MESOSCALE RESPONSE OF A MOBILE SEDIMENTARY SHORELINE: BASIS FOR NEW DIRECTIONS IN COASTAL MANAGEMENT AT THE COMMUNITY LEVEL; FALMOUTH, MA

Falmouth, MA, on the southern tip of Cape Cod, is a peninsular town with nearly 70 miles of salt-water coast including the south-facing (Vineyard Sound) shore; the west-facing (Buzzards Bay) shore; and numerous salt-water embayments with variable shoreline orientation. The Falmouth South Shore (FSS) presents a classic "river-of-sand" system with source area at glacio-tectonic uplands in the western sector. Littoral drift is uni-modal (west-to-east), delivering sand along the south-dipping, low-gradient, Mashpee outwash plain. This plain is dissected by numerous spring-sapped valleys which have been drowned during Holocene sea-level rise, enlarged to Carolina Bay-type entities by littoral "sculpting," and barred by lateral transport of sand.

In 1900, the FSS was a sedimentologically-responsive coast with clearly-defined meso-scale dynamics related to local forcing factors. The geophysical systematics and derivative organismal habitats have been severely altered in the 20th Century by continued building of coastal engineering structures; the current shoreline presents a condition of near-total armoring. Structures have impacted the river-of-sand in three ways: 1) shore-parallel structures (seawalls, revetment) "lock-out" sand at source areas; 2) groin fields "hold-out" sand from normal littoral transport and; 3) jetty pairs (at stabilized inlets, "cut-out" sand from the littoral stream on ebb tides.

A recent change in thinking may lead to entirely different directions in coastal zone management on the local and community scale. Along the entire 15-mile segment of the "open" south shore and the 5-mile system of Great Pond - Falmouth’s largest salt-water embayment, recommendations call for a phased, long-range plan of "whole-coastal restoration" designed to re-establish the shoreline to pre-1900 conditions. The Falmouth plans are closely aligned with and (in part) modeled on Martha’s Vineyard’s island-wide pre-facto "no-build buffer zone". If restoration proceeds, it will be the first time that coastal engineering structures have been removed from a significant stretch of stabilized and degraded USA shoreline in an effort to improve both aesthetic and environmental conditions.