Clean-Up and Repair of Transportation Infastructure, Montecito Debris Flow, Januiary 2018

Location

Montecito, California

City or County Responsible for Project

Santa Barbara County

Category

Safety or Intelligent Transportation System Projects

Author

Bill Tracy

Organization

Department of Public Works, County of Santa Barbara

Address

4417 Cathedral Oaks Road

Phone

805-681-5694

Project Description

Clean-up and Repair of Transportation Infrastructure Damage Montecito Flood, January 2018 County of Santa Barbara, Department of Public Works January 10, 2019 Clean-up and Repair of Transportation Infrastructure Damage Montecito Flood, January 2018 County of Santa Barbara, Department of Public Works January 10, 2019 Introduction On January 9, 2018 an atmospheric storm of tremendous intensity passed thru Santa Barbara County. A radar image of the storm is presented in Figure 1-Intense Storm located just to the east of Santa Barbara in the community of Montecito. Several cloudbursts began dropping rainfall at 3:34 AM at the rate of one-half inch of rain in 5 minutes, according to the County Flood Control Agency website. This high intensity corresponds to a 200 year rainfall event, according to the National Weather Service. Figure 1-Intense storm pushed into the community of Montecito just east of Santa Barbara. The 9 hour storm dropped a total of 2.1 inches of rain. The run-off was of great size and the flood waters included the entrainment of mud, rocks, wood branches and trees, and forms what is known as a debris flow. Community of Montecito Montecito is located along the coastline against the Santa Ynez Mountains that abruptly rise 3,000 feet above the Pacific Ocean. The transportation infrastructure in Montecito includes: 100 lane miles of maintained roads, 200 culverts, and 20 bridges. The semirural small-town atmosphere along with ocean views and proximity to Los Angeles have made it a haven for Hollywood celebrities and the ultra-wealthy, including Oprah Winfrey, Ellen DeGeneres, Jeff Bridges, Natalie Portman etc. Tremendous Debris Flow January 9, 2018 This particular flood event was exasperated because of high intensity (one-half inch in 15 minutes) rainfall on freshly burned watershed. The debris flow roared down the small and large creeks, overflowed their banks and sent boulder, trees and mud thru residences. Safety of residences was in jeopardy from this event. The County recommended the previous day that all residences in Montecito evacuate because of the pending storm. The largest debris flow flowed down Olive Mill Road which transects US Highway 101 as shown on Figure 2-US Highway 101. The debris crossed over the US Highway 101 in the center of the photo and spilled half of its load onto the freeway below and the remaining half continued down to the Pacific Ocean. Figure 2-US Highway 101 turned into a mud bog as shown in the central portion of this photograph. Throughout Montecito, the flood obliterated concrete landscape walls, wiped away cars and houses that broke apart to further the destruction downstream. The flood progressed the two to three miles as it rushed into the ocean. By the next day 17 citizens were killed along Montecito Creek another four killed in San Ysidro Creek, and another two died in Romero and Hot Springs creeks. Bodies were located more than a mile from their homes. Flood Damage Throughout