Coastal Development in an Era of Climate Change
Can coastal communities survive rising sea levels? One Virginia
town struggles to find an answer.
By Mary H. Cooper Ellis, Student ASLA
Of all the havoc wreaked by global warming, rising sea levels may
pose the biggest immediate threat. More than one-third of the globe’s
2.4 billion human inhabitants reside within 60 miles of an oceanic
coast, and coastal populations are increasing faster than the rate
of population growth worldwide.
Some coastal communities are beginning to consider one or more
of three basic approaches to deal with rising sea levels:
- hardscape—protecting land to maintain existing uses with dikes,
levees, seawalls, and the like
- softscape—restoring and expanding wetlands, coastal marshes,
dunes, and beaches
- adjustments—accommodating current uses by raising structures
on pilings and cultivating flood- and salt-tolerant plants and
Policy makers in Britain have adopted an innovative strategy of
purposeful abandonment of vulnerable coastal areas before disaster
strikes. Under the moniker of “managed retreat” or “managed realignment,”
local governments are identifying sites that are likely to be inundated
by rising seawater and banning all construction on these lands.
The British approach has not received widespread attention in the
United States, but a few states have begun to examine this strategy.
In 1995 state agencies in Maine drew up a blueprint for identifying
vulnerable coastal areas and recommended two options for managed
One involved the prohibition of all new development within areas
expected to experience flooding due to sea-level rise over the next
century. The other involved adoption of the “rolling easement,”
a regulatory tool that bars construction of bulkheads and other
hard structures to impede the natural flow of water and requires
removing all structures and restoring sites to their natural state
as the shoreline moves inland. Clearly written into the deeds of
affected waterfront properties at the time of sale, rolling easements
would be reflected in the properties’ value and preclude charges
of adverse possession that have figured in several recent lawsuits
involving eminent domain.
Maine, Rhode Island, and South Carolina subsequently adopted forms
of rolling easements, while North Carolina prohibits construction
of new houses in areas deemed likely to be eroded by wave action
in coming decades. Common law in Texas recognizes rolling easements
along its Gulf Coast beaches.
High Stakes: The Chesapeake Bay
The Chesapeake Bay, where there has been little discussion of such
policy changes, is especially vulnerable to rising sea levels. The
largest estuary in the United States, the bay is a vast, brackish
water body where freshwater from several major rivers mixes with
saltwater from the Atlantic Ocean, ebbing and flowing with the ocean
tides. The bay is a unique habitat for myriad plant and animal species,
serves as an essential nursery for spawning marine fish, and supports
a vital fishing industry. At the same time, the Chesapeake is drawing
new residents in search of waterfront homes.
The Chesapeake Bay’s water level is rising twice as fast as the
global average, mostly owing to sediment compaction as a result
of the removal of groundwater through wells serving the bay’s growing
coastal population. Another factor is isostatic adjustment, as the
land is still shifting in the wake of the retreat of ice sheets
to the north many millennia ago.
Whatever the cause of the bay’s rapid rise in water level, the
impacts are becoming increasingly apparent. Several islands have
slipped underwater, forcing residents to relocate to the mainland,
a fate that now threatens the inhabitants of Smith Island, Maryland,
and Tangier Island, Virginia. Bay shore communities are reporting
more frequent flood events from storm surges and extreme high tides,
flooding houses, destroying septic systems, and washing caskets
out of centuries-old graveyards. Many communities reported unprecedented
flooding in September 2003 in the wake of Hurricane Isabel, a mild
storm by historical standards. Large numbers of dead trees along
the bay front bear witness to salt incursion, which kills many plant
species and may render low-lying coastal agricultural land useless
Public concern about the bay’s health has focused on the harmful
effects of polluted runoff from urban storm sewers and fertilized
croplands on the aquatic vegetation, fish, and shellfish that comprise
this unique ecosystem. But efforts to improve the bay’s “water quality”
have not been matched by concern over its “water quantity.” Even
in the wake of Hurricane Katrina’s devastation of the Gulf Coast
in September 2005, there has been little sign that bay-side residents
perceive the need to protect their communities and plan for the
day when they, too, may face the ocean’s inexorable force.
The need to prepare is all the more urgent in light of development
pressure. According to the National Oceanic and Atmospheric Administration,
the counties of Virginia and Maryland fronting the Chesapeake Bay
drew more than two million new residents from 1980 to 2003. With
the impending retirement of millions of Baby Boomers beginning in
2008, this trend seems certain to intensify.
Cities on the Chesapeake Bay and their tidal tributaries, such
as Baltimore and Annapolis, Maryland, have long defended themselves
from high water with seawalls. Although floodgates may conceivably
be an additional option for cities like Washington, D.C., or Richmond,
Virginia, which lie along narrow stretches of tidal rivers flowing
into the Chesapeake Bay, such barriers would be of limited value
to the most vulnerable cities—Norfolk, Virginia Beach, and neighboring
communities near the broad mouth of the bay.
Amid burgeoning development, armoring the Chesapeake Bay’s 8,000
miles of shoreline with bulkheads or riprap also would be prohibitively
expensive. In any case, rising sea levels would overtop such structures
in a matter of decades.
A more realistic strategy to deal with rising sea levels on the
bay would reserve hardscape solutions like seawalls for the most
vulnerable and valuable urban centers while employing innovative
land-use policies and tax incentives to enable property owners to
use their properties as long as possible but also allow nature to
take its course. But coastal communities may wish to turn to planners,
landscape architects, and architects rather than structural engineers
for solutions to the problem. The regulatory vehicles that permit
innovative land use, such as easements, have to be approved by local
or state legislatures. Planners can draw up these vehicles, while
landscape architects and architects can provide the design ideas
for the interim use of land that is threatened by eventual inundation—such
as parks, cultivation of salt-tolerant plants, or structures on
stilts. Though still in its infancy, Britain’s pioneering strategy
of managed retreat offers an intriguing model for forward-thinking
state and local governments.
A Thought Experiment: Kilmarnock, Virginia
How might such a policy look if put into practice here? The town
of Kilmarnock, Virginia, is a useful model for considering the potential
impacts of and responses to rising seas on the Chesapeake Bay because
it includes the agricultural, residential, and industrial uses typical
of the region and because it is sufficiently undeveloped to accommodate
design and planning tools for dealing with sea-level rise. Located
at the tip of the Northern Neck—a 100-mile-long peninsula stretching
from Fredericksburg to the bay between the Potomac and Rappahannock
rivers—Kilmarnock is a rural community of 1,200 residents that is
surrounded by low-lying fields and woodlands stretching to the water’s
edge at Indian Creek, a mile east of town.
Kilmarnock’s relationship with the bay was traditionally purely
utilitarian, as a watery highway for transporting grain and other
farm products and a fertile ground from which local watermen extracted
the oysters, crabs, and fish for which the bay became famous. But
over the past several decades, changing economic forces have affected
the area. Farmers have switched from truck-farming produce shipped
to buyers in Richmond and Washington to the more lucrative and larger-scale
growing of wheat, corn, and soybeans for poultry and industrial
buyers on the Eastern Shore and beyond. Small waterfront landowners
have cashed in on the growing demand for residential parcels by
second-home owners and retirees. The water is now valued as an amenity.
Unlike many communities here, Kilmarnock lies not at the water’s
edge but inland, atop an escarpment marking an ancient beachfront
that runs down the western side of the bay. At about 90 feet above
current sea level at its highest point, Kilmarnock illustrates the
impacts of rising seas at multiple stages because the town itself
would survive most plausible future increases in water level. However,
the low-lying area that stretches eastward from town to the waterfront
is vulnerable to sea-level rise, and changes in land use there will
affect Kilmarnock proper.
The 660-acre study site lies east of Kilmarnock, from the town
boundary to the shores of Indian Creek, a branch of the Chesapeake
Bay. Lancaster County records place the total value of the land
and its structures in 2005 at $27,611,800.
Residential property occupies just over 20 percent of the area
but accounts for almost three-quarters of its total value, making
private residential development by far the most valuable use of
the site. Most of these properties lie on the waterfront, however,
making residential use especially vulnerable to sea-level rise.
Like most of the residential areas, all of Kilmarnock’s industrial
sites are vulnerable to early-stage rises in sea level. The town
sewage treatment plant, the Southern States grain storage facility,
the Chesapeake Boat Basin (Kilmarnock Wharf), and two adjoining
gas and oil facilities occupy less than 5 percent of the land but
account for 20 percent of the site’s total value.
Three-quarters of the site is undeveloped or marginally developed.
The largest single parcel is the 95-acre Alexandria Police Department’s
Boys Camp, valued at more than $2 million for its waterfront location.
The rest of the marginally developed land—more than 60 percent
of the site—is cultivated farmland or woodland, much of which is
harvested for timber. Located mostly inland, these parcels are the
The prospect of rising sea levels could prompt a series of events
along these lines: After a heated debate, Virginia joins other coastal
states in adopting rolling easements and other policies to discourage
waterfront development as sea levels rise. From the ridge, the town
of Kilmarnock barely perceives a five-foot rise in sea level. Although
it is somewhat broader and deeper, Indian Creek still provides a
safe haven away from the rough waters of the open bay, and most
of the site would remain above high tide. But the peninsula that
provides that essential buffer, Bluff Point, already is undergoing
a radical loss of dry land, and the open water has captured much
of the point’s vast wetlands, exposing the site to flooding from
The grain facility shuts down two of its silos, which have been
contaminated by high tides.
The town wharf raises its boathouses on piers to provide adequate
clearance for vessel traffic.
The small community of 1960s-era houses adjacent to the silos is
subject to periodic basement flooding, prompting several residents
to sell their houses at a loss.
Encroaching saltwater is killing many of the hickories, loblolly
pines, and oaks that comprise the densely wooded buffer along the
low-lying shoreline of the Boys Camp.
When water overtops existing bulkheads and riprap, all illusions
that the previous way of life on the waterfront could endure are
put to rest. At 10 feet, much of Bluff Point is underwater, and
most of its luxury waterfront houses must be abandoned. Floating
houses are options at this stage, as long as roadways to town remain
above water. But many waterfront residents are newcomers to the
area, retirees with no family roots in Kilmarnock and little stomach
for the arduous task of rebuilding sustainable housing on an unpredictable
waterfront. Most will retreat from the area.
As the region’s farmland falls to inundation and salt incursion,
demand for grain storage has plummeted. Forced to move farther inland
or shut down because of flooding, Southern States dismantles its
silos and closes the facility for good.
The Boys Camp has lost about half its dry land. Virtually all the
trees that once covered much of the site have died, and most of
the property is covered by wetlands. The Alexandria Police Department
reluctantly closes the facility to campers.
As bulkheads and riprap fail, virtually all waterfront properties
have been abandoned. A new federal program helps property owners
pay for the removal of structures, cleanup of septic systems, and
remediation of their land.
The bright side of rising sea levels is the spread of wetlands
and the wildlife they support. Long degraded by development and
shoreline armoring, wetlands thrive at a sea level of 15 feet above
the 2007 mark. Thanks to the site’s almost level topography at this
elevation, the seawater stretches over a vast, shallow substrate,
creating ideal conditions for wetland plants and animals.
About one-third its former size, the site is dominated by woodlands,
with a few small open fields.
All former waterfront development has been destroyed. Former residents
have moved to town or left the area altogether.
Newly exposed to the open bay by the inundation of Bluff Point,
the town dock and marina services have sought a safer harbor at
the town of Irvington, six miles away on the Rappahannock River.
With more than half the site under a relatively shallow sheet of
water, local watermen try their hand at farming oysters and crabs,
once mainstays of the region’s economy.
Blessed with ample high ground for new construction and viable
highway connections to inland cities, Kilmarnock’s remaining residents
decide to hold their own. Taking a cue from Gulf Coast communities
that have decided to adapt to the menacing water instead of retreating
from it, Kilmarnock identifies sites that are suitable for accommodating
new residents and businesses while maintaining its historic core.
The town has expanded its boundaries to encompass undeveloped areas
in its immediate vicinity that lie at least 70 feet above 2007 levels.
These sites have been targeted for cluster development, supplanting
the old suburban pattern and offering mixed commercial and residential
uses. The ultimate town boundary is the encroaching water, accentuated
by a deep vegetated buffer, held in the public trust as parkland.
Speculating about the future based on current and likely ephemeral
conditions is a risky business. Using existing topographic maps
to envision future landforms under conditions of rising sea levels
further clouds the picture: A single Katrina-like storm surge could
reshape a coastal site. Many years of surge and wave action would
surely alter the topography. Add to all that the unpredictability
of human response to a creeping crisis like widespread flooding
and waves of environmental refugees from coastal cities, and the
picture is blurred beyond recognition.
So the scenarios envisioned in this article are speculative. But
the message is not. “Sea level rise under warming is inevitable,”
the Intergovernmental Panel on Climate Change flatly concluded in
November 2007. Managed retreat implies a revolution in current thinking
about climate change and its impacts. But we would be well served
to assume the worst in order to better protect our descendants from
Mary H. Cooper Ellis, Student ASLA, received her master of landscape
architecture and master of urban and regional planning degrees from
Virginia Tech in 2007. She lives in Kilmarnock, Virginia.
New | LAND | Annual
Product Profiles & Directory