 File photo by Lara Wilent.
As the Mountain community enters the cold and dark season
(all while dealing with a pandemic), the 10-year anniversary of the 2011 flood
reminds us all that a little warmth at the wrong time can be a very dangerous
thing. Unseasonably warm temperatures coupled with heavy rainfall and melting
snow wreaked havoc in mid-January 2011, causing flooding in the Sandy, Zigzag
and Salmon Rivers while leaving more than 200 people without electricity, water
or telephone service, and necessitating a human chain up and down Lolo Pass
Road. Thankfully, nobody perished in the flood, but three houses were lost.
“It was quite an endeavor,” said Mic Eby, who served as the
Hoodland Fire District Chief at the time and has spent more than 40 years with
the district.
Eby noted that the district began preparations for the flood
in the days before and watching the weather reports. He added that the
district’s volunteers came out in force, including members of the CERT group,
to help fill and transport sandbags, provide traffic control, perform welfare
checks and more.
“It was amazing how the community came together for that,”
he said.
Jay Wilson, Clackamas County Resilience Coordinator,
recalled that in the aftermath of the flood, a town hall was held, featuring
all the County Commissioners and a large crowd of community members.
“It was quite a heated, passionate conversation,” he said.
“It was a packed house.”
Wilson noted that out of that conversation, among many
others, it became clear that members of the community wanted to “fix” the
rivers in a similar fashion to what the Army Corps of Engineers did following
the 1964 flood.
“That just became the biggest single issue that our office
worked on for the next five years,” he said, adding that they had to shift
those expectations to help people understand that it was not a case of trying
to control the river, but trying to manage the risk involved with the river.
Wilson explained that when people protect a property with
riprap, rock formations placed to prevent erosion, the hydraulic energy bounces
off of it and creates a slingshot, sending the destructive force elsewhere in
the river.
In light of that, efforts have been made to restore the
rivers to their natural floodplains, which takes some pressure off of the
homeowners.
“It doesn’t make the risk go away, it just helps to give it
more stability,” Wilson explained, while also noting that fighting a river will
also harm fish habitat.
Wilson pointed to two big projects on the Mountain
connecting the rivers to their floodplains: one completed in 2016-17 upstream
of Timberline Rim that opened a side channel and installed big lumber erosion
management structures (which has already demonstrated that cutting the flow and
energy out of the water does work) and the removal of levees and opening of
side channels at the confluence of the Sandy and Salmon Rivers.
While the 2011 flood helped to shift in this thinking
process, the recovery from the event was different for the county than anything
it had done before, Wilson noted. In the past, the county mostly dealt with
permits for emergency work on properties impacted by flooding, but Wilson described
the county’s efforts in 2011 as being a community recovery facilitator, doing
“more listening than talking” and trying to find common ground through a
transparent public process.
He noted that the county formed an interdepartmental flood
recovery group that met weekly and then bi-weekly for approximately eight years
to coordinate their efforts primarily on the Sandy River flood issues.
The aftermath of the flood also revealed that the county
needed a scientific analysis of the behavior of the rivers to better understand
what the best approach was for policies and programs. The result was a 2015
channel migration zone study, which Wilson described as the “single biggest
development” resulting from the flood.
“Oregon didn’t have anything like that before,” he said.
“This was the state’s first assessment of that degree.”
The study, which has not yet been formally adopted, came
with hazard and risk maps that identified hundreds of homes on the Mountain
that are currently in imminent threat if a repeat of the 2011 flood took place.
Wilson added that the numbers jump to several thousand homes in imminent threat
if we have another flood similar to 1964.
“That got a lot of people’s eyes open,” he said.
By adopting the hazard and risk maps in that study, the
zoning and land use designations of those areas would change. But Wilson added
that there are complications that have prevented that.
To help share the valuable information, the county has held
a “Flood of Information” event every year (except 2020, thanks to the pandemic)
to provide new information, including a mapping tool that is also available
online (https://www.clackamas.us/dm/channelmigrationzoneresources.html).
Wilson noted that for two years in a row, he met couples at
the event that realized their property was in the channel migration zone, and
therefore at a higher risk, and noted they wouldn’t have purchased the property
if they had known before. But there is no law requiring the disclosure of the
risk during the sale of one of these properties.
Wilson added that people’s perception of risk has changed
since the 2011 flood, noting that at some of the public meetings immediately
following the flood, a lot of people expressed interest in the possibility of a
buyout for their property. But after time, fewer and fewer people were
interested.
“Unfortunately, I think a lot of human nature is to be
reactive,” he said.
Wilson added that the biggest single finding from the 2015
report confirms that the deck is stacked against homes that are right next to
the Sandy and Zigzag Rivers. That’s because these rivers lie in a volcanic
landscape and the homes are built on terraces that are still unstable, and that
doesn’t even account for climate change causing glaciers to retreat and
revealing loose soils.
“It doesn’t take much to mobilize it,” Wilson said.
“Sediment creates erosion patterns. Anything that brings more sediment into the
river, it creates a lot more uncertainty.”
And despite the magnitude of the 2011 flood and the strong
emotions that followed, the past 10 years have been fairly quiet for flood
events, perhaps creating the appearance that the risk has diminished.
“I think people get lulled into complacency despite all the
work we’ve done up there,” Wilson said.
To make matters worse, Wilson added that should the Mountain
community be impacted by wildfires, the loss of vegetation in the forest would
mean a diminished ability to manage runoff from heavier rainfall.
“If we ever have a fire in the upper Sandy basin, you can
bet the jeopardy of the riverside homes will go up as the river reacts to the
new environment,” he said.
Wilson noted that now is the time to rethink our assumptions
about living in a community with such dynamic rivers. Perhaps instead of
property owners taking what they can get after a home is destroyed, programs
that buy out properties in harm’s way could solve the problem before it arises
again, with the potential for bringing more land into the public domain and
providing greater recreational opportunities on the rivers.
“We’re still working to try and find a way to live with the
river, rather than fighting it,” Wilson said.
By Garth Guibord/MT | 
