Dams That Were Engineering Marvels 100 Years Ago Being Mothballed
SANDY, Ore. A century ago, when engineers for the Portland General Electric were looking for places to harness rivers to supply growing demand for electricity, they found the Sandy River tumbling off the flanks of Mount Hood, the snowcapped volcano that is the highest point in Oregon.
Named by Lewis and Clark for the great quantities of sand washed downstream from past eruptions, the Sandy offered the perfect opportunity for the fledgling utility. It was close to Portland, and offered a free and unlimited source of power. No one worried about harming the salmon and steelhead that spawned in its beds.
Unable to build towering concrete edifices like those erected on the Columbia River in the 1930s, the engineers created an intricate network of dams, canals, tunnels and a miles-long wooden flume on stilts.
Even with high prices for energy today, PGE has decided the Bull Run Hydroelectric Project that went on line in 1913 is no longer economical, can be replaced more cheaply by wind generation and causes too much harm to salmon for the power it produces. The utility is spending $17 million to remove the Marmot and Little Sandy dams and Roslyn Lake between 2007 and 2008, and donating 1,500 acres for fish and wildlife habitat and public recreation.
Utilities around the West are facing similar choices, weighing the economic, social and environmental costs of hydroelectric projects that made sense 100 years ago, but now pose significant problems not just economically but for fish and wildlife protected by the Endangered Species Act.
"It was a critical component to the young Portland General Electric when it first brought this generation on line to meet a rapidly growing customer base," said Julie Keil, PGE's head of hydropower licensing. But when they looked at getting a new federal license, "It didn't meet any of the tests."
Operational and maintenance costs, particularly of the wooden flume, were too high. Output was too low. And the harm to salmon was too great.
"With the great societal concerns about impacts on fisheries and other wildlife, it's not likely we are going to see many new hydroelectric projects developed," said Dave Kvamme, spokesman for PacifiCorp, a utility based in Portland that serves Utah, Oregon, Wyoming, Washington, Idaho and California. "We're not planning any."
So far, only 17 hydroelectric projects have been decommissioned by the Federal Energy Regulatory Commission out of more than 1,600 nationwide. With a rated capacity of 22 megawatts, enough to power 11,300 homes, Bull Run is the biggest so far, according to the commission. But scores of others will face the test.
Sue Doroff, vice president of the Western Rivers Conservancy, which worked with PGE on plans to remove Bull Run, said it is anybody's guess how far dam removal will go.
"The bigger the dam the more power it generates and therefore the more economically viable it is," she said. "The variables are pretty far ranging -- the health of the salmon run in any particular stream impacts the importance of removing the dam, the amount of benefits to the community and society for power generation."
In Washington, PacifiCorp has removed one dam from an irrigation canal on a tributary of the Yakima River and agreed to remove another from the White Salmon River, said Kvamme. It has agreed to remove one from the American Fork River in Utah, and one on Hood River in Oregon. Pacific Gas and Electric, California's biggest utility, plans to remove another from a tributary of the Feather River in Northern California.
All these small dams date from the first years of the 1900s. In Portland, companies burning waste from sawmills to power streetcar lines were just organizing as utilities, and starting to offer electricity for streetlights and homes, Kvamme said.
Now up to 70 percent of the electricity in the Northwest comes from hydroelectric power, compared to 8 to 12 percent nationally, according to the National Hydropower Association.
Work started on Bull Run in 1906 and it was finished in 1913.
"The need to provide electricity was really a new front then, and they were doing pretty amazing things for their time," Keil said.
The centerpiece is 45-foot-tall Marmot Dam on the Sandy River. Originally built of timbers filled with rocks, it was replaced with roller-compacted concrete in 1989 after being washed out by a flood. Most of the river flows over the dam, but some is diverted down a concrete canal, through a tunnel, and dumps into the Little Sandy River. There it hits the Little Sandy Dam, a 16-foot-tall concrete structure that totally blocks the river except during floods. It sends the water down 15,000 feet of wooden flume equipped with railroad tracks to transport maintenance crews, through another tunnel into Roslyn Lake, a manmade reservoir where the water is collected and sent to the powerhouse. The water finally ends up in the Bull Run River.
Salmon and steelhead, a seagoing trout, get upstream over Marmot Dam with a fish ladder to reach spawning beds, but not the dry riverbed created by Little Sandy Dam. The fish find their home streams by smell, and water from the Sandy dumped into the Little Sandy and then into Bull Run River confuses fish.
Hydroelectric power still accounts for 43 percent of PGE's output, but new production will come from wind and natural gas, said spokesman Mark Fryburg.
When PGE looked at its resources on the nearby Clackamas River -- eight dams, seven reservoirs, four sets of generators, 13 miles of pipelines, canals and tunnels and two miles of fish ladders, all built between 1907 and 1958 -- it decided to spend $200 million to upgrade. The payoff is much greater -- 173 megawatts of electricity, enough to power 56,000 homes.
"People often say water for fuel is free," said Fryburg. "Well, it is, but there are a lot of other costs as well."
Source: Associated Press