Local-scale water level differences and meteorological drivers in Annapolis, MD

Localized nuisance flooding, or high tide flooding, affects coastal infrastructure and can severely impact local economies. Increased coastal development and rising global mean sea level can exacerbate nuisance flooding, especially in coastal communities currently at-or-around sea level. But since nuisance flooding is a function of relative sea level, astronomical tides, local-scale meteorological forcing, and geomorphology of the coastline, it can be challenging to predict.

The City of Annapolis, MD, where the U.S. Naval Academy (USNA) is located, has a densely populated waterfront with a high degree of economic development and activity. The frequency and duration of nuisance flood events in Annapolis has increased exponentially since 1930 and is expected to continue to increase. Better predictions of local-scale nuisance flooding are required to allow city managers and decision makers to plan to adapt to these events.

In this study, we analyzed differences in water levels measured at the National Oceanic and Atmospheric Administration, National Ocean Service Annapolis Tide Gauge (Station ID: 8575512) located at the USNA, Hendrix Oceanography Laboratory on the Severn River with those measured by a RBR Solo pressure sensor deployed at Annapolis City Dock since February 2018. Observed differences in water levels were compared with synoptic- and local-scale meteorological observations collected by an Onset HOBO weather station located near City Dock.

Preliminary results of this study indicate significant differences in measured water levels between the two locations, separated by less than 2 km, under specific wind forcing conditions relative to the local orientation of the coastline. Other factors such as precipitation and land cover may also affect water levels. These results have the potential to help inform models to better predict the frequency and duration of nuisance flooding at Annapolis City Dock and other at-risk coastal communities.