Regional Water Quality Control Board, Region 1 (North Coast), Santa Rosa
Repair Culvert Near Benbow Project
NOE - Notice of Exemption
As a result the series of storms in the winter of 2017, a series of issues related to over-saturation occurred at post mile (PM) 6.03 and PM 7.3 on State Route (SR) 101. At PM 6.03, a sinkhole surface in the shoulder of the northbound (NB) lane above a 54-inch corrugated steel pipe (CSP) culvert. Large voids were visible around the culvert and extended beneath the two NB lanes to the centerline of SR 101. Given the presence of these voids and the sink within the NB #2 lane, Caltrans Maintenance immediately set up a closure of both NB lanes and requested assistance as the situation was beyond their ability to repair. At PM 7.3, excessive saturation at the top of the slope resulted in landslide deposition of debris onto the roadway, requiring closure of the NB #1 lane. The roadway remains under traffic control given the roadway distress and associated lane closures. With forecasts of continued wet weather, repairs are necessary to prevent additional loss of the travel way.
Specific actions necessary to prevent or mitigate an emergency. This does not include long-term projects undertaken for the purpose of preventing or mitigating a situation that has a low probability of occurrence in the short-term.