Qwuloolt Estuary
The City of Marysville was founded in 1872. The early settlers quickly discovered the rich soil of the Qwuloolt Estuary just south of the town, and diked and drained the land to use for cattle and farming. “Qwuloolt” (qʷəlult) means “salt marsh” in the Lushootseed language spoken by the local Native American tribes. The levees the settlers established along Ebey Slough, as well as the drainage channels and tide gates, significantly degraded the estuary by preventing the salt water from Puget Sound from mixing with the fresh water from the local creeks. For over a hundred years the area was cut off from the natural influences of the Snohomish River and Puget Sound tides, and the native shrubs and grasses were supplanted by a monoculture of invasive reed canary grass. In 2015, as part of the effort to restore the estuary, the Army Corps of Engineers breached the levees and re-exposed the area to tidal influence.
The Qwuloolt Estuary is located within the Snohomish River floodplain, approximately three miles upstream from its outlet to Puget Sound. The Snohomish River watershed drains 1,856 square miles of the western Cascades and is the second largest river basin draining to Puget Sound. River flows carry sediment downstream and deposit this rich, nutrient-laden material in the river’s delta. The deposition of these sediments coupled with the erosive power of the river helped to form the estuary’s 19.5 square miles of marshes, forested islands, distributary sloughs, mudflats, and connecting channels. The balance between salt and fresh water, mediated by tides and river flow, influence the composition and diversity of plants and animal habitats found in the estuary.
What is an Estuary?
An estuary is a partially enclosed body of water along a coastline where the fresh water and sediment created by river systems meet and mix with the salt water and tidal flow of the sea. The fresh water input dilutes the estuary's salt content.
Geologically, there are four types of estuaries:
Coastal Plain – Created by retreating glaciers at the end of an ice age. As the ice melts and the water warms, the sea level rises and invades low-lying coastal river valleys. Chesapeake Bay in Maryland is an example of a coastal plain estuary that was once a river valley.
Tectonic – Created by the shifting together and rifting apart of the Earth's crust, usually due to earthquakes. These types of estuaries are usually found along fault lines. San Francisco Bay in California is an example of an estuary created by tectonics.
Bar-built – Also called restricted-mouth estuaries. Sandbars or barrier islands are built up by ocean currents and waves in coastal areas, creating a protected area fed by small streams or rivers. Bar-built estuaries are common along the coast of Texas, including Matagorda Bay and Galveston Bay.
Fjord – Created by glaciers that carve out deep, steep valleys. When the glaciers retreat, seawater rushes in to fill the narrow, deep depression. Glacier Bay in Alaska is an example of a fjord.
Logging Requirements
To log this EarthCache, you will need to hike to the end of the 1.6-mile Ebey Waterfront Trail, and answer the following questions. Please note that Ebey Waterfront Park and Trail are closed from dusk until dawn.
1. Stop at Waypoint 1. Here you can see one of the effects of the levee being breached and the farmland being flooded with salt water. Describe what you see.
2. Proceed to the final coordinates, and answer this question: what percent of Snohomish River estuaries remain intact today?
3. The final coordinates provide an excellent viewpoint of the estuary. Looking at it from here, which kind of estuary do you think the Qwuloolt Estuary is?
Pictures of yourself at GZ are also encouraged! Please DO NOT post the answers to these questions in your log. You also do not need to wait for a response before logging your find. Have fun, and enjoy the amazing views along the trail!