Shoreline Energy and Sea Level Dynamics in Lower Chesapeake Bay: History and Patterns
- 283 Downloads
A long-term (1948–2010) shoreward energy history of upper tidal shorelines in lower Chesapeake Bay was developed using a simple calculation of kinetic energy from corresponding wind and tide data. These data were primarily used to determine the likelihood of shoreline energy increases coincident with local sea level rise. Total annual shoreward energy ranged from 620 kJ/m of shoreline in 1950 to 17,785 kJ/m of shoreline in 2009. No clear linear trends are apparent, but mean annual energy shows an increase from 2,732 kJ/m before 1982 to 6,414 kJ/m since then. This increase in mean energy was accompanied by more numerous spikes of comparatively higher annual energy. Shoreward energy delivered to lower Chesapeake Bay’s upper tidal shorelines was enabled by an increasing amount of time per year that tidal height exceeds mean high water, accompanied by increasing heights of tidal anomalies. An index termed the Hydrologic Burden was developed that incorporates the combination of time and tidal height that demonstrates this increasing trend. Although opportunities for greater shoreward energy increased as the Hydrologic Burden increased, and even though there is evidence that greater energy was delivered to the shorelines during the latter time series, energy per hour delivery was shown not to have increased, and may have decreased, due to a steady reduction in average wind speed in lower Chesapeake Bay since the mid-1980s. Energy delivery in lower Chesapeake Bay was primarily from the northeast, and energy delivery over the time series is shown to organize symmetrically around a point between the northeast and north–northeast directions. This is evidence of a self-organizational phenomenon that transcends changes in local wind and tide dynamics.
KeywordsChesapeake Bay Sea level rise Shoreline energy
I am grateful to Valerie Woodard, Donna Milligan, Scott Hardaway, Tiffany Backer, and Gary Anderson of the Virginia Institute of Marine Science for data management assistance. I am indebted to John Billet of the National Weather Service in Wakefield, Virginia and Dr. John Hoenig of the Virginia Institute of Marine Science for guidance on particular data analyses. I also thank the reviewers, whose contributions greatly improved this paper. This paper is Contribution No. 3294 of the Virginia Institute of Marine Science, The College of William and Mary.
- Austin, H.M. 2002. Decadal oscillations and regime shifts, a characterization of the Chesapeake Bay marine climate. American Fisheries Society Symposium 32: 155–170.Google Scholar
- Boicourt, W.C. 2005. Physical response of Chesapeake Bay to hurricanes moving to the wrong side: Refining the forecasts. In Hurricane Isabel in Perspective, ed. K.G. Sellner, 39–48. CRC, New York.Google Scholar
- Boon, J.D., J.M. Brubaker, and D.R. Forrest. 2010. Chesapeake Bay land subsidence and sea level change: An evaluation of past and present trends and future outlook. Special Report No. 425 in Applied Marine Science and Ocean Engineering, Virginia Institute of Marine Science. 72 p.Google Scholar
- Bosley, K.T., and K.W. Hess. 2001. Comparison of statistical and model-based hindcasts of subtidal water levels in Chesapeake Bay. Journal of Geophysical Research 106: 16869--16885.Google Scholar
- Graham. H.E. and D.E. Nunn. 1959. Meteorological considerations pertinent to standard Project Hurricane, Atlantic and Gulf Coasts of the United States. National Hurricane Research Project Report No. 33. U.S. Department of Commerce, Weather Bureau, Washington, D.C.Google Scholar
- Knauss, J.A. 1978. Introduction to physical oceanography. Englewood Cliffs: Prentice-Hall, Inc.Google Scholar
- Knudsen, M.F., M.-S. Seidenkrantz, B.H. Jacobsen, and A. Kuijpers. 2011. Tracking the Atlantic multidecadal oscillation through the last 8,000 years. Nature Communications. doi: 10.1038/ncomms1186.
- Li, M., L. Zhong, W.C. Boicourt, S. Zhang, and D. Zhang. 2007. Hurricane-induced destratification and restratification in a partially-mixed estuary. Journal of Marine Research 65: 169–192.Google Scholar
- NOAA. 2010. 2009 Local Climatological Data Annual Summary with Comparative Data, Norfolk Virginia (KORF). National Climate Data Center, Asheville, NC. ISSN 0198-5345.Google Scholar
- Saville, T. 1954. "The Effect of Fetch Width on Wave Generation," Technical Memorandum 70. Washington, DC: Beach Erosion Board.Google Scholar
- U.S. Army Corps of Engineers. 1984. Shore protection manual, vol. I. Vicksburg: Coastal Engineering Research Center.Google Scholar