State Water Board previews redesigned Safe2Swim map and BeachWatch data changes

Michelle Tang, research data specialist in the State Water Board’s Office of Information Management and Analysis, demonstrated a prototype of a redesigned Safe2Swim public map aimed at making beach bacteria monitoring data easier to find and interpret.

Tang said the map combines monitoring from BeachWatch, SEED/CDN and a Central Valley E. coli map in a single interface that uses recent single-sample results plus a calculated six-week geometric mean to assign site statuses: “blue for low risk, orange for use caution, and gray for not enough data,” she said. The dashboard includes a site panel with coordinates, last sample date and graphs that show status history and the underlying data points.

The prototype also implements three quality-assurance objectives for BeachWatch: new bulk-upload data fields (for example, sample and lab agency codes, lab batch analysis date, detected-above‑MDL flags and QA codes), controlled-vocabulary lists to prevent inconsistent values, and automated data validation that checks for duplicates, blanks and valid units and station codes. Tang said IT will test the system in November and December and agencies will receive the new bulk-upload template this month for review.

Asked how frequently the map refreshes, Tang said the goal is a daily refresh on workdays but that some IT-related processes may cause occasional lag: “right now, it’s being updated daily, so kind of every workday,” she said. Agencies pressed about including posted advisories and closures; Tang and other staff said adding real-time advisory and closure feeds is a longer-term goal but requires additional data coordination with counties.

State Water Board staff emphasized coordination: the new upload template is being designed to align with CDN 2 (the next-generation SEED/CDN schema) so BeachWatch will be compatible with planned statewide data standards. Staff also said the changes will be reflected in upcoming grant-agreement language to reduce duplicative quality-assurance documentation for local agencies.

The state invited feedback from county health departments and local agencies on the map’s public messaging and whether additional datasets (for example, San Francisco Public Utilities Commission beach data) should be integrated. Tang said the office plans office-hour sessions in January to walk agencies through the new upload process if needed.

The prototype remains in testing; Tang said she expects a potential public go-live in late winter or early spring, subject to management review and agency feedback.