Belmont Creek at Harbor Blvd at Old County Road
Future / Actual / Minor
OWP 2.0 WWA Modal Title
01/11/2021, 10:04 PM UTC through 01/11/2021, 10:04 PM UTC
Sender
Sent
- Upstream gauge unavailableDownstream gauge unavailableWarning: no valid ratings curve available. Transformations to and from FEET/CFS/KCFS will not happen.No secondary data available. Transformations for Flow data and a secondary Y axis cannot be made at this time.
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Observed (OBS) 06/25/2025 4:08 PM PDTCATEGORY STAGE 
Major Flooding 5.2 ft Moderate Flooding 4.5 ft Minor Flooding 4.1 ft Reliability of the Forecast:
NOTE: Graphical forecasts are not available during times of high water, forecast crest information can be found in the local WFO web page.
National Water Model Hydrograph
Official NWS streamflow forecasts are produced by NWS hydrologic forecasters for river gauge locations using hydrologic models which are calibrated to that location. This process considers additional guidance and information, including local expertise and experience, to produce the best forecast possible. The NWM output provides supplemental guidance to NWS forecasters and should not be considered an official NWS river forecast.
Flood Impacts
- 5.2 - Major Flooding. CalTrain culvert upstream of Old County Road at full capacity, likely backwatered upstream. Most roadways and businesses in the vicinity of the gauge flooded and impassable. Lower elevation industry and businesses along Old County Road flooded, with the Harbor Blvd/Old County Road intersection under several feet of water. Belmont Creek above channel capacity downstream of Old County Road.
- 4.5 - Moderate Flooding. Storm drain outfall into Belmont Creek on either side of Old County Road completely backwatered, causing street flooding on Old County Road south of Harbor Boulevard. Harbor Boulevard underpass beneath CalTrain rail line also likely flooded. Culvert beneath Old County Road submerged and backwatered. NWS will issue Flash Flood Warning, if not yet already issued.
- 4.1 - Minor Flooding. Water level is approximately 2 feet below lowest storm drain inlet on Old County Road. Storm drains on both side of Old County Road that outfall into Belmont Creek are already backwatered by 2 to 3 feet. NWS will issue an Urban/Small Stream Flood Advisory, if not yet already issued.
Gauge Location
Gauge Photos
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Probability Information
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Collaborative Agencies
The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.