A series of floods around southwest Idaho highways in early September cost hundreds of thousands of dollars in maintenance funds, took thousands of worker-hours and required the removal of millions of pounds of debris.
The most significant was the flood in the Zimmer Creek area a few miles north of Banks. The final tally shows that 10,450 cubic yards of material were removed from the highway in the immediate aftermath of the mudslide and subsequent cleanup the following week. Each cubic yard weighed between 2,500 and 3,000 pounds. That represents at least 26 million pounds of debris hauled away or pushed off the road during the cleanup.
More than 2,000 hours of labor and another 3,000 hours for equipment were used in the effort, requiring $130,000 in personnel costs and equipment rental.
Farther south, in Owyhee County, the rain and runoff flooded Idaho 78 area near Murphy. The culvert, 1.2 miles northwest of Murphy at milepost 27.9, was plugged and buried by silt, rock and debris. The floods of Sept. 4 started on Idaho 45 but did most of the damage on Idaho 78.
ITD crews uncovered and removed material in the culvert that serves Rabbit Creek, on Oct. 1.
“When it was all over, the bottom of the 48-inch culvert was probably six or seven feet below the new surface,” said ITD’s Jeramie Gregory, Marsing maintenance leadworker .
The crew also re-established the channel for the creek.
Those efforts required 500 combined worker and equipment hours and more than $16,000 in equipment and personnel costs. About 120 cubic yards of material were used to rebuild damaged highway shoulders.
“We are starting to see more of the aftermath of these slides. People tend to look at the initial effort to open the roads, but the work put in afterward to restore the areas can be significant,” said David Dansereau, coordinator for Southwest Idaho’s Transportation Asset Management System.