A dopt-A-Stream-Foundation, an environmental education and restoration group, is nearing completion of its new Trout Exhibit, which is expected to become a key attraction at the organization's environmental learning center near Everett, WA.
Visitors to the Northwest Stream Center will soon have a close-up view inside the world of Cutthroat Trout. The unique exhibit will show how the fish progress from fresh spawn in the gravel bed, to hatched fingerlings, and eventually into 8-inch to 10-inch-long mature fish within a carefully created artificial stream.
The Stream Center is adjacent to 78 acres of abandoned landfill that Snohomish County Parks Department has developed into family-oriented recreation facilities. The county leased 20 acres to AASF in 1993 to create the Northwest Stream Center, the first facility in the Pacific Northwest themed to stream and wetland ecology as well as fish and wildlife habitat restoration. Funded by donations, the center has been developed in phases. Recently, a major part of the work has been donated by construction industry suppliers and members of the Seattle District Chapter of the Associated General Contractors.
“We were able to convince the Parks Department to allow us to create an environmental education center,” said Tom Murdoch, AASF director. “A lot has been accomplished without using any county funds. Our mission is to teach people how to become stewards of their environment. To carry that out, we recruited 25 adjunct professors to teach Streamkeeper Academy courses for all ages … and we have a team of ecologists and technicians who provide the local community with stream and wetland restoration technical assistance.”
“The Trout Stream Exhibit was designed as another means to teach people about stream ecology,” he noted.
“We wanted it to function like it was created by Mother Nature,” Murdoch explained. “Our goal is for visitors to take lessons learned at the NW Stream Center back to their home watersheds, where they will work to protect and enhance streams throughout the Pacific Northwest.”
The organization had planned the Trout Exhibit for a long time, he said, but progress on it lagged until interest from the local construction community picked up momentum over the past two years. Prior work at the center included restoration of a 3-acre wetlands displaced by a former parking area, and completion of the 6,000-square-foot Visitor Center building that houses a library, auditorium, conference room, and classroom. Future components in the master plan include 1 mile of raised boardwalk interpretive trail, a forest canopy viewing tower and a salmon habitat viewing platform next to North Creek, a salmon stream that flows through the site. AASF's goal is for up to 45,000 visitors a year to learn the interconnections between forest, wetlands, streams, fish, wildlife, and people.
Though the headwaters of the Trout Exhibit are between concrete retaining walls, the channel will replicate a natural stream with a gravel and cobble bottom and stream banks covered with native vegetation to shade the stream and keep the water cool and oxygen levels high. The flow rates will vary with the seasons, controlled by an intricate pumping system. Murdoch also hopes to have a photovoltaic energy system and backup generator to offset the estimated $250-per-month electric utility cost.
The site plan finds the native creek and the Trout Exhibit extending along either side of a path from the entrance to the Visitor Center. The closed-loop water flow of the Trout Exhibit originates at a two-level, L-shaped headworks with a below-grade mechanical room housing sand filters beneath a 14,000-gallon vault situated 8 feet above it. Two pumps are installed within a wet-well manhole located between the source water pond and the headworks structure.
From the cascade at the headworks structure, the water flows between 10-foot U-shaped concrete retaining walls in a downward gradient at a current rate that maintains different habitat types before reaching the 6-foot-deep pond recovered from the former parking lot. Along the way are riffles and pools created by simulated debris. Unlike hatchery-fed fish, the cutthroat trout will thrive on underwater insects – caddis fly, mayfly and stonefly larvae – as a natural food source in the channel. Interpretative stations along the adjacent trail include two 4-foot by 8-foot windows in the channel wall that provide views into the critical habitat features in natural streams before the flow terminates in the 1/3-acre pond.
The Seattle office of Gray & Osborne Inc., consulting engineers, donated civil engineering services, surveying, water treatment, HVAC, structural, and electrical designs for the exhibit, and more than 40 construction-related companies participated in the project led by Everett-based Wilder Construction as the general contractor.
ITT Flygt donated Whitney Equipment Co. 7-1/2- and 15-horsepower submersible pumps as the heart of life-giving waters through the channel's recirculation system from the pond back to the headwaters. The Model NP3153 1,700-gallons-per-minute (gpm) and CP3127 340-gpm submersible pumps recirculate the water from within a common manhole. A supplemental well will have another pump capable of adding 5 to 10 gpm.
The challenge for the AASF and the design engineers resides in creating healthy stretches of stream habitat as close to natural as possible within manmade construction. The channel is far more than just an aquarium. It functions as a balanced ecosystem. Regulations prohibited merely diverting some flow from the adjacent wild stream into the channel and discharging back into it because endangered Coho Salmon spawn there. Therefore, a closed-loop flow of re-circulating water was necessary.
The smaller Flygt pump draws approximately one-third of the return flow from the pond and passes it through sand filters, while the larger pump feeds the headwaters cascade with enough direct return off the pond to maintain the variable current within the channel's different habitat zones. The new resident trout, whose initial population will be transplanted from the adjacent North Creek, require water temperatures within a critical range of 50 to 55 degrees Fahrenheit and oxygenation at a ratio of 9 to 11 parts per million per liter. The supplemental well and shading plants along the channel will help maintain this balance of the channel's lifeblood, as will an air-induction system dovetailed into the well's water line. The pond's recirculation line and the filtration system should also contribute to the desired water quality.
The organization's ambitious initiative originated with a growing public interest and concern about salmon and trout populations being hindered by deterioration of natural streams and related habitat. The Trout Exhibit should eventually represent a $1.5-million project that will encourage the region's residents who visit to help restore and preserve their local watersheds.
Story courtesy of Steven London Associates for ITT Water & Wastewater of Trumbull, CT.