Hurricane Isabel and Sea Level Rise

Did sea level rise, land subsidence and ground water extraction increase the flooding and damage caused by Hurricane Isabel?

This page contains several resources on the issues related to the level of damage caused by Hurricane Isabel, a Category 2 hurricane which made landfall between Cape Lookout and Cape Hatteras on North Carolina’s Outer Banks on Thursday, September 18, 2003. Throughout the next several days, Isabel’s destructive effects were felt throughout the heart of the Chesapeake Bay and the entire Mid-Atlantic region.

Please visit our discussion forum on 'Hurricane Isabel and Sea Level Rise' as part of our Chesapeake Bay Seminar Series and Newsletter discussions, and the Isabel in Perspective Conference.

Conceptual Diagram

Details the role of sea level rise and land subsidence on the magnitude of coastal flooding. Mouseover the various numbers on the diagram for reference material on the processes described.


Resources

This section contains a variety of resources on Hurricane Isabel, including a storm surge model, a variety of multimedia seminars, a newsletter and several journal articles.

Hurricane Isabel in Perspective: A Conference Review
Mark Trice

This presentation reviews the findings presented at the Hurricane Isabel in Perspective conference (November 15 - 17, 2004).


    

Integrating Science and Management for Storms and Hurricanes: A Panel Discussion
Donald F. Boesch

The conference on Hurricane Isabel in Perspective provided an impetus for scientists to pull together a rich array of information about the physical, ecological, and human responses in the Chesapeake Bay ecosystem to this unusual event.

Preliminary animated SLOSH model of the storm surge through Chesapeake Bay during Hurricane Isabel.
National Hurricane Center, NOAA

Click on the thumbnail to view the animation in a popup window.

   

Assessing the impacts of Hurricane Isabel on Maryland water quality and erosion. February 2004

Presentation at the Maryland DNR MANTA seminar series by Mark Trice (Acting Chief, Tidal Water Quality Assessment, DNR) and Jeff Halka (Chief, Coastal and Estuarine Geology, DNR).

The flooding and associated property damage from Hurricane Isabel was well documented in the news. Yet, what were the effects of the hurricane, and one of the wettest years on record, on water quality for living resources and shoreline erosion? The DNR speakers will present results from routine and special sampling efforts to answer these questions. Water quality and nutrient results from pre- and post-hurricane sampling on the mainstem Bay and Potomac River will be presented along with examples of impacts observed from continuous and spatial monitoring throughout the Bay's tributaries. Results will be compared to available long-term data and related to possible impacts to living resources. Results from post-hurricane shoreline mapping will be shown to document the impacts of erosion to Maryland's coastal environments.

Available in multimedia format (slides and audio) or as a PDF.

   

Anatomy of a storm surge: Hurricanes on the dark side of the Bay. December 2003

Presentation at the Chesapeake Bay Seminar Series by Bill Boicourt. Available in multimedia format (slides and audio) or as a PDF.

  

Coping with sea level rise in Chesapeake Bay and around the world. November 2003

Presentation at the Chesapeake Bay Seminar Series by Court Stevenson. Available in multimedia format (slides and audio) or as a PDF.


Hurricane Isabel and Sea Level Rise
October 2003

This IAN newsletter discusses the effects of sea level rise, land subsidence and ground water extraction on the flooding and damage caused by Hurricane Isabel. The damage caused by Hurricane Isabel was significantly worse than an unnamed hurricane of the same magnitude (category 2) in 1933. Sea level rise in Chesapeake Bay (30 cm / 1 ft in the last 100 years since the 1933 hurricane) is nearly double the global average suggesting that the effects of tropical storms and hurricanes may increase in severity in the future. Global sea level rise in the 20th Century is an order of magnitude higher than for the past several millenia. Chesapeake Bay islands are generally less than 1 m elevation, and many are suffering from erosion and submergence. Sharps Island is completely drowned, Poplar Island has lost more than 90% of its land, and Blackwater National Wildlife Refuge has lost around 2,000 hectares, or one-third of its total marsh area between 1938 and 19881. Erosion may also contribute to the decline of submersed aquatic vegetation (SAV), through an increase in water turbidity due to suspended sediments.

  

Sea level and coastal change: What the last several years tell us about future coastal vulnerability in Chesapeake Bay. October 2003

Presentation at the Chesapeake Bay Seminar Series by Michael Kearney. Available in multimedia format (slides and audio) or as a PDF.

Landsat Imagery Shows Decline of Coastal Marshes in Chesapeake and Delaware Bays

Kearney, M.S., Rogers, A.S., Townshend, J.R., Rizzo, E., Stutzer, D., Stevenson, J.C. & Sundborg, K. 2002. Eos Transactions, American Geophysical Union 83 (16), 173,177-178.

The use of satellite imagery may improve estimates of marsh loss by discerning the range of regional variations. Up to 70% of the marshes along the New Jersey shore of the Delware estuary have been affected due to modifications to the hydrography and species composition from the construction of dykes and berms. Widespread disappearance of Atlantic coast marshes could severely affect food webs and biogeochemical cycles of littoral ecosystems, but also the massive export of particulates into nearshore waters from eroding marshes will have serious implications for estuarine water quality.


Shallow Water and Shoreline Ecosystems of the Chesapeake Bay Compared to the Northern Adriatic Sea: Transformations of Habitat at the Land-Sea Margin

Stevenson, J.C., Marusic, J.I., Ozretic, B., Marson, A., Cecconi, G., and Kearney, M.S. (1999). In: Ecosystems at the Land-Sea Margin: drainage basin to coastal sea. Coastal and Estuarine Studies. Vol. 55, Malone, T.C., Malef, A., Harding Jnr, L.W., Smodlaka, N., and Turner, R.E. (eds). American Geophysical Union, Washington DC, pp 29-79.

Rates of sea-level rise, are surprisingly similar in the Chesapeake Bay (CB) and Northern Adriatic Sea (NA). The underlying mechanism determining local rates of sealevel rise in both the CB and the NA, land subsidence, is largely due to groundwater withdrawal from underlying aquifers. Other common problems include agricultural land-clearing and varying kinds of development, dredging of sediment from shipping channels. Nutrient enrichment may be the most significant threat for shallow water communities (especially seagrasses) in both systems.


The Health and Long Term Stability of Natural and Restored Marshes in Chesapeake Bay

Stevenson, J.C., Rooth, J.E., Kearney, M.S., and Sundbert, K.L. (2000). In: Concepts and Controversies in Tidal Marsh Ecology, Weinstein, M.P., and Kreeger, D.A. (eds). Kluwer Academic Publishers, Dordrecht, The Netherlands, pp 709-735.

Recent evidence in Chesapeake Bay suggests that the majority of the tidal marsh acreage has been negatively affected by sea level rise in recent years. Marsh loss (conversion to open water) in the Blackwater National Wildlife Refuge is over 50% during the 20th century. Restoration efforts have been hampered by excessive grazing by muskrats and nutria, reduced diel tidal amplitude because of road building, and increasing salinity because of canals. Restoration efforts depend on groundwater pressure or supplementation of sediment to counteract sea level rise and promoting rhizosphere oxygenation.


Shoreline dynamics on the windward and leeward shores of a large temperate estuary

Stevenson, J.C., and Kearney, M.S. (1996). In: Estuarine Shores: evolution, environments and human alterations, Nordstrom, K.F., and Roman, C.T. (eds). John Wiley and Sons, Chichester, England, pp 233-259.

Although sea level rise underlies much of the past (and recent) history of the Chesapeake, its manifestation in landforms and processes varies considerably depending on which side of the Bay is considered. This review discusses the impacts of sea level rise on marshes and shorelines of both sides of Chesapeake Bay. Relative sea level rise along any coast manifests itself in different ways, depending on the rate of apparent sea level rise (including land submergence), availability of upland sediment supplies, elevation of the eroding shoreline, tidal range as well as exposure to prevailing winds and wave attack (not to mention anthropogenic features). In a large estuarine system like the Chesapeake, shoreline processes also are a function of the diversity of shoreline types. We conclude with a bay-wide perspective on the sediment budget of the Chesapeake, suggesting that the influx of particulates is not high enough to keep pace with relative sea level rise (including
submergence).

Imacts of Sea Level Rise on Tidal Wetlands and Shallow Water Habitat: A Case Study from Chesapeake Bay

Stevenson, J.C., Kearney, M.S., and Koch, E.W. (2002). In: Fisheries in a Changing Climate, McGinn, N.A. (ed). American Fisheries Society, Symposium 32, Bethesda, Maryland, pp 23-36.

Along with greenhouse gases and temperature, sea level has also increased globally over the last century. In the Chesapeake Bay, where there is postglacial fore-bulge collapse, the rate has
increased from 0.5 mm per year, from 1000 to 1850 AD, to more than 3.2 mm per year during the 20th century. Moreover, the decadal rate in the 1990s was very high, more than 1.3 cm per year. This unprecedented rate triggered marsh losses in the Chesapeake and Delaware Bays. Evidence from Thematic Mapper satellite imagery suggests that more than half of the tidal marsh area of the Chesapeake Bay now shows signs of degradation. As marshes erode, the resulting open water is marginal habitat for most biota. Among the problems for fish are the periodic hypoxia events in late spring. Contrary to expectations, landward migration of marshes is inadequate to replace marshes lost because sea level is rising faster than the plants can colonize new substrates and create new peat. Although they are complex and highly dependent on shoreline sediment type, sea grasses usually do not replace lost marshes at the seaward edge. In conclusion, massive marsh erosion spurred by rising sea level will have large impacts in a variety of coastal environments that once supported significant fisheries.


Marsh Loss in Nanticoke Estuary, Chesapeake Bay

Kearney, M.S., Grace, R.E. & Stevenson, J.C. 1988. Geographical Review 78(2), 205-220.

Marsh loss in the Nanticoke estuary dates from the 1920s. Since 1938 overall rate of loss has averaged 49.6 ha annually, with rates increasing down estuary. Most losses have occurred in submerged upland marshes; tidal freshwater marshes are stable. Interior ponding has been the primary mechanism of loss. Rising water levels are postulated to be the underlying force behind marsh losses in this estuary.