2007 GSA Denver Annual Meeting (28–31 October 2007)
Paper No. 33-1
Presentation Time: 1:30 PM-1:50 PM


KELLEY, Joseph, School of Earth & Climate Sciences, Climate Change Institute, University of Maine, Bryand Global Sciences, Orono, ME 04469-5790, jtkelley@maine.edu and BROTHERS, Laura, Earth Sciences, University of Maine, Bryand Global Sciences, Orono, ME 04469-5790

In 1867 the US Army Corps of Engineers (COE) built a jetty on the north side of the mouth of the Saco River, ME to facilitate commercial navigation. A beach community, Camp Ellis, soon developed on new beach land created by the collapsed ebb-tidal delta, and gradually recreational and residential interests replaced industrial in the area. For more than a century, beach erosion claimed property at Camp Ellis, with several properties protected by ~3 m high seawalls collapsing in 2007. During the same time, a south jetty was built and extended to 1463 m and the north jetty extended to 2030 m to prevent sand from entering the estuary. Seven COE studies found no linkage between on-going beach erosion and episodic jetty growth until graduate student research in the 1990's demonstrated that the Saco River sourced local beaches and that the COE misjudged the direction of longshore sand movement. By the mid-1990's, after building a physical model at WES, the COE acknowledged the river as a source of beach sand, the direction of longshore transport, and the association between the jetty and erosion. This led to more than $5 million of modeling studies on local wave behavior. The COE now proposes to build a $26 million breakwater to save Camp Ellis. Continued university observational research hints at rates of river-sand introduction and suggests complex shoreface transport patterns not contemplated by COE models. It is possible that more expensive engineering will lead to more erosion to the north of the proposed breakwater. Also uncertain are the long-term fiscal costs associated with construction and maintenance of the breakwater and how potential negative consequences of such a structure would be addressed. All of these risks are to save buildings that are worth less than the cost of their protection. How did all this happen? Obvious errors abound: homeowners failed to recognize the temporary nature of “new” land in the early 1900's and later refused a buyout; the COE failed to recognize the source of sand and direction of longshore movement, relied exclusively on physical and numerical models in the absence of observations and built accordingly; government at all levels failed to promote a buyout of properties, and instead rebuilt and added new infrastructure (sewer line) despite growing erosion problem.

2007 GSA Denver Annual Meeting (28–31 October 2007)
General Information for this Meeting
Session No. 33
Identifying America’s Most Vulnerable Oceanfront Communities: A Geological Perspective
Colorado Convention Center: 708/710/712
1:30 PM-5:30 PM, Sunday, 28 October 2007

Geological Society of America Abstracts with Programs, Vol. 39, No. 6, p. 95

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