Tidal Wetland Restoration
in the Fort Clatsop unit of Lewis and Clark National Historical Park
Since 2006, the National Park Service has been actively restoring these areas to more closely resemble the landscape encountered by the Corps of Discovery in 1805, and to allow natural process to return to the system.
Juvenile Coho Salmon, photo taken by Byren Thompson at Coho Sanctuary in Seaside, OR
Through passive and active restoration of tidal wetlands, the park is contributing to the recovery of the Youngs Bay watershed and endangered salmon stocks.
The Colewort Creek Restoration Site is a 44-acre site and consists of three subsites, South Clatsop Slough, Alder Creek Marsh, and Colewort Creek. In 2007, a culvert was replaced with a bridge, restoring hydrological connection with the Lewis and Clark River in South Clatsop Slough.
Pedestrian bridge where Colewort Creek flows into Lewis and Clark River
In 2012, 2.5 acres of invasive reed canarygrass were excavated in Alder Creek Marsh.
In that same year, 5,000 feet of additional side channels and excavation to low marsh elevation were completed as part of the Colewort Creek Restoration Project.
Click on the map to learn more.
Otter Point is about half a mile downstream from Colewort and the Reference Marsh. Construction for this project spanned 2010 – 2012, and included excavating approximately six acres of reed canarygrass, channel excavation, excavating to low marsh elevation, dike breaching, and constructing a cross-levee to protect the neighboring property.
Otter Point in 2012
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After construction, native plantings and seeding techniques were implemented throughout the sites.
Biological Technician planting at Otter Point, 2011
Volunteers planting native shrubs at South Clatsop Slough, 2012
Plant community development is an important indicator of the overall health and productivity of a tidal wetland. To measure each project’s success, monitoring of herbaceous plants has been conducted following, “Protocols for Monitoring Habitat Restoration Projects in the Lower Columbia River and Estuary” (Roegner et al. 2009).
Following the protocols, permanent baselines were set up along elevational gradients within the site. Transects were laid along each baseline and plots were monitored along each transect.
Park youth set up measuring tape along baseline for vegetation monitoring
This map is an example of the monitoring plots within the Reference Marsh.
Plants were identified down to species and cover was recorded in the 1 meter by 1 meter plots. Monitoring was conducted in the late summer months during peak vegetative growth.
Figure showing how observed cover is recorded.
Mosaics intern identifying slough sedge (Carex lyngbyei) at South Clatsop Slough, 2017
Wetlands are an important habitat and food source for birds, small mammals, amphibians, fish and more. These projects provide a critical transition zone for juvenile salmon in the Columbia River estuary.
Great Blue Heron along Lewis and Clark River captured by volunteer, Dennis Adams
Are you interested in learning more about science in your park or citizen science?
Become a Volunteer-in-Parks (VIP) and help make our great places better!
Cocoa & Coho Event at Colewort Creek in 2016
Participate in a BioBlitz event and use iNaturalist to record your observations!
BioBlitz 2016 at Yeon
Visit us at 92343 Fort Clatsop Road, Astoria, OR 97103
Website: https://www.nps.gov/lewi
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Roosevelt Elk at South Clatsop Slough
Support for this project was provided by National Park Service, Lower Columbia Estuary Partnership (LCEP), and Columbia River Estuary Study Taskforce (CREST).
Sammy, the Salmon to the rescue with restoration!
