Study will weigh options to turn 357-acre gravel mining site near Healdsburg back into flood plain

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From the air, the middle stretch of the Russian River south of Healdsburg looks like it has a string of small lakes along its meandering course.

The dozen or so ponds aren't natural, though; they are remnants of gravel mining that went on for decades along the river.

Sonoma County, state and federal agencies are moving to repair the damage from those operations, now that river terrace mining has been phased out, with a new environmental emphasis on saving endangered fish.

The State Coastal Conservancy recently awarded $300,000 for a feasibility study to evaluate restoration options for the 357-acre Hanson Aggregates gravel quarry west of Windsor, off Eastside Road.

The aim is to restore the site to be more like the flood plain it once was, a wetland complex that evolves naturally with the fluctuations and dynamics of the river.

Scientists say it will help sustain a complex riparian system that supports coho and chinook salmon and steelhead trout by providing a nursery of sorts with a rich source of nutrients for juvenile fish on their way to the ocean.

"They can grow and get strong enough to survive in the ocean," said Jennifer Barrett, Sonoma County's deputy director of planning. "That's been largely missing since the flood plain was disconnected from the Russian River."

The plan includes public access, such as a possible kayak take-out and walking trails.

Instead of the existing deep, spring-fed pits, which sometimes trap fish during floods and river overflow, there could be more shallow "benches" with wetlands that connect and interact with the river.

Advocates say it represents a paradigm shift in the way old mining sites have been handled in the past, when the approach was to seal them off from the river with a berm, or fill them in. They say it could serve as a model for restoration in California and beyond.

"River systems are ubiquitous to Planet Earth, and almost across the board through the course of history we've tamed, channelized and polluted them and basically done everything we can to degrade them," said Michael Beck, president of Endangered Habitats Conservancy. "This is part of a beginning of a shift."

The fish population has been cut not only by mining, but channelization, logging and agricultural practices, he said.

"We're restoring habitat that has been lost nearly a century ago, and it's work that needs to happen," said north county Supervisor Mike McGuire, whose district encompasses a number of the old quarry sites.

"Over the last six months, we've made more progress than we have in the last 10 years. We are at a very exciting point," he said.

The value of rivers is recognized at many levels, Beck said, not just for fish, filtering contaminants and recreation, but also for their aesthetic value.

Bodies of water "are so magnetic to humans," he said.

Beck's San Diego-based, nonprofit organization, which helps conserve wildlands and open space, secured the $300,000 state grant. The money will be used for computer modeling of the river hydrology and conceptual design of the wetlands.

The area studied will extend along the river from Highway 101 near Healdsburg, to approximately eight miles downstream to Wohler Bridge, according to Beck.

The work will be done by the U.S. Geological Survey in coordination with National Marine Fisheries and other experts. It will address sediments, flooding and the biological implications of flood plain restoration.

Beck acknowledged that creating wetlands can in theory lead to more bank erosion in other parts of the river.

"We will determine to what degree that will be an issue," he said.

But supplanting the gravel pits with a more natural "off channel" flood plain is generally viewed as desirable from a biological point of view because it allows the wetlands to foster food and habitat for the fish.

"On the way to the ocean, they (fish) could really bulk up. The ocean is a very tough neighborhood. If you show up as a 98-pound weakling, you don't make it," said Don McEnhill, director of Russian Riverkeeper, a conservation group that advocates for clean water and healthy rivers.

Endangered Habitats Conservancy holds an option with Hanson Aggregates, which calls for the company to donate the property for $1 if agreement can be reached on the design and reclamation plan.

One possibility under consideration is to convey the acquired parcel to the Sonoma County Parks Department after the restoration is complete. It would be managed as a component of the existing Riverfront Regional Park, a recreation area about a mile downstream that is also next to former river mining ponds.

The lead agency for the restoration is Sonoma County's Planning and Resource Management Department, which has a longstanding interest in seeing a reclamation plan for the Hanson property. It also is kicking in $60,000 toward the feasibility study, from mitigation funds collected from mining companies.

Mining operations on the site began in the early 1960s under Kaiser Sand and Gravel. Hanson Aggregates bought the land in 1999 and continued operations until 2002, when mining stopped.

The sand and gravel was used in road asphalt and cement concrete in construction.

Such pit mining was entirely phased out along the river in 2006, but river bar skimming operations -- essentially above the water line -- are still allowed, according to PRMD's Barrett.

But the old model of "reclamation" of gravel mining sites -- essentially sealing them off from the river -- has given way to "restoration."

"New scientific studies indicate that it would be much more beneficial to allow periodic flooding of a restored flood plain rather than maintaining a separation," stated Michael Bowen, a project manager with Coastal Conservancy.

McGuire said talks with interested parties have been positive, including with the owners of the Hanson site.

The county also is exploring ideas for similar rehabilitation of gravel pits upstream belonging to Syar Industries.

"We have to develop a unified front with the landowners, the environmental organizations, the regulatory agencies, the county and neighbors to ensure long-term success when it comes to restoration efforts," McGuire said.

You can reach Staff Writer Clark Mason at 521-5214 or clark.mason@}

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