Master of Science (M.Sc.)
Virginia Institute of Marine Science
In order to better understand storm tides in the Lower Chesapeake Bay, water levels during eleven storms at eight stations were analyzed using several methods. Storm tide was separated into individual components: predicted tide, storm surge, and local anomaly. These components were quantified and then analyzed for spatial trends. Trends were verified using Principal Component Analysis (PCA). The predicted tide and the storm surge each exhibited spatial variability, while the anomaly was spatially uniform. Anomaly values varied from storm to storm, ranging from 0.01m to 0.3m.
Potential water levels were determined for each storm by applying a time-shift to match the minimum or maximum predicted tide with the maximum storm surge and the anomaly. In many cases if the maximum observed level had occurred at high tide, the potential observed could have been as much as 0.5m larger than actually experienced. If the maximum observed level had occurred at low tide, the potential observed level could have been as much as 0.8m lower. Thirteen-year potential maximum results indicate that this potential maximum has not been reached at any station. Stations are between 0.3m and 0.5m away from their thirteen-year potential maximum.
Maximum storm tide values were assessed relative to both mean lower low water (MLLW) and highest astronomical tide (HAT). HAT was determined to be a better metric for storm impact than MLLW. Integrated intensity, or area under the storm tide curve relative to HAT, is a metric that combines storm duration with the height above HAT. Integrated intensity values were generally higher during extratropical storms than during tropical storms due to the long duration of these storms.
© The Author
Wilkerson, Carissa N., "Analysis of Extreme Water Levels in the Lower Chesapeake Bay" (2013). Dissertations, Theses, and Masters Projects. Paper 1539617934.