PORT ANGELES — Part of the Lower Elwha glowed red Tuesday during one of the tests needed to prepare for the removal of two dams up river.
The color, called “blood red” by some callers to the Peninsula Daily News who spotted it in the river at the end of Lower Elwha Road, dissipated later in the afternoon after U.S. Geological Survey scientists put a nontoxic, fluorescent dye, Rhodamine WT, upstream.
Scientists are tracking the dye, which can be detected by equipment at low concentrations, as it flows downstream, said John Clemens, spokesman for the USGS Washington Water Science Center in Tacoma.
The dye will show scientists how long water takes to travel from one point to another in the river, and illustrate the complexities of the river’s structure because channels, rocks and woody debris slow the movement of the dye, Clemens said.
“It will provide a ‘before’ snapshot of what the river is like now,” he said.
“After the removal of the dams, we will be able to tell what has changed.”
The 108-foot Elwha Dam and the 210-foot Glines Canyon Dam, which were built without fish ladders, are scheduled for removal in a $308 million project that will begin in 2011.
The dam removal project, the largest of its kind in the nation, is intended to restore the river to its natural state and enhance salmon habitat.
Dye harmless
Often used in hydrologic studies, Rhodamine WT is harmless, USGS scientists said.
“You might see a reddish tint to the water during the week of September 28th, but it’s nothing to worry about,” said Rich Sheibley, USGS hydrologist and leader of the dye study, in a prepared statement.
“Scientific use of this dye is very common, and has been shown to be harmless to aquatic life and human health.”
The experiment will provide a baseline condition for comparisons to additional dye releases after the dams are removed in 2011.
“It’s important to document and define all the conditions of the river prior to the removal of the dams,” Clemens said.
The picture of the movement of the water in the river provided by the red dye test will help guide the process of the dam removal, he explained.
“It’s good to have a ‘before’ and ‘after’ [picture], so you can see what happened here and why,” he said.
The dye test is one of many needed before the dams are taken down.
On such tests was to draw down the pools behind the dams to saee how sediment will behave when the dams are removed, Clemens said.
“There are all kinds of things to get done before any dam removal,” he added.
Color fades quickly
He said that the color of the dye is a bright red, but that it fades relatively quckly.
“If you are in immediate area where the dye has been added to the river, it will be very notable. But as it moves downstream, it will become fainter.”
The study is part of ongoing work by the USGS, the state Department of Ecology, the Lower Elwha Klallam tribe, the National Park Service, and the Bureau of Reclamation to document conditions in the Elwha River prior to removal of the two dams.
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Managing Editor/News Leah Leach can be reached at 360-417-3531 or at leah.leach@peninsuladailynews.com.
