessively used and developed without considerations on the environment. Top seven largest estuaries, except for the Han Estuary which has been protected by the Demilitarized Zone ever since the Korean War, already lost their natural integrity because of the river-mouth barrage construction. About 329km2 of estuarine wetlands have been reclaimed during the last 20 years and according to the National Reclamation Plan, more than 30% of the current estuarine wetlands will be further reclaimed by the year 2011. There are 77 industrial complexes which produce about US$ 4billion/year export goods, more than 300,000 companies which comprise about 40% of national level, and 7 major national trading ports which are responsible for 46% of national capacity in the estuaries. These economic and development activities are also clearly reflected in much higher population increase rate (average 3.6%) in the estuaries than the national average (0.98%) during the last five years.
A few estuaries, which are protected by the DMZ (lower part of the Han Estuary) or designated conservation area (a part of the Nakdong estuary), still have extensive wetlands and are well known as both nationally and internationally protected birds habitats. However, other estuaries were severely damaged, and thus show a very low geo-biodiversity and poor environmental quality. Most estuaries show less than 0.5 geodiversity evaluation ratio (=number of observed geomorphological features/ number of reference geomorphological features), and have lower biodiversity evaluation ratio (=number of important flora and fauna species/number of total flora and fauna species) than 0.15. Water quality (in term of BOD) ranges Grade III~IV, except for the small estuaries located on east coast, and temporal data indicate that water qualities of Sapgeu, Donjin, and Tamjin estuaries have been consistently deteriorated. Particularly, the estuaries with river-mouth barrage showed more serious environmental problems such as decrease of biodiversity and fish stock, deterioration of water quality, destruction of wetland, as well as sediment contamination.
Despite the tremendous development pressure and degraded environmental quality, government efforts to protect and improve estuarine environment have remained at nominal level mainly because of the fragmented management structure and policy barriers between the responsible government agencies. So far, no integrated laws, regulations, comprehensiv |
