Nisqually Refuge Restoration

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Nisqually Delta in 2013 following the refuge restoration

The Billy Frank Jr. Nisqually National Wildlife Refuge (Refuge), Nisqually Indian Tribe and the US Geological Survey are collaborating in monitoring the restoration of an estimated 762 acre tidal reconnection in the Nisqually Delta. The Refuge dyke removal is located across the river from the Red Salmon Slough Restoration.

While the Refuge Restoration is the largest action on the site, ongoing adaptive management is being conducted at the Nisqually Delta scale. This page primarily documents efforts leading up to the refuge restoration.

West of ring dike from vegetated fringe looking NNW in 2014

Project Background[edit]

On February 8, 1996 there was major flooding of the Nisqually River with crest height reaching 17.3 feet and a discharge of 50,000 cubic feet per second.

Taking into account the recent flood damages and growing invasive reed canarygrass (Phalaris arundinaceae) and management challenges within the diked area of the refuge, Nisqually NWR staff initiated a planning effort to reevaluate habitat management, including consideration of some form and amount of tidal restoration. On July 25, 1996 a preliminary scoping meeting was held. Following the meeting, the regional office chose Nisqually NWR to undergo "Comprehensive Management Planning" to evaluate the entire refuge, increasing the scope of the planning process, and allocating for money to allow for additional staff. Planning Update #1 - August 1996

Furthermore, in 1996 the Nisqually Indian Tribe completed their pilot restoration project in Red Salmon Slough, restoring 9 acres.

Over the next eight years, a Comprehensive Conservation Plan and an Environmental Impact Statement was drafted. The Regional Director officially approved one of the four possible alternatives on November 1, 2004. The plan chosen provided the largest potential Refuge boundary expansion of all the proposed plans, 3479 acres, and called for the maximum estuarine restoration in addition to improving freshwater wetland and riparian habitats on the Refuge. The Final Comprehensive Conservation Plan was released in March of 2005 to specify a management direction for the Refuge for the subsequent 15 years, replacing the 1978 Conceptual Plan.

Comprehensive Conservation Plan[edit]

Specifically, the CCP: (1) determined that the Refuge boundary should be expanded; (2) determined the extent of restoration of historic estuarine habitat; (3) addressed the compatibility and quality of wildlife-dependent recreation and environmental education; (4) addressed waterfowl hunting and related needs for sufficient wildlife sanctuary; and (5) provided a basis for budget requests to support the Refuge’s operational needs for staffing, operations, maintenance, and capital improvements.

Consultation and coordination[edit]

The CCP process included public involvement through scoping meetings, open houses, and public meetings. In addition there was a Grassland Workshop, a Public Use Workshop, and an Estuarine and Freshwater Wetland Workshop. Other outreach programs included planning update mailings and a formal notice of intent published in the Federal Register. Over 50 presentations were given to a variety of interest groups, and the Service met with the Nisqually Indian Tribe 14 times during the planning process. Public comments were accepted to highlight issues, concerns, and opportunities. Seven major issues were identified and analyzed.

During 1997, the Refuge also established a cooperative management agreement with Ducks Unlimited to assist with the CCP and provide technical support on habitat management and restoration.

Supporting research[edit]

In early 1998, USFWS and Ducks Unlimited hired the consulting firm ENSR (now Battelle), who prepared two models to assess restoration alternatives. Using the RMA-10 model for hydrodynamics and the RMA-11 model for sediment transport, the study showed that full tidal and marine environment restoration was feasible with breaches and dike removal options. According to these models, dike breaches and removals would reduce flood impacts and restore marine and tidal environment.

Other informative studies included "The Regional Context of Intertidal Habitat Restoration in the Nisqually River Delta" by Curtis Tanner (1999) and a "Characterization of Fishes in the Nisqually River, Estuary, and Reach" by Carrie Cook-Tabor (1999).

In 2000, USFWS hired EDAW, Inc. to assist in the completion of the CCP/EIS and aid with public involvement.

Project Design and Implementation[edit]

New Exterior Structure Construction[edit]

The first phase of restoration, starting in the summer of 2008, was the construction of a new exterior dike inside of the dike that would be removed. The new footprint was cleared and grubbed and approximately 84,539 cubic yards of compacted fill was used to create the 9,691 linear food set-back dike that ranges from 13 to 14 feet in elevation. An estimated 22,428 cubic yards of fill was used to create 5,791 linear feet of new interior levees which range from 9 to 12.5 feet in elevation (Ellings 2011). Construction of these dikes used dirt from the seasonal freshwater wetland area by deepening and enlarging the seasonal ponds located there. Levees were constructed using surplus material from the Brown Farm Dike removal. Together, these structures protected 246 acres of freshwater wetlands important to waterfowl as well as the headquarters facilities from flooding events. (Estuary Restoration Brochure). In addition, a 48 inch tidegate was installed at the north end of the McAllister Creek overflow channel in to allow water to continue to drain from I-5 and private lands on the south side of I-5. Riprap taken from the exterior dikes against the Nisqually River and McAllister Creek for protection. (Ellings 2011).

Old Exterior Structure Removal[edit]

In May of 2009 the removal of most of Brown Farm Dike began and was officially finished on November 11, 2009. Before this could occur, reed canary grass was mowed and disked to help colonization of native plants while some areas were graded, scraped, or disked to enhance salt marsh establishment. Where riprap was able to be removed, the area was planted with native shrubs, woody debris placed at the toe, voids filled with soil, and the area was seeded. The Brown Farm Dike was cleared of trees and shrubs, using some of the trees as large woody debris within restored habitat. About 23,296 linear feet of dike was removed by excavating 260,738 cubic yards of earth, with 181,273 cubic yards used to fill the adjacent borrow ditch.

Other Restoration Activities[edit]

Other projects to restore the estuary include the re-connection of large tidal channels to historic sloughs. Earth removed from the Brown Farm Dike was used to enhance two surge plain riparian sites. Higher elevations on these sites were planted with native tree species and snags found in adjacent surge plain forest in a phased approach.

Boardwalk Construction[edit]

In spring of 2010, construction for the mile-long boardwalk through the estuary restoration area began. This project received $2.8 million in funding from the American Reinvestment and Recovery Act. It was completed in February of 2011. The boardwalk uses concrete pier blocks for a foundation to support pressure treated lumber framing.


Following restoration, a range of monitoring activities led by USGS Western Ecological Research Center, the Refuge and Tribe was conducted to measure impacts. Some of the various characteristics studied include invertebrates, birds, vegetation, fish, water level, water temperature, water conductivity, water velocity, discharge, net sediment transport, geomorphic change, elevation change, sediment deposition, erosion and bathymetry mapping.

In the monitoring framework outlined in Ellings 2011 three main objectives were identified:

  • Implementation monitoring - ensure that the project components are built as designed and to document any deviations from the design
  • Effectiveness monitoring - determine if the project objectives are being met
  • Adaptive management - provide information critical for adaptive management

According to The Nisqually Watershed Salmon Recovery Newsletter: Winter 2013/2014, there are already several lines of evidence indicating that restoring tidal flow to the estuary is restoring many of the ecological functions of natural tide marsh ecosystems that are important to juvenile Chinook salmon. Stomach fullness was similar across the reference site and restoration site, while stomach content has become more similar over time. Bioenergetic models showed similar growth potential for juvenile Chinook salmon for the reference and restoration sites as well. One noted difference between sites was that the restoration sites had more variable and warmer water temperatures, possibly caused by the lack in overhanging marsh vegetation and wider, shallower channels allowing for more sun exposure than those at the reference sites.

  • Early phase restoration performance and prey contributions to juvenile Chinook salmon is summarized in the ESRP summary report.
  • Habitat availability for juvenile salmonids following restoration Ellings et al. 2016
  • Invertebrate prey production following restoration Woo et al. 2018
  • Prey consumption by juvenile Chinook salmon following restoration Davis et al.2017
  • Dietary differences between hatchery and wild Chinook salmon in the Nisqually estuary Davis et al. 2018
  • Growth potential for juvenile Chinook salmon of different estuarine habitats Davis et al. 2018