Section 401 Water Quality Certification Public Notice
39th and 40th Avenue Channel Emergency Project
The San Francisco Regional Water Quality Control Board is currently reviewing an application for the following project for water quality certification under Section 401 of the Clean Water Act. We encourage public comments on the proposed work, which will be considered in the decision on certification. You may submit comments on this project to the staff member below.
| Project Name: |
39th and 40th Avenue Channel Emergency Project |
| City/County: |
San Mateo, San Mateo County |
| Comment Period: |
10/29/2026 - 11/18/2026 |
| Project Description: |
The City of San Mateo has identified a substantial flood risk within the 39th/40th Avenue Channel due to dense vegetation obstructing stormwater conveyance. The approximately 410-linear-foot concrete-lined drainage channel is located between E. 39th Avenue and E. 40th Avenue, immediately adjacent to residential properties. Overgrown cattails, bulrush, willows, and other vegetation have substantially reduced the channel's available flow capacity, increasing the potential for stormwater backup and overtopping during heavy rainfall. With the 2026–2027 winter season approaching, the potential for severe rainfall amount, intensity, and storm frequency are all heightened due to the current El Niño condition and the anticipation of a very strong winter due to unprecedented temperatures in the Eastern Pacific Ocean due to El Niño. Immediate action is needed to reduce the risk of flooding and protect adjacent residences, roadways, public infrastructure, and public safety. |
| Project Files: |
Contact Staff for files |
| Staff Contact: |
Jackson Fimrite (510) 622-2310 Water Quality Control Board 1515 Clay Street, Ste 1400 Oakland, CA 94612 |
