Earlier this year (January 2023), the Bay Area experienced flooding from numerous back-to-back storm systems that included heavy rain and strong wind. Throughout Livermore, damages of varying degrees called for swift action. Public safety and public works crews worked diligently to prepare for and respond to the storms. The City’s emergency operations team, in coordination and collaboration with other agencies such as Zone 7, LARPD, and federal and state regulatory and funding agencies, was able to maintain operations throughout the City and successfully respond.  

It was not long ago in 2017 that a previous set of inclement weather events led to a series of improvements by the City that we are happy to report withstood this year’s storm events. Here are just a few examples of improvements the City conducted after the 2017 flooding events and how they performed this year: 

Cottonwood Creek: 

The 2017 storm events caused channel and bank erosion at Cottonwood Creek. A large scour hole formed at the water pipeline crossing where the 22-inch steel encasement protecting the water line was fully exposed. In November 2017, the City conducted emergency repairs to protect the exposed pipeline from failure. Gravel was packed around pipe followed by several feet of rock riprap. These repairs withstood this year’s storm events. The rock riprap is intact and the pipeline is protected. 

Collier Canyon Culvert: 

During the February 2017 storm event in the City, a large amount of sediment and debris was washed down Collier Canyon Creek causing blockages at the culverts upstream and downstream of the Collier Canyon Rd. culverts. These blockages caused water to overtop the headwalls and travel overland along Collier Canyon Rd. The Collier Canyon Culvert project is anticipated to begin construction soon, which will install two weir structures, two flood walls, and an emergency overflow drainpipe to help convey flow upstream of Collier Canyon Road, which in turn will minimize sediment and debris from entering the culverts and reducing the culvert capacity. This site sustained only minor damage in the 2023 storm events. 

Trails and creek banks along Arroyo Mocho: 

Many sites were damaged during the storms of 2017. Bank repair was completed on several areas of the Arroyo Mocho along the Mocho trail including segments near Robertson Park, Holmes St. Bridge, Concanon Blvd., Creek Rd., Granada Native Gardens, and Stanley Blvd. Most of the bank repair work remained intact after the 2023 storms. A few areas such as Arroyo Mocho at Concannon Blvd. and Stanley Blvd. suffered damages from the January 2023 storms and will be repaired throughout the summer and next year. 

Springtown: 

In September-October 2022, the City performed stream maintenance work on the Arroyo Las Positas near the Heather Lane culverts. This area experienced flooding issues in the past where water built up at Quince Ct. Contractors removed sediment and dense vegetation in the creek and performed vegetation management further downstream, limbing up trees and removing cattails to restore the creek’s capacity. This part of the creek performed very well during the 2023 storms and no flooding occurred.