Managed Shoreline Retreat

Sea-level-rise hazards and planned retreat from shoreline:

Sea levels are already on the rise, and the rise is accelerating. So this is a matter of global concern. All low-lying areas, especially cities and populated areas, are experiencing changes to their shoreline environments. In Hawaii, we have noticed a lot of beach loss and nearshore roadways are being eroded into the ocean. In many cases, hotels, condos, and houses on the beach are starting to fall into the ocean.  Planning rules have now taken sea-level rise into account, and this has resulted in increased set-backs, as well as specified building codes, and used restrictions for oceanfront land in anticipation of the rising levels. The effects of sea-level rise are most obvious during high tides, storm surges, and at different times of the year. Most noticeably and dramatically during high wave events when the highest reach of the waves can rapidly erode property and undermine structures.

Rising water tables will cause inland flooding in low lying areas.
Rising water tables will cause inland flooding in low lying areas.

Global warming and predicted sea-level rise:

Because of global warming and predicted sea-level rise we should be planning for a population to retreat from the shoreline.  So all County-sponsored and subsidized developments such as affordable housing should not be approved close to the shoreline or on the Kihei floodplain for example.  Affordable housing should be located where it will not be impacted by sea-level rise, rising water tables, flooding, or located in areas that are already high-density housing. The predicted sea-level rise puts vital infrastructure underwater, or at risk from high wave events, storm surges etc. Infrastructure like roads, sewerage systems, electrical supply, and the shoreline itself is at risk. Sea level rise also raises the underground water tables causing them to saturate low-lying areas, and increases the flood risk in these areas. Areas that were one-time wetlands will become wetlands again as nature takes back the land.

3.2ft Sea Level Rise in Kihei
Coastal flooding caused by 3.2ft Sea Level Rise in Kihei

Mitigating the effects of sea-level rise:

Beaches come and go, so we need to accept that. But we do not need to accept that our homes and hotels will fall into the ocean, that is if we do not put them in harm’s way. New structures should be built at higher elevations, and farther back from the shoreline. And there should be a moratorium on all new construction at the shoreline. By limiting the types of uses, and what can be built we can make our inevitable retreat less painful and less expensive.

Who pays for this retreat?

Landowners will suffer billions of dollars of loss as they see their shoreline properties slip into the ocean, and get chewed away by waves. Structures will be destroyed and investments lost.  But also communities will also suffer as marine resources are lost and nearshore habitats are destroyed. Beachfront communities that rely on beach-based tourism will lose their sources of income. And fishing communities may suffer as erosion and pollution affect fish stocks and ravage fishing grounds. So administrators, scientists, and communities are looking for creative ways to mitigate the harm caused by rising sea levels, and increasing shoreline hazards.

A planned retreat takes many forms: 

One such solution is shoreline communities buying back shoreline properties from private owners. So that they can choose the best time to demolish the structure and minimize the hardship and financial costs of a catastrophic failure, disaster, or emergency relocation. Providing investment capital too but back shoreline housing, allows communities to turn beachfront condos into affordable rental units for example, and use them until they are no longer viable. Planning for these investments to have a finite time frame allows for an orderly and cost-effective retreat from the shoreline.

Shoreline open-space preservation:

The added bonus of creating a construction moratorium, is the preservation of unimproved shoreline land, that can be used for recreation, and shoreline access for the community. Vacant lots can become temporary beach parks, and playgrounds for the community before ultimately being surrendered to the sea.

Another solution is creating an ESG:

ESG investment is the buzzword. Environmental. SOCIAL, Governance. Socially and environmentally conscious investors are investing in ethical and sustainable portfolios, that do not harm the environment for example.  We can create an ESG economic zone at the shoreline, that would encourage capital investment in the types of projects that be beneficial for the environment as well as do no harm. Such investment might be buying back vacant land for preservation as parks and open space, restoration of wetlands as green infrastructure, or investments in parks or other public amenities. It could even provide money for new wastewater treatment facilities, clean power generation (solar, wind), and the possibilities are endless.