Avoidance

EXAMPLE: Coastal setbacks on the island of Kauai (USA)

nst — Mon, 16 Jan 2017 13:34:18 +0000

EXAMPLE: Coastal setbacks on the island of Kauai (USA) nst Mon, 01/16/2017 - 14:34

Coastal floods or storm surges

Erosion

Avoidance

Channel, Coastal and Floodplain Works

Managed retreat

Grey infrastructure

On the island of Kauai, Hawaii in the USA, the local governing county has implemented flexible and protective coastal setbacks that protect communities from coastal erosion and avoid shoreline armouring in the long term.

Based on J.F. O’Connell et al. (2010): "The island of Kauai, Hawaii's progressive shoreline setback and coastal protection ordinance" In: Shifting Shorelines: Adapting to the Future,The 22nd International Conference of The Coastal Society , June 13-16, 2010 ,Wilmington, North Carolina.

General description

In this particular case, there is a disconnect between state regulations on coastal zone management and local or County regulations. In Hawaii, there are state laws that require setbacks along shorelines that are no less than 20 and not more than 40 feet inland from the shoreline and armouring the shoreline is permitted. The regulations at the state level, have however, led to inappropriate constructions in areas that jeopardize the island’s valuable sandy beaches. Thus in spite of an innovative and flexible Ordinance developed in 2008 called the ‘Shoreline Setback and Coastal Protection Ordinance’, the state still allows armouring.

The Ordinance puts into place procedures establishing minimum construction setbacks based on average lot depth and long-term shoreline erosion rates that are generated by the University of Hawaii.

The objectives of the Ordinance are manifold:

To provide a buffer zone to protect shorefront development from loss due to coastal erosion for a period of time;
To provide protection from storm waves;
To allow the natural dynamic cycles of erosion and accretion of beaches and dunes to occur;
To maintain beach and dune habitat;
And to maintain lateral beach access and open space for the enjoyment of the natural shoreline environment.
To avoid armouring or hardening the shore which along eroding coasts has been documented to ultimately eliminate the fronting beach.
The Island of Kauai is a county within Hawaii and is also the fourth largest of the Hawaiian islands. It is vulnerable to a variety of coastal hazards including inundation, erosion, hurricanes, and tsunamis.

Local Setting

On the island of Kauai the coasts and sandy beaches are important to the economy and the community. Shoreline armoring as a measure for dealing with climate change can benefit coastal infrastructure but it can also threaten coastal marine habitats and beaches. The potential loss of sandy beaches due to coastal hardening is particularly important in a state like Hawaii and specifically on Kauai where the local economy depends on tourism and beach activities.

In Kauai, the county takes the state wide implemented setback of 40 feet as a minimum standard and finds flexible and specific setback lines based on average lot depth and long-term coastal erosion rates that are developed and provided by the University of Kauai. The county, therefore, has taken steps to avoid shoreline armoring and establish safe and environmentally effective setback distances for construction of structures with a 2008 Ordinance. However, the regulations developed at the County level do not match those set by the state.

Political setting

The Kauai case study provides an example of when different levels of government set different regulations that are in conflict with one another. In Kauai, a local level Ordinance has set environmentally protective standards in place that go further than State coastal zone management laws to ensure the integrity of Kauai’s sandy beaches. While the State sets general measures for coastal setbacks and infrastructure development, the County appears to be setting up legislation that is more accurately informed by local circumstances and data and that prioritizes environmental considerations.

The Ordinance puts into place procedures establishing setbacks that go beyond the state-wide laws. The County setbacks also consider lot depth and long-term shoreline erosion rates. In order to determine the erosion rates of different areas around the island, the County has partnered with the University of Hawaii Sea Grant College Program to conduct an assessment on Climate Change and Coastal Hazards in Kauai and to provide data regularly.

Innovative aspect

In Kauai, the county takes the state wide implemented setback of 40 feet as a minimum standard and finds flexible and specific setback lines based on average lot depth and long-term coastal erosion rates that are developed and provided by the University of Kauai. For existing structures 20 feet is the minimum setback area. It also requires lot depths of greater than 160 feet with a proposed building footprint less than or greater than 5000 square feet to calculate the setback by multiplying the erosion rate by 70 or 100, respectfully on top of a forty food safety buffer.

The purpose of the Ordinance is to ensure that structures are not built in areas that are vulnerable to hazards and that shoreline hardening is avoided and not depended on to protect property during its lifetime. There are also specific rules regarding activities and structures that are allowed within the setback are, however, no structure approved within the setback area by variance will be eligible for protection by shoreline hardening.

Key lessons learnt

There are several interesting elements of the Kauai case study. Firstly, there is an inter-change between local levels of the island County and established state laws on zoning and management. The Ordinance that determines county rules for setback measures is more protective and exact in determining the rules for building and at the same time was designed in a way that is flexible to specific projects and also informed by local data and research. The partnership between the County and the University of Kauai to establish appropriate setback measurements based on erosion rates on the island illustrates the importance of partnerships between governing entities and institutions with relevant scientific data and knowledge. Finally, the Ordinance is designed to be somewhat flexible but is ultimately environmentally focused in protecting the integrity of sandy beaches and avoiding the hardening of the coast in the future to protect any existing structures.

Relevant case studies and examples

Coastal and river setbacks

O'Connell, James and Aiu, Imaikalani and Milnes, Leslie and Smith, Lisa Ellen (2010) The island of Kauai, Hawaii's progressive shoreline setback and coastal protection ordinance. In: Shifting Shorelines: Adapting to the Future,The 22nd International Conference of The Coastal Society , June 13-16, 2010 ,Wilmington, North Carolina

O'Connell, James et al. (2009): A PROGRESSIVE, BALANCED COASTAL CONSTRUCTION SETBACK ORDINANCE ON THE ISLAND OF KAUAI, HAWAII: IMPLEMENTATION AND LESSONS LEARNED. Proceedings of Coastal Zone 09, Boston, Massachusetts, July 19 to 23, 2009

Measure category

Prevention

Coastal and river setbacks

giacomo.cazzola — Wed, 31 Aug 2016 12:38:11 +0000

Coastal and river setbacks giacomo.cazzola Wed, 08/31/2016 - 14:38

Riverine or slow rise floods

Flash floods

Estuarine floods

Coastal floods or storm surges

Erosion

Avoidance

Managed retreat

Non-structural measure

Coastal setbacks are an demarcated area where all or certain types of development are prohibited. Coastal setbacks can be measured either as a minimum distance from the shoreline for new buildings or infrastructure facilities, or may state a minimum elevation above sea level for development. Setbacks determined by distance from the shore are used to combat coastal erosion, while setbacks determined by evaluation are used to control flooding.

Based on kindly provided information by the ClimateTechWiki and the TNA Guidebook on 'Technologies for Climate Change Adaptation' by Matthew M. Linham & Robert J. Nicholls

A set back can be determined at a fixed distance or it can be ‘floating’ and adapt t the dynamic of an area’s topography and shoreline movement. Setbacks can also cover parts of a shoreline or area, or an entire administrative zone. It is important that setbacks are strategically placed in relation to historic erosion or water level rates, rather than by arbitrary placement.

Advantages

Setbacks are considered low cost and less intrusive than solid barriers such as sea walls and dikes. Setbacks maintain natural vegetation and shorelines and allow for the natural dynamics and rhythms of the shoreline to exist and are considered an environmentally sustainable measure for this reason (NOAA 2010). Setbacks can also have spillover benefits by making the shoreline accessible and providing open public recreational space.

Disadvantages of the technology

One of the disadvantages of setbacks is that they are vulnerable to a changing sea line and specifically sea level rise. For this reason, setbacks must be re-evaluated over time to ensure that the buffer zone provides continued protection in light of a changing environment.

Another important point, is that setbacks are not necessarily capable of protecting against strong storm surges and associated flooding and therefore a certain level of risk remains when implementing them as a protection measure.

The nature of setback zones is also subject to controversy because it implies that an area cannot be built on and development of the coast in certain areas cannot take place. This can result in conflicts between users or in the case of a reassessment can even mean that existing structures are newly within the no-build zone. Often structures are allowed to remain, or are compensated for having to move.

Financial requirements and costs

Again, the costs of implementing a coastal setback approach will be variable, depending on local conditions. A number of costs will be incurred when implementing setback in any situation. They are discussed below.

Firstly, a decision must be taken as to how far to set back. Costs involved in taking this decision include the collection and analysis of historic erosion rates or water levels, the cost of modelling likely shoreline evolution, and the associated cost of buying in modelling services and expert consultation. The cost at this stage will vary depending on the method used to determine setback distance. Less technical solutions are likely to be cheaper.

Secondly, the setback policy must be communicated to relevant bodies in order that the policy is taken into account in the planning process. Costs involved at this stage may also involve the additional costs of incorporating coastal setback into local planning policies.

Finally, enforcement is essential. The cost of enforcement may however be low as it is possible to enforce setback via pre-existing local planning bodies.

Additional costs may be incurred if private landowners are required to be compensated for loss of development potential and also when the setback distance undergoes periodic review.

Implementation of a setback policy is likely to have the lowest costs when implemented proactively, before significant, inappropriate development occurs. In this way it should be possible to minimise compensatory payments to private landowners.

Barriers to implementation

One of the challenges associated with implementing setbacks is public opposition. Land ownership and coastal development are often contentious issues, particularly if setbacks require restrictions that affect individual landowners. In such cases, landowners can be compensated for costs of lost development, however, this also increases the costs incurred from implementing a setback.

Many coastal areas also experience pressure to develop the coast for touristic purposes. In many instances, coastal regulation that has been put in place to protect the coastline is overridden in the face of development (Sanò et al., 2010).

Opportunities for implementation

Implementing setbacks is an issue closely related to land use and building regulations and is therefore dealt with by the same policies that regulate building standards. Environmental policy, therefore, has an opportunity to be streamlined into these policy areas.

Setbacks are complimentary measures, meaning that they benefit when implemented in combination with other measures such as sand dune reconstruction or wetland restoration. Implementing a setback in unison with dune reconstruction or wetland restoration helps to ensure that these areas are left alone to properly develop and also improve the capacity to act as a buffer to coastal flooding and erosion.

Relevant case studies and examples

EXAMPLE: Coastal setbacks on the island of Kauai (USA)

Literature sources

Main source: Matthew M. Linham & Robert J. Nicholls (2010): TNA Guidebook on 'Technologies for Climate Change Adaptation' UNEP , 166p.

NOAA (National Ocean and Atmospheric Administration) (2010) Construction Setbacks. Charleston, SC: NOAA.

Sanò, M., Marchand, M. and Medina, R. (2010) Coastal setbacks for the Mediterranean: a challenge for ICZM. Journal of Coastal Conservation, 14, 33-39.

Scale

Local

Measure category

Prevention

Adaptive management

nst — Tue, 14 Jun 2016 14:50:07 +0000

Adaptive management nst Tue, 06/14/2016 - 16:50

Riverine or slow rise floods

Estuarine floods

Coastal floods or storm surges

Erosion

Avoidance

Deal with the effects

Ecosystem based approach

Highly dynamic coastal systems (like sandy beaches, dunes or estuaries) might be best managed by not interfering with the natural processes, but instead accepting that change will occur and adapting backshore management accordingly. Key in this approach is a proper monitoring of the processes to analyze and evaluate the changes (for examples at eroding cliffs or dunes). With a proper planning horizon, these changes can be anticipated and with enough room for the environment to involve this can be a very cost-extensive approach.

Based on kindly provided information by the Scottish Natural Heritage

Technical feasibility

Adaptive management should be considered at all sites before considering any of the other options of hard engineering coastal defence measures. In some cases this can mean loss of land or other values, so an assessment of these impacts has to be carefully undertaken with the integration of relevant stakeholders.

In contrast to managed realignment, this measure is not a planned retreat (e.g. with opening of dykes or removal of groynes). Instead it is the allowance of natural processes that could lead to relocation of the coastline but does not necessarily have to.

If management of marine erosion is being considered it is assumed that assets of value are being threatened. These assets may be natural, such as a rare habitat or a particularly interesting geomorphological feature. In general erosion of such features would be considered part of their natural evolution and therefore preferable to management interference. More often the assets will have socio-economic importance, ranging from amenity access to a beach up to an industrial complex or power station. The shoreline manager must start by considering the value of the assets that may be at risk, then try to establish an understanding of the likely future evolution of the beach/dune system. Finally the manager must determine whether it is better to lose/move the assets or attempt to prevent or reduce the erosion.

Consideration from Italy: Retreat is expensive - staying too!

Political & social feasibility

Monitoring, consultation and education are at the heart of adaptive management. The shoreline should be continuously assessed using data collected from site, combined with any available historic or published data. The monitoring will allow the management policy to be reviewed from time to time. Impacts of the policy on recreation, land use and habitats should also be monitored.

Consultation is required to assess the values associated with the backshore, and to develop a consensus view on how to deal with the assets. This process is firmly linked with education, requiring the manager to set out the background issues in a language that can be readily appreciated by those who are affected.

Those responsible for the management of eroding dunes and cliffs should be aware of the potential danger to the public of a collapsing dune or cliff face. Dangers exist both from falling down the face and from being buried at the base. Warning signs set up along the crest and at public access points should be the minimum response to these dangers.

Cost of implementation & maintenance

The value of the backshore may be assessed in economic terms, based on the present replacement cost of buildings, infrastructure or land. The assessment should also consider the wider values such as potential loss of jobs, transport routes, rare habitats, recreation or cultural heritage (i.e. archaeological sites). This assessment therefore considers costs and benefits (SET LINK).

Costs associated with adaptive management are site specific and cannot be generalised. Accepting the gradual loss of a site valued as an undeveloped public recreation area may incur no actual cost at all apart from monitoring and minor works to delay erosion or encourage. At the other end of the scale the demolition and replacement of threatened shoreline buildings or recreational facilities may be very cost intensive.

Ecological feasibility

Adaptive management minimises interference with the natural processes and ecosystem of an evolving dune system. The approach allows for the sustainable, long term management of the shore, with no environmentally disruptive engineered schemes.

Key lessons learnt

Adaptive management can result in the controlled loss of backshore assets and the continued evolution of dune habitat and land form. This approach can be highly emotive, with local interest groups protesting vigorously and demanding that more positive actions be taken. However, it must be accepted that both erosion and accretion are natural elements of coastal evolution, and that maintenance of natural evolution is, wherever possible, preferable to costly and environmentally disruptive intervention.

Scale

Local

Regional

Measure category

Prevention