1
Coastal Land-use Change by Reclamation of Tidal Flats along the
Western Coast of the Capital Region in Korea
Manik HWANG
Seoul National University, Seoul, Korea
Abstract
This study examines tidal flat reclamation along the western coast in the Capital region of Korea. The
study investigates developments of large-scale reclamation and subsequent land-use changes in surrounding
areas using Landsat TM data of 1985 and 1997. The Coastal zone of the study area has an extensive
development of tidal flats. Reclamation of the mud-flats has been ongoing for nearly 800 years for additional
paddy land. It was during the 1970s when large-scale reclamation was practiced for arable land, irrigation
water resources, industrial and residential uses. There are increasing public concerns of environmental issues
associated with the large-scale reclamation in very recent years. In the long run, conservation of the tidal-flat
and its rich ecosystem as natural resources must take precedence than its single-minded economic purposes.
1. Introduction
The coastal zone is the narrow fringe where the sea impinges on the land. It is particularly important to
the Korean people who live in one of the most densely populated nations of the world. This zone has provided
valuable coastal fisheries for thousands of years, and rich fish farming and marine cultivation for recent several
decades. Extensive tidal flats are in development along the western coast of Korea in the Yellow Sea, and along
the southern coast of the Korean peninsular. Reclamation in the shallow coastal zone provides valuable land
resources. With limited agricultural land, the nation is in constant search for additional farmland for food selfsufficiency.
Reclamation of tidal flats has been ongoing for several hundred years in small scales. In recent years,
however, very large-scale reclamation for agricultural land as well as for industrial demand, port facilities and
other urban uses, has brought about conflicts between land uses. The Capital region, which surrounds Seoul,
has experienced rapid urbanization during the last few decades, and its coastal area has experienced very active
land-use changes through a series of large-scale tidal flat reclamation projects. According to the National
Statistics Office of Korea, in 1997, as much as 45 percent of the nation’s population inhabited Seoul and its
surrounding areas. As a result, the demand for urban and industrial land has been continuously increasing. The
reclamation of tidal flat for agricultural, industrial and urban purposes from rural use has been a very significant
change to the coastal area.
Land use conflicts occurs between conservation and reclamation of tidal flats. Large-scale coastal
reclamation causes detrimental environmental changes and related problems. It lowers the environmental
quality by neutralizing benefits associated with tidal flats—storm protection, waste neutralization, and wildlife
habitats—that are related directly to the amount of wetland loss(1). In particular, inflows of not-fully treated
industrial and urban sewage cause serious water pollution problems in the newly constructed fresh water
reservoirs. Conservation supporters emphasize the importance of benefits and values deriving from the tidal flat
ecosystem other than the immediate economic benefits.
The purpose of this study is to examine tidal flat reclamation along the western coast in the Capital
region in Korea. In particular, it focuses on the development and distribution of the land reclamation and
subsequent land-use changes in the surrounding areas. To investigate recent land-use changes, this study uses
Landsat TM data of 1985 and 1996, which can provide relevant data on land-use changes because of the
Landsat’s regular monitoring. Land use is classified into five broad categories in the analysis: urban,
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agricultural, forest, water, and tidal flats. Based on these land use categories, a simple quantitative change
detection method was applied to measure changes by individual unit area. The post-classification comparison is
based on independently produced land use images of 1985 and 1996. Data sets are independently classified and
then compared by individual pixels to detect changes between the two different time periods. This study shows
only those changes from tidal flat to urban uses, however.
Topographic maps of 1:250,000 scale were also used to examine coast line changes since early 1960s.
2. Development of Tidal Flat Reclamation
2.1 Natural characteristics of the tidal flat
Tidal flats are formed by the deposition of fine inorganic and organic debris, which are held in
suspension in the sea and estuaries. Deposits of these fine materials occur where the turbulence of the sea is
reduced considerably, such as in the study area. The study area is a large embayment exposed to the Yellow
Sea, which is another embayment to the Pacific Ocean. There are vast areas of deposits within the inter-tidal
flat.
The study area has the largest proportion of tidal flats among all provinces in Korea. According to the
Korean government’s survey, the study area has almost 17% of the total of 280,500 ha. of tidal flats in the
nation(2). Such development of mud-flat in the area are largely caused by two major factors: the shallow water
in the extensive area toward the western coast line and the large vertical range of low and high tides. In fact, the
average depth of the entire Yellow Sea is less than 100 meters. Also, the average of the vertical difference
between inter-tidal periods is as much as 9 meters in the study area, which is the largest in any part of the coasts
in the nation and is not common elsewhere in the world.
The mud-flat provides a unique ecosystem. It is a place of high productivity, a rich nutrient source and a
sink. It is reported in a foreign study that tidal marsh’s productivity might equal to that of the best agricultural
lands even without any overt acts of fertilization.(3) Tidal flats provide spawning grounds and nursery area for
fishes and a variety of clams. It is also a major site for sea-weed cultivation, which is an important industry of
fishing villages along the western coast of this country. Wetlands in general, including tidal marshes, have
always served as natural filters. Researchers indicate that certain kinds of organic sediments in the tidal mud
probably contribute to the retention of harmful pollutants. Through the accretion process, many contaminants
are buried in the sediments, preventing the dispersal of pollutants. (4)
It provides feeding grounds for a variety of birds, including migrating birds. Those birds use the tidal
mud as a staging area during migration. Another importance of tidal flats is its function as a storm buffer.
During a storm, water advances in a broad sheet flow over the mud before it reaches to the coast. As a result, a
wide, shallow inter-tidal mudflat is very efficient at dissipating wave energy.(5) As briefly described above,
tidal flats are of great value to human and should not be modified unless it is most necessary.
2.2 Historical developments of reclamation of tidal flat in western coast
Land claim from the sea has been for many centuries. The wide expanses of inter-tidal mud flat provide
ideal areas for land claim and development. One of the earliest places in which reclamation was practiced in this
country is Kwang-Hwa Island, a large island in the study area. According to Choe(6), it was as early as AD
1256 when public reclamation of tidal land was officially performed on the island, although historical records
show that land reclamation was already practiced by AD 1248, north of the study area. Since then, many mud
flats in the island were converted into agricultural land (Fig. 1). They were built by government projects using
advanced construction technologies of those early days. They must be public projects because it was most
certainly impossible to construct dykes in such considerable scale by private civilian groups. The major purpose
of reclamation was to increase farm-land acreage for production of grains for military consumption. However,
civilians and individuals performed some of the reclamation, although they were in small-scales because of lack
of technology, labor and equipment, in comparison to the large public projects. The early reclamation of tidal
flats in this island was forced by Mogolian invasion to the Korea dynasty. The King of the dynasty fled to this
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island in AD 1232. Since then, the island became a refugee island for over 40 years as the King, his royal
families, and tens of thousands of high government officials and their families moved from the capital city in
the mainland to this island. Choe’s study estimates that the total population on the island must have reached up
to several hundred thousands. It is notable, compared to total number of people at present, which is less than
64,000 at present. Reclamation was an important alternative to increasing arable land within the island at such a
national emergency.
Most of the potential areas for reclamation on the island were recovered by the end of the 18th century,
and there were no major constructions until modern equipment and technologies were introduced in the 20th
century. Additional reclamation in a few areas was added in the southern part of the island in this century. As a
result of the continuous reclamation for several hundred years, this island has the largest proportion of paddy
land to total area among all islands in this country(6).
Fig. 1 Reclamation of tidal flat in Kwang-hwa island,
Between 1256 and 1991.
Source: redrawn based on Choe(7)
Reclamation of the coastal muddy flat was not active in this country until Japanese control began in
1917. Under the Japanese control, reclamation was practiced in larger scale in comparison with earlier periods
as a part of nation-wide movement to increase rice production(8). There was no major land conversion after the
Second World War. However, massive reclamation of coastal zone was planned to increase arable land during
the 1960s(Fig. 2)(9), and the coastal reclamation was one of the major components of the nation’s First Fiveyear Development Plan. The Reclamation Act of Public Waters was enacted in 1962 (amended in 1986) for
agricultural development, by which large-scale constructions for land reclamation were possible. In 1963, the
Dong-Jin River Estuaries project (located in further south of the study area) was the first large-scale project
under this Act and the Development plan, by which 2500 hectares of new arable land was recovered (10). Since
then, a total of 62,090 hectares of new land was reclaimed in the nation(Table 1). The average area of each
reclamation increased considerably after early 1970s, as shown in the Table 1. There were about equal
proportions of government and private projects, but private projects were smaller in scale.
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Year
1946-1960
1961-1969
1970-1979
1980-1989
1990-1994
Table 1 Tidal flat reclamation in Korea after the Second World War.
Government Project
Private Project
Total
No. of
Area(ha)
No. of
Area(ha) No. of
Area(ha)
projects
projects
projects
39
3,777
138
2,552
177
6,329
58
7,634
1,078
9,581
1,136
17,215
50
8,245
183
11,127
233
19,372
25
5,266
38
4,041
63
9,307
4
8,105
3
1,742
8
9,847
176
33,027
1,440
29,043
1,617
62,090
Source: Rural Development Corporation(11).
A considerable amount of land will be added when those projects under construction or at planning stage
are completed in future. At present, those projects under construction in large-scale by government project
alone will contribute to additional 60,000 hectares of new land for agricultural and industrial uses (12), which is
as much area as the total reclaimed land during last 50 years.
3. Land-use changes in the Coastal Zones
3.1 Utilization of the Reclamation Land
Land conversion projects significantly influenced land-use change(Fig.2) and environmental changes
mainly by their large scale and by their usage which cause environmental degradation. Of the many reclaimed
lands during the last several decades, a single project in the study area was as large as 18,419 hectares and 9,000
hectare(Table 2).
The mud-flat has an inherently high fertility because of the rich organic content of the mud. Because of
these advantages, most of the converted land by reclamation has been used as paddy land in the past. Food selfsufficiency has long been one of the top priorities on the national development plan for many decades,
particularly since early 1960s. Thus, government policies have attempted to achieve this goal by providing
additional arable land.
In recent years, however, the reclaimed land has also been developed for such non-agricultural uses as
water resource development, industrial sites, and municipal waste dump sites. A study of 1989 reported that 92
percent of total reclamation land in the nation are for agricultural purposes, but industrial and residential
purposes are only 7 percent and 1 percent, respectively(13). However, industrial and residential uses and other
non-agricultural uses are expected to rise up soon by rapid urban expansion in the Capital region. Such changes
have already been occurring in the region. Virtually all land-use change inland represents a conversion of land
from agricultural or rural uses to one of three urban uses: residential, commercial or industrial.
Seoul, the capital city, and its surrounding areas have experienced rapid urbanization, increasing
population concentration and skyrocketing land values during the last few decades. At present, the capital
region shares as much as 43 percent of the total population in the nation. Ever increasing demand for urban land
caused the searching for new sources of land, which resulted in demand for land reclamation of mud flat in its
coastal areas(Figure 4). Two major reclamation during last decade were projects of the Shi-Hwa(I and II) and
the New International Airport in Young-Jong Do(Table 2). Newly reclaimed land by the Shi-Hwa I and II
projects are planned to be used for industrial(13.4%), urban commercial and residential(23.1%),
agricultural(28.6%) and remaining for Shi-Hwa fresh-water lake(35%). As shown in this statistics, agricultural
use shares less than 1/3 of total reclaimed area. The new fresh-water lake was expected to be major sources for
irrigation for the new farm land by the reclamation. Another large scale project is ??? in the works for the
construction of a new international airport by reclamation in Young-Jong island(Table 2) (Fig. 3).
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Table 2 Major very large-scale reclamation projects completed
In the westerrn coast of the capital region.
Project name
Area (ha.)
Construction Period
Pyung-taek
18,419
1970-1977
Kim-po
4,900
1981-1986
Shi-wha I
2,303
1986-1991
Shi-wha II
9,000
1991-1997
Young-Jong Do
5,618
1992-2020
Source: simplified based on Hong, S.Y.(14), p. 397, and other sources.
Fig. 2 Reclamation planning in the western coast
of the Capital region in early 1960.
(Source: compiled from the Ministry of Construciton(15))
Fig. 3 Major reclamation of tidal flats in the
western coast of the Capital region since
early 1960s.
Fig. 4 Land-use changes in the western coast of the Capital region, 1985-1996.
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3.2 Environmental Issues and Coastal Land Use Conflicts
Man has utilized the immense resources of tidal flat in harmony with nature for thousands of years.
However, environmental changes by a very large scale of reclamation of coastal mud flat in recent years raise
conflicts between conservation of the tidal flats and economic development by reclamation. The mud flat
ecosystem is based on organic materials. As mentioned earlier, the mud flat, estuaries, and their surrounding
wetlands are the spawning grounds for fisheries, and they support shell-fishery industries in many coastal zones.
Especially at high tide, the flats are important feeding grounds for fish and other wildlife.
Modern industrial society with rapid economic growth in Korea during the past decades has seen the
inter-tidal mud land, not as a natural resource, but as potential new land for economic development. There were
strong economic and social reasons to support individual development of reclamation. Despite this, groups of
people began to advocate conserving inter-tidal mud flats. Reclamation destroys a biologically rich natural
resource whose productivity may one day be of even greater benefit to us than at the present (16). Also, it is
uncertain to measure benefits and costs involved in the reclamation because of the astronomical cost involved in
its construction.
Public involvement in the environment and land use management is a new but important issue in recent
years. We need to know much more about the ecology of tidal flats and its capacity. As Daiber indicates,
exploitations and use for economic gain were for a single purpose and with little concern for, or even
recognition of, the consequences(17).
The Lake Shi-Hwa provides a good example of such environmental issues. The lake was a reclaimed
fresh water lake as mentioned above (Fig. 3). The land conversion project was planned as early as 1975, but
actual construction of its dike began in 1987 and completed building a dike of 12.4 km in 1995 (18). The Lake
Shi-Hwa, a newly created fresh water lake of 6100 hectare, began to replace its water from sea water to fresh
water. At the same time, 17,451 hectare of land was reclaimed from mud flat to be used for agricultural,
industrial, municipal and residential purposes. The new lake was adjacent to one of the largest industrial parks
in the nation, and had many livestock feeding lots, and urbanized areas. However, municipal government and
the management office of the new lake failed to control of inflow of untreated or less treated municipal,
industrial and agricultural sewage. The polluted water caused serious problems in the lake. As a result, water
quality of the lake was so serious that all the polluted lake water had to be dumped into the ocean by breaking
the dike for irrigation of farmland. This triggered NGO movements to request government to review land
reclamation planning and related policies, and conservation movements of the mud flat became widespread in
the nation in the most recent years. At the same time, NGOs started to re-evaluate and advocate economic
values of the natural tidal flats in contrast to the economic value of conversion into land. Major issues??? in
support of conservation are bio-diversity and habitat conservation, economic value, natural filters for water
pollutants, waterfowl, protection from storms, and aesthetic values of the coastal zones.
4. Conclusion
This study has examined tidal flat reclamation along the western coast of the capital region of Korea.
Land-use changes by the reclamation has been analyzed using Landsat TM images of 1985 and 1997. KwangHwa Island in the study region was one of the earliest places where land reclamation from tidal flat was
practiced. It was as early as AD 1256 when the government officially constructed reclamation in the island.
The major purpose of reclamation in the early period was purely for increasing agricultural land. There had not
been any specific planning for mud-flat reclamation by the government prior to early 1960; it was after early
1960s when national economic growth was rapid and the national economy was improving that many of the
projects by the public as well as private became large-scale. Most of those tidal flat conversion projects were for
agricultural purposes until 1970s, but since then, their utilization became diversified. Some of the projects were
built for multiple uses including irrigation, industrial, residential, and transportation.
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The importance of development of new farm land was the major driving force behind land reclamation
up to 1980s. However, it is expected that increasing proportions of reclamation will be used for non-agricultural
purposes because of rapid urbanization in the Capital region where almost one half of the nation’s total
population and the nation’s total number of manufactured employees are located at present. The large-scale
non-agricultural purpose of the reclamation will bring about significant environmental changes and related
problems such as ocean and fresh water reservoir water pollution caused by municipal and industrial discharges,
and critical air pollution. The problem of water pollution was already well illustrated by the Shi-Hwa
Reclamation project. It was publicly criticized as a failure because of serious water pollution by municipal and
industrial discharges into Shi-Hwa Lake, the newly constructed huge fresh water reservoir.
Modern industrial society with rapid economic growth in Korea during the past few decades has failed to
recognize the inter-tidal mud flat as a natural resource, but rather as potential new land for economic
development. There were strong economic and social reasons to support reclamation project in the past.
However, reclamation may destroy biologically rich natural resources whose utility may one day be of even
greater. Because of its astronomical construction costs, it is difficult to measure the benefits and costs of
reclamation. It is time to make a balanced management of the coastal zone to meet both our economic needs
and duty towards a sustainable coastal environment.
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