Dune Restoration at Willard Beach in Simonton Cove, South Portland, Maine

Introduction

Willard Beach is one of Maine's few urban beaches. It lies within the arcuate Simonton Cove on the eastern shore of South Portland. Facing east, the beach overlooks the Portland ship channel and beyond to Cushing and Peaks Islands in Casco Bay (Figure 1). The islands of Casco Bay shelter the beach from some waves although ocean swells can approach the cove from the south in the Portland ship channel.

Figure 1

Figure 2

The cove is bordered on the north and south sides by bedrock headlands. The bedrock in this area is Ordovician in age and the folded metamorphic rocks are interesting in their own right and are described on a separate MGS bedrock geology page (Folded Metamorphic Rocks Near Willard Beach, South Portland). The northern edge of the beach and dunes tapers against bedrock cliffs that front the campus of Southern Maine Community College (SMCC). Over the bedrock surface are sediments primarily left by glaciers and modified by changes in sea level over the last 18,000 years. The most recent modification to the glacial sediment was the formation of Willard Beach by wave action over the last few thousand years (Figure 2; Bernotavicz, 1999).

A Review of Willard Beach from Historical Air Photos

In the cove is a relatively sheltered beach and dune system that has been a very popular recreational location for over a century (Figure 3 and Figure 4). The extensive use of the beach prevented some of the natural dune vegetation from growing. In Figure 3 the vestiges of a dune can be seen in the foreground. Some of the buildings were built on posts and it appears that wave action could reach them in storms due to the lack of a frontal dune (Figure 4).

Figure 3

Figure 4

Residential development has fringed Willard Beach for generations and a strong sense of community exists there today. In 1956, development consisted primarily of single-family homes (Figure 5), many of which were close to the beach and not protected behind sand dunes (Figure 6, Figure 7, Figure 8). In fact, based on the shape of the shoreline and wide berm (the flat dry sand surface), relief of historical dunes was probably lost due to foot traffic and use of the beach for storing, launching, and hauling boats.

Willard Beach in 1964 appears quite similar to 1956 with a large open expanse of sand and few dunes (Figure 9). On the lower beach profile, structures associated with pipe outfalls can be seen. The large building at the end of Franklin Street (with a t-shaped roof) was removed in 1967 and a smaller structure built in 1976 sits in its place surrounded by open sand. A rock breakwater (known as the wharf jetty) extends from the bedrock headland southern end of the cove. Timson (1977) concluded that the wharf jetty had no significant influence on beach erosion.

Figure 9

Figure 10

Figure 11

By 1986 sand dunes with sparse vegetation had begun to build seaward of some homes (Figure 10 and Figure 11). These incipient dunes probably trapped sand and benefited from fewer people walking or driving across them. Dune vegetation (particularly the common American beach grass) is sensitive to foot traffic, so the plants do not survive if they are repeatedly walked on. Through a combined citizen and city effort, sand fencing and signs have allowed more dunes to increase in area and elevation in the last 20 years (visit the Maine Office of GIS online air photo viewer to see how complete the dunes are in 2003).

Historical Erosion Studies

Two studies of historical shoreline change have been completed for Willard Beach. In 1977 Barry Timson (a consulting geologist) completed a study for the City of South Portland. In his analysis, he concluded that the shoreline underwent periods of erosion and accretion. Erosion rates can be as high as 3 to 5 feet per year. From 1950 to 1976 there was a minimum net annual erosion rate of 0.65 feet per year (Timson, 1977). This report is available in an appendix to the Willard Beach System, Research Resource & Management Guide.

In 1982 the U.S. Army Corps of Engineers released a report on Willard Beach. By analyzing old maps and charts of depths offshore of the beach, the Corps noted that the 6, 12, and 18-foot depth contour lines all moved inland from 1853 to 1941. While some of the shift could be attributed to different surveying methods, some of the underwater beach profile may be getting steeper over time (Figure 12 and Figure 13). This change in beach slope may indicate that sand is transported offshore. The Corps report suggested using a long-term erosion rate of 0.65 to 1.0 ft per year in beach planning.

Figure 12

Figure 13

Coastal Flooding in the Dunes

Figure 14

The elevation and inland extent of the 100-year coastal flood is represented on Flood Insurance Rate Maps (FIRMs) produced by the Federal Emergency Management Agency (FEMA). There are two V-zones in Simonton Cove (Figure 14). For most of the cove with buildings from Beach Street to Deake Street, the V-zone flood elevation is 13 feet NGVD (National Geodetic Vertical Datum of 1929). The northern part of the cove near SMCC has a slightly higher V-zone elevation of 14 feet due to a more open exposure to waves from the southeast.

NGVD should not be confused with tidal elevations reported in the news and elsewhere. NGVD starts at an elevation about 4.5 feet higher than the Mean Lower Low Water (MLLW) tidal datum. For comparison, the highest annual tide produced by astronomical conditions (not storms) is about 7.2 feet NGVD. So, in a general sense, the 100-year flood level is about five feet higher than the highest tides.

Most of the frontal dune is in a V-zone with an elevation of 13 feet NGVD. A V-zone represents an area where water depths are 3 feet or more over the beach elevation and ocean water has a "velocity" or surf coming ashore. V-zone flooding results from wave action in storm swells and a coastal storm surge or flooding that exceeds the normal high tide level. The A2-zone in Willard's dunes represents slower moving floodwaters and a lower height of water than the V-zone because some of the surf will have broken on the beach profile and frontal dune. All of the flood zones represent areas where beach and dune sand will be actively moved by water in a 100-year storm. Frontal dunes with a crest elevation over the 100-year flood elevation will provide more flood and erosion protection to buildings than dunes that are lower.

Topographic Mapping of Dunes

Figure 15

Recent improvements in topographic mapping from aircraft have allowed detailed measurements of beaches and dunes. The use of National Oceanic and Atmospheric Administration LIDAR (Light Detection and Ranging) data by the Maine Geological Survey allows examination of the elevations of the frontal dune and identification of areas where the dune ridge is lower than the 100-year floodplain. Topographic analysis is used to determine areas of active sand transport and erosion hazards. Figure 15 shows an example of the topography of Willard Beach and dunes in 2004. The shaded relief colors represent different elevations in the sand. Over time, repeated surveys will allow more detailed erosion surveys and trends in dune elevations that will complement the monthly beach profile monitoring by SMCC (described below).

Improved Dunes through Local Management

Beach profile monitoring by faculty and students at SMCC takes place on a monthly interval. The surveys along six transects from the dune to the low tide line monitor sand elevation changes over time. The rise and fall of beach elevations is affected by many factors including erosion by storms, transport along the beach by currents, and structures on the beach such as the pipe lines and seawalls. Figure 16 shows a transect down the beach in the vicinity of Myrtle Avenue. The upper and lower parts of the profile show the most steady positions while the greatest change occurs on the central and steepest section. These data show that the beach elevation changes about half a meter (1.5 feet) in the course of a year. In any particular storm, the beach may change that much in elevation in a tidal cycle or two, but often that sand is returned to restore the profile in a few days or weeks of calmer waves.

Dune access paths that focus foot traffic in specific areas and a 2003 beach management plan (The Willard Beach System, Research Resource & Management Guide by The Willard Neighborhood Beach Committee) have led to higher and wider dunes along the beach. These bigger dunes afford more protection to homes. Big dunes also provide a storage bank of sand that can buffer ocean flooding by absorbing wave energy. In severe winter storms dune sand can be released to the beach to break waves farther offshore. The neighborhood-led committee of citizens has developed improvements to access paths that benefit the dunes (Figure 17 and Figure 18). Stranded seaweed is better managed and used, in part, for a nutrient supply for dune vegetation. Through beach cleanup efforts, citizens and the city remove debris that strands on the beach (with the exception of seaweed; Figure 19). Water quality is tested regularly in the summer as part of the Maine Healthy Beaches program to advise swimmers about unsafe conditions if they arise. The City of South Portland maintains the recreation facilities and manages beach cleanups and litter removal.

Conclusion

Willard Beach in Simonton Cove in South Portland, Maine has experienced over a century of intense "working waterfront" use for commercial fishing and recreational boating and sun bathing. The protected pocket beach has continual use due to the proximity of year-round homes and a college campus. In the last few decades, awareness of the importance of dunes in preventing coastal flooding, protecting properties, and reducing erosion has led to a citizen-led beach management initiative that has succeeded in restoring much of the frontal dune. Protecting the dunes has had the benefit of avoiding the need for expensive beach nourishment (considered in 1982) and for avoiding serious erosion and flooding near beachfront homes in severe storms.

References and Related Links

Bernotavicz, A., 1999, Surficial geology of the Portland East quadrangle, Maine: Maine Geological Survey, Open-File Map 99-95.

City of South Portland, 2006, Parks and Recreation.

Federal Emergency Management Agency, 1985, Flood Insurance Rate Map, Community Panel No. 230053 00009 D, South Portland, Maine. Online flood maps from FEMA.

Maine Geological Survey, 1998, Folded Metamorphic Rocks Near Willard Beach, South Portland.

Maine Healthy Beaches, Willard Beach water quality testing results.

Maine Office of GIS, Aerial Photo Viewer.

Maine Sea Grant, Beach profiling.

National Oceanic and Atmospheric Administration, 2004, LIDAR data, Coastal Services Center.

Southern Maine Community College.

Timson, B. S., 1977, Historic shoreline changes, effects of a wharf pier, present erosion conditions, and nourishment feasibility, Willard Beach, South Portland, Maine, submitted to Terrence Dewan and the City of South Portland.

U.S. Army Corps of Engineers, 1982, Detailed Project Report and Environmental Assessment, Small Beach Erosion Control Project, Willard Beach, South Portland, Maine.

Willard Beach System, Research Resource & Management Guide.

Willard Neighborhood Association (and Beach Committee).

Site by Stephen M. Dickson

Originally published on the web as the February 2006 Site of the Month.

Last updated on February 21, 2006