By MARK G. PEDERSON
Shapiro and Associates

Puget Sound chinook salmon and bull trout are complicating life for owners of waterfront property throughout the state, although some results can be positive for both fish and humans.

Replacing slab bulkheads and seawalls with a design of boulders and vegetation provides valuable fish habitat while enhancing the natural appearance and aesthetics of the shoreline.

When chinook salmon and bull trout were listed as threatened under the federal Endangered Species Act, it was generally known that another layer of regulatory compliance would be added to development projects. What may not have been so apparent to individual property owners is that the same regulations that apply to large shoreline developments apply to them when it comes to the important task of controlling the erosion of their beaches.

Waterfront property is susceptible to the natural erosion of waves and weather. At highest risk for erosion are flat beaches or beaches with low or high banks. Property with rocky shorelines or those that have gentle sloping beaches with adequate natural vegetation and a good supply of heavy drift to hold soil are less at risk.

A traditional remedy for shoreline erosion is the construction of a bulkhead or seawall. Obtaining permits from the U.S. Army Corps of Engineers to construct or repair them had been a straightforward process in the past. With the listing of chinook salmon and bull trout under the ESA, the permitting process has become more complex for the Corps and, therefore, for waterfront property owners.

The Corps and ESA

ESA Section 7 directs federal agencies to ensure that actions they authorize, fund and/or conduct are not likely to jeopardize the continued existence of any federally proposed or listed species, or result in destruction or adverse modification of critical habitat for such species.

In the case of building or repairing a bulkhead, the Corps is required to contact the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) before authorizing any construction activity. If USFWS and NMFS determine that threatened or endangered species may occur in the project area, a Biological Evaluation (BE) or Biological Assessment (BA) must be prepared. Both studies are conducted the same. If it is determined there would be no significant impact resulting from the proposed project, the study becomes a BE. If, however, adverse impacts are anticipated, the study becomes a BA and additional analysis and mitigation are required.

Until a programmatic (blanket) BE/BA is established, the Corps is requiring that a separate BE/BA be prepared for every project requiring a Section 10 (Rivers and Harbors Act) or Section 404 (Clean Water Act) permit under its jurisdiction. In addition, many local jurisdictions are requiring a BE/BA to assure projects are in compliance with Washington State Environmental Policy Act (SEPA) and Washington State Shoreline Management Act (SMA).

Mitigation for biological assessments

Since February of this year, nearly all shorelines of waters to which chinook salmon have access have been designated as critical habitat for this species under the ESA. Juvenile salmonids, many smaller fish species (herring, smelt and sand lance), and bottom-dwelling freshwater and marine invertebrates upon which growing salmon feed, rely on natural shorelines and the associated dynamic shoreline process for survival. Any project that would have a negative impact on chinook habitat triggers the Biological Assessment and need for mitigation.

Because of the high priority of protecting chinook salmon and other fish species, mitigation has become more creative. Pre ESA, bulkheads were routinely designed as hard slabs or walls of boulders that reflected the force of incoming waves. While they have been very successful at stopping or significantly reducing beach erosion, they also have resulted in the creation of coarse substrate, which is preferred as a spawning substrate for bass, a known predator of chinook salmon. The ESA listing of salmon has resulted in the use of erosion control facilities that strive to meet the habitat needs of juvenile salmonids and associated food organisms. The goal is to create a more natural shoreline that provides erosion control through the use of large, irregularly shaped boulders and native vegetation.

New erosion control designs

For a recent private landowner, Shapiro and Associates designed such a natural breakwater to comply with federal agencies’ interpretations of ESA requirements while achieving the landowner’s erosion protection objectives. The property, located on Lake Washington, had a failing concrete bulkhead. It is typical of both new construction and replacements.

Of primary importance is scheduling construction for late summer to late winter to protect juvenile salmonids. Prior to work starting, a silt curtain is installed to reduce the amount of disturbed sediment spreading through the water. Demolition of the existing concrete bulkhead is accomplished with a shore-based hydraulic excavator capable of removing the concrete wall in large pieces to minimize fallback of crushed concrete below the ordinary high water mark.

The site is then prepared for new construction by excavating the shoreline and grading upland areas to match the overall beach gradient. Boulders 2 to 6 feet in diameter are arranged along an irregular shoreline, and a portion of the excavated native soil is used as backfill.

A major benefit of the natural breakwater design is the creation of a shallow-water bench. Smaller boulders are secured into the lake bottom 4 to 6 feet lakeward of the water line to act as wave breaks and provide cover for juvenile salmon (wave break revetment). Large flat slab rocks are placed on top of these small boulders to create overhangs. The bottom of the bench is designed to be between the ordinary high water and low water lines. This creates shallow water refuge and hiding cover for juvenile salmonids.

Boulders for the outer wave break revetment are then set so they will be submerged during a portion of the year and be viewed as elevated rock slabs that are exposed at periods of ordinary high water. A 3- to 4-inch layer of gravel is spread to about 5 feet lakeward of the wave break. The remaining near shore boulders are set to create planting pockets for overhanging vegetation and as foundation rocks for cantilevered rock slabs.

Gravels 0.25 to 4 inches in diameter are placed at a 3- to 4-inch depth over the remaining areas below the ordinary high water mark. Bulrush is planted in the more protected areas nearshore and land ward of the wave break. Finally, shrubs and emergent wetland vegetation are planted to create a natural shoreline.

Positive results

While the listing of chinook salmon and bull trout under ESA has added an additional layer of regulatory compliance, the results can be viewed as positive for both the threatened species and owners of waterfront property. Replacing slab bulkheads and seawalls with a design of boulders and vegetation provides valuable fish habitat while enhancing the natural appearance and aesthetics of the shoreline. It’s a win-win situation.