About This Location
Just over a hundred years ago the water in front of you was nothing more than Ross Creek, a trickling body of water which served as a portage area between Lake Union and Salmon Bay. Similarly, the waters of Lake Washington and Lake Union used to be separated by a narrow neck of land which prevented the waters from intermingling except during the heaviest of rainy seasons. This narrow strip of land was known to the indigenous peoples as "sxWátSadweehL" or literally "Carry a Canoe." When the first non-indigenous settlers arrived in the area, it looked quite different than it does now. As entrepreneurs sought to change the city to make it more commercially viable, they filled in and built on shallow areas of marshlands, razed trees, and even leveled hills. In order to construct a continuous waterway from Puget Sound to Lake Washington, two separate and sequential channels had to be excavated through intervening landforms. The Westernmost of these is directly in front of you - the Fremont Cut.
Above: A view of Seattle before the Fremont and Montlake cuts. Note how none of the bodies of water were naturally connected.
One cannot simply alter the course of a creek, create a new river, disrupt a saltwater bay, and connect three bodies of water without some environmental consequences. Within months of opening the Montlake cut and connecting the three bodies of water, the level of Lake Washington dropped by 8 to 9 feet. This had the interesting side effect of causing an entire river to disappear. The Black River, which had previously connected Lake Washington to the Duwamish Waterway, dried up completely as the lake was now lower than the mouth of the old river. As rain and snowmelt enter Lake Washington (particularly in the spring and fall) this water had previously discharged through the Duwamish Waterway via the Black River. Now that water has to go another route - straight through Fremont.
In addition to causing an entire river to disappear, the leveling of water in Lake Union, Lake Washington and Salmon Bay destroyed the saltwater tidal flats in that region and created a freshwater bay. Most importantly, the creation of a single waterway connecting Lake Washington to the open ocean created an area of flowing water where before little to none existed. By turning the tiny Ross Creek into a robust waterway, where water can flow freely to the open ocean, turn-of-the century Seattleites had created a potential erosion nightmare in Fremont.
Above: A look at the historical makeup of nearby Salmon Bay. Before the cut the bay was made up of Freshwater (blue), Saltwater Wetlands (Pink), Tidal Flats (brown), and Freshwater Wetlands (Yellow). This area is now all freshwater.
Riverbank erosion is the removal of material from the banks of cuts and rivers when flowing water forces exceed bank resisting forces by soil and vegetation. In extreme cases this can cause damage to structures along the bank such as bridges, docks, and buildings. When early Seattleites created the Fremont Cut they turned a small tributary of a creek into a large body of flowing water which opened the banks of the Fremont waterfront up to erosion. All the water which previously flowed through the black river along a historical riverbed are now redirected through the Fremont Cut.
There are a wide variety of ways by which erosion can be mitigated and reduced along a riverbank or a cutbank. These erosion control measures are critical to preventing bank erosion.
- Natural Vegetation: By planting trees, shrubs, and other plants with deep root systems, erosion can be mitigated as the roots help to stabilize the bank and provide additional bank resisting forces.
- Rip Rap Construction: Building angular man-made banks that help reduce overall erosion by creating a barrier between the water and the more susceptible natural bank. This can be constructed of small rocks, cement, or even construction debris.
- Dam and Lock Construction: Building a lock or a dam (such as the one between Salmon Bay and Shilshole Bay) can allow engineers to control the rate at which the water flows. This does not however alleviate the overall need for this water to flow.
- Terracing: This is the practice of cutting progressive steps up a bank and then planting a variety of vegetation to create a tiered bank that helps to reduce overall flow.