Recent Cancellation of a Proposed New International Airport next to an estuary in Portugal: something for us to learn from!

Dr Nial Moores, National Director, Birds Korea

(With thanks in advance for letting me know if there are any factual errors or misrepresentations in the post below, so that they can be swiftly and wholly corrected!, and for sharing any other useful materials that you might have…)

Already, airports are under construction on bird important Ulleung Island and on Heuksan Island. If the remaining proposed new airports in the Republic of Korea (ROK) proceed as planned, then they will directly impact at least five or six more of the nation’s most bird-rich and important areas. The importance to birds of these proposed airport locations is already well-known to Birds Korea members, either from birding trips or through posts over the years on the websites and blog: Saemangeum and the adjacent Geum Estuary (most of which is now designated as the Seocheon Getbol World Heritage serial property); Gadeok Do, and the Nakdong Estuary; Jeju Second International, and the Seongsan coast; Seosan, by Lake A; Baengnyeong, by the reclamation lake; and even perhaps a new Gyeonggi international airport within the Hwaseong Wetlands…

The original source of this figure taken from a social media post is unknown, but the data were sourced from local governments, with existing international airports shown in pink, existing domestic airports shown in turquoise; and proposed new airports, a mixture of domestic and international, shown in black. It is a little unclear why the Hwaseong airport was not included here.

Trying to assess the potential threats to birds and impacts on their populations that might be caused by each of these new airports, separately and in combination, requires a lot of study, including reading through massively long and often vaguely-worded Environmental Impact Assessment (EIA) reports and trying to digest as much expert literature relating to birds and airports as is available. In the past few weeks, thanks to the generosity of Nicola Crockford of the RSPB in the UK, this includes literature relating to a recently cancelled airport in Portugal which really needs to be shared as widely as possible. This is because the proposed airport was going to be constructed next to one of Western Europe’s most important estuaries for shorebirds but was cancelled because of the estimated impacts of noise on shorebirds which would be caused by over-flying aircraft. The legal case against the proposed airport also highlighted the inter-connectivity of sites along a Flyway, demonstrating that actions in one nation can prevent success of conservation measures in another. The cancellation of the airport in Portugal therefore has some relevance to an assessment of impacts at all of the proposed airports here – and particular relevance to the proposed New Saemangeum Airport.

The tidal flats of the Yellow Sea form the heart of the East Asian-Australasian Flyway (EAAF) and at the turn of this century, Saemangeum was the Yellow Sea’s most important known shorebird site. As the seawall grew longer, numbers of shorebirds started to fall, and they collapsed following seawall closure in 2006 (Moores et al 2016; Lee et al. 2018), Now, the Geum Estuary is the most important remaining site for migratory shorebirds in the ROK. As a welcome conservation response to large-scale reclamation of much of the coast, most of the Geum Estuary was first designated as nationally protected Wetland Conservation Area, then as Ramsar site, and more recently as part of the Getbol, Korean Tidal Flat, World Heritage serial property – with Natural World Heritage sites widely understood to meet the very highest global standard among Protected Areas.

According to the EIA report (EIASS 2021), as currently proposed the New Saemangeum international airport will be built within the northern part of the Saemangeum reclamation area. Based on waterbird data within EIASS (2021) and from Winter Census data gathered under the auspices of the national Ministry of Environment between 1999 and 2023, if the airport proceeds it will inevitably result in the destruction of what is still – within 3km of the runway – an internationally important wetland for waterbirds, as defined by Ramsar Convention criteria (Ramsar 2024). It will also result in the destruction of a high tide roost site, used presumably during highest high tides by shorebirds that forage at low tide within the adjacent Geum Estuary. The high number of Grey Plover Pluvialis squatarola 개꿩 reported in EIASS (2021) in the area closest to the proposed runway area suggests that these will be birds that forage at low tide primarily on tidal flats within the Seocheon Getbol, Korean Tidal Flat, World Heritage serial property rather than the buffer zone.

In addition, the proposed airport area is frequently used or overflown by many thousands of Great Cormorant Phalacrocorax carbo 민물가마우지 and geese. Flying from this airport will therefore entail a substantial risk of bird strike, especially considering the known history of bird strikes in the area already.

Figures from EIASS (2021) for the proposed New Saemangeum Airport, depicting movements of a small number of tracked Great Cormorant 민물가마우지 and geese across the proposed airport area (approximately the area with much yellow hatching – and see immediately below).

Importantly too, the runway of the proposed New Saemangeum airport is depicted in one of the figures in EIASS (2021) (below) as reaching to within 5.0km-5.5km of the southern boundary of the Seocheon Getbol, Korean Tidal Flat, World Heritage Serial Property (from here on, “Seocheon Getbol WH”). Use of Google Earth suggests that the real distance of the runway from the Seocheon Getbol WH, however, might perhaps be closer to 7km or 7.5km (?).  Either way, aircraft will be flying low on approach and take off over the Geum Estuary, with figures in EIASS (2021) showing aircraft flight paths will be directly over the western side of the Seocheon Getbol WH. In addition to the rather high risk of bird strike, there is also the issue of the impact of noise on shorebirds. At least one figure in EIASS (2021) indicates noise levels of up to 70db at the edge of the Geum River channel – within about 500m of the Seocheon Getbol WH designated buffer zone and 1km of the property itself (EIASS 2021). Wright et al (2010) assessed that between 5% and 47% of waterbirds show a strong negative response to noise levels within the 55–65 db noise interval; and that the probability of birds showing a strong negative response increases to 47-80% once noise levels exceed 65db.

Figure from the EIA report, showing distances from the proposed airport (outlined in red)

Figure from the World Heritage Nomination materials showing the Seocheon Getbol World Heritage serial property (“Seocheon Getbol WH”).
Google Earth image (2024) showing the Geum River channel, which forms the southern boundary of the Seocheon Getbol WH, and extensive tidal flats (known as “getbol” in Korean). The airport as proposed will be built on open land, adjacent to an existing airport and airbase just to the south of or perhaps replacing some of the large solar farm.
Lowest low tide along the western flank of the Seocheon Getbol WH: the preferred foraging area of both Spoon-billed Sandpiper 넓적부리도요 and Great Knot 붉은어깨도요 © Nial Moores.

Disturbance from human activities, including as a result from aircraft over-flights, is already known “to have a high energetic cost to shorebirds and may compromise their capacity to build sufficient energy reserves to undertake migration”; and “disturbance that renders an area unusable is equivalent to habitat loss and can exacerbate population declines” (Far Eastern Curlew Task Force / EAAFP 2017).  

The obvious question therefore is: How might an increase in disturbance caused by an increase in the number of over-flying aircraft going to and from the proposed New Saemangeum Airport impact migratory shorebirds and other globally threatened waterbirds in the Seocheon Getbol WH?  

van der Kolk et al. (2020) state that, “overflight of large aircraft can cause birds to take flight, and substantial increases in shorebird daily energy expenditure when exposed to such aircraft disturbance have been recorded, even when the airport has been operational for decades”; and “to make proper impact assessments of disturbance on biodiversity, it is crucial to observe the entire disturbance landscape and quantify the cumulative impact of all relevant disturbance sources over a range of species and sites, over longer periods of time, and covering a range of weather conditions, seasons and times of the day.”

Currently, the nearby Gunsan International airport reportedly has up to six flights a day.  I have not had time to recheck the approximately 1,600-page EIA report to see whether it shows flight paths, and whether these are sometimes low over the Seocheon Getbol WH. Certainly, I do not remember seeing such aircraft during my research in the outer parts of the Geum Estuary. There is also an air base next to the existing airport, with occasionally frequent flights by jets, including noisily over the Seocheon Getbol WH. There are also occasional fly-overs of the general area by helicopters, and some helicopters used to (still now?) conduct training flights over the tidal flats before they were designated as Seocheon Getbol WH. Disturbance levels are therefore already high – and are in all probability already negatively impacting shorebirds. However, none of these existing sources of disturbance are even considered by EIASS (2021).

Helicopter training exercise over the Geum Estuary, April 2016, before designation of this area as a natural World Heritage property © Nial Moores. Does anyone know if such training flights still take place?

The New Saemangeum airport is initially proposed to carry a million or more passengers annually (so perhaps initially 10-15 flights a day?).  Although not indicated anywhere in the EIA report, it seems reasonable to assume that once the Saemangeum reclamation area is fully built-up (it is currently still largely “vacant”), then the number of aircraft each day can be expected to increase substantially: why else invest so much money building a new international airport right next to an existing one?

The EIASS (2021) does contain a lot of good waterbird count data from the Seocheon Getbol WH, as the whole property is within the 13km radius called for in the development of Wildlife Hazard Management Plans by ICAO (2020).  However, I could not find any research in the EIA report or supplementary information aimed at assessing impacts on shorebirds and other threatened waterbirds that might be caused by increased noise levels as aircraft descend into and ascend out of the proposed New Saemangeum airport.

A full and detailed assessment of such impacts is needed. The Seocheon Getbol WH, one of four tidal flat WH properties nationwide, contains most of the Geum Estuary.  It is the best remaining site in the ROK for e.g., the Critically Endangered Spoon-billed Sandpiper Calidris pygmaea 넓적부리도요 and also supports thousands of globally Endangered Far Eastern Curlew Numenius madagascariensis 알락꼬리마도요 and Great Knot Calidris tenuirostris 붉은어깨도요. The former species is listed in Australia as Critically Endangered, and has been the focus there of some intensive and costly conservation initiatives; and declines in the latter species were observed in Australia, following the closure of the Saemangeum sea-wall (Far Eastern Curlew Task Force / EAAFP 2017; Rogers et al. 2009).

Spoon-billed Sandpiper 넓적부리도요, Seocheon Getbol WH © Nial Moores.
Great Knot 붉은어깨도요 (and a few other shorebird species!), Seocheon Getbol WH © Nial Moores.

Now, these same and many additional threatened migratory waterbird species are explicitly recognized by the UNESCO Committee and the IUCN as forming part of the “Outstanding Universal Value” (OUV) of the Seocheon Getbol WH, and of the natural World Heritage properties elsewhere in the ROK and along the Chinese coast (see e.g., World Heritage Criterion X and the World Heritage Nomination Text p.98-99).  

The international / global value of the Seocheon Getbol WH is further affirmed by studies using leg flags (coloured tags put on the legs of shorebirds) led by e.g., the Australasian Wader Studies Group and the Global Flyway Network, supported by an increasing number of studies employing transmitters (e.g. Lilleyman et al. 2020). There are now many thousands of records of “marked” birds and these help to confirm that waterbirds’ migrations connect the Seocheon Getbol WH to other sites; and that the Seocheon Getbol WH is part of a network of internationally important protected and unprotected areas within the Yellow Sea, and north to NE Russia and Alaska and south to Australia and New Zealand. This network is now, of course, known more popularly as the East Asian-Australasian Flyway.

Great Knot 붉은어깨도요, Seocheon Getbol WH © Nial Moores. Sightings of individually coded colored leg flags like this help us to learn about the life of an individual shorebird; and also reveal how key sites for waterbirds along the Flyway are connected to each other.
Spoon-billed Sandpiper 넓적부리도요, Seocheon Getbol WH © Nial Moores. This was the last documented sighting of the world’s most famous individual Spoon-billed Sandpiper, with the flag “01”, better known as the “Monument Bird”, who was responsible for fathering multiple broods of this Critically Endangered species.

Importantly, in stark contrast to the New Saemangeum airport EIA report, research in Portugal was conducted during the EIAs on the expected impacts on shorebirds of over-flying aircraft if the new Lisbon International Airport were to be built, as proposed next to the Tagus Estuary. And subsequent, higher quality research on the impacts of noise on shorebirds was then conducted and used to underpin much of the legal challenge to the same airport, after it was approved in 2020. Like the Geum Estuary, the Tagus Estuary is an internationally important wetland, with much of the estuary included within a national Protected Area system. What those challenging the airport made clear was that the increase in noise to be caused by aircraft would result in shorebird declines.

Catry et al. (2022), while acknowledging the risks of bird strike entailed in locating airports near estuaries, assessed that noise caused by overflying aircraft following the implementation of the new Lisbon airport would “lead to a loss of up to 30% of the conservation value of the Tagus estuary in terms of intertidal feeding areas of wintering birds alone. The global impact will likely be greater when effects on supratidal roosts, as well as on passage birds, are also considered. The Tagus estuary, which is internationally important for six of the 10 species included in our analysis, is just one of a network of already depleted sites along the EAF [East Atlantic Flyway]. Thus, negative impacts on bird populations on the Tagus estuary will have repercussions and undermine conservation efforts elsewhere. The plight of shorebirds at the Tagus estuary is thus a matter of international conservation concern.”

This research was then followed by additional detailed analysis by Nightingale et al. (2023), who evaluated the extent of noise disturbance on Black-tailed Godwits Limosa limosa 흑꼬리도요 using the Tagus Estuary, and estimated “disturbance impacts on up to 68.3% of individual Black-tailed Godwits overall, greatly exceeding the estimates of 0.46–5.5% in the airport’s Environmental Impact Assessments which derived from count data.” Moreover, Nightingale et al. (2023) also highlighted that because Black-tailed Godwits are migratory, the airport development would impact transboundary conservation efforts and impact negatively on conservation efforts along the Flyway. This is because the “impact footprint does not simply equal the spatial extent of the impact itself, but also encompasses all additional areas used by impacted individuals… by representing movements between sites in a network, practitioners can gain a more accurate picture of how the effects of a localized impact or protection may be felt at connected sites.”

This expert analysis was supported by a severe critique of the under-estimated risk of bird strike by Luit Buurma (“Flight Safety and Bird Conservation Mutual exclusion of a new Lisbon airport and the Tagus Estuary Nature Reserve”); and by a successful legal challenge brought by ClientEarth, which included an analysis by the RSPB of costs to ongoing conservation efforts in the European Union. This analysis concluded that the proposed airport will, “severely (undermine) past and future international conservation efforts and the enormous investments those efforts entail. We show that failing to consider the international consequences, including damage to the integrity of the Natura 2000 network, is a major omission that does not align with international agreements aimed at the conservation of migratory species” (Verhoeven et al. 2023).

Legal frameworks for the conservation of biodiversity in the EU are of course very different to those in the ROK.  In addition to stronger national legislation, there are also regional frameworks, including Natura 2000 and the Convention on Environmental Impact Assessment in a Transboundary Context (or Espoo Convention).  An important difference from the ROK can also be found in the capacity and strength of civil society, with some of the world’s leading specialists working not only in universities but in NGOs too. The legality of the new Lisbon airport was therefore challenged on the basis of robust data and evidence gathered by researchers from within Portugal who were then supported by experts within national member organisations of BirdLife International. In that way, plaintiffs could harness expertise from across a continent to bring a legal challenge led by ClientEarth, an environmental law charity, with 300 staff and offices in London, Brussels, Warsaw, Berlin, Beijing, Madrid and Los Angeles (see:

In the ROK, we still do not have robust national population estimates for the vast majority of bird species (why not?); there is no obvious guideline on how much negative impact is acceptable / unacceptable when caused by a specific development project (why not?); and EIA reports for airports do not include commentary on the impacts of projects on species at the population level (e.g., expressed in clear percentage terms) (again, why not?). In addition, researchers and academics seldom publish research that aims to assess the impacts of specific development proposals and there are no large expert NGOs specializing in biodiversity conservation. Instead, as large development projects continue to be proposed conservation of biodiversity has to depend on a fairly rapid, largely closed formal EIA process. According to Ro (undated), “Projects subject to EIA under the Environmental Impact Assessment Act do not undergo a distinct screening procedure. Instead, the scoping process for EIA is conducted by a designated Environmental Impact Assessment Association. An EIA agency or business operator conducts a thorough survey and projects impacts based on the results of deliberations of an Environmental Impact Assessment Council. An Environmental Impact Statement (EIS), often referred to as a draft EIA report, is prepared based on the gathered results”.  

In the case of the Saemangeum New airport, fieldwork and the EIA report apparently took less than a year to complete. A short period (for most EIA reports in the ROK, little more than a month) was allocated to conduct a formal review of the EIA report. Until recently, this review role legally fell entirely within the remit of the Korea Environmental Institute (KEI), though more recently, as many more EIAs are being conducted, this remit has been expanded also to include four research institutes within the Ministry of Environment (Ro undated).  Fortunately, there is substantial institutional expertise in the ROK; and there is strong evidence that this review process has helped to reduce the impacts of some development projects (Ro undated). Indeed, the review for the New Saemangeum airport EIA report did correctly highlight many major issues. However, it did not, to the best of my understanding, include any commentary on noise disturbance to waterbirds in the Seocheon Getbol WH.

With so many EIA reports to process in such a short time period, it seems reasonable to wonder if the expert reviewers in the ROK really have the time and opportunity to keep up to date with global best practice, and to call for a similar standard of excellence in the EIA reports that they review. For now, responses given to the review in the Supplementary sections of EIA reports suggest that development proponents are free to dismiss many of the reviewer’s concerns without being compelled to explain appropriate mitigation measures.

Presumably as a result, even though “expert opinions advocate for consistency with the precautionary principle” (RO undated), a meta-analysis of 288 EIA reports found that there was, “a substantial need for improvement in current mitigation strategies” (Kim et al. 2024).

 So by way of summary: if the New Saemangeum airport is built as proposed, then one shorebird roost will be lost and there will be an increased number of large aircraft over-flying the Seocheon Getbol WH. Based on available evidence, just as in Portugal, the resultant increase in noise will then likely cause increased levels of disturbance to threatened migratory waterbirds. Any loss of roost sites and any increase in disturbance can be understood to be a potential threat to the OUV of the Seocheon Getbol WH. ROK authorities have already stated formally that, “The central and local governments will work together to block any development that might damage the OUV of the nominated property.” (World Heritage Nomination Text, Section 7D, Supplementary Details). It is important to note use of the verb “might” in this sentence. And also to ask, why has this airport plan been allowed to proceed?

If national biodiversity is to be conserved, then internationally important wetlands, whether or not they are designated as Ramsar sites, need to be protected. The National Biodiversity Strategy and Action Plan (an ongoing commitment derived from accession to the Convention on Biological Diversity) should ensure that. Article 35 of the Natural Environment Conservation Act, also stipulates that, “The Government shall formulate and implement measures for conservation and sustainable utilization of biological diversity and biological resources, proper management of biological resources, and implementation of the Convention on Biological Diversity, the Convention on International Trade in Endangered Species of Wild Fauna and Flora and the Convention on Wetlands of International Importance, Especially as Waterfowl Habitat, etc. (hereinafter referred to as the “Convention on Biological Diversity, etc.”) to which the State is a signatory.”  

The ROK has therefore made a clear legal commitment to conservation of biodiversity at the national level, and internationally to the maintenance of populations of migratory waterbirds though accession to the intergovernmental Ramsar Convention.  Designation of the Getbol, Korean Tidal Flat, World Heritage serial properties based in large part on the OUV of migratory waterbirds is also a formal recognition by both central and local government that the ROK is responsible for protecting these migratory birds when they are in Korea – because these birds have value to the nation and to the world as a whole. Any loss of OUV will not only have an impact on the ROK; it will also impact other sites in other nations that these birds depend on at other times of the year.

Once again, as stated by Nightingale et al. (2023) an “impact footprint does not simply equal the spatial extent of the impact itself, but also encompasses all additional areas used by impacted individuals.”  EIA research and reports, EIA reviews and national laws must start to accept and reflect this reality.

“Outstanding Universal Value”: shorebird flocks at high tide, Yubu Island, Seocheon Getbol WH – looking south towards Gunsan City and the proposed airport area © Nial Moores


Catry, T., Ventura, F., Dia, M. P., Santos, C. D., Martins, R. C., Palmeirim, J. M. & Grandeiro, J. P. 2022. Estimating the conservation cost of the projected new international Lisbon airport for migratory shorebirds of the Tagus Estuary, Portugal. Bird Conservation International (2022) 32: 232-245. Published by Cambridge University Press on behalf of BirdLife International. doi:10.1017/S0959270921000125

EIASS. 2021. 새 만 금 신 공 항 건 설 사 업 전 략 환 경 영 향 평 가 서 (Strategic Environmental Impact Assessment for the Saemangeum New Airport). Published on the EIA Support System by the Ministry of Land, Infrastructure and Transportation. 2021.

Far Eastern Curlew Task Force / EAAFP. 2017. International Single Species Action for the Far Eastern Curlew Numenius madagascariensis. Adopted by the Convention on Migratory Species 12th Meeting, Manila, 2017.

ICAO. 2020. Doc 9137—Airport Services Manual—Part 3—Wildlife Control and Reduction, 5th ed.; ICAO: Montreal, QC, Canada.

van der Kolk, H., Krijgsveld, K.L., Linssen, H., Diertens, R., Dolman, D., Jans, M., Frauendorf, M., Ens, B.J. & van de Pol, M. 2020. Cumulative energetic costs of military aircraft, recreational and natural disturbance in roosting shorebirds. Anim. Conserv. 23, 359–372

Lee J. K., Chung O-S., Park J-Y., Kim H-J., Hur W-H., Kim S-H. & Kim J-H. 2018. Effects of the Saemangeum Reclamation Project on migratory shorebird staging in the Saemangeum and Geum Estuaries, South Korea. Bird Conservation International (2018) 28:238–250. © BirdLife International, 2017 doi:10.1017/S0959270916000605.

Lilleyman, A., Bradley K. Woodworth, Richard A. Fuller, and Garnett, S. T. (2020) Strategic planning for the Far Eastern Curlew.
NESP Threatened Species Recovery Hub Project 5.1.1 final report, Brisbane, December 2020.

Moores, N., Rogers, D.I., Rogers, K. and Hansbro, P.M. 2016. Reclamation of tidal flats and   shorebird declines in Saemangeum and elsewhere in the Republic of Korea. Emu, 116, 2: 136-146. Published by CSIRO.

Nightingale, J., Gill, J. A., Þórisson, B., Potts, P. M., Gunnarsson, T. G. & Alves, J. A. 2023. Conservation beyond boundaries: using animal movement networks in protected area assessment. Animal Conservation. Vol 26, Number 6, Pages 753-765.

Ramsar Convention. 2024. The nine criteria for identifying Wetlands of International Importance, at:

Ro T.H. Undated. Can Korea Maintain Environmental Standards? The Implications of Shifting EIA
Review Privileges to Ministerial Affiliates. Manuscript for Environmental Impact Assessment Review. Publications/Tae Ho Ro _KEI-4806441.pdf

Rogers, D., Hassell, C., Oldland, J., Clemens, R., Boyle, A. & K. Rogers. 2009. Monitoring Yellow Sea Migrants in Australia (MYSMA): North-western Australian shorebird surveys and workshops, December 2008.

Verhoeven, M. A., Barber, I., Crockford, N. & Burgess, M. D. 2023. The international flyway connectivity of waders that use the Tagus Estuary. A report to ClientEarth. RSPB Research Report Number: 72. ISBN: 978-1-905601-68-4

Wright, M. D., Goodman, P. and Cameron, T. C. 2010.  Exploring behavioural responses of shorebirds to impulsive noise. Wildfowl 60: 150–167.

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