King County, Corps of Engineers bringing extra flood protection to Pacific
October 7, 2009 · 5:57 PM
More than three-quarters of a mile of temporary flood barriers will soon be built along the White River through the City of Pacific to help protect the residents and their property from flooding this season.
Next week, King County work crews will begin work to place roughly 4,000 linear feet of barriers along the river so that floodwaters can flow into the county’s Pacific City Park. Installing the flood barriers along the White River is expected to be completed before the end of October.
“Allowing the river into undeveloped areas gives floodwaters someplace to go while lowering the risk of flooding in neighborhoods in Pacific and elsewhere along the White River,” said King County Flood Control District Chair Julia Patterson. “It is critical to get these barriers in place before flood season begins.”
“Protecting people and their property is our number-one priority, and installing these advance flood-fighting measures in Pacific helps achieve our mission,” added King County Executive Kurt Triplett.
The U.S. Army Corps of Engineers is providing King County with “Hesco” barriers, which are caged sacks filled with sand. Each of the barrier “cells” measures 3 feet by 3-by-4-feet tall, and are linked with other cells to form solid wall against floodwaters.
These flood barriers have been used successfully in flood prone areas of the country, and are also being deployed along stretches of the Green River in King County.
The City of Pacific was flooded in January 2009 by water releases from the Corps’ Mud Mountain Dam on the White River.
The rate of release from the dam was not unusually large. Based on past water releases at a similar level less than three months earlier, only minor flooding in non-residential areas of Pacific should have occurred.
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 in January 2009 compared with those taken in November 2008 indicate an approximate 30 percent loss of channel capacity at the gage location.
The Corps is working with King and Pierce counties, the City of Pacific and other communities on the White River to improve the flood notification and communication procedures. All agencies are encouraging citizens to be personally prepared for winter storms.