Virginia Coastal Zone Management - Summer/Fall 2008
In the Village of Oyster, Northampton County, homeowners have elevated their homes in expectation of more storm surges, like the one brought by Hurricane Isabel below.
The US Geological Service shows Virginia’s coastal zone to be one of the most vulnerable areas in the nation to inundation as sea level rises. (Thieler, E.R., and Hammar-Klose, E.S., 1999. National assessment of coastal vulnerability to sea-level rise: Preliminary results for the U.S. Atlantic coast. U.S. Geological Survey Open-File Report 99-593. http://pubs.usgs.gov/of/of99-593/).
Stormy Weather
Maximum Storm Surge Innundation
2008 Virginia Huricane Evacuation Study
The zones depicted represent maximum modeled storm surge inundation based on values determined by the National Weather Service (NWS) SLOSH program. As such, this map does not depict a single storm scenario and is for planning purposes only. The zones were modeled by the USACE between 2003 and 2006 using best available local elevation data and the NWS SLOSH program.
Scientists predict that climate change will result in more frequent and intense coastal storm events such as hurricanes and nor’easters. Coastal flooding from these events is likely to be worsened by the anticipated rise in sea level. Although Hurricane Isabel in 2003 was not as strong as the famous August 1933 storm that devastated Virginia’s coast, the extent of flooding was similar because water levels are now higher. The effect of increasing coastal property damage is already being seen as a number of major insurance companies are no longer offering coverage to some coastal localities.
Many more people and properties are also now in harm’s way because of rapid coastal population growth and a boom in waterfront development since World War II. Hampton Roads is now considered to be the largest population center at the greatest risk from sea level rise outside of New Orleans. According to the Virginia Department of Emergency Management, updated storm surge predictions for even a category 1 hurricane would require evacuation of 100,000 people from the Hampton Roads area alone (see above map).
Habitat Effects
The Chesapeake region is near the southern extent of the range of eelgrass, an important species of submerged aquatic vegetation that provides critical habitat for Blue Crabs and other animals. Eelgrass is extremely susceptible to warmer water, as was shown in 2005 when a large scale die-off occurred in late summer due to unusually high water temperatures.
Higher water temperatures are a double strike against a species already struggling to maintain a foothold in nutrient polluted waters. “Unless strong measures to improve water quality in the Chesapeake Bay are adopted by management and regulatory agencies, the future of eelgrass, which requires a significant amount of sunlight and is limited to the shallowest areas of the Bay and its tributaries, is uncertain,” says Dr. Robert Orth with the Virginia Institute of Marine Science, the foremost expert on eelgrass in Virginia.
Wildlife Effects
Some southern species previously at the northern extent of their range are experiencing significant population growth as their habitat expands. Brown Pelicans, for example, didn’t nest in the Chesapeake region before 1987 but are now common with more than 2000 breeding pairs.
According to Dr. Bryan Watts, director of the Center for Conservation Biology at William and Mary, some Brown pelicans are also trying to overwinter in Virginia, but are facing a variety of problems. Pelicans have lots of exposed skin and can’t tolerate the cold. The fish they feed on also move to deeper waters in winter, making feeding more difficult. In 2006, for example, 30-40 pelicans were found starving because they could not feed during a period of extended cold weather.
Water Quality Effects
When combined with heavier nutrient loadings from increased runoff, warming coastal waters may face larger and more persistent oxygen depleted “dead zones,” and more harmful algal blooms. More sediment from runoff, coupled with an increase in nutrients may also result in declining water clarity and corresponding impacts on underwater grasses. Coastal waters may also become more acidic as atmospheric carbon dioxide levels increase and more CO2 is absorbed into the water. Already, ocean acidity has changed from a pre-industrial pH of about 8.2 to a current pH of less than 8.1. This may result in problems with shell formation for organisms like phytoplankton, shellfish and corals.
"Fueled by heat and pollution, algae splotches waterways" - Virginian-Pilot Article (August 23, 2008)
“Hard” shoreline erosion control techniques like this bulkhead don’t allow fringe wetlands to retreat landward as sea level rises. The result will be the loss of critical wetland habitats along developed shorelines as marshes are drowned by rising waters and scoured by wave action.
“Living shorelines,” like this restored wetland with a rock sill, can protect property from erosion while maintaining the natural habitat and water quality protection functions of a fringe marsh. These techniques can better accommodate sea level rise by allowing marsh plants to slowly migrate inland.
Climate Change: Understanding Challenges and Adapting to Changes on Our Coast
By Shep Moon, Virginia CZM
Although news about the earth’s changing climate has been common since NASA scientist James Hansen first spoke to the U.S. Senate twenty years ago, the release of the United Nations Intergovernmental Panel on Climate Change (IPCC) report in 2007 heightened interest in the subject. Hansen warned in 1988 that climate change was already occurring and wasn’t just a potential threat for future generations.
In the absence of a national initiative, the issue has become more localized as state governments have begun to consider the potential implications of climate change and to evaluate what their response should be. Virginia Governor Tim Kaine created the Governor’s Commission on Climate Change in December 2007 with the charge of preparing a plan for reducing greenhouse gases and evaluating the expected impacts of climate change on Virginia’s citizens, natural resources and economy. In its draft findings, the Commission acknowledged that that global climate change is happening and could affect Virginia in a number of ways including its ecosystems, agriculture and forestry industries, fisheries harvest, transportation network, military installations and insurance industry.
Although the entire Commonwealth may be affected, Virginia’s coastal zone is likely to face the greatest challenges. Threats to coastal resources include rising water levels, more frequent and stronger hurricanes and storms, changes in precipitation patterns and warmer air and water temperatures that will affect coastal habitats and the livelihoods and lifestyles of coastal residents.
Rising Waters
The most publicized change is probably the expected rise in sea level, which is predicted to be at least two feet within the next 100 years, or double the rate from the past century. The region has added vulnerability because it is also gradually subsiding as a result of geologic changes related to the last ice age. As a result, Virginia’s coastal zone faces the highest rate of relative sea level rise on the East Coast. According to a recent report by the National Wildlife Federation, the Chesapeake Bay region, rimmed with marshes and other low-lying lands, may be one of the hardest-hit areas in the country.
Rising water levels pose a threat to both private development and public infrastructure. Roads, rail lines, wastewater treatment plants, water and sewer lines, and port and military facilities could all be endangered by rising water levels. Saltwater intrusion into potable groundwater supplies may also affect both public and private sources of water.
While many of the expenses of adapting to higher water levels will have to be born by the various levels of government, a significant burden will fall on individual waterfront property-owners. Already, many have been forced to elevate their houses in response to increasingly severe storm flooding and to rebuild seawalls and revetments that were originally designed for lower water levels. Septic systems are also being affected by higher water levels and frequently the only replacement options are expensive alternative on-site wastewater treatment systems. In other cases houses, especially on low-lying islands, are being abandoned as waters rise and land washes away.
Some coastal lands may eventually be completely inundated and converted to marsh, while other wetlands are flooded and become open water. A draft EPA study predicts inundation of 760 square miles of wetlands and adjacent uplands in Virginia’s coastal zone over the next 100 years. Some estimates show that up to 80y percent of Virginia’s tidal wetlands could be lost by the end of the century. Other wetlands will undergo significant species changes as water levels rise and salinities increase. Fringe marshes and beaches along developed lands with shorelines hardened by bulkheads or revetments are likely to vanish because they are unable to “migrate” inland as sea level rises. Along with the loss of wetlands, of course, comes the loss of their habitat and water quality protection values.
A Changing Climate
Scientists also predict long term changes in air and water temperatures and precipitation patterns. Temperatures in the Chesapeake Bay have already risen by about two degrees since the 1950’s and are expected to continue to warm with average water temperatures increasing by about .6 degrees Fahrenheit per decade. Precipitation is predicted to increase overall, with up to a 10% increase in total rainfall, but may arrive through fewer but more intense rain events. Increasing periods of heavy rain, especially during the spring, would have a severe impact on coastal water quality. Extreme rain events, like the remnants of Hurricane Agnes that deluged the Chesapeake Bay watershed in June 1972, wash tremendous amounts of extra sediment and nutrients into the estuary along with enough fresh water to significantly lower salinity levels. According to some theories, the effects of this one huge storm, which occurred early during the Bay’s growing cycle, are still being felt today.
Conversely, we may also experience more frequent and severe droughts. These may actually temporarily improve coastal water quality because of less runoff, but at the expense of agricultural production and potable water supplies. The saltier waters that move up the tributaries during prolonged periods of drought also cause habitat changes and affect less salt tolerant species of vegetation. Warmer temperatures also contribute to the decline of some species through additional environmental stress. Warmer waters hold less oxygen and are more favorable to various diseases that may affect important species like oysters and rockfish. Higher air and water temperatures may also affect important habitats and aggravate current water quality problems.
Taken together, the changes brought by climate change are likely to have far-reaching impacts on Virginia’s coastal zone and present a range of challenges for coastal resource managers. According to Skip Styles, director of Wetlands Watch and a member of the Governor’s Commission on Climate Change, the first step should be to look at the combined impacts of sea level rise, temperature changes, and weather variability on our coastal ecosystems. Then, he notes, the tough work begins: managing that ecosystem in a rapidly changing world.
Adapting to Change
Taken together, the predicted effects of climate change are likely to result in significant alteration of natural habitats and lifestyle changes for watermen, waterfront property owners and coastal communities. Recognizing the potential severity of these changes, many states have begun their own climate change initiatives. While the primary goal of these initiatives is often to reduce greenhouse gas emissions, coastal zone management efforts will need to focus more on planning for, and adapting to, the climate change impacts that now appear inevitable.
Coastal programs from around the country are developing policies to address issues such as the siting of public infrastructure, development project planning, wetland conservation and restoration, shoreline building setbacks, building elevations and alternatives to shoreline hardening for erosion control. The Maryland Coastal Program, for example, has developed a sea level rise response strategy to help guide state efforts. Through initiatives such as “StormSmart Coasts” from the Massachusetts Coastal Zone Management Program, local decision-makers are gaining access to better information on how to protect themselves from coastal storm damage and flooding, and to prepare for sea level rise and climate change. The program provides regional workshops and an extensive website that translates complex technical information into user-friendly guidance with links to the best information and data from around the nation. (See text box on page 7.)
The Virginia CZM Program is responding to climate change issues through several initiatives. The December, 2007 Coastal Partners Workshop in Portsmouth focused on climate change and included a discussion of coastal issues to be addressed through the Program’s next “focal area.” The priority issue identified was sustainable community planning, with an emphasis on both local adaptation to climate change and blue-green infrastructure protection planning. The Virginia CZM program will be providing about $1.1 million in grants to planning district commissions and state agencies over the next three years to address these issues.
The Virginia CZM Program’s shoreline management strategy grants also address climate change by promoting the use of more environmentally friendly “living shoreline” techniques to manage shoreline erosion. These techniques help preserve the habitat and water quality protection functions of natural shorelines while still protecting property from erosion. They also allow for the gradual landward retreat of fringe wetlands as sea levels rise. The shoreline management strategy includes a variety of projects with total funding of $750,000 over a five-year period that runs through September 2011.
Initiatives are also underway at the federal level. The National Oceanic and Atmospheric Administration (NOAA) has proposed creating a National Climate Service to mirror the work of NOAA’s National Weather Service, providing a clearinghouse for climate- related research, data and community assistance. The Coastal Zone Management Act (CZMA) also provides a ready structure for helping states better prepare for climate change. Congress is currently considering reauthorization of the CZMA, and an amendment has been proposed that would provide additional funds and authority for states to develop specific coastal climate change plans.
Future Challenges
Climate change is likely to bring new coastal resource management challenges to the network of agency partners that constitute the Virginia CZM Program. Rising water levels, for example, may eventually cause changes to lands designated as resource protection areas under the Chesapeake Bay Preservation Act. Stormwater management techniques and calculations for determining total maximum daily loads (TMDLs) of pollutants may need to be altered in response to changing precipitation patterns. And localities may need to re-examine land use designations in low-lying areas given the anticipated consequences of sea level rise and more storms. This last issue has grown in importance with recent changes to on-site septic regulations that now allow development with alternative systems in many low-lying areas that were previously considered undevelopable.
In order to adequately plan for climate change, Virginia will need more information in the form of higher resolution elevation mapping, research into the effects of climate change on coastal resources, and other data collection, modeling and forecasting products. There will also be a need for intergovernmental coordination and technical assistance to local governments. At this point we can only speculate as to what future challenges climate change may bring. There may even be some positive changes. In any case, climate change is likely to be a key issue for coastal resource managers for the foreseeable future.
Learn More About Climate Change
Intergovernmental Panel on Climate Change - http://ipcc.ch
Governor’s Commission on Climate Change -
http://deq.virginia.gov/info/climatechange.html
VIMS Center for Coastal Climate Change - http://vims.edu/climatechange
Maryland Coastal Program’s Sea Level Rise Response Strategy -
http://dnr.state.md.us/Bay/czm/sea_level_rise.html
Massachusetts StormSmart Coasts - http://mass.gov/czm/stormsmart
Chesapeake Bay Foundation - Climate Change and the Chesapeake Bay: Challenges, Impacts, and the Multiple Benefits of Agricultural Conservation Work - http://cbf.org
National Wildlife Federation - Sea Level Rise and Coastal Habitats of the Chesapeake Bay - http://nwf.org
EPA Climate Change Initiatives - http://epa.gov/climatechange
Chesapeake Bay Program, Science and Technical Advisory Committee - “Climate Change and the Chesapeake Bay: State-of-the-Science Review and Recommendations” -
- http://chesapeake.org/stac/Pubs/climchangereport.pdf
Climate Impacts Group - University of Washington - “Preparing for Climate Change: A Guidebook for Local, Regional, and State Governments” - http://cses.washington.edu/cig/fpt/ guidebook.shtml