Saemangeum: The Impacts of the Reclamation on Waterbirds,
and some Selected Peak Counts
Nial Moores, July 17 2003

This note aims to present some peak waterbird counts recorded in the Saemangeum area, with further supporting information.

Saemangeum is part of a historical "super estuarine system", comprising three rivers (the Geum, the Mangyeung and the Dongjin) and some of the world's widest tidal-flats (stretching to 25 km at widest). Reclamation in the area has been practiced for several hundred years, largely very small-scale impoundments of upper tidal areas. With Japanese occupation in the first half of the twentieth century, the scale of projects increased (with possibly 20 000 ha or more reclaimed locally to create expansive rice-fields), and with the military government through the 1960s to the late 1980s comprehensive national "land" use plans targeted no less than 480 000 ha of tidal-flats and shallows nationwide (ca 80-90 % of that which remained) also for conversion into rice-field. These plans included the now ongoing reclamation of Saemangeum (a project of 40 100 ha) started in 1991 and the proposed reclamation of the neighboring Geum estuary (still being promoted by local government).

In Saemangeum's case, the reclamation is to be achieved through the construction of a 33-km long seawall, linking several offshore islands. This outer dyke is now 80-90% complete. Reference to aerial photographs or sediment maps shows that after construction almost all of the tidal-flats (ca 95%) will be impounded. For much of its length, the outer edge of the seawall drops down into permanent sea (several meters deep at low tide), and an examination of offshore currents suggests that erosion of the remaining area of outer (largely sandy and relatively unproductive) tidal-flat remaining after construction will likely increase.

Impacts on Migratory Waterbirds by the reclamation of the Saemangeum estuarine system

Considering that:

  • Nationwide surveys of waterbirds (both by government and independent researchers) prove that Saemangeum is the single most important natural wetland habitat for waterbirds in South Korea, in terms both of numbers and diversity;

    Present data suggests that Saemangeum is the most important shorebird site in the whole of the Yellow Sea, with 18 shorebird species recorded there in internationally important concentrations (17 listed in Barter in lit. 2002; one further, Grey-tailed Tattler Tringa brevipes, so recorded in 2002 [ pers.obs]);

  • The reclamation will remove almost all shorebird foraging areas, and convert the estuarine areas into freshwater habitats or "non-wetland";

  • Estuary barrages already exist across the Geum estuary (since the late 1980s) and many of the major rivers flowing into the Yellow Sea;

  • Reclamation has been extensive throughout the Yellow Sea, and that much of the system is already significantly degraded (e.g. Birdlife International, in press [late edit version attached as addendum])

It can be stated with confidence that the Saemangeum project if completed will therefore lead to significant declines in overall populations of a number of species that depend on estuarine systems during a significant part of their biological cycle. Several of these (such as the larger shorebirds, including Great Knot Calidris tenuirostris and Red Knot C. canutus, and Bar-tailed Godwit Limosa lapponica) have populations that are now considered to undertake non-stop migrations from New Zealand and Australia to the Yellow Sea, including South Korea. It is unlikely that such long migrations can be completed without the continuing existence of adequately productive and extensive tidal-flats required for refueling.

Consideration of the direct impacts of the Saemangeum reclamation on waterbird numbers through loss of habitat needs to be considered further in context.

There is no historical long-term data on waterbird numbers in South Korea, or historic estimates of the overall regional populations of a significant number of species to prove or disprove absolutely the impacts of reclamation projects in South Korea.


  • Surveys of the Nakdong estuary conducted before and after barrage construction, and at Yeongjong island, conducted before and after the construction of the international airport, reveal significant declines in most specialized species of estuarine-dependent species, in accordance with declines detailed in published information from other regions (detailed in Moores, 1999)

  • Many of the more specialized tidal-flat and estuarine species in East Asia are considered to be in decline by e.g. Rose and Scott (1997);

  • Many species listed as threatened by the IUCN and Birdlife International (e.g. 2003) are estuarine dependent;

  • The total number of migratory shorebirds using the East Asian-Australasian Flyway (that stretches between New Zealand through coastal east Asia up to Siberia and Alaska) has been estimated already to be between only ca 4 million and 6 million individuals: far smaller than numbers found in other major flyways. In neighboring Japan, where data on shorebirds trends has been collected with a reasonably consistent methodology since 1976, clear and major declines have been detected in a number of species, and such declines are considered a direct product of tidal-flat reclamation (e.g. Hanawa 1985; subsequent JAWAN shorebird counts [part-funded by the Japanese Ministry of Environment]; international JAWAN symposia proceedings 2000, 2001).

  • Data on fisheries and marine pollution, both largely dependent on the health of the tidal-flats and estuaries, is also clear: fish catch per unit of effort is now greatly reduced when comparing data from the 1960s with data from the 1990s and algal blooms have become both frequent and extremely widespread (e.g. Moores et al, 2001),

Bird surveys: Saemangeum

As noted in Barter (2002), limited surveys have been conducted in the Saemangeum area (an area comprising two of the adjacent estuaries - the Mangyeung and the Dongjin) since 1993, with increasing regularity since 1997/1998. Most such surveying has been conducted at three or four discrete high-tide roost sites, typically by a handful of government researchers (working under the auspices of the Ministry of Environment). These counts have been supplemented by NGO surveys most especially in 1998 and 1999 (Moores, 1999), and by coordinated joint Australian and Korean research in recent years. Overall numbers of birds are not well understood, as there is very high turnover of birds seasonally, and many areas are inaccessible. In addition, local movements of species can be significantly affected by even subtle differences in tides (the tidal range reaches almost 8 m at highest). On some tides birds move between estuaries; on other tides they appear not to.

Many birds in outer areas of the estuarine system (and thus out of view of land for most/all of the tidal cycle) are also presumably overlooked during surveys, and significant numbers of some species - including Chinese Egret Egretta eulophotes and Black-faced Spoonbill Platelea minor - have been claimed by observers who on very rare occasions have used boats, while some shorebirds (especially Great Knot) are also suspected of flying out from the Saemangeum complex to the outer Geum estuary at high tide, further confusing count data. In addition, many other shorebirds (individuals and species) found in the inner parts of the system are also presumed overlooked, as they both feed and roost in low densities.

Even with limited surveying, on present knowledge at least 27 species of waterbird are known to have been recorded regularly in internationally important concentrations (in accordance with the Ramsar Convention, here defined as concentrations of either 1% or more of the estimated population or more than 20 000 individuals). Several other waterbird species, including White-naped Grus vipio and Hooded Crane G. monachus, some Anatidae and Ardeidae, are also suspected of occurring in similarly important concentrations (ir)regularly, along with very small numbers of other threatened waterbird species.

Due to the lack of data it is difficult to state confidently exactly how many waterbirds use the Saemangeum area through the year, and even how many species of Special Conservation Concern occur regularly.

However, as a single day count of 155 000 shorebirds was recorded in May 2001 (Gosbell in lit.), and shorebird specialists tend to consider that the total number over the course of a year will be several times higher than single day peaks due to asymmetrical migration strategies (e.g. in Wells and Mundkur, 1996), it can be suggested that the annual number of shorebirds alone is probably between or in excess of 300 000 and 500 000 annually. Probably significantly in excess of 150 000 other waterbirds (mostly ducks and geese) are also supported by the site.

Of the regularly occurring waterbird species, the most important concentrations on the global scale include: Great Knot (minimum 25% of world population), Spotted Greenshank Tringa guttifer (minimum 6%), Spoon-billed Sandpiper Eurynorhynchus pygmeus (ca 10%) and Saunders's Gull Larus saundersi(ca 8%). All four are estuarine dependent species.

Table of the Most Important Waterbird Species supported by the Saemangeum Estuarine System.

SpeciesScientific NameGlobal StatusWet'd TypePeak Count at SaemangeumSource
Chinese EgretEgretta eulophotesVuEData unclear: >1%. 120 at mouth of GeumUD
Black-faced SpoonbillPlatelea minorEnEData unclear: reg 10-15 (WP: 1%); claim of ca 100 by some obs 2001e.g Moores, 1999
Eastern Taiga Bean GooseAnser fabalis middendorffi F/E1 648: 1-2%UD
Greater White-fronted GooseAnser albifrons frontalis F>1% (ca 3%)NIER
Common ShelduckTadorna tadorna E1 300: ca 1-2%Moores, 1999
Baikal TealAnas formosaVuF> 1%NIER
MallardAnas platyrhynchos F>70 000UD
Grey PloverPluvialis squatarola E*4 700 - 8 300Barter
Kentish PloverCharadrius alexandrinus dealbatus E*11 000 -19 900Barter
Lesser Sand PloverCharadrius mongolus E*4 320 - 8 400Barter
Black-tailed GodwitLimosa limosa melanuroides E*8 008 -10 750Barter
Bar-tailed GodwitLimosa lapponica E*8 430 -11 800Barter
WhimbrelNumenius phaeopus variegatus E*1 070- 1600Barter
Eurasian CurlewNumenius arquata orientalis E1 830UD
Far Eastern CurlewNumenius madagascariensisntE*1 100- 1 690Barter
Common GreenshankTringa nebularia E* 1 585Barter
Spotted GreenshankTringa guttiferEnE*59-111Barter
Terek SandpiperTringa cinereus E* 1 600- 2 000Barter
Grey-tailed TattlerTringa brevipes E376 one roostUD 2002
Ruddy TurnstoneArenaria interpres E*450 - 850Barter
Great KnotCalidris tenuirostris E*60 000 -119 000Barter
Red-necked StintCalidris ruficollis E* 10 000Barter
DunlinCalidris alpina (articola/sakhalina) E*47 650 - 86 000Barter
Spoon-billed SandpiperEurynorhynchus pygmeusVu-EnE*180-280Barter
Broad-billed SandpiperLimicola falcinellus sibiricus E* 800 - 1 500Barter
Black-tailed GullLarus crassirostris E 1997: NIER
Saunders's GullLarus saundersiVuE624Moores, 1999
Additional Waterbird Species
Oriental White StorkCiconia boycianaEnF? 
Swan GooseAnser cygnoidesEnE/F? 
Asian DowitcherLimnodromus semipalmatusntE2UD
Relict GullLarus relictusVuE1UD
Red-crowned CraneGrus japonensisEnE/F4UD
White-naped Cranefont-family:Verdana'>Grus vipioVuF? 
Hooded CraneGrus monachusVuE/F? 

In column 3: En, Vu, nt indicate Endangered, Vulnerable and Near-threatened as listed by Birdlife International in the online version of "Red Data Book: Threatened Birds of Asia" (at:
In column 4, E and F represent the two main wetland categories of Estuarine or Floodplain dependent species.
In column 5, counts marked with an asterix indicate peak count at one of the estuaries; the higher count value is the sum of the peak counts recorded at both the Dongjin and Mangyeung estuaries.
In column 6, Barter refers to Barter (2002); UD indicates NM's unpublished data. NIER indicates the National Institute of Environmental Research, a research center housed in the Biodiversity department of the national Ministry of Environment.


The Saemangeum estuarine system is, for waterbirds, the most important natural wetland in South Korea, and one of the most important wetlands in East Asia.
It regularly supports at least 27 waterbird species in internationally important concentrations, with probably 10-14 threatened waterbird species also occurring annually.
The vast majority of important species supported by the site are estuarine species.
In total a minimum 500 000 waterbirds are considered dependent upon the wetland annually, with most of these migratory shorebirds.

The reclamation of the Saemangeum estuarine system would convert almost all of the area's tidal-flats into either freshwater wetland or "non-wetland", and completely remove the brackish zone. It would therefore produce significant negative affects on a large number of species, many of which it is confidently predicted would show both significant local and also global declines (in clear contravention of obligations held by South Korea under both the Ramsar Convention and the Convention on Biological Diversity).


  • Wells, D. & T. Mundkur (eds). (1996). Conservation of Migratory waterbirds and hier Wetlands Habitats in the East Asian-Australasian Flyway. Proceedings of an international workshop, Kushiro, Japan. 28 Nov-3 Dec 1994. Wetlands International-Asia Pacific, Kuala Lumpur, Publication No. 116.
  • Barter, M. (2002). Shorebirds in the Yellow Sea. Importance, Threats, and Conservation Status , Wetlands International Global Series 9. International Wader Studies Group 12, Canberra, Australia.
  • Hanawa, S. (1985). Results of the Nationwide Counts of Waders in Japan. Strix 4: 76-87 (in Japanese).
  • Moores, N.(ed.) (1999). Korean Wetlands Alliance National NGO Wetlands Report: Ramsar 1999. Yullimaul, Seoul.
  • Moores, N., Kim S-K, Park, S-B & S. Tobai. ( 2001). Yellow Sea Ecoregion: Reconnaissance Report on Identification of Important Wetland and Marine Areas for Biodiversity. Volume 2: South Korea. Joint publication of WWF-Japan, Wetlands & Birds Korea, and Wetlands International China Program.
  • Rose P., and D. Scott. (1997). Waterfowl Population Estimates - Second edition. Wetlands International Publ. 44, Wageningen, The Netherlands.