Crime

Threshold raised for warning of minor flooding on Puyallup River near Orting

The Puyallup River near Orting was starting to remind Pierce County’s flood control manager of the boy who cried wolf.

Countless warnings about minor flooding have accompanied nearly every sizable storm to bring heavy rain to the county in the past two decades. In most cases, the water rose and sometimes spilled onto the river banks but rarely threatened homes.

Now that several flood mitigation projects have proved the river is better managed, the National Weather Service has more than doubled the flood warning level for that section of the Puyallup River.

Flood flows help forecasters determine when and where to issue minor, moderate or major flood warnings.

On March 1, the threshold for a warning for minor flooding went to 10,000 cubic feet per second from 4,500 cfs. The warnings for moderate and major flooding (13,500 cfs and 16,000 cfs, respectively) remain unchanged.

Pierce County requested the change in November, returning the flood warning level to what it was 25 years ago, before development encroached and changed the river’s behavior.

“You always want people to be safe, but at the same time, if they are warned repeatedly about a flood that never comes, that’s when people become complacent,” county operations manager Tony Fantello said. “We want flood warnings to mean something.”

Historically, the river’s flood stage was set at 10,000 cfs, but that changed once more houses were built and the river no longer could meander its natural course.

Officials tried to keep the water under control by building levees, but major storms repeatedly washed out the levees and repairs became costly.

Areas most at risk were Neadham Road, Orville Road East, the Tomolla Tree Farm area and spots south of Brooks Road East and north of Electron Road.

A section of the river above Neadham Road prompted forecasters to lower the flood stage about 25 years ago, knowing that a flood control system is only as good as its weakest link.

“At night, we could rest knowing that at 10,500 (cfs), water would still stay in the banks,” Fantello said. “For the past 10 to 15 years, we lost that ability to rest.”

In the past 10 years, records show the Puyallup River went over 4,500 cfs 21 times and over 10,000 cfs six times.

Before settling on the flood stage level, forecasters analyze areas where rivers typically spill onto their banks, past incidents and the likelihood of a minor flood affecting surrounding land.

“We set these levels at a point where the river level begins to flood and have some kind of negative impact,” said Brent Bower, a hydrologist at the Weather Service. “And that changes in our area quite a bit.”

Several projects combined to reduce flooding on the Puyallup River near Orting.

The first levee setback was built in 1997. A second built in 2006 near the Orting Soldiers Home was meant to accommodate a 100-year flood happening. The $45 million project opened another 85 acres for the river to spread out.

Officials made two significant repairs to the levees and did logjam projects in an attempt to minimize flooding.

The county also began buying homes in high-risk areas and demolishing them. Last year, the county purchased 19 homes and hopes to soon close on two more, capital improvement program manager Hans Hunger said.

He estimates hundreds more homes are in harm’s way.

“We want to give the river room back and move whoever is there out of there,” Hunger said.

The last major flood on the Puyallup near Orting happened in 2006 in the Village Green neighborhood, causing about $400,000 in damage. Since then, the levee overflowed three times.

So the city started planning for new flood control.

A year ago, Orting started construction on the Calistoga Setback, which includes a new levee and a new channel for storm water. It replaces a 1.5-mile stretch of levee from the Calistoga Bridge to the High Cedars Golf Club.

The $18 million project gives more space for the river to move, offers more salmon habitat and helps protect private property by allowing the river room to swell and naturally rid itself of large debris.

The new flood protection system was tested in November when the Puyallup River rose to its fourth highest level since 1962 but did not flood as it historically would have.

Record flows along that stretch of the river are 21,000 cfs, Fantello said. The Weather Service shows the Puyallup has reached 16,000 cfs already this year.

Flood control workers will continue to monitor the river regardless of where the flood warning is set, but the county could save money if it does not have to mobilize as quickly.

Raising the trigger for the minor flood warning will delay the opening of the county emergency alert system and not send emergency personnel out to knock on doors or do reconnaissance before it’s necessary.

“You will see a lot less talked about the Puyallup River now,” Bower said. “Good riddance to that level.”

  Comments