|
Getting your Trinity Audio player ready...
|
PRESS RELEASE. From OneShoreline CEO, Len Materman, on July 11th, 2025. Interactive Flood Early Warning System map for San Mateo County.
San Mateo, CA — The tragedy unfolding in the Texas Hill Country over the past week underscores the
urgent need for effective early warning systems to save lives in the event of catastrophic flooding. Through its countywide Flood Early Warning System (OneShoreline.org/flood-warning), the San Mateo County Flood and Sea Level Rise Resiliency District, also known as OneShoreline, is taking proactive steps to alert people to, and reduce the impact of, extreme weather events.
This system is an integrated network of stream, precipitation, and tide gauges that provide two major benefits to people and property in our region:
1) during storms, it alerts local agencies and the public to anticipated flooding, and
2) the data it collects informs the planning of projects to reduce flooding.
On July 9, 2025 OneShoreline installed facilities at Skylawn Memorial Park along SR 92 to enable an extension of its Flood Early Warning System to parts of the unincorporated County and the City of Half Moon Bay. With the new communications infrastructure at Skylawn and the future addition of a stream
gauge on Pilarcitos Creek, emergency managers and public safety officials will be better able to predict and respond to extreme weather events such as the intense storms of late December 2022 and early January 2023 that flooded a Half Moon Bay neighborhood and electrical facilities of the Coastside’s wastewater treatment plant.
Earlier this year, OneShoreline installed early warning facilities atop San Bruno Mountain (photo at right) and a stream gauge at the Green Hills Country Club golf course to provide advance warning to residents and businesses in Millbrae.
In addition to the gauges described above, OneShoreline’s Flood Early Warning System is connected to weather and stream monitoring stations operated by the federal government and regional collaborations. OneShoreline is working with additional cities to bring the benefits of this system to other neighborhoods that flooded during atmospheric rivers in 2021, 2022, and 2023.
The System’s public website includes a map with the locations of most of the 32 stream, precipitation, and tide gauges we rely on, as well as dashboards with easily digestible real time information for four flood-prone waterways: Atherton Channel, Belmont Creek, San Bruno Creek, and Colma Creek, for
which automated alerts are sent when two thresholds based on modeling and experience are triggered: 75% of downstream creek capacity (flood watch) and 100% of downstream capacity (flood warning).
“OneShoreline’s Flood Early Warning System has demonstrated the benefits of coordinating flood alerts,”
said Half Moon Bay Vice Mayor Debbie Ruddock, who serves as the Chair of OneShoreline’s Board of
Directors. “Given what we’ve seen in Texas this past week and throughout our county in recent years, it
makes perfect sense to expand the capacity of this system to notify our emergency response personnel and the public during major storms, especially in Coastside communities.”
“As OneShoreline, San Mateo County, and our cities work on projects to build long-term resilience to the
impacts of climate change, we must also reduce the impacts of today’s events,” said San Mateo County
Supervisor Lisa Gauthier, who serves as the Vice Chair of OneShoreline’s Board of Directors. “One way to
protect people and property is to give them, and the emergency responders who protect them, all of the
timely information we can. OneShoreline’s Flood Early Warning System aims to do just that.”
Funding to build, operate, maintain, and expand the System is provided by the California Department of
Water Resources, San Mateo County, and OneShoreline operating funds.
About OneShoreline
The expansion of the Flood Early Warning System is a critical part of OneShoreline’s mission to build
climate change resilience throughout San Mateo County. Established by State legislation in 2020,
OneShoreline is the first independent government agency in California to work across jurisdictional
boundaries and with a wide range of stakeholders to plan for, and build resilience to, the water-related
impacts climate change.
In addition to its work related to the advance warning of flood threats, OneShoreline provides standardized resources so that local land use policies and project reviews account for climate change-fueled increases in flooding, sea level rise, and groundwater rise (OneShoreline.org/planning-guidance). Such land use planning with future conditions in mind enables new private developments and public infrastructure to support and align with community-wide resilience projects led by OneShoreline or other agencies.
More on OneShoreline on Coastside Buzz
OneShoreline is governed by a seven-member Board of Directors. Two board members serve on the San Mateo County Board of Supervisors, and five serve on different city or town councils that govern municipalities throughout the county.
Author: mdrag
x
