Challenges to climate change adaptation in coastal small towns: Examples from Ghana, Uruguay, Finland, Denmark, and Alaska

The ability of a coastal settlement to adapt to climate change is largely dependent upon access to a range of resources, which many coastal towns and small cities lack. Coastal small towns of less than 10,000 are therefore at a significant disadvantage compared to larger settlements when it comes to adaptation. One way to begin to overcome this disadvantage is to compare coastal small towns in order to identify efficiencies and support knowledge sharing. In this article we present and analyse five case studies of coastal small towns: Fuvemeh, Ghana; Kiyú, Uruguay; Hanko, Finland; Lemvig, Denmark; and Nome, Alaska, USA. A number of key outcomes and lessons were identified which highlights the need for a formal network of international coastal small towns to encourage and develop knowledge sharing practices going forward. A further lesson is the importance of using a range of indicators in order to establish the regional/national importance of a town. Basing this solely on population size can result in an erroneous interpretation of the significance (and therefore adaptive capacity) of a coastal small town. Finally, despite many barriers to adaptation in coastal small towns, being small offers some potential advantages, such as the possibility of being able to form a community consensus more easily, using 3D visualisations for adaptation planning, and having managed realignment as a realistic management option. It is imperative that climate change resilience in coastal small towns is increased by focussing on overcoming barriers and developing appropriate adaptation approaches by governments, non-governmental organisations, business, and researchers.


Introduction
Denmark has an extensive coastline (7,300 km) and it is estimated that 40% of the Danish population lives within 3 km of the coast (Sørenson, 2013, p. 96).The coast includes numerous urban areas, holiday homes, and recreational areas, but substantial lengths remain natural (Kappel, Rasmussen, & Waneck, 2010).Lemvig is a town of 6,978 people, located with Lemvig Municipality (20,015 population in total), western Jutland, Denmark (Figure 1).The municipality shows negative population growth (one of the highest in the country) and more than 50% of the residents are aged over 40.While the overall population growth is negative, the predictions for population growth amongst those age 65 and above are increasing (Lemvig Kommune, 2017) Lemvig is situated on the Limfjord, a shallow sound that has narrow openings to the Kattegat in the east and the North Sea in the west (1.5 km and 0.5 km wide respectively).Lemvig has areas of low elevation and is in close proximity to water, resulting in flooding due to storm surges on a number of occasions, overflow of sewers in cloud burst events, flooding from increased storm intensity, groundwater flooding, and flooding along streams (Lemvig Kommune, 2014).Within this case study, the coastal hazards Lemvig is and will be exposed to will be described in further detail, as well as the current management approach that has been implemented to address these hazards.

Coastal Hazards in Lemvig
Lemvig is situated at the head of narrow inlet of the Limfjord, which makes the town especially prone to storms surges.Further contributing to this risk is climate change with, the mean sea water level in Denmark expected to rise by between 0.3 m and 0.6 m by 2100 (Miljøstyrelsen, 2015).Consequently, this affects the level and return period of storm surge events.In Lemvig, the 10-year storm surge (0.1 probability) is 166 cm, whereas by 2120, this is expected to be 260 cm (Table 1 and Figure 3).Therefore, flooding from storm surges is likely to become more severe and more frequent in the future.Within Lemvig, this equates to a storm surge flooding risk of 3.7 million Danish Kroner (approximately $565,000 US Dollars) in 2017, to 440 million Danish Kroner ($67 million US Dollars) in 2117 (COWI, 2017).In addition to storm surges, flooding is also possible via the watercourse that drains Lemvig Lake (Figure 2), just south of the town (Lemvig Kommune, 2014).This can potentially create an 'in combination' risk, as with a high storm surge, the water is not able to drain (via gravity) into the harbour as it usually would.

Flood Management in Lemvig
In response to the coastal flood risk in Lemvig the municipality chose to install a sea wall along the harbour front, as well as redesign the waterfront layout in in 2012-13.The sea wall was designed to be multifunctional, and has a number of gates within it (Figure 4), which are open during normal conditions and allow the public to walk around and utilise the area to sit, as well as access a children's play area (Figure 5) (Faragò, Rasmussen, Fryd, Nielsen, & Arnbjerg-Nielsen, 2018).The gates are closed when a storm surge is predicated therefore the sea wall acts like a traditional barrier.
Although this is a hard solution, and could be seen more of as mitigation, rather than adaptation, it demonstrates a mixed use and benefits beyond solely coastal protection.
The sea wall is designed to prevent flooding that is 2.1 m above sea level, and since its construction, a number of storm surges have occurred, with the seawall successfully preventing flooding in the town.This therefore limits the life of the sea wall, as with sea level rise, storm surges and wave overtopping are expected to regularly exceed this height.Initially, the sea wall was expected to give protection for approximately 25 years, with sea wall being redesigned or upgraded in the future (Harbour, 2015).This of course will come at an economical cost, but also if the sea wall is raised further it will being to impinge on the sea view, and the aesthetical quality of the harbour front could be lost.The multifunction of the current sea wall design may not be possible within future designs.
In order to mitigate the flooding created as a result of drainage from Lemvig Lake during a storm surge event a pumping station behind the sea wall at the harbour has been considered (Lemvig Kommune, 2014).The same system could also be used to remove flood water as a result of wave overtopping.As of January 2019 the pumping station has not been implemented.As part of the C2C CC, the Climatorium is being built in Lemvig.The Climatorium is a new building that will be built in Lemvig Harbour with the aim of fostering innovation, gathering knowledge on climate change adaptation with regards the sea, coast, and water, and also act as a tourist attraction for the town (http://www.c2ccc.eu/english/sub-projects/action-c21-klimatorium).

Conclusion
Lemvig is a small town that has been impacted by coastal flooding in the past and is likely to be further at risk due to sea level rise.While currently an innovative multifunctional sea defence structure is in place, this only has a design life of approximately 25 years.Planning for the future is therefore required, and the C2C CC and the Climatorium projects will support this as the town will be able to obtain expertise and knowledge from a range of stakeholders in Denmark to support the adaptation of the harbour front.

Figure 1 :
Figure 1: The Jutland Peninsula in Denmark, showing the location of Lemvig.Denmark.

Figure 2 :
Figure 2: The town of Lemvig, and the location of the two main water sources, the Limfjord and Lemvig Lake.

Figure 4 :
Figure 4: An example of the sea wall in Lemvig with gates that allow pedestrians to use the waterfront, but can be closed during a storm surge event.Photo credit: Authors.

Figure 5 :
Figure 5: An example of the play area situated in front of the sea wall in Lemvig that would temporarily be flooded during a storm surge event.Photo credit: Authors.Lemvig is part of the Coast to Coast Climate Challenge (C2C CC) which is a 6 year project (2017 to 2022) focussing on climate change adaptation, and includes municipalities in the Central Denmark Region and 50 partners.The aims of the project are to develop a long-term strategy to adaptation, implementing climate adaptation plans, and identifying and improving resources and capacities among citizens and municipalities, utilities and companies in the water trade (http://www.c2ccc.eu/english/).

Table 1 :
Change in storm surge height with sea level rise inLemvig (COWI, 2017) Signficiant amounts of data available that is regularly updated.This is the responsibility of the national mapping agency to maintain.Climate modelling at national scales is also available

Table 2 :
Typology to assess exposure and vulnerability of a coastal locality