Restoring a San Mateo County Creek to Keep New Generations of Fish Thriving
By Peter Fimrite, San Francisco Chronicle, Nov. 5, 2019
The heavy construction equipment had been removed, so Kelly Nelson walked out on a breezy bluff to take stock of the stunning panorama of newly channeled waterways and marsh that she helped design near Pescadero State Beach.
The executive director of the San Mateo Resource Conservation District was admiring the restoration of 8,000 feet of the Butano Creek stream channel, the largest and most ambitious of a series of projects the district is spearheading to stop chronic flooding, bring back endangered fish and restore 28 acres of degraded wetlands at Pescadero Marsh Natural Preserve.
"Over many years people have altered this landscape - and Butano Creek has become disconnected from the floodplain," said Nelson as she looked out over the creek, which snakes through coastal wetlands south of Half Moon Bay. "We’re trying to restore something that has ecosystem function."
The 235-acre marsh, on the eastern side of Highway 1 in southwestern San Mateo County, is renowned for its natural beauty and is home to many rare plants and animals, including the California red-legged frog and the San Francisco garter snake.
The Butano Creek Reconnection Project will restore endangered coho salmon to a Creek in San Mateo County.
The two main creeks, Pescadero and Butano, flow through a patchwork of publicly and privately owned land and converge just west of the town of Pescadero. The watershed drains more than 8,000 acres of coastal mountains and redwood forests where winter storms have been known to dump 6 inches of rain or more. The problem, Nelson said, is that sediment flowing down from the hills built up over the years, forming a wall of mud that blocked the annual migration of coho salmon and steelhead trout. It also caused the two creeks to back up regularly and flood, sometimes all the way to the town of Pescadero. That floodwater would then filter through old farmland and regularly poison the lagoon with oxygen-depleted water. Fish die-offs have been occurring there for more than two decades.
The project, co-managed by California State Parks and paid for using $7 million in federal, state and local grant money, removed 45,000 cubic yards of mud along 4,000 feet of lower Butano Creek and used it to fill in drainage ditches and deep-water gullies that contributed to the oxygen depletion problem. "This project removes that plug of sediment," Nelson said, "giving water a place to go so that it doesn’t flood the town, giving fish a place to go so that they can spawn and complete their migration, and reuses that dredged material to fill up these low places in the marsh so that there’s a smaller volume of the oxygen-depleted water to minimize fish suffocating."
The fix was needed, project officials said, because, even in a place as beautiful and seemingly pristine as this, the impact of human development on the environment is severe. Both Butano and Pescadero creeks are listed under the federal Clean Water Act as being impaired by sediment.
Thousands of coho salmon and steelhead trout once spawned in the watershed, a bounty memorialized in the name Pescadero, Spanish for fishmonger.
The two salmonid species historically swam from the Pacific Ocean into a natural lagoon, through the marsh and up toward the headwaters near present-day Butano State Park, Pescadero Creek Park and Big Basin Redwoods State Park, where they spawned in gravel scoured clean by cold, fresh water.
The sprawling wetlands near the beach served as a refuge for wintering waterfowl and as a nursery for coho, steelhead, and many other fish, amphibians and reptiles. In the late 19th century, Pescadero and Butano creeks were renowned fishing spots for vacationing San Franciscans.
Then, in 1923, the Santa Cruz Lumber Co. built a sawmill over Pescadero Creek. Rail lines were built, log ponds were created, and lumberjacks cleared the pristine forests of redwood and Douglas fir. At about the same time, farmers began building levees and draining portions of the marsh.
Much of the marshlands were used for agriculture from the 1930s through the early 1960s, when the state began acquiring land in the area. All the activity increased the runoff of sediment into the creek system. At that time, the farmers would dredge silt that accumulated in Butano Creek below Pescadero Bridge to prevent the channel from filling up and spilling over.
The state acquired the marsh and lagoon in 1974 and created the preserve, which is part of Pescadero State Beach. It is the largest coastal wetlands estuary between Elkhorn Slough in Monterey County, 58 miles south, and Tomales Bay, about 90 miles north by car.
But without the farmers dredging, the mud built up, and by the early 1990s a solid block of silt separated upper Butano Creek from the lower portion of the stream. The water backed up almost every year, flooded roads and farmland, and sometimes lapped up against homes in the town of Pescadero, 2 miles away, where residents often had to stack sandbags.
The situation infuriated the locals, many of whom blamed state park officials for exacerbating the problem by halting dredging and not removing logjams in a timely fashion. Makeshift efforts by farmers, including bulldozing drainage channels, worsened the runoff problem, environmental scientists said.
Anoxic water - low in dissolved oxygen - that seeped through oxygen-depleted soil was also blamed for suffocating hundreds of juvenile salmon, and endangered tidewater gobies, crabs and other species that entered the lagoon each year in the late fall when the sandbar between the lagoon and the ocean was breached.
Steelhead are still found in the watershed, but studies have shown that their numbers have declined steadily from about 10,000 in 1985 to less than 750 a few years ago.
No coho were returning to the two creeks by 2003, when 17,000 hatchery-raised coho were released into Pescadero Creek. Researchers said only three of their descendants were counted in 2015. Although a few carcasses have been found in Pescadero Creek in recent years, the species is considered functionally extinct in the Butano watershed.
The dredging project is an effort to reverse that downward spiral.
"This could be a key in recovering enough coho and steelhead to give them a fighting chance for survival," said Nelson, who worked closely with landowners, local agencies and Pescadero residents to identify projects that would adequately address flooding and improve habitat for wildlife. "This is a dynamic system, so we want to manage it as a dynamic system, which is what is important to the species."
The work reopened 10 miles of the upper watershed to salmon and steelhead and restored marsh habitat for the San Francisco garter snake, California red-legged frog and tidewater goby.
It is considered a critical step in a long-term effort, which will also include improvements to stock and farm ponds, rainwater storage projects, removal of fish barriers, and adjustments to farmers' water rights so they can store water during the rainy months instead of taking it all during low flows in the summer.
The conservation district next plans to begin restoration of floodplains in the upper reaches of the watershed to improve spawning habitat and increase the number of baby fish that imprint on the creek and return to bear offspring three years later.
Peter Fimrite is a San Francisco Chronicle staff writer. Email: email@example.com.
Fish-friendly changes at Nevada dam to help threatened trout
By Scott Sonner, Associated Press
WADSWORTH, Nev.- Federal officials are making fish-friendly modifications to a northern Nevada dam that for more than a century has blocked off native spawning grounds for a threatened trout species that once migrated 120 miles upstream from a high-desert lake to the alpine waters of Lake Tahoe.
Officials for the U.S. Bureau of Reclamation, Fish and Wildlife Service and Pyramid Lake Paiute Tribe broke ground Tuesday for a $23.5 million fish-passage project to help Lahontan cutthroat trout navigate the Truckee River’s Derby Dam about 20 miles east of Reno.
As soon as next fall, fish screens in a bypass canal longer than a football field will allow the trout - once believed to have gone extinct - to get past the dam for the first time since it was built in 1905.
Commissioned by President Theodore Roosevelt, the dam was part of the first major irrigation system established in the West to "help make the desert bloom," diverting water to farmers and ranchers in a region where only about 5 inches of rain falls annually.
"This day is 100 years in the making," said Jody Holzworth, deputy regional director of the U.S. Fish and Wildlife Service. "The fish screen will allow this iconic species to travel beyond Derby Dam, from Pyramid Lake to their spawning grounds, for the first time in more than a century."
Lahontan cutthroat trout, the state fish of Nevada and largest trout in North America, used to grow as large as 60 pounds when they would climb 2,500 feet through mountain river canyons to Lake Tahoe, elevation 6,228 feet.
Tribal leaders and state and federal wildlife officials have been working for two decades to restore the fishery in Pyramid Lake - a remnant of ancient Lake Lahontan, an inland sea that covered 8,450 square miles of western Nevada during the Ice Age. The Lahontan cutthroat trout also are native to parts of Oregon, Utah and Wyoming.
Dan Mosley, executive director of the Pyramid Lake Fishery for the Pyramid Lake Paiute Tribe, said the tribe has a long history of "fighting for the fish."
"They are really important in our stories and our culture," Mosley said.
In recent years, the fish have made their way several miles upstream from Pyramid Lake but haven’t been able to get past the Derby Dam.
The trout was thought to have gone extinct in the 1940s and was listed as threatened in 1970. But a remnant population later was discovered in a small brook on Pilot Peak along the Nevada-Utah border.
Beginning in 2006, that population has been used to successfully restock Pyramid Lake, where Holzworth said anglers now regularly catch cutthroats as big as 25 pounds.
Cutthroats successfully spawned in Pyramid Lake in 2014 for the first time in 80 years and this year, 775 successfully spawned in the river between the lake and dam.
The bypass canal will include an 80-foot-wide, 390-foot-long horizontal fish screen - actually a metal plate with slots that pushes water down through the water system while sending the fish and other debris through the side channel.
The Farmers Irrigation District of Hood River, Ore., first developed what is now known as the "Farmers Screen" after severe flooding in 1996. The district licensed the patent to the nonprofit Farmers Conservation Alliance which since has completed 50 similar projects in several Western states.
This one is the largest and the first the Bureau of Reclamation has commissioned.