In July, an eight-pound steelhead swimming up the Elwha River generated more excitement than 15,000 yards of concrete ripped out of a dam that had impounded the watercourse within Washington state's Olympic National Park since its construction 99 years ago. The largest-ever dam removal and river restoration program in U.S. history is under close scrutiny by a wide range of interest groups. The steelhead, the first of a smattering of fish to venture that far upstream, past the 108-ft-tall Elwha Dam site, signified the first meaningful step in the restoration of fish and wildlife to the 45-mile Elwha River, which has been choked by two monolithic dams for as long as anyone can remember.
The National Park Service is overseeing a two-step process: removal of the Elwha Dam, five miles from the river's mouth at the Pacific Ocean, and the demolition of the 210-ft-high Glines Canyon Dam, built in 1927, eight miles upstream from Elwha Dam.
Removing concrete plunked into pristine mountain waters—a total of 35,000 yards in both structures—plays just one part in a $325-million effort to restore the Elwha River to its natural state. Other key components of the job include an extensive revegetation effort and a river sediment-clearing plan. A successful project would herald the return of natural salmon and steelhead populations of 100 years ago.
The Elwha River project began decades ago, long before arguments about dam removal ever heated up in the Pacific Northwest. Brian Winter, Elwha project manager for the National Park Service, says it is the first instance in which dam removal was imposed against the owner's wishes. When the neighboring dams, which were then owned by Crown Zellerbach Co. and had a combined generating capacity of 28 MW, sought operating licenses in the 1970s, local Native American tribes and environmental groups presented opposition, forcing the Federal Energy Regulatory Commission (FERC) to consider dam removal as part of its environmental impact statement. FERC never handed down a final ruling. In 1992, Congress stepped in with the Elwha Act, which gave control to the secretary of the interior. A federal court ordered the removal of the two dams.
Planning for restoration started long before crews began chipping away the first concrete at Elwha Dam on Sept. 17, 2011. Winter has been involved with the dams for many years. In 1985, he started working as a consultant for the Lower Elwha Klallam tribe—whose property encompasses the mouth of the river outside of national park land—and, soon thereafter, moved over to the National Park Service (NPS).
A Careful Start
But taking out two aging concrete structures with no fish passages has an immediate and powerful impact on the surrounding environment. A sudden removal would send 800 acre-ft of water rushing downstream from Lake Mills behind Glines Canyon and Lake Adwell behind Elwha, scouring away any vegetation that remained on the riverbanks and likely flooding tribal land. The deluge would also unleash a century's worth of sediment—24.3 million cu yd of gravel, silt and woody debris—through roughly five miles of river, essentially poisoning every living creature in its path.
A demolition plan called for deliberate movements. With dam-removal experts Barnard Construction, Bozeman, Mont., aboard for the $26.9-million dam destruction contract, the NPS set up four work-stoppage windows ranging from 45 days to two months, giving the fish time to acclimate to the changing water conditions. The plan also restricted the amount of water that could be released during active working times, thus effecting a more natural erosion of the riverbanks and deltas.
The NPS and the Bureau of Reclamation put together a work plan to ensure the delta erodes efficiently, Winter says. Whenever river levels drop by 15 feet, the contractor implements a 14-day construction hold. The river has played along nicely: The average cu-ft-per-second flow rate has remained slightly below the historical average of 1,500 cfs, still high enough to "get the delta erosion that we want to see," Winter says.
"The river is doing a great job eroding the Lake Mills delta," he says. "We have no complaints. It is going as expected, and that in and of itself is exciting."
The NPS planned a three-year window for the full removal of Elwha Dam, but Barnard knew the firm could do it quicker. The contractor finished the task in a breathtaking six months that included a two-month fish window that forbade in-water work. Brian Krohmer, Barnard project manager, says the shallow reservoir behind Elwha and the less-than-average flows allowed for a speedy removal.
Crews used two hydraulic hammers mounted on Caterpillar 330 excavators to chip away, four feet per day, the spillway on one side and the dam on the other. Using earthen cofferdams, they diverted the river back and forth about 10 times, working on the dry side after each movement. Besides keeping the reservoir at a fish-friendly depth, the alternating pattern kept the water on the other side of the dam at an even level, allowing crews to work safely even if the cofferdam were to fail.
Work at Glines Canyon, which started in conjunction with Elwha, is ongoing and should wrap in March 2013. There, because the dam was only six feet wide at the top, Krohmer brought in a barge-mounted excavator with a hammer to start the work. One the right-hand bank, a rock shelf prevented barge access, so crews used a crane-mounted drill to reach the structure.
Because the dam gets wider at the bottom, Krohmer expected all along to use the barge for only the top third of the structure. As the upstream debris pile rose, there was less and less water in which to float the barge. So, crews finished with the barge in October 2011 and started drilling and blasting with a nitroglycerine-based product. They used the crane to move and remove materials and equipment. Now using two drills—a hydraulic-operated pneumatic drill on a platform and an Atlas Copco D3 hooked to a crane—crews are methodically removing Glines Canyon.
By adding blasting to the demolition mix, Krohmer plans to ease maintenance headaches associated with the hammers and prepare for unknown safety concerns that come from resting large pieces of equipment on the crest of an aging dam.
While the demolition process has gone as planned, the only unknown is what exactly the bottom of the dam looks like and how tricky it may be to remove.
While the fish windows and drawdown restrictions obviously are slowing the project, Krohmer planned around them, removing powerhouses and performing other out-of-river tasks during the Aug. 1-Sept. 15, Nov. 1-Dec. 31 and May 1-June 30 windows.
The Look of It All
On the project since 1989, Pat Crain, a fisheries biologist with the NPS, says that if he had his way, the project would have included a slurry-dredge component to clear the harmful sediment from the entire river—at 1,000 parts per million, sediment actually kills the fish. But that approach would have tripled the project's cost. So far, the staged drawdown and fish windows have kept sediment at a level that enables fish survival, according to Crain.
While not in conjunction with the NPS effort, an existing fish hatchery run by the Lower Elwha Klallam tribe and a separate, state-operated rearing channel will help return fish upstream for the first time since the dams blocked their migration. Crain says a combination of native and hatchery-raised fish are needed to reach the goal of returning the 10 native species of fish to the historical level of 400,000 from the current level of 3,000.
Crain says next summer will offer the first big test for Chinook salmon, the most populous fish in the region. Once Glines is removed, how quickly will the salmon return upstream? The fact that steelhead already have ventured past Elwha Dam's old site is positive. "Any time you take a barrier out and you have some colonizers that are willing to go up and try it out right away, I think that is really exciting," Crain says. "And those fish were moving up when sediment levels were pretty high—not lethal—but still uncomfortable."
Officials will monitor fish movement for at least the next 10 years. If they need to assist the native fish movement by introducing hatchery fish upstream, the option is there. Crain says that without hatchery-raised fish mixed into a dwindling population—the natural steelhead run had dropped below 100 fish annually—returning to a healthy population simply wouldn't happen.
Concern over water quality wasn't just for the fish, though, as part of the legal agreement involved in removing the dams called for the neighboring city of Port Angeles to receive a new industrial water treatment plant, complete with sediment-filtering abilities.
Seeds of Renewal
To encourage other wildlife to move into the area and restore the natural look and sway of the river, a revegetation effort started eight years ago with new native planting. The program will renew in earnest this fall, with 400,000 native plants spanning 80 species and another 5,000 seedlings planned, as the river levels have declined enough to leave the now-vacant riverbed exposed. Winter expects another three years of heavy planting, repeating the process eight years later.
Returning a natural flow to the river also will help wash away accumulated sediment at the Pacific Ocean shore, providing a natural beach restoration program simply by letting the river flow—just another facet in which to "learn how quickly a natural ecosystem can respond to taking dams out," Winter says.
A National Issue
As Elwha and Glines illustrate, dam removal is an intricate process, but one that is going on across the nation, says Stephanie Lindloff, the New York City-based director of the river restoration program with the Seattle non-profit American Rivers. She estimates that, in 2012, about 60 dams will be removed throughout the U.S. Lindloff also predicts a slight upswing in dam removal—up to 75 removals annually—in the next two years. There already has been, since 2006, a 40% increase in dam removal compared to the previous five years.
While no planned projects match the size of the Elwha-Glines project and many of the dams are simple $20,000 removal projects, there are examples—such as the ongoing removal of the Great Works Dam and the potential removal of the Veazie Dam, both in Maine's Penobscot River—that prove as technically challenging or as important to fish passage.
The rationale behind dam removal varies, but the two primary drivers are to save money and fish. As sediment accumulates and reduces the head for hydro production, aging dams provide electricity less efficiently. Upgrades to restore electricity production and protect fish often prove to be cost-prohibitive. Owners also want to remove dams to save on maintenance costs and address safety and liability issues. "It's often discovered that removal is the most cost-effective solution," Lindloff says. "It's a win economically, a win for public safety and a win for the environment."
In Washington, bringing together those wins required a plan that joined the NPS with the Lower Elwha Klallam tribe, the Bureau of Reclamation for engineering expertise, the U.S. Army Corps of Engineers for flood analysis, the U.S. Fish and Wildlife office, National Marine Fisheries, Washington Dept. of Fish and Wildlife, U.S. Geological Survey for data, Dept. of Natural Resources, Washington Dept. of Ecology, Washington Dept. of Health, the city of Port Angeles and Clallam County. Winter says the level of cooperation "demonstrated that parties that were at odds can get together and come up with a solution and jointly implement that solution."
"An overarching lesson from Elwha is that dam removal—big dam removal—is realizable," Lindloff says, "and that means large-scale river restoration is also realizable. What once may have seemed the stuff of fiction has become possible."
As Lindloff looks at nationwide river cleanup programs, Winter is anticipating an exciting moment still to come, something even more dramatic than the steelhead he already has seen: a river unimpeded by the Elwha and Glines Canyon dams.
"I want to go to Krause Bottom, the next big valley up from Glines Canyon, where you can sit on the banks and look into the water so clear," Winter says. "I want to sit on the bank and watch the wild Chinook swim upstream." Nobody's done that in 100 years.