McKinleyville moves ahead with coho rearing ponds

Jessie Faulkner
Mad River Union

McKINLEYVILLE – The  McKinleyville Community Services District (MCSD) is considering transforming its riverside percolation ponds to a safe and sustaining harbor for young salmon.

The ponds are above the Mad River, west of Fisher Ranch and due south of the end of School Road, near the natural curve in the river.

CalTrout, which is working with the services district to shepherd this facilities transition, presented three alternatives and the result of its initial study at last week’s MCSD board meeting. A question-and-answer session with community members followed.

Essentially, the plan is to remove and/or lower the levees from around the former percolation ponds, allowing the area to become a natural refuge for salmonid away from the turbulence of the winter high waters in the river. In this locale, the small fish can grow up and prepare themselves for the ardors of moving into the ocean.

The ponds, installed in 1983, had been used to dispose of treated wastewater, but the cost of complying with a state mandate proving that the disposal did not affect the river proved too costly for the district. The facility also was becoming a less-than-ideal way to dispose of the treated wastewater, so the district was planning to decommission the ponds. The original plan to backfill and replant the area was estimated to cost $170,000.

The idea to convert the area to a refuge for growing salmonid was a matter of happenstance. A member of the public reported to California Fish and Wildlife that the district was draining a wetland near the end of School Road in 2012. State Fish and Wildlife officials made a site visit and confirmed that ongoing activity to install a culvert to maintain stormwater drainage was permitted. However, the conversation turned to the soon-to-be abandoned percolation ponds, which Fish and Wildlife noted could be used to shelter young fish, stating that grant funds were available for just such a project.

MCSD subsequently entered into an agreement with California Trout – a statewide nonprofit organization –  to study the proposed project, and the conceptual design was unveiled at the May 4 board meeting.

“We are here to get comment and feedback from the board and the audience,” said CalTrout Project Manager Mary Burke.

MCSD General Manager Greg Orsini stressed before last week’s meeting that the result would not be a fish hatchery but an off-channel refuge for the salmonids.

Officially deemed the Salmonid Restoration Project, the effort is in the conceptual design stage. Studies have been completed on water temperature and flow levels. The consultants have developed three possible designs, two of which will include construction of a channel from the river, near School Road, heading south along the bluff above the river and ending at the former percolation ponds. The channels will provide a means for young fish to reach the pond area where they can rest and grow during the rainy season without undergoing the stress of the fast-moving river. Engineering designs are scheduled for the upcoming winter, followed by permitting and implementation.

Board president George Wheeler asked if the proposed channel would be deep enough to provide cooler water for the fish, noting that summertime water temperatures can be high in the upper levels.

Consultant Rose Patenaude of Northern Hydrology & Engineering is the project’s design engineer. She said that any channel created would be connected to groundwater and tidal water and will take into consideration data collected, including the temperature of the river.

“This is a very dynamic system,” she said. “Ultimately, we’re trying to develop self-sustaining restoration facilities for fisheries.”

As well as habitat restoration, the project includes components of public access and biofiltration.

All of the public access options are the same for the three presented alternatives, Patenaude said. Those plans include installing “boulder steps” to the river, making an Americans with Disabilities Act-compliant trail to a river overview, improving an existing trail to the former pond location and expanding parking options. The conceptual plan also suggested adding river access and viewing points along the trail as well as a boat launch area for non-motorized craft hand-carried to the site.

The first alternative does not include the addition of a channel for the salmonids to travel to the former pond area; the second and third alternatives contain that option. The first alternative also proposes removing the ponds’ interior levee and lowering the height of the levees facing the river to the floodplain elevation.

Alternative two proposes breaching the levee and connecting it to the proposed backwater channel while also excavating the ponds. The third alternative includes plans to lower the floodplain between the southwest corner of the ponds and the river to allow inundation, where wetland and riparian vegetation would then be planted. The northern pond would be excavated, and the levee lowered and breached to allow connection with the proposed backwater channel.

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