Exposed hillsides still at risk when it rains
By Ann McCreary
Ron and Cheryl Race are digging out again from a flash flood that deposited mud and debris at their Texas Creek property for the second time in less than three months.
The flooding, which also spilled over Highway 153 at Leecher Creek near Carlton, is a legacy of last summer’s Carlton Complex Fire, which destroyed vegetation in watersheds throughout the Methow Valley. Those exposed hillsides are expected to pose a risk of flooding, erosion and slides for several more years, until new vegetation stabilizes them.
An isolated storm late Saturday afternoon (Aug. 15) turned Texas Creek, normally a small stream that flows in front of the Race home, into a deluge that grew to about 30 feet wide and “took out about 2 feet of earth” in an area that Ron Race had recently reseeded after a flood on May 28 destroyed landscaping and threatened the house, Race said.
A flood diversion dike and culvert were installed earlier this summer at the Race home through a federal flood prevention program. A wall of concrete ecology blocks was also erected in front of the house to protect it from future flooding.
The diversion structure “did exactly what it was supposed to do,” pushing the water away from the house and directing it across the yard, Race said. “I felt the house was safe.”
The isolated storm also sent water and debris across Highway 153 at Leecher Creek — the same location that flooded after thunderstorms last summer and caused severe damage to the roadway and a nearby home.
Back to drawing board
The most recent flooding has engineers from the Washington State Department of Transportation (WSDOT) going back to the drawing board to determine what needs to be done to prevent future floods at that location, said Don Becker, WSDOT maintenance supervisor in Twisp.
“The engineers are trying to figure out what to do … whether we need to enlarge the culvert a bit plus do some work up the creek, like a diversion dam that could collect some sediment up above,” Becker said.
WSDOT installed a 4-foot diameter culvert under the highway to carry future runoff from the creek — normally a trickle of water — after it flooded following thunderstorms last August. That culvert became plugged during a storm last December, flooding the highway again, so WSDOT crews enlarged a settling pond in front of the culvert designed to catch debris.
“Engineers thought by going with a 48-inch culvert it would be more than sufficient,” Becker said. “Maybe 10 years from now it will be sufficient, but it’s going to take up to three to four years to get enough growth [on burned hillsides] to stabilize the soil.”
WSDOT crews made temporary repairs on Saturday to the driveway of a home about 300 yards upstream from the highway. The driveway washed out when a culvert got plugged and the residents were unable to drive out.
Crews were continuing this week to clear debris from the settling pond by the culvert and from ditches along the roadway that carried the runoff. Becker said he expected to meet with engineers next week to discuss possible solutions to the flooding problem.
The storm that caused the flooding appears to have been a localized storm cell, Becker said, because other nearby drainages that flooded after last summer’s thunderstorms — including Benson and Canyon creeks — carried almost no additional water.
A rain gauge at Leecher Mountain, west of Leecher Creek and Texas Creek, recorded .75 inches of rain in a one-hour period beginning at approximately 4:25 p.m. on Aug. 15, said Craig Nelson of the Okanogan Conservation District. A total of .88 inches fell during the ensuing 24 hours.
Cheryl Race was outside the house at about 6 p.m. Saturday when she heard what sounded like wind in trees around the house — but the leaves and branches weren’t moving, Ron Race said.
“When she looked up the creek it was the mudflow coming through the trees,” he said. “It filled our entire culvert up, which is a 3-foot-wide culvert.”
After the last floods, Race constructed a temporary bridge out of metal grating and concrete ecology blocks and elevated about 5 feet over the creek in front of his house. On Saturday, he and Cheryl used the bridge to cross over the flooded yard to a shop and garage located across from the house on higher ground, and they called 911.
“The reason I built this bridge was for this — as a temporary structure to get over the creek,” he said.
Race said last weekend’s flood was not as severe as the one in May, during which the creek swelled to more than 60 feet wide and reached depths of almost 6 feet in places.
He planned to try to hose the mud, pine needles and other debris off his yard. “I’ll have to do some backhoe work to fill in where the water ate away” lawn and dirt, he said.
“The grass was the only thing that was able to withstand the flood,” Race said. “If they’re saying we’re going to have this [flood risk] for three to five years, my only hope to prevent land erosion is planting grass.”
The Races received help in repairing damage to their property earlier this summer from volunteer groups brought in by the Carlton Complex Long Term Recovery Group. They met again with a disaster case manager on Monday to see if there might be some additional assistance to help with the latest incident.