Visitors to San Juan Island National Historical Park are drawn to places where the sea meets the shore. The shoreline is the intersection of the water with the terrestrial shore or beach. In ever changing motion tides, currents, winds and storms constantly change the face of this narrow, but dynamic strip where land and sea interplay. The park’s 6.67 miles of shoreline varies from long stretches of sand/gravel beach to rocky headlands and coves, pocket beaches and an enclosed bay with mudflats at low tide.
The beaches of American Camp vary from open and windswept, to narrow and protected. Pocket beaches and rocky coves and headlands complete the varied coastlines. A stretch of South Beach, east of Pickett’s Lane, is backed by high bluffs, actually glacial moraines composed of deposits of glacial till, up to 100 feet high. These bluffs are extremely vulnerable to erosion by wind, rain and wave action. The entire 3.12 miles of the South Beach section of shoreline is exposed to the open waters of the Strait of Juan de Fuca, including the high winds and seas of winter storms. The narrow 1.75-mile strip of beach fronting Griffin Bay includes the Fourth of July and Jakle’s Lagoon areas of American Camp. This beach is flanked by low to high banks, forest and brackish lagoons. This shoreline is less exposed to weather extremes as other islands and narrow channels provide protection.
English Camp’s 1.8 miles of shoreline fronts a tranquil bay backed by a low to medium forested bank. A level hiking trail leads to a scenic point. The head of Garrison Bay is a shell midden formed from the discarded clamshells of prehistoric Native Americans, and the historic parade ground of the British Royal Marines. Extreme low tides reduce the area to mudflats, where clams, oysters, and mussels thrive.
Shorelines are not static. Geologic, climatic, environmental, and human factors can alter the physical appearance, biological composition, and environmental health of coastlines. Terraces at South Beach represent former beaches created as a result of changing sea levels and isostatic rebound following the most recent glaciation. Shorelines will continue to change as eustatic (worldwide sea level) rise is affected by vertical land movements (subsidence and uplift). In the last century sea levels rose 1-2.5mm/yr with projections for the next century at 2-8.6mm/yr, or an average rise in sea level of 50cm or 20 inches by 2100. Salmon Banks off South Beach was a thriving salmon fishery from prehistoric times to the 1980s. Since then, the numbers of salmon have declined, as have the bottom fish they feed on. Also is decline are eel grass beds, biologically rich and productive habitats. Even the orca is in receding.
