Decades old landslide still harming Deschutes River coho

OLYMPIA (August 5, 2008) – A nearly 20 year old landslide is still hurting salmon according to a recently completed analysis of sediment in the Deschutes River by the Squaxin Island Tribe.

“The sediment from that landslide is still working its way through the river system,” said John Konovsky, environmental program manager for the Squaxin Island Tribe. “It has a relatively high proportion of minute dirt particles that continue to hinder coho reproduction.”

In January 1990, a huge storm hit the Deschutes River blocking an old culvert under a logging road. The resulting landslide sent tons of hillside sediment into Huckleberry Creek, a headwater tributary to the Deschutes.

“Huckleberry Creek used to be a major coho factory in the Deschutes watershed,” Konovsky said. “That slide wiped out all of the coho rearing there and the population has never recovered.”

Coho production in the 1980’s was typically around 80,000-90,000 smolts per year, but in the early 1990’s, it crashed. “Certainly marine survival has played a major role,” said Scott Steltzner, fisheries biologist for the tribe. “But the sudden decline in local habitat conditions is also a strong contributing factor.”

Salmon need cool, oxygen rich water in which to spawn. “High levels of fine sediment in spawning gravel smother freshly laid eggs,” Steltzner said.

New forest practice rules initiated since 1990 would likely help prevent the same type of catastrophic landslide that is still impacting watershed health and wiped out the upper Deschutes River coho. “The rules that allowed this to happen have changed, but we’re still encountering the after-effects of this slide,” Konovsky said.

“While floods, landslides and sediment are part of the natural cycle of a river, the 1990 landslide was an unnatural event,” Konovsky said.

The state Department of Ecology (DOE) is currently looking at the river to decide how to improve spawning conditions for coho. A technical report is expected later in the year.

“We’ve been feeling the impact of this landslide for nearly 20 years,” said Andy Whitener, natural resources director for the tribe. “For now, we’ll have to make sure we do everything else we can to re-establish good spawning and rearing habitat.”


For more information, contact: John Konovsky, environmental program manager, Squaxin Island Tribe, (360) 432-3804. Emmett O’Connell, information officer, NWIFC, (360) 528-4304, [email protected]