A Higher Tide

Planning for sea-level rise.

By Madeline Bodin

The blue tape is everywhere in coastal South Carolina. It's on the brass door handle of the Palmetto Hammock and Resort Shoppe in Charleston, and it's on the window of the Lowcountry Bistro next door. In fact, blue tape is plastered on the exteriors of businesses all the way from Charleston to North Myrtle Beach.

Discussions about sea-level rise, like other aspects of climate change, are difficult. Frank Knapp, president and CEO of the South Carolina Small Business Chamber of Commerce, wanted to make sea-level rise real for people. The blue tape distributed by the chamber's South Carolina Businesses Acting on Rising Seas project marks the worst-case scenario: the high-tide mark in 2100 under the highest sea-level rise predictions, a six-foot rise above the current high tide.

In Charleston's low-lying Market District, the tape marks a spot nearly five feet above street level. And with one step up to reach the door, that means high tide may one day reach door-handle height at the hammock shop.

Knapp found that even in a "red state" like South Carolina, about half the small business owners that his team contacted were concerned about the effect of sea-level rise.

 

Blue tape on the door of Palmetto Hammock in Charleston, South Carolina, indicates where the sea level may be in 2010 under scientists' most dire scenario

 

'Rise' defined

"Sea-level rise" is shorthand for the increase in the global mean sea level, which has been measured by tide gauges for over 150 years, and more recently by satellites. According to the National Oceanographic and Atmospheric Administration, these measurements show that the global mean sea level has risen about eight inches since 1900. Sea level is expected to continue rising — and at an accelerated pace.

There are two main causes of sea-level rise: ocean water expanding as it warms, and land-based ice melting. Land-based ice includes glaciers, ice sheets, and the polar ice caps. In some places, sinking land adds to the impact of sea-level rise. Typically, land sinks because of the movements of the Earth's crust or groundwater removal.

While sea-level rise is global, its impacts are local. A town perched on a rocky cliff high above the ocean may not suffer as much from sea-level rise as a town on a flat coastal plain. Similarly, the dips and folds of a landscape can direct rising tides toward some neighborhoods while sparing others. Storm surges, extreme precipitation, exceptionally high tides (known as spring, neap, and king tides) all play a role in previewing the impacts of sea-level rise now, and will add to those impacts in the future.

Sea-level rise is a problem of coastal communities, but planning for it offers lessons for all communities concerned about the increase in extreme weather events that accompany climate change.

 

Facing the inevitable

The prevalence of coastal flooding means that sea-level rise is a concern in many states. In Florida, with its frequent hurricanes, coastal flooding is a constant worry. The Mid-Atlantic states are aware, too: They were shaken by Hurricane Sandy. And on the Pacific Coast, where earthquakes are the top natural disaster, coastal flooding is often associated with quake-driven tsunamis.

Susan E. Love, AICP, a planner with the Delaware Coastal Programs, points professional and volunteer planners to the many resources Delaware has developed for preparing for sea-level rise. The state offers a grant for sea-level rise assessment that can be used in several ways, including as part of a comprehensive development plan or as a stand-alone assessment. It also provides sea-level rise maps and maps that combine sea-level rise with storm surges.

Because Delaware has just 57 municipalities, Love's team can assist towns individually. The municipalities have responded. Love says 40 towns have passed ordinances that exceed Federal Emergency Management Agency standards. "That's a big win for resiliency in the state," she says.

Her message is that resources are available no matter where you practice. If your state doesn't offer sea-level rise resources from its planning department, and even if it lacks a climate change or sea-level rise program, your state's coastal management program and the federally funded Sea Grant programs typically have information about preparing for sea-level rise, she says.

Nationally, there is Digital Coast, which NOAA created in partnership with the American Planning Association and other groups. The program offers training, access to maps of coastal inundation scenarios, and the data to create maps specific to your area.

The Georgetown Climate Center offers a Sea-Level Rise and Coastal Land Use Adaptation Toolkit. This 100-page PDF booklet was created in 2011; an updated, online version will be available soon. It explains how 18 different tools, from zoning overlays to building codes to rolling conservation easements, can be used to prepare for sea-level rise. It also provides model documents.

The National Estuarine Research Reserve System, a partnership between NOAA and coastal states, provides training specific to coastal land-use planning. Nicole Faghin, coastal management specialist with Washington Sea Grant, reports that many of these sessions provide credit toward AICP certification maintenance. "These are huge resources that people should be tapping into," she says.

 

It's political

"One reason we took the approach we did with the sea-level rise toolkit is that there isn't one size that fits all," says Jessica Grannis, adaptation program manager at the Georgetown Climate Center. Big cities and small towns each have their own challenges and opportunities. "We designed the Sea-Level Rise and Coastal Land Use Adaptation Toolkit as a choose-your-own-adventure, useful for a variety of landscapes."

A rural town on the North Carolina coast might do best by guiding development through buffers and setbacks and protecting existing development by offering permits to create living shorelines. But in New York City, where high-rise buildings have already been built within feet of churning waves, better permitting of seawalls, bulkheads, and tide gates may be the most effective ways to prepare for sea-level rise. The climate center's toolkit offers tips and model language for each of these diverse tools.

The political landscape is as much a part of the process as the physical landscape. And the politics of the matter isn't just about the small percentage of climate change deniers — it's also about the everyday work of politics: influencing people, and identifying partners and resources for collaboration.

The Southeast Florida Regional Climate Change Compact is a national leader in preparing for sea-level rise despite some (yes, political) resistance at the state level. Compact participants are Miami-Dade, Broward, Palm Beach, and Monroe counties. Together their population is greater than that of many states (about six million in the four counties).

In an Earth Day speech this year, President Barack Obama called the compact a worldwide model for climate change preparation. The bipartisan effort has received praise, too, as a model for regional cooperation. Jennifer Jurado, director of Broward County's Environmental Planning and Community Resilience Division, says that Miami-Dade County assessed its transportation infrastructure early and was able to guide Broward through the process. Similarly, Broward took early interest in hydrologic modeling, which Miami-Dade was able to build on in its own work.

In 2012, the compact published a five-year regional climate action plan with 110 items. Recent progress on those action items includes a new ordinance in the city of Key West that raises the maximum height of buildings an amount up to four feet that is equivalent to the amount the first floor is raised above the base flood elevation.

"Because we are four larger counties, we do have internal resources to move forward," says Jurado. "We are not reliant on the state and its resources. In places where the state agencies have been partners, it has been great."

But even in "blue state" California, planning for sea-level rise can be an uphill battle. "On the West Coast, when we are working with governments, there isn't a debate on whether climate change is real," says Steven Goldbeck, chief deputy director of the San Francisco Bay Conservation and Development Commission, another national leader in sea-level rise planning. Still, it took three years and 30 public hearings to win acceptance from local governments and businesses for those first adaptation laws, he says.

 

Assessment

In Washington County, on Maine's northern coast, citizens are preparing for sea-level rise because they are already seeing the impacts of climate change, says Judy East, AICP, executive director of the Washington County Council of Governments. They now worry about the ticks that carry Lyme disease and tree-damaging insects that were once only found to the south. They have suffered flooding from several unprecedented storms.

The Washington County COG took advantage of the U.S. Department of Housing & Urban Development's National Disaster Resilience Competition to assess its vulnerability to sea-level rise and other coastal flooding events. WCCOG received about $180,000 of an $800,000 grant to the Northern Maine Development Commission. HUD also provided several forms of technical assistance, including hiring a consulting firm to help assess the county's water system infrastructure.

Rather than create a set of documents, East says, the COG launched a website full of accessible tools that allow the area to plan dynamically. At the heart of the website are maps of the county's coast under various conditions, including sea-level rise and four categories of hurricane. Click on a scenario and blue covers flooded land while flooded roads and buildings change to red.

In Maine, as in other places, mapping coastal flooding revealed surprising vulnerabilities. Goldbeck says that in the San Francisco Bay region, "Maybe the facility wouldn't be inundated, but its connections would be." So, even if a manufacturing plant came out unscathed, if its railway connection to the port is flooded, the facility is totally cut off.

In Maine, Delaware, and elsewhere, sea-level rise maps can be used in concert with FEMA's flood insurance rate maps designating 100-year (or one percent) flood zones for a more comprehensive view of flooding risk over time, says Delaware's Love.

These coastal flooding maps are proving useful not only for sea-level rise scenarios that are decades away, but for emergency management planning today. "We wanted to give emergency managers access to this information at home at 2 a.m. in their bunny slippers," says East.

 

Tools for adaptation

The idea of responding to rising seas by building something large and durable between the ocean and whatever needs to be protected has been around at least since the Dutch started building their dikes in the Middle Ages. Demands for these structures are expected when vulnerabilities to flooding become known.

However, current coastal protection practices favor natural solutions. "The more natural the habitat between the water and people, the more protection you have," says Love. "Unlike some hard infrastructure like rip-rap or bulkheads, natural features can repair themselves."

Hurricanes Katrina (2005) and Sandy (2012) demonstrated that natural resources such as wetlands, dunes, and forests provide the most resilient flood protection. "Understanding the value of natural resources for flood abatement and climate change adaptation," Love says, is a keystone of planning for sea-level rise.

Putting traditional planning tools to work on sea-level rise goals ideally begins with a comprehensive plan, since other land-use tools build on it. Fort Lauderdale and other Broward County communities were leaders in including adaptation and resilience planning in their comp plans, says Jurado. But first these Florida municipalities needed to clear the way for these additions through state legislation. The necessary law, called the Community Planning Act, was passed in 2011.

Regulatory tools, such as zoning overlays for areas especially vulnerable to sea-level rise, building codes that raise buildings above expected floods and high tides, and subdivision regulations that cluster development away from natural protective areas or flood-prone areas, make up most of the tools in the Georgetown Adaptation kit. Experts agree that these traditional land-use tactics are the most powerful tools available to protect communities from the consequences of sea-level rise.

Other broad categories include spending tools, such as conservation easements that preserve dunes or wetlands, and tax- or market-based tools such as a requirement that sellers reveal when a property is in an area vulnerable to sea-level rise.

"There are ways to simplify this," says Love. "If you have a strong setback, or don't allow subdividing in the flood zone, you might not need certain building codes." She adds that this can be a lot to ask of a municipal government, but state experts such as Love and national resources can help.

 

Getting it going, keeping it going

The science of climate change is constantly being refined. It's as important to keep sea-level rise plans up-to-date as it is to make them in the first place.

That's a challenge met by the San Francisco Bay Conservation and Development Commission, which began planning for sea-level rise more than 25 years ago and has remained a leader.

"We realized that we couldn't do this once and then move on," says Goldbeck. "We approached it knowing that we had to plan for uncertainty, and that made it easier. What's the best number of feet or inches to use for sea-level rise? We knew that was going to change. We needed approaches that could change under different scenarios."

"Climate change and sea-level rise is certain, but the effectiveness of what we can do about them is uncertain," says Love. "Our adaptation efforts are adapting, particularly because there are so many emerging technologies that seem effective, but are untested."

Preparing for sea-level rise and other flooding appears to be contagious. East says that when she presented the coastal flooding maps for Washington County, they unleashed a cascade of preparations by emergency services departments and suggestions for map enhancements.

Love adds, "I know I've been successful because now I'm not the only one in the room saying, 'Have you seen my sea-level rise map?' City councils, wastewater treatment staffs, people managing forests, fishermen, citizens are all responding in their own way."

It's tempting, in the face of so much uncertainty, to put off sea-level rise preparations until the path is more certain. But the experts all say that the time to start is now.

Broward County, Florida, has been moving its water well fields westward, away from the encroaching ocean, for more than a decade, Jurado says. Communities in the region have already begun testing technologies like one-way flood valves against extreme high tides. [See "Miami Beach Readies for Sea-Level Rise," February 2015.] They are being protected today because they didn't wait until the consequences were dire.

Some South Carolinians have said that it is too soon to prepare for changes that may not be felt for 50 years, but for a process that depends on the lifespan of buildings and roads, 50 years may be cutting it close.

"It takes a while to understand the science, the planning, the funding, the governance," says Goldbeck, whose organization began its sea-level rise preparations decades ago. "It takes a while to build a depth of knowledge. Getting started was the best thing we did."

Madeline Bodin is a freelance journalist specializing in science and the environment.

 

Resources

Image: Blue tape on the door of Palmetto Hammock in Charleston, South Carolina, indicates where the sea level may be in 2100 under scientists' most dire scenario. Photo by Kate Thorton.

"Climate Adaptation and Sea-Level Rise in the San Francisco Bay Area," by Laura Tam, a web-only sidebar to the January 2012 issue of Planning: www.planning.org/planning/2012/jan/waterwarriorsside2.htm

NOAA's National Hurricane Center has developed a prototype storm surge warning system to highlight vulnerable areas along the Gulf and Atlantic coasts. Arcadis-US, a Colorado-based consulting firm, helped develop the model. See www.nhc.noaa.gov/surge/resources.php and www.arcadis-us.com.

Digital Coast (a partnership between NOAA, APA, and other organizations): www.coast.noaa.gov/digitalcoast

Georgetown Climate Center, Adaptation Toolkit: Sea-Level Rise and Coastal Land Use: http://tinyurl.com/pm6t9nc

National Estuarine Research Reserve System: www.nerrs.noaa.gov

Washington State Sea Grant, based at the University of Washington College of the Environment: http://tinyurl.com/qjn8hbm.