Towne Pass Flood Emergency Repair

Towne Pass Flood Emergency Repair

Tropical Storm Kay produced heavy rain in and around Death Valley National Park between Sunday, September 11, 2022, and Tuesday, September 13, 2022. A rain event on Sunday, September 11th damaged SR 190 in and around Towne Pass between PM 60 and 72. A rain event on Tuesday, September 13th damaged the portion of SR 190 between PM 18 and 41. The project area is located within the boundaries of Death Valley National Park (DVNP) and Bureau of Land Management (BLM) lands. The project occurs within the Caltrans easement within these federally owned lands with the exception of two work locations within DVNP on the west side of Towne Pass (post miles 64.20 and 65.20). In total, the flash flooding damaged State Route 190 intermittently in about 30 locations. About 4,000’ of paved shoulder and lane was damaged by being undercut or completely removed. Several culverts were dislodged from their bedding and are no longer functional. Debris, up to 6 feet in depth, was deposited on the roadway. Drainage appurtenances including headwalls, wingwalls, and paved aprons were under mined or washed away. Earthen berms and flood control dikes were eroded and breached. Drainage courses need to be graded to remove deposited material and to restore hydraulic function. Clogged or buried culverts need to be cleared and flushed. Rock slope protection needs to be replaced. Rock and flood debris on the roadway will be removed and disposed of. Damaged pavement will be removed and disposed of. Paved lanes and shoulders will be restored. Highway embankments will be re-established using native material deposited by the flooding event, reducing potential for importation of invasive species. Debris deposited in culverts will be removed, and culverts will be reset. Drainage appurtenances including headwalls, wingwalls, paved aprons, and rock slope protection will be reconstructed. Flood debris will be removed from the channels and flowlines will be re-established to restore hydraulic function directing flows to culverts and at-grade crossings. Earthen berms will be reconstructed to direct water into drainage structures. Erosional gullies will be filled. Traffic control will be provided once a safe public lane can be provided and managed. The project has 5 proposed staging areas. All staging areas and staging activities (equipment storage, refueling, vehicle maintenance, stockpiles, etc.) will be located over 100’ from any jurisdictional resource.

Inyo

Southern California

Inyo