Third Lagoon Preserve


Photo Credit: Bud Hardwick
A trip to Third Lagoon allows visitors the opportunity for both quiet hidden observation of animal life and with the tides permitting, a pleasant walk along the narrow sparsely vegetated berm that forms the thin coastline separating the lagoon from the saltwater bay. Most of the lagoon is located within the National Park boundary with the remaining eastern end of the lagoon within a preserve created by the San Juan County Land Bank and the Washington State Department of Natural Resources to protect the exceptional habitat and natural resources found here.

Third Lagoon is an important natural area located along the same shore as the other, more famous lagoons of American Camp (which include Old Town and Jakle’s Lagoons; alternately known as First and Second Lagoon). On the sometimes steep banked northern slopes of this the most southeastern “hook” of San Juan Island, known as Cape San Juan, the combinations of salt and freshwater mixing and relatively protected waters of Griffin Bay provide critical habitat for many species of plant and animal life. Not only are these types of lagoons an unusual feature in the San Juan Islands but they are only rarely found anywhere along the northwest Pacific coast. Their importance extends beyond resident species to include migratory waterfowl and sea mammals as well as the plankton and other marine organisms found in Griffin Bay.

The relatively small basin that supplies the freshwater component to the lagoon is highly dependent on rainfall; fresher in rainy winter months and saltier during the dry summers. In addition to runoff, freshwater also seeps slowly through the surrounding hillside and may even enter the lagoon through small upwellings from underwater connections with the island’s aquifers. Thus the species diversity varies not only with the seasonal weather but with the changing salinity and water levels found in the lagoon. Additionally the limited but nearly constantly saturated soil zones that are created provide habitat for unusual and rare plants.

Hiking from the Jakele’s Lagoon Trailhead in American Camp, several side trips are available including of course Jakele’s Lagoon, as well as Old Town Lagoon, Old San Juan, The Nature Loop, and Mt. Finlayson. The most direct route to Third Lagoon follows the way of an old wagon road (and at one time the only road access to Cape San Juan) that parallels the coast in lovely dense forest, though out of view of the water the entire time. At a little more than a mile, an obvious signed junction marks a trail down slope toward the shore.

Approaching the shoreline quietly with the aid of tree and shrub cover increases your chances of not only seeing waterfowl and shorebirds but mink, otter and even marine mammals enjoying a little peace and serenity. Once you’ve had a chance to scout the area, an easy walk-off from the trail to the sand and gravel berm is usually possible. Walking out onto the long thin berm provides unlimited views of the waters and surface wildlife on either side. Seaward, rafts of birds commonly congregate in the relative calmness of Griffin Bay, sometimes swirling in the eddy currents sent this way from the violent waters of nearby Cattle Pass.

Across the lagoon waters, at perfect viewing distance, is a nearly impenetrable wall of trees, shrubs and driftwood. Birds, both seasonal visitors and year-round residents make good use of this habitat. A heron rookery, a critical habitat for these gregariously nesting birds, exists among the moderately tall trees just beyond the lagoon waters.

While berms like their one-ended relations, sand spits, are notorious for changing shapes, heights, and tidal connections; Third Lagoon has been fairly stable for a number of years. This has allowed a scattering of shoreline vegetation to establish, further increasing the diversity of habitat provided by the lagoon. Near the midpoint of the berm a tidal connection serving the daily flushing of salt and brackish waters has become somewhat established. Depending on the level of the tide and the rate of change this minor waterway may appear as a thin still stream or a fairly raging river. Use care if attempting to cross, there’s no benefit to any risk, you can easily return the short distance to the main trail and loop around to the eastern side without this danger.

Beyond the lagoon, a trail follows the shoreline before connecting with the end of the Cattle Point Road. Signs of shoreline erosion are evident in the missing or abandoned sections of the trail closest to the water. While being mindful of your footing, look carefully at the nearby rocky outcrops just offshore. These appear to grow considerably as the tides lower and are often a pull-out for marine mammals getting their required daily dose of land time.

While the waters of the lagoon are off limits to any recreational use; much of the wildlife and scenery can be enjoyed from a near shore paddle. Passing along the coast provides wonderful gliding glimpses into these unique habitats and may cause fewer disturbances for some of the wildlife than the presence of land bound visitors or large motor boats. Beyond Third Lagoon the entrance to the historically important Fish Creek area can be seen and beyond that, impressive Harbor Rock stands alone, just offshore from the toe-like tip of Cape San Juan and the last point before entering turbulent Cattle Pass.
Written By: Bud Hardwick
On: 10/15/2009


On the far southeast corner of San Juan Island; Third Lagoon is located astride the northeast boundary of the American Camp Unit of San Juan Island National Historic Park. The Lagoon is best accessed from the National Park trailheads such as the ones serving Jakle’s Lagoon and Mt. Finlayson. Other walk-in approaches from the end of Cattle Point Road are also possible but the nearest public parking from this end is at the Cattle Point Interpretive Area (see article this website).


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