dendroica:

After its dams came down, a river is reborn (The Elwha, unleashed) — High Country News

Before the dams, the Elwha flowed out of the mountains, down a deep canyon, past rich bottomlands and grassy hills near its mouth. In 1880, the Washington Standard described it as one of those “rapid, cold mountain streams abounding with trout.” All five Pacific salmon species spawned in its waters, sustaining the economy of the Lower Elwha Klallam Tribe. As many as 17,000 chinook returned each fall, along with 96,000 pink salmon. One week in early September 1893, a fisherman reportedly caught nine wagon-loads of salmon in a single net — about 3,000 fish.

That all changed in the early 1900s, when the Elwha Dam severed the river’s headwaters from the ocean. The Olympic Power and Development Company built the dam during an era of rapid infrastructure expansion and economic change. The electricity it provided helped industrialize the town of Port Angeles, Washington, powering mills that processed logs from the forests of the Olympic Peninsula. The Elwha Dam’s success led to the construction, in 1927, of the Glines Canyon Dam upstream.

Neither dam had any kind of fish passage, in violation of state law. The river’s 45 miles were sliced down to just five. In the 1980s, the Lower Elwha Klallam, whose reservation sits at the river’s mouth, began to defend their treaty rights to the Elwha’s fish, pushing for the dams’ removal. Congress determined that the fishery would have to be fully restored and the destruction of the dams, rather than fish passage or mitigation, proved the only way to do that. In 2001, the government purchased the dams with the intention of removing them. It took a decade to actually do so.

When the Elwha’s dams came down, the removal of many other Western dams seemed likely. In some cases, the cost of bringing aging dams up to date exceeded the profit from the electricity they generated. Environmental concerns became unavoidable as fisheries faltered. And tribes increasingly asserted their sovereignty and pushed back against long-standing violations of treaty agreements.

While the political climate regarding dams has shifted under President Donald Trump, more removals are likely in coming years. In Utah, officials removed the 14-foot-tall Mill Creek Dam, as part of an effort to restore Bonneville cutthroat trout. In August, crews began removing Cline Falls Dam on the Deschutes River near Redmond, Oregon. And the Karuk, Yurok, Hoopa Valley and Klamath tribes have secured a deal to remove four large dams on the Klamath River in southeast Oregon and Northern California, starting in 2020 — a project that will surpass even the Elwha in scale.

The Elwha remains one of the most closely watched removals. In the past, most research has focused on isolated elements of what happens after a river returns, rather than the ecosystem’s overall response. As early as the 1990s, researchers discussed treating the Elwha as a “living laboratory”; they began to monitor the river prior to dam removal, accumulating over a decade of data. Every few years at the Elwha River Science Symposium, many of them share findings, plan further research and collaborate. There have been surprises along the way: For example, engineers failed to predict the effects of the bedrock rebounding after the weight of Glines Canyon Dam was lifted. After the initial blasting, the cliff that held up the dam collapsed, blocking fish passage and slowing sediment movement. In May, Elwha researchers and officials met with Klamath-area researchers, officials and tribal representatives to discuss what insights they might draw from the Elwha.

Ritchie’s research has provided some of those lessons. He was a last-minute hire, added to keep up with the river’s dynamics on a daily basis. Ritchie, a stocky, scruffy Washington native, grew up along the Elwha; his first memory of the river is of his father carrying him there in a backpack. When he got his driver’s license, he used it to go straight to the Elwha and fish. He calls the river his muse, talks about it like a sentient creature: “When my heartbeat matches her heaving breath at Goblin’s Gate / And tumbling boulders shake polished upturned teeth of slate,” he wrote of the Elwha in one poem, “I know I’m home.”

When Ritchie joined the Elwha project, his tools were rudimentary: 20 gauges placed along the river’s 45-mile length and handheld lasers and GPS to measure the river’s width. But he quickly realized that he could construct a more complete model of its movements by mounting a pair of cameras on the bottom of a plane and taking aerial photographs at rapid intervals. Over the course of five years and more than 100 flights, he collected countless pictures of the river’s flows. On-the-ground work detailed the amount of sediment suspended in the water and deposited on the river bottom. The result is a month-by-month reconstruction of the river’s wild movements, which have so far shifted 22 million tons of sediment downstream.

While the dams were in, the river ran in a straight and narrow channel. “You can think of sediment and wood as tools the river uses to shape and reshape the channel,” Ritchie says. The logs it carries can redirect its flow and build new banks; sediment builds up in the channel and flushes out to the ocean to form beaches and estuaries. Without these forces, the water dug a rocky chute, and the forest formed a skeleton that calcified the river’s course. With them, Ritchie found that the river quickly returned to its old, winding ways.

Below Lake Mills, it has whipped back and forth repeatedly, eating up two campgrounds and a road. At one site, an outhouse stands watch over a loop road that abruptly ends in a two-foot dropoff where the river ripped away several campsites. The National Park Service was forced to permanently close the popular campgrounds; it plans to rebuild one elsewhere. This spring, it began investigating moving the road to former Lake Mills to avoid a repeat washout. The Elwha “is reoccupying its historic floodplain,” Ritchie says. “Some would say ‘with a vengeance.’ I would say ‘with enthusiasm.’ ”