Since OneShoreline was established in January 2020, “atmospheric river” storms have resulted in substantial flooding along many creeks throughout San Mateo County. Intense rainfall and extreme tides/storm surge, coupled with a lack of creek flow capacity, were leading causes of this flooding and removing built-up debris in creeks can help reduce flood risks today and in the future.
Removing debris under countywide permits from state and federal environmental regulatory agencies is more efficient than working on one creek at a time under separate permits for each creek. Thus, immediately following widespread flooding in the winter of 2022–23, OneShoreline began work to secure 5-year permits to remove debris from four of our tidally influenced, most flood-prone creeks within six cities and an unincorporate County area.
The cumulative permanent riparian impact of this in-channel work in all four creeks will be just under 1,100 square feet, but the permitting of this work is expensive — thus far, permitting has cost $525,000 in taxpayer dollars. And it takes time to secure the required permits.
In the early fall of 2025, OneShoreline secured required permits to complete targeted sediment removal at locations on San Bruno Creek, Cordilleras Creek, and Atherton Channel. Under these permits, in October 2025, OneShoreline took action in San Bruno Creek consistent with its flood protection responsibilities. Work under these permits by cities and/or transportation agencies in Cordilleras Creek and in Atherton Channel can occur starting in June 2026. Finally, debris removal work at two flood-prone locations in Belmont Creek has conditional approvals from three agencies pending permit approval by the Bay Conservation and Development Commission (BCDC), which is expected in May 2026.
