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The 2009 State of Maine's Beaches report provides a two-year follow up from the first report issued in 2007 (Slovinsky and Dickson, 2007). The purpose of the report is to summarize morphologic characteristics and changes of Maine beaches that are monitored as part of the State of Maine Beach Profiling Project (SMBPP, Maine Sea Grant Extension, 2003). The SMBPP utilizes trained volunteers to collect monthly beach profiles which start at a known point or benchmark (usually in the frontal dune or in a seawall) and continue shore-perpendicular to roughly the low-water line. Fixed starting locations are used with the Emery Method of beach profiling (Emery, 1961; Woods Hole Sea Grant, 2001). Volunteers enter collected data into an online database, where it is accessible for outside researchers (Maine Shore Stewards, 2007). The SMBPP is funded and managed by combined efforts of the Maine Geological Survey, University of Maine, Maine Sea Grant, and Maine Coastal Program.
The previous State of Maine's Beaches report discussed the data collection methodology used by the SMBPP program, and documented the changes that were observed in beach and dune topography at each beach profile on a year-by-year and seasonal (summer vs. winter) basis since the start of data collection (1999 for some beaches) and continuing through April 2006. This report reviews the changes that have occurred at each beach profile in response to the Patriots' Day Storm of 2007 (April 2007) and documents the recovery of the beach and dune, or lack thereof, at each location.
Spatial and Temporal Extent of Data for 2009 Report
Several beaches have not had recent data recorded since 2006, including Fortunes Rocks Beach in Biddeford, and select profiles at certain other locations have incomplete datasets (see Table 1). Additionally, many beach profile starting points were lost in the Patriots' Day Storm, which led to some post-storm data gaps, or problems in relating profiles taken from front stakes (lost in the storm) to profiles recorded from back-stake starting points. This report will compare profile data from immediately post-Patriots' Day Storm (i.e., April or May 2007), and profile data from the subsequent closest months from 2008 and 2009, as available. We also include profile data from a year before the 2007 Patriots' Day Storm (i.e., from April or May 2006, as available), for comparison's sake as "pre-storm" conditions. With this overall dataset, we are attempting to document the immediate impact of the storm, and review beach and dune recovery within the two-year post-storm period.
The 2007 Patriots' Day Storm
The Patriots' Day Storm of 2007 battered the Maine coastline for days with heavy winds and rain, large waves, and a high storm surge, and had a large impact on Maine's beaches. Offshore waves during the storm reached upwards of 8 meters (30 feet), and stayed above 3 meters (9 feet) for several days (Figure 2). Winds were measured at 60 mph in Portland, and gusts approaching 80 mph were reported in Cape Elizabeth.
Tide gauge recordings (NOAA COOPS, 2007) of water levels in Portland Harbor from April 15th through 18th are shown in Figure 3. The rhythmic rise and fall of the tides twice a day is shown as predicted by the National Oceanic and Atmospheric Administration (NOAA) in the lower blue line. The blue line shows a rise and fall (range) larger than the mean due to "spring tide" conditions forced by the gravitational pull of the moon and sun. These astronomically high tides were the largest of the year and coincided with the Patriots' Day Storm. The second tidal line (shown in red) is a plot of the data recorded at the Portland Tide Gauge. The storm produced a surge (an extra elevation of the sea) driven by the wind and low barometer to levels of 0.7 meters (or 2.5 feet) above that predicted. The storm surge is the difference from the predicted tide and the storm tide and shown by the green line on the graph. It peaks between 10 and 11 a.m. on April 16, 2007 and remains elevated for 6 more high tides before the storm's influence abates. The surge seemed to get slightly higher during flooding tides.
As a result of the high winds, waves, and tides, extensive beach erosion occurred. Measurements by the Maine Geological Survey showed that many of the southern beaches lost between 3 and 4.5 meters (10 to 15 feet) of frontal dune from the storm, with some areas such as Willard Beach in South Portland losing almost 12 m (40 feet) of frontal dune (Slovinsky, 2007). Volunteer profiles extensively captured the post-storm profile shapes - with some data gaps and some locations requiring a new starting point - in order to monitor the recovery of beaches in response to the event.
In the following discussion of beach response, figures display pre-storm profiles by a yellow line, while immediate post-storm profiles are shown as a blue line. One year post-storm profiles are represented by a green line, and two year post-storm profiles are shown by a red line.
Last updated on November 19, 2009
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