OLYMPIC NATIONAL PARK — The southern end of Lake Mills looks idyllic.

With towering mountains, a dense, green forest and the quietly burbling, crystal-clear waters of the Elwha River flowing nearby, one might imagine this area in Olympic National Park has remained essentially unchanged for 1,000 years.

Loud, electronic beeping noises disrupt the peace.

They signal the approaching end of the Glines Canyon Dam, construction of which created the lake, and the demise of its sister edifice, the Elwha Dam, downriver.

The beeps emanate from yellow, big-bucketed Caterpillar 320 excavators operated by workers with Cherokee Construction Services of Vancouver, Wash., under a $743,708 contract with the park.

Clearing trees

Last week, they began clearing a 37-acre grove of alder trees on a delta where the river meets the lake.

The delta will be cleared by Friday, Olympic National Park spokesman Dave Reynolds said.

Once the portion of delta is bare, a channel will be dug in preparation for the tear-down of the dams, which will begin in September 2011 (with extensive preparations earlier in the year) and end in March 2014.

Channel digging will begin no earlier than Sept. 27 and be finished by Oct.4, when Lake Mills, which is closed, reopens to the public, Reynolds said.

Small island

From the air, the delta looks like a small, forested island, with the Elwha River mostly flowing along its east side.

Ever since the Elwha Dam was built in 1910 and the Glines Canyon Dam in 1927, the river has been depositing and piling up sediment at the mouth of the lake, creating the delta and allowing the trees to grow.

That has blocked sediment from flowing downriver and salmon from spawning, reducing their numbers from 400,000 annually to the approximately 4,000 that return to just five miles of the river between the Elwha Dam and the Strait of Juan de Fuca.

The salmon are expected to return to their former strength within 30 years after the dams are gone in what’s known as the Elwha River Restoration project, a $350 million effort that’s gaining worldwide attention as the largest project of its kind in U.S. history.

On Wednesday, an excavator pushed against one of the 50-foot-tall trees and effortlessly snapped the trunk with a great cracking sound.

Stabilized by roots

The tree’s roots have stabilized the delta, and that hinders the park’s goal of digging a 1,100-foot-long, 50-foot-wide channel through the delta to help the river break it up and redistribute it down river.

The tree fell, and the excavator grasped it with its clawed bucket, shifting it aside before it moved on to the next tree.

The trees are beings stacked like so many pick-up sticks on the delta’s north end. They’ll eventually be redeposited in the lake, Reynolds said.

Excavator operators, he said, “are just knocking those trees down” 12 hours a day, five days a week.

Erosion potential

“By removing [the trees] now, this is going to allow the river to maximize its erosion potential,” Reynolds said as he watched the excavators.

Last week, workers finished taking apart a log jam that will be relocated to help the channel redirect the river’s flow so it slices through the heart of the delta, eventually moving an estimated 13 millions cubic yards silt downstream.

The sediment that’s dug up will be redistributed on both sides of the delta, Reynolds said.

Once the dams are removed, the normal course of sediment flow will be restored.

“Salmon will return to the Elwha,” Reynolds said.

“They’re already using the lower five miles.”

The lake was drawn down 5 feet earlier this month to expose the delta, spilling 2,000 acre-feet of water over the Glines’ rampart.

Since the delta is not accessible via a road, workers must use a tennis-court-sized barge to move equipment from a launch site near the Glines Canyon Dam to the delta site at the southern end of the lake.

“We’re currently on schedule,” Reynolds said.

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Photographer Chris Tucker can be reached at 360-417-3524 or at chris.tucker@peninsuladailynews.com.

Senior Staff Writer Paul Gottlieb can be reached at 360-417-3536 or at paul.gottlieb@peninsuladailynews.com.