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Restarting a Sediment Engine of the Strait of Juan de Fuca: The Twin Rivers Nearshore Ecosystem Restoration


UPDATE: Ecosystem evolution along the Twin Rivers nearshore published: Restoration of Coastal Beach Forming Ecosystem Processes through Shoreline Armoring Removal of a Former Mine Site Increases Our Understanding of Coastal Resiliency and Large Scale Landslides Along the Northeast Pacific Coastline


Located on the north Olympic Peninsula along the Strait of Juan de Fuca, approximately 25 miles west of Port Angeles Washington, the Twins Nearshore Ecosystem Restoration project implements an innovative decades long collaborative project that will result in restoration of over 14 acres of nearshore habitat, including extensive eelgrass beds and surf smelt spawning beaches.
One of the largest restoration projects in the Salish Sea, the project  removed the armoring around the perimeter of a 5.6 acre earthen filled pier (also called a ‘mole’) to allow natural processes to restore over 14 acres of nearshore habitat.
The project  removed over 30,000 cubic yards of riprap (non-native rock armor), concrete and 425 linear feet of sheet pile to  allow clean native sediment that makes up the fill of the almost 6 acre mole to naturally erode and replenish the local shoreline. After fourteen years of planning and funding pursuit, armor removal began 24 July 2017 and concluded 31 August 2017.Rock armor removed from tidelands is stored on the upland portion of the Lafarge owned property. The Twins site  is very popular for beach goers. It is also an extremely important fossil site, including an important Paleolithic whale fall site.  According to Dr. Jim Goedert, Burke Museum, University of Washington:’….The Twins quarry has produced a lot of important fossil whale specimens, many of which are undescribed. Most of these specimens are in the collections for the Los Angeles Museum of Natural History (LACM), and include my favorite, Fucaia goedertorum (editor: named for Dr. Goedert and his recently deceased wife). There are also several specimens from that quarry that are in the Burke Museum collections, including the recently named new genus and species that is on display.’ Given the important of this property, CWI and staff have sponsored a number of funding proposals over the last 14 years to conserve the upland property as a public access site along with restoring the shoreline. Unfortunately, politics prevailed, so grant funding failed. As a result, we’ve had to drop the public access portion of the project and focus solely on the nearshore ecosystem restoration component of the project. Securing public access to this beautiful and important site will have to wait.

Twins Nearshore Overview

The Twin’s nearshore drift cell includes approximately four linear miles of rocky and sandy shoreline. The shoreline is highly erosional. Parks (2005) concluded that there is no long-term net apparent sediment transport direction, but rather a high degree of inter-annual variability between east/west/ and north offshore across the shore platform, and that sediment transport may be impacted by shoreline modifications. The shoreline of the Twins nearshore is a mixture of private and state ownership. A significant portion of the Twins shoreline is owned and managed by Lafarge.

Ecologically, the Twins nearshore is rich and complex. Miller et al 1985 concluded that the Twins nearshore was one of the most diverse shorelines of the Strait of Juan de Fuca. Dan  Penttila, WDFW (retired), first documented surf smelt spawning along this shoreline in 1999.  Additional spawning areas were identified along Twins shorelines in 2003 (Shaffer and Moriarty 2003).  
The site is diverse for nearshore fish assemblages, and important for forage fish,  juvenile steelhead, cutthroat, and chum migration and rearing (Shaffer and Ritchie 2008), which is consistent with ecological function of the east and west Twins Rivers documented by Roni et al. 2008. Recreationally the area is  important for fossil hunting, beach walking, surfing, crabbing, and smelting area.

Overview of the Twins Mole and Quarry

The mole is a pier structure associated with the inactive Lafarge Twin Rivers Clay Quarry, a 214-acre quarry site located immediately west of the west Twin Rivers. Elevation of the quarry ranges from 226 feet above mean sea level to mean high water. The quarry loading facility is a filled pier structure (locally termed a ‘mole’) that occupies  intertidal area directly north of the quarry .The pier (or mole) structure begins at mean high water and extends northward 250 to 300 feet into the intertidal zone to below mean low water. Elevation of the mole structure ranges from 33.2 feet to –2.2 feet below mean low water (Parks 2005). In total the mole is approximately 5.6 acres and made up of approximately 83,000 cy of fill, 20,000 cy of riprap and 425 linear feet of sheet and creosote treated piles. The structure was installed on state tidelands in the mid-1960s and operated as a clay mine during the mid-1980s by private landowners including Leonard Pfaff and Bud Schmidt. The site was first built during the early 1960’s. Operation included the dredging of the east side  to allow barge access for loading purposes. Dredging records suggest that 102,000 cubic yards (77,994 m3) of sediment were removed from the access channel between 1982 and 1985 (Parks 2005; WDOE, 1982).
The site was purchased by Lafarge  in 1998, then placed in ‘strategic reserve’ status and taken out of production. The mole is on state tidelands that are managed by the Washington DNR, and is leased by Lafarge. The current aquatic lease ends in 2020.

Twins Nearshore Ecosystem Restoration Project

Todd et al. 2006 describes the Twins nearshore as a moderately impaired stream delta complex. The mole is the feature that is impairing the shoreline by disrupting sediment transport along the shoreline and disconnecting upland sediment sources from the shoreline.  Once removed the ecosystem forming processes of the region will be largely restored.

The project removed the armoring around the perimeter of a 5.6 acre earthen filled pier (also called a ‘mole’) to allow natural processes to restore over 14 acres of nearshore habitat. Approximately 30,000 cubic yards of riprap (non-native rock armor) concrete and sheet pile were removed. Removing these armoring features is allowing clean native sediment that makes up the fill of the mole to naturally erode and replenish the local shoreline. After fourteen years of planning and funding pursuit, armor removal began 24 July 2017 and concluded 31 August 2017. Rock armor removed from tidelands is stored on the upland portion of the Lafarge owned property.

Supporters and partners of the project include the WRIA 19 community, the Washington state WDFW, and DoE, and Lower Elwha Klallam Tribe, the North Olympic Land Trust, Clallam County and Surfrider Foundation.
The project is included in the PSNERP 2011 and NOPLE 2016 work plans and the 2015 WRIA 19 Salmonid Restoration Plan. The nearshore ecosystem restoration project is led by the Coastal Watershed Institute (CWI) thru sponsorship of Lafarge. Jonathan Hall is the manager in charge of the project for Lafarge.  Dr. Anne Shaffer, CWI senior scientist, led the development of the original restoration plan and leads scientist monitoring changes as they unfold. Dave Parks, senior hydrologist and CWI collaborator,  is leading the sediment science.  Jamie Michel, nearshore restoration biologist with CWI, is  in charge of implementing the restoration project. Tara McBride, field biologist with CWI, is leading the field sampling. CWI (Peninsula College/UW) interns Seren Weber, Josh Davis, Marisa Christopher, and Mike Miller are working on aspects of the project.  The contractor is the Port Angeles based Bruch and Bruch. The site is now closed for public access, and will remain so indefinitely. Public access is a topic that the community will need to consider in the future. As in the years past, Lafarge remains open to selling the upland portions of the property for public access.

For more information on the Twins nearshore ecosystem restoration project see:

Parks, D. 2005. Preliminary assessment of sediment transport processes resulting from decommissioning of the Twin River clay quarry loading facility, Clallam County, WDNR, Port Angeles, WA. Penttila,D. 1999. Documented spawning areas of the pacific herring, surf smelt, and sand lance, in Clallam County, Washington. WDFW technical report, Olympia, Washington. Puget Sound Nearshore Ecosystem Restoration Project. (PSNERP) 2011. Nearshore Restoration Strategy for Twin Rivers. Strategic Restoration Conceptual Engineering‐Design Report. USACE, Seattle, WA and WDFW, Olympia, WA. Roni, P. R. Holland, T. Bennett, G. Pess and R. Moses. 2008. Straits intensively monitored watershed contract report: results of FY07 PIT tagging on east and west Twin rivers. Northwest Fisheries Science Center, NMFS, Seattle, Washington 98112. Shaffer, JA.2004. Nearshore mapping of the Strait of Juan de Fuca: II. Preferential use of nearshore kelp habitats by juvenile salmon and forage In T.W. Droscher and D.A. Fraser (eds). Proceedings of the 2003 Georgia Basin/Puget Sound Research Conference. CD-ROM or Online. Available: Shaffer, JA. Moriarty R, Sikes J and Penttila D 2003. Nearshore Habitat Mapping of the Central and Western Strait of Juan de Fuca Phase 2: Final Report to Clallam County  Washington. Shaffer JA, Paul J,   Crain  P,   McHenry, M., Jensen, P, Whitey, T. Parksand Schouten A, 2009. Nearshore restoration strategy for Twin Rivers: A revised proposal by the Twins nearshore restoration work group (2004, revised 2009). Port Angeles, WA. Shaffer JA and Ritchie T. 2008. Chapter 4. Fish use of the Twins nearshore. In ‘Nearshore assessment of the central Strait of Juan de Fuca. Smith, Carol. 1999. Limiting factors analysis WRIA 20. Washington Conservation Commission, Olympia, Washington Todd, S., Fitzpatrick, N., Carter-Mortimer, A. and Weller, C., 2006. Historical changes to estuaries, spits, and associated tidal wetland habitats in the Hood Canal and Strait of Juan de Fuca regions of Washington State.Final Report. Point No Point Treaty Council Technical Report, pp.06-1. Water Resource Inventory Area 19 (Lyre-Hoko) Salmonid Recovery Plan. Clallam County, WA.