چالش ها در راستای توسعه پایدار از شن و ماسه دریایی در کره

Marine sand is not only essential to the construction industry, but also functions as a habitat, nursery, and buffer for shorelines. As resources of sand on land are depleted the demand for marine sand has increased rapidly and is expected to continue. However, marine sand is limited in quantity and sand mining brings environmental externalities such as environmental degradation, habitat destruction and coastal erosion. Recently, the public and government agencies have recognized the value of marine sand. Although, sand mining is already well established and implemented, both the public and government in Korea are pushing for the sustainable development of marine sand.

Marine sand is not only an essential input in construction, but also functions as marine habitat and a buffer for shorelines. Marine sand is limited in quantity and should be managed sustainably. Traditionally, large amounts of aggregates (sand and gravel) have been consumed in Korea in construction projects such as buildings, houses, apartments, roads, ports, dams, dikes, and reclamation, which are essential infrastructure for economic development. The construction industry has been important to the Korean economy on the whole as indicated by its large share in GDP. Until now, most sand has been supplied by dredging rivers. However, sources of land-based sand are being depleted and marine sand has become a new source. The supply of marine sand has increased rapidly and is expected to increase continuously. One problem is that marine sand is a limited natural resource and is no longer supplied from rivers because many underwater dikes have been constructed in major rivers to store water for agriculture. Scientists expect that the maximum period of mining sand will be less than 50 years, if the present consumption of sand continues. Also, excess dredging of marine sand may bring negative effects such as degradation of the marine environment, destruction of spawning and nursery habitats for certain fisheries, changes of underwater sea beds, currents and tides, and thereby erosion of coastal shorelines. The problem of sustainable development of marine sand is one of the most controversial issues in Korea. Ocean users, such as fishermen and NGOs, have recognized the value of marine sand and are strongly opposing mining for sand. One government agency is trying to establish a new system for the conservation of marine sand. However, the voice of the construction industry and other government agencies are powerful, and the development system for marine sand has long been established. Until now, the government has viewed the demand for aggregate very important to economic development policies in Korea. So, the government has emphasized the need to supply aggregate efficiently and has established a very strong system of supply, including marine sand. This article reviews the status of supply and demand for marine sand; analyzes the imbalance between the development and conservation system for marine sand; extracts major issues on the sustainable development of marine sand; and identifies how the public, NGOs and the government are attempting to solve the problem of sustainable development of marine sand in Korea, of which lessons can be shared with the international marine society.

Until now, the government has viewed the demand for aggregate (sand and gravel) as important to the economic development of Korea. This is because aggregate is essential for the construction industry, which has contributed greatly to economic development. The construction industry includes essential infrastructure for economic development such as construction of houses, apartments and buildings: supply of land for cities and industrial complexes: and construction of roads, ports and dams. Given the demand, the government has only focused on supplying enough aggregate efficiently. The consumption of aggregate and cement per capita in Korea is the largest in the world. As the resources of sand in rivers get depleted, marine sand is being substituted as a new source. However, the resources of marine sand are limited and scientists expect that the maximum period of mining is less than 50 years if the present consumption of marine sand continues. Also marine sand mining may impose environmental externalities such as environmental degradation, habitat destruction, change of underwater seabed, and coastal erosion. Therefore marine sand has been mined by the present generation at the expense of future generations. Also it has been supplied at a low price for the whole society at the sacrifice of people such as fishermen. The problem of substantial development of marine sand can and should be solved in two ways: by reducing demand and by seeking alternative materials. Reducing demand is very hard because the development system is strong and the whole economic system has been long established under the large consumption of aggregate. Now the public, NGOs and the relevant government agency (MOMAF) have recognized the value of conservation of marine sand. They claim their rights on marine sand in the courts, appeal the precious natural bounty of marine sand through TV broadcasting, and try to balance the power between the development and conservation systems, all of which would be a starting point to contribute to sustainable development of marine sand. Seeking alternative materials for construction project is also hard and beyond the control of the marine community. However, it should be done. In this small land of 99,291 km2 and population of 47.6 million, 100 thousands tons of construction wastes are generated every day. So reuse or recycling of these wastes and other alternative materials should be encouraged and developed. Alternative materials for marine sand are also addressed in European countries. To enable future planning and investment decisions users and producers of marine sand and gravel in northwestern Europe will need to know about the potential of, and government policies towards, the use of alternative materials. Alternative materials in this case include aggregates from other sources (such as from superquarries), the use of secondary aggregates (recycled and reused materials, industrial by-products and synthetic aggregates) as well as the use of material of different specifications throughout northwestern Europe (e.g. fine sand for concrete) [14].