Walking along the banks of Butano Creek earlier this month, ecologist Jim Robins saw something of a surprise in the murky waters of the freshwater stream running from the mountains to the Pacific Ocean — a crab.
Modest in size, the crab Robins spotted near a section of the creek flowing under Pescadero Creek Road might not be the sort of catch that would fetch a high price at local markets. But it was a source of excitement for Robins and Kellyx Nelson, executive director of the San Mateo Resource Conservation District, who saw the crab as a sign that the monthslong project to dredge the creek may be helping restore it to the rich, natural habitat home to a diverse set of species.
“It’s really cool to actually be able to watch the tide come up,” said Robins.
Some five months ago when the excavation project began, sections of the creek were nearly filled with sediment, to the point where vegetation was growing out of the middle of the creek, said Nelson. She explained human intervention with the waterway — which includes straightening and channelizing the creek to allow for roads, development and farming, among other changes — accelerated the flow of water through the creek over time, preventing sediment from naturally dropping out of the water as it would if the creek were in its meandering, natural state.
This trend has resulted in sediment dropping out in parts of the creek that are flat, creating a build-up of sediment that has reduced the depth of the creek on certain stretches and sent water flooding across Pescadero Creek Road, agricultural fields and nearby properties, noted Nelson. She said the clearance under the bridge where Pescadero Creek Road goes over the creek reduced from some 14 feet to some 2 or 3 feet in June, she said.
“The flooding of the town of Pescadero has never been a problem of too much water,” she said. “It’s a problem of too much sediment in the wrong place.”
In scoping strategies for addressing the flooding, community members invested in the project knew they had to solve three problems — stem the flooding to land surrounding it, remove the buildup of sediment preventing steelhead trout and coho salmon from migrating to their ancestral spawning grounds and address the collection of low-oxygen water in the marsh known to kill large numbers of fish, said Nelson.
Because Pescadero Creek Road is the only route in and out of the town of Pescadero, the chronic flooding limited economic opportunities, emergency access and everyday activities like commuting to school, said Nelson. She added that the buildup of sediment was blocking coho salmon, an endangered species, and steelhead trout, a threatened species, from more than 10 miles of natural habitat where they could spawn and foster the next generation of species.
‘A triple win’
Backed by the National Oceanic and Atmospheric Agency, California State Parks and San Mateo County, the restoration project removed some 45,000 cubic yards of sediment and placed it in low areas in the marsh where the low-oxygen water was collecting, explained Nelson. Instead of big pools of stagnating water, the marsh is now home to shallower water that can mix with the breezes and become a habitat more conducive to fish species, she said.
“This one project is a triple win,” she said. “You help the community with the flooding, you help the fish with their migration and you help … stop these annual fish kills.”
In the months since work to restore the creek began in June, Nelson and Robins have seen an amphibious excavator, long-reach excavator and specialized trucks excavate and dredge large amounts of sediment and place them in other parts of the watershed. Robins noted that in addition to the steelhead trout and coho salmon, the creek also serves as a habitat for a diverse set of species including the California red-legged frog, San Francisco garter snake, snowy plover and tidewater goby, among others. In designing plans for the restoration, officials had to be careful to minimize disruptions to their habitats, he said.
He said the project received a permit allowing those working on it to take steps to move fish and other species to temporary locations as well as dam off sections of the creek in the last five months as sediment was moved.
“We weren’t just taking all the dirt out and placing it in the marsh … we were doing it in an area with all of these endangered species,” he said. “It had to be incredibly well thought-out.”
Robins added officials are expecting the watershed to be dynamic and change over time, which he said they are very excited to observe in the future as species make their way into the watershed.
Nelson acknowledged the years of planning that preceded the start of the dredging and excavation work, which included pursuing a series of permits needed before the dredging could begin, coordinating a 2014 study upon which much of the restoration work is based and identifying funding sources for the work. She noted many other restoration projects lie in store for the creek as officials continue to monitor the ecosystem.
Finding a solution
Nelson also credited the many stakeholders in the Pescadero community for coming together to scope solutions to the many issues stemming from the creek, noting there was a fair amount of contention among community members about what approach to take in addressing them. With many seeking relief from the flooding and others focused on habitat restoration, Nelson said those working on solutions focused only on strategies that could address both priorities.
“It takes a village,” she said. “It was a fair amount of consensus-building and trust-building across many different types of entities for many years to get to the point where people were willing to have this be a first step.”
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