By QUINTON SMITH/YachatsNews.com
A landslide that for years has been looming over a unique salmon and steelhead research center 25 miles east of Waldport, gave way during torrential rains Sunday night, wiping out a bridge and causing the evacuation of center employees and residents downstream along Fall Creek.
The central Oregon coast was hit with more than eight inches of rain from Thursday through Sunday, including more than six inches Saturday and Sunday. That appears to be the most over a two- or four-day period since at least December 2016, according to weather watchers.
The deluge pushed the Alsea and Siletz rivers to just below flood stage, and sent smaller coastal streams like the Yachats, Beaver and Big creeks, Tenmile and anothers surging to the sea. The flow in the Yachats River was three to four times its normal for December, according to the city of Yachat’s stream gauge.
While most areas were spared damage, the Oregon Hatchery Research Center and a Lincoln County bridge over Fall Creek one mile above it were not. The creek is a tributary of the Alsea River.
The research center is operated by the Oregon Department of Fish & Wildlife in conjunction with Oregon State University. It sits on the site of a state coho salmon hatchery that closed in 1997. Eight years and $7.5 million later it reopened as a research center for scientists from around the Northwest and the world to conduct research on salmon and steelhead.
Following the December 2016 rains, 35 acres of steep Weyerhaeuser land started slipping one mile upstream of the research center. It contained second-growth trees that were 30-40 years old, according to the Oregon Department of Forestry. While the land didn’t move much, silt from the slide was a constant wintertime problem for the clean water intake at the research center.
The bigger worry was that if the slope failed completely, it could smother Fall Creek with a debris dam, water would build up behind it and then the whole thing collapse and wipe out the center and homes in the valley below.
In 2018, the state installed a low water alarm at the center and the county set up a “reverse 9-1-1” call system to alert hatchery employees and downstream residents of a landside.
Landslide called “significant”
On Tuesday, county and Oregon Department of Forestry officials said their investigation showed a “significant amount” of the slide gave away Sunday night. That blocked the stream for 1-2 hours, the ODFW said, and triggered low-flow alarms at the research center.
Hatchery workers evacuated Sunday night and also contacted 8-9 property owners living downstream from the center. They also initiated the reverse 9-1-1 system that notified residents. Lincoln County Sheriff’s deputies checked the homes of people who didn’t respond to the 9-1-1 calls.
Center staff returned Monday morning but left again because of safety issues, said Michelle Dennehy, an ODFW spokeswoman. They returned Tuesday afternoon to work and live at state housing at the center.
“It appears that a large chunk of the landslide came down last (Sunday) night and there is still material up there that can move,” Dennehy said in an email Monday to YachatsNews.
There was no major damage to the center’s property even after the debris broke loose and the creek returned to its normal level, Dennehy said. On Thursday Dennehy said the facility is fine “there is water for the fish, and the creek is starting to clear up some. So business as usual, including normal storm cleanup.” She said staff is reporting sediment in the intake area that they will be dealing with, “but that has been an ongoing issue for several years.”
While the research center is getting back to normal, Lincoln County officials said the slide severely damaged a concrete county bridge one mile upstream of the center. The county said it did not know if the bridge could be repaired or if it would have to be replaced – at an estimated cost of $1 million.
The county and state forestry officials also said in a news release Tuesday that a “significant amount of the known slide area did in fact give way, leaving a portion of the slope which appears to be vulnerable to future movement.”
The county said it was also monitoring and assessing the debris flow from slide in the residential area downstream from the center.
ODFW aware of landslide risks
“ODFW is well aware of slide risks to OHRC facility,” Dennehy said in her email Monday. “The area was investigated for slide risk, failure potential and risk to the facility in early 2019 by River Design Group. The investigation found that a significant landslide risk does exist at the site and nothing can be done to mitigate the risk to the structures if there were such a catastrophic event.”
Dennehy also said that over the past three years “a fair amount of slide material has ‘bled off’ into the river.”
Water – although high and muddy – was flowing again Monday in Fall Creek below the research center, said John Caudle, who lives 1½ miles below the facility.
Caudle, his wife, Carolyn, evacuated their property about 9:30 p.m. Sunday after hatchery employees called to warn them of the alarms. They also got calls from emergency dispatchers, who sent deputies to his door because he had already left and did not answer his landline.
“All the systems they had in place worked very good,” Caudle told YachatsNews. “Everyone’s safe, and that’s what counts.”
Caudle said Fall Creek below the center filled with debris Sunday night. Now that has stopped and it’s just high and muddy.
“It’s fine. It’s flowing. It’s dark,” he said.