Carmel Valley >> It didn’t take long for Mother Nature to put her stamp on the Carmel River reroute project. She made quite an impression.
An historic series of storms this winter roared through a section of the new Carmel River channel, rearranging a multimillion-dollar creation effort by casting aside boulders and rocks that made up dozens of step pools designed to accommodate migrating steelhead, carrying away giant piles of wood and uprooting much of the fledgling vegetation.
The carefully engineered $5 million river channel work was a central part of the $84 million San Clemente Dam removal and river re-route project completed in 2015. It was designed to serve as a bridge for steelhead between the initiation of a brand-new, human-made channel and its eventual return to a natural state. The channel, which included 56 step pools designed to allow steelhead passage during low-flow periods, was intended to absorb significant storms over a multi-year period, allowing time for vegetation to grow and the river to slowly re-create the channel itself over time.
Everyone seems to agree there was no way to anticipate what happened this winter, the confluence of last summer’s Soberanes Fire that denuded hillsides in local watersheds and created masses of dead wood and loose soil, a four-year drought that had slowed river water flow to a relative trickle, and the four-storm series that hit this winter capped by a “bombogenesis,” or mini-cyclone, that sent water rushing down the untested channel at thousands of cubic-feet per second.
That combination of circumstance may have increased river flows and their impact by up to 30 percent, according to Monterey Peninsula Water Management District official Larry Hampson.
Winter surprise
While everyone acknowledges a major storm would eventually test the channel, no one expected it so soon and with such ferocity.
However, a year after spending another $1 million to repair more than a dozen step pools last summer, no one seems eager to recommend more spending on the channel. Environmental experts, meanwhile, are expressing optimism the channel will be capable of its primary mission — allowing steelhead to migrate upstream and downstream.
Ultimately, they say regulators with National Marine Fisheries and the state Department of Fish and Wildlife will decide. In any event, they are unanimous in agreement that the river and its steelhead habitat are much better off without the dam.
During a recent tour of the river channel, National Marine Fisheries research fishery biologist Tommy Williams said scientists “hit the lottery” with the winter storms, despite the impact on the new channel and step pools, because it helped “reset” the river so quickly, sending sediment and other river-building materials such as rocks, trees and sand downstream more quickly than anticipated. That created a “diversity of habitat” that the dammed-up river had lost.
Williams, who has studied the river for decades but is not a regulator, said he had “no concerns” about steelhead passage through the new river channel even after the step pools were rearranged. He did acknowledge some regulatory officials have expressed concern about the width of the channel and the potential for higher water temperatures than is optimal for steelhead.
“It looks like a real river now,” Williams said, “not like Splash Mountain. I think (we should) let the river do it. The system was in such bad shape with the dam here. What you’re seeing now is much better. The system is coming back much quicker (than anticipated). It’s pretty resilient.”
Steelhead should be fine
CSU Monterey Bay professor Doug Smith, whose Watershed Institute students are studying the river reroute project and conducting computer modeling, said the students are in the midst of finishing up a second-year assessment of the river restoration and early indications are steelhead will “be fine with the new geometry.”
Smith said assessments so far show three locations in the restored channel where adult steelhead might encounter difficulty making it through during “moderately low flow conditions,” but noted that adults don’t migrate and spawn during low flow periods. He added that the channel is now “able to convey steelhead about 100 percent better than when there was a dam.”
“Once you get over the shock of how different it looks, you can see that we have a ‘naturalized’ river that is going to evolve to an equilibrium condition using the materials supplied to it,” Smith said, adding that the river channel work was designed to maximize steelhead passage while rivers naturally adjust themselves to “optimize sediment transport,” which he said should be the basis of any river design. “It will be exciting to see how (the river channel) changes each year.”
Coastal Conservancy official Trish Chapman, who led the dam removal and river reroute project team, said technical experts charged with monitoring the project have been “very pleased with the reorganization of the channel,” and there appears to be consensus that little or no adaptive management work will be needed.
Taking another look
However, Chapman added that the regulatory agencies won’t be able to make final decisions until river flows drop.
Lower flows could occur as soon as June or July, Hampson said, noting that steelhead have been spotted upstream at Los Padres Dam albeit under higher flow conditions. The question for future dam removal and river restoration projects, he said, is whether rivers should be left alone to find their own way or if money should be spent on constructing “something pretty.”
California American Water president Rich Svindland, whose company partnered on the project and whose Monterey-area customers are paying $49 million toward the endeavor, said it could cost about $200,000 to conduct river channel repairs but noted that there’s no inclination to spend money if it’s not necessary, and Cal Am’s goal is to avoid billing customers.
“We have no intention of going back every year to fix things, but we are open to solutions,” Svindland said. “I think it makes sense to let the river take over from here.”
‘A really natural river’
Granite Construction project manager Bill McGowan, whose company completed last summer’s repairs and has a five-year project maintenance obligation, said he believes there will be a lot of thought devoted to any further river channel repair work given the “infinitely variable” nature of the waterway. McGowan said his company covered the cost of last summer’s repairs and any remuneration is the subject of discussion, but added Granite Construction would not be responsible for any further repair expense.
“It’s been pretty incredible to finish construction and watch the ultimate landlord, Mother Nature, take over and shift the furniture around,” he said. “Now we’re starting to see a really natural river, and I think people are getting used to a different look. I think people will think long and hard about getting back in there now.”
Jim Johnson can be reached at 831-726-4348.
An earlier version of this story misstated the rate at which the rain-swollen river flowed.
