One valley city understands how devastating a flood can be.
And today it is better prepared because of it.
Unlike neighboring communities, Pacific already has waded through insidious, costly flooding.
Last January, an expected but familiar culprit, the White River, spilled floodwaters over its swollen banks into the small city of roughly 6,000 people.
The flood went on to damage more than 110 homes and 10 businesses, leaving behind $15 million in losses in its wake. At one point, a fifth of the city’s residents – about 1,200 – had to evacuate their homes and apartments as floodwaters reached 10-feet high.
While everybody learned hard lessons from last winter’s flooding, city officials and residents hope to be better prepared for this storm season. They are bracing for the worst, yet hoping for the best.
While the flood-prone Green River is of little concern to the community that sits in the shadows of Auburn, it is indeed wary of the turbulent White River, of which a mile-long section runs through the city.
“We don’t expect flooding from the White (River) but if we do, we want to be prepared,” said Mayor Richard Hildreth. “Just let me ask, ‘If people are prepared and it doesn’t happen, will they be disappointed?’ ”
Hildreth, city and public safety officials have stepped up efforts to improve levee conditions and taken the necessary steps to better monitor river conditions.
More than three-quarters of a mile of temporary flood barriers was built along the river through the city to help protect residents and property, including the White River Estates.
King County work crews placed roughly 4,000 linear feet of barriers along the river so that floodwaters can flow into the county’s Pacific City Park.
Volunteer work parties packed and stacked sandbags along the park’s perimeter.
And this week, city staff orchestrated Pierce County efforts to reinforce the White River levee along Butte Avenue. The multi-agency project included support from the U.S. Army Corps of Engineers and Icon Construction & Development.
Work-release crews from Pierce County District Court Probation were busy filling 50-pound sacks with sand and positioning them in a pre-staged area along the west side of the river.
The crews will be working throughout the week to help bolster the levee setback area in unincorporated Pierce County that separates the river from residential and commercial property. The crews are working under the direction of Pierce County District Court, Public Works and Utilities, the Department of Emergency Management, and the City of Pacific.
Crews are expected to fill 20,000 sandbags and have them ready along the 250-300-foot-long berm area along the river.
“They put in a lot of hard work, but in the end of the day they get a sense of accomplishment and a sense of knowing they helped the community,” said Greg Crawford, work crew supervisor.
Earlier, the county filled and city volunteers placed 15,000 sandbags along the King-Pierce County line.
“I’m encouraged by two things,” Hildreth said of the efforts. “One, the intergovernmental cooperation. Everybody has worked together. And secondly, we have been proactive. This is the first time in the city’s history and the first time in the state’s history that we have been proactive in the mitigation … to plan for such an extended event.”
Improvements made
The improved levee setbacks will brace Pacific for any possible flood, officials said.
“Allowing the river into undeveloped areas gives floodwaters some place to go while lowering the risk of flooding in neighborhoods in Pacific and elsewhere along the White River,” said Julia Patterson, King County Flood Control District chairperson. “It is critical to get these barriers in place before flood season begins.”
While the barriers are a temporary measure, other mitigation projects are a year away, Hildreth estimates. The city also hopes to lead efforts to scalp sections of the river channel free of debris, sand and gravel deposits as soon as possible.
“We need to established a maintenance program,” Hildreth added.
Hildreth pointed out that the suggested projects, environmentally sensitive or not, will be contingent on permits.
Last January, the Corps of Engineers released water over Mud Mountain Dam, built upstream from Enumclaw to control flooding on the Puyallup and White rivers, when the reservoir was near capacity. The release was necessary to ease stress on the earthen dam and to make room for incoming water over the next few days.
The water volume – 11,700 cubic feet per second at its peak during the storm – was the same volume released over the dam in November 2006, when the city last flooded, a Corps spokesman said. But the ’06 flood was considered “nuisance flooding,” not the widespread inundation in January that put the city’s main park and White River Estates under as much as 10 feet of water.
Corps officials said they followed information that suggested that nuisance flooding can start up to 12,000 (cubic feet per second) release, “but nothing significant.”
Still, the waters came.
According to an after-action report by the Corps, the apparent cause of the increased flooding was a substantial change in channel capacity. U.S. Geological Survey channel measurements at the river gage location last January compared with those taken in November 2008 indicate an approximate 30 percent loss of channel capacity at the gage location.
Hildreth estimated the river’s channel hasn’t been dredged in 20 years. Until a scalping effort can be approved, that worry still exists, he said.
“Unlike our neighbors to the north (Auburn, Kent, Tukwila) we are not concerned about the Howard Hanson Dam,” Hildreth said. “Our concern is caused by the enormous amount of debris that settled in Pacific during last January’s flood event.
“The capacity for the White River has been reduced from 10,000 cfs to 5,100 cfs,” Hildreth added. “In 2008, we had more than 30 days with flows above that point.”
Well aware of the issues downstream, Corps officials maintain that the dam is sound and ready to handle the demands of a wet season. While repairs go on at nearby Howard Hanson Dam, it will be businesses as usual at Mud Mountain Dam.
Many of the issues Hanson Dam is facing, Mud Mountain Dam has repaired, including the installation of a concrete cutoff wall more than a decade ago.
“Mud Mountain Dam is completely fine. Everything is working well,” said Patricia Graesser, public affairs chief for the Seattle District, Corps of Engineers. “We’ve been working well with the USGS (U.S. Geological Survey) and King County to assess the channel capacity of the White River down by Pacific.”
County officials, meanwhile, was asked to lead the way for appropriate levee setbacks. Such a setback, especially along the eastside of the river, would double the capacity of the river as well as “create a great salmon habitat,” Hildreth said.
The river’s existing levees appear to be in good shape, Hildreth said. In the aftermath of last winter’s flooding, the Corps strengthened and raised the rock wall along the river.
“Most of the critical areas have been armored with concrete and asphalt pavement to protect the levee from washing out,” Hildreth said.
Spotters in place
In addition, Hildreth said that Corps, county and city officials are working together to improve communications in monitoring river conditions. While the Corps accepted blame for releasing too much water from a full dam, there were communication breakdowns among emergency personnel at the local, regional and federal levels, a Corps report said.
The Corps and county intend to train staff and volunteers to monitor the river level more effectively. The Corps said it would explore adding gauges and other technology that would allow it to better determine river levels.
Levee patrols are under way along the Green and White rivers.
In addition, a call-down checklist among officials will be updated and practiced.
The city and its residents, meanwhile, are asked to do their part. The city will have pre-staged sandbags handy and available to businesses and property owners, Hildreth said.
Business, home and property owners also are urged to immediately buy flood insurance.
Hildreth said there is plenty of blame to go around for the messy flood of ’09. But he maintains all sides will learn from the mistakes and prevent another episode from happening.
