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Web Portal Changes: In Spring 2024, the Advanced Hydrologic Prediction Service (AHPS) hosted at https://water.weather.gov will be replaced by the National Water Prediction Service (NWPS) at a repurposed https://water.noaa.gov. A preview of NWPS is available here, where you can see your station hydrograph by replacing SSSSS with the station 5-character id: https://preview.water.noaa.gov/gauges/SSSSS.

Flood Inundation Mapping: Experimental real-time flood Inundation mapping services for 10% of the United States are now available via the NWS Map Viewer. Additional products and geospatial services depicting River Forecast Center and National Water Model forecasts continue to be accessible as described in the StoryMap here.

Please visit https://www.weather.gov/owp/operations for more information.



Hydrograph River at a Glance Download
Willow Brook at Stony Point Road Stage (ft)Observed: 31 ft at 4:00AM Mar 14, 2024Observed: 31 ft at 5:00AM Mar 14, 2024Observed: 31 ft at 6:00AM Mar 14, 2024Observed: 31 ft at 8:00AM Mar 14, 2024Observed: 31 ft at 9:00AM Mar 14, 2024Observed: 31 ft at 10:00AM Mar 14, 2024Observed: 31 ft at 11:00AM Mar 14, 2024Observed: 31 ft at 12:00PM Mar 14, 2024Highest Observation: 31.01 ft at 1:00PM Mar 14, 2024Observed: 31 ft at 2:00PM Mar 14, 2024Observed: 31 ft at 3:00PM Mar 14, 2024Observed: 31 ft at 5:00PM Mar 14, 2024Observed: 31 ft at 6:00PM Mar 14, 2024Observed: 31 ft at 7:00PM Mar 14, 2024Observed: 31 ft at 8:00PM Mar 14, 2024Observed: 31 ft at 9:00PM Mar 14, 2024Observed: 31 ft at 10:00PM Mar 14, 2024Observed: 31 ft at 11:00PM Mar 14, 2024Observed: 31 ft at 12:00AM Mar 15, 2024Observed: 31 ft at 1:00AM Mar 15, 2024Observed: 31 ft at 2:00AM Mar 15, 2024Observed: 31 ft at 4:00AM Mar 15, 2024Observed: 31 ft at 5:00AM Mar 15, 2024Observed: 31 ft at 6:00AM Mar 15, 2024Observed: 31 ft at 7:00AM Mar 15, 2024Observed: 31 ft at 8:00AM Mar 15, 2024Observed: 31 ft at 9:00AM Mar 15, 2024Observed: 31 ft at 10:00AM Mar 15, 2024Observed: 31 ft at 11:00AM Mar 15, 2024Observed: 31 ft at 12:00PM Mar 15, 2024Highest Observation: 31.01 ft at 2:00PM Mar 15, 2024Observed: 31 ft at 4:00PM Mar 15, 2024Observed: 31 ft at 5:00PM Mar 15, 2024Observed: 31 ft at 6:00PM Mar 15, 2024Observed: 31 ft at 7:00PM Mar 15, 2024Observed: 31 ft at 8:00PM Mar 15, 2024Observed: 31 ft at 9:00PM Mar 15, 2024Observed: 31 ft at 10:00PM Mar 15, 2024Observed: 31 ft at 11:00PM Mar 15, 2024Observed: 31 ft at 12:00AM Mar 16, 2024Observed: 31 ft at 1:00AM Mar 16, 2024Observed: 31 ft at 2:00AM Mar 16, 2024Observed: 31 ft at 3:00AM Mar 16, 2024Observed: 31 ft at 4:00AM Mar 16, 2024Observed: 31 ft at 5:00AM Mar 16, 2024Observed: 31 ft at 7:00AM Mar 16, 2024Observed: 31 ft at 8:00AM Mar 16, 2024Observed: 31 ft at 10:00AM Mar 16, 2024Observed: 31 ft at 11:00AM Mar 16, 2024Observed: 31 ft at 12:00PM Mar 16, 2024Observed: 31 ft at 1:00PM Mar 16, 2024Highest Observation: 31.01 ft at 2:00PM Mar 16, 2024Observed: 31 ft at 3:00PM Mar 16, 2024Observed: 31 ft at 4:00PM Mar 16, 2024Observed: 31 ft at 5:00PM Mar 16, 2024Observed: 31 ft at 6:00PM Mar 16, 2024Observed: 31 ft at 7:00PM Mar 16, 2024Observed: 31 ft at 9:00PM Mar 16, 2024Observed: 31 ft at 10:00PM Mar 16, 2024Observed: 31 ft at 11:00PM Mar 16, 2024Observed: 31 ft at 12:00AM Mar 17, 2024Observed: 31 ft at 1:00AM Mar 17, 2024Observed: 31 ft at 2:00AM Mar 17, 2024Observed: 31 ft at 3:00AM Mar 17, 2024Observed: 31 ft at 4:00AM Mar 17, 2024Observed: 31 ft at 5:00AM Mar 17, 2024Observed: 31 ft at 6:00AM Mar 17, 2024Observed: 31 ft at 8:00AM Mar 17, 2024Observed: 31 ft at 10:00AM Mar 17, 2024Observed: 31 ft at 11:00AM Mar 17, 2024Observed: 31 ft at 12:00PM Mar 17, 2024Observed: 31 ft at 1:00PM Mar 17, 2024Observed: 31 ft at 2:00PM Mar 17, 2024Observed: 31 ft at 3:00PM Mar 17, 2024Observed: 31 ft at 4:00PM Mar 17, 2024Observed: 31 ft at 5:00PM Mar 17, 2024Observed: 31 ft at 6:00PM Mar 17, 2024Observed: 31 ft at 7:00PM Mar 17, 2024Observed: 31 ft at 8:00PM Mar 17, 2024Observed: 31 ft at 9:00PM Mar 17, 2024Observed: 31 ft at 10:00PM Mar 17, 2024Observed: 31 ft at 11:00PM Mar 17, 2024Observed: 31 ft at 12:00AM Mar 18, 2024Observed: 31 ft at 1:00AM Mar 18, 2024Observed: 31 ft at 2:00AM Mar 18, 2024Observed: 31 ft at 3:00AM Mar 18, 2024Observed: 31 ft at 4:00AM Mar 18, 2024Observed: 31 ft at 5:00AM Mar 18, 2024Observed: 31 ft at 6:00AM Mar 18, 2024Observed: 31 ft at 7:00AM Mar 18, 2024Observed: 31 ft at 8:00AM Mar 18, 2024Observed: 31 ft at 9:00AM Mar 18, 2024Observed: 31 ft at 10:00AM Mar 18, 2024Observed: 31 ft at 12:00PM Mar 18, 2024Observed: 31 ft at 2:00PM Mar 18, 2024Observed: 31 ft at 3:00PM Mar 18, 2024Observed: 31 ft at 5:00PM Mar 18, 2024Observed: 31 ft at 6:00PM Mar 18, 2024Observed: 31 ft at 7:00PM Mar 18, 2024Observed: 31 ft at 8:00PM Mar 18, 2024Observed: 31 ft at 9:00PM Mar 18, 2024Observed: 31 ft at 10:00PM Mar 18, 2024Observed: 31 ft at 11:00PM Mar 18, 2024PTVC1(plotting HGIRR) Graph Created (3:15AM Mar 19, 2024)ObservedLatest observed value: 31 ft at 11:00 PM PDT 18-Mar-2024. Flood Stage is 37.7 ft
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About this graph
Tabular Data (UTC)
Tabular Data (PDT)
XML Data
RSS Files
Datum: Not Available
Metadata
NOTE: Graphical forecasts are not available for the Willow Brook at Stony Point Road. During times of high water, forecast crest information can be found in the text products.
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Flood Categories (in feet)
Major Flood Stage: 40.4
Moderate Flood Stage: 39
Flood Stage: 37.7
Action Stage: 33.7
Low Stage (in feet): -9999

Historic Crests
Currently none available.

Recent Crests
Currently none available.

Low Water Records
Currently none available.
Zoom Level:16
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Gauge LocationGauge Map Marker
Disclaimer
Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.
Flood Impacts & Photos Collapse
If you notice any errors in the below information, please contact our Webmaster
40.4 Major Flood Stage. Water reaches bridge deck height.
39.3 Water reaches bottom of bridge and soffit.
39.1 Stony Point Road at Petaluma Blvd. flooded.
39 Moderate Flood Stage. Water is above bankfull over north side of levy (pumpkin patch).
38.9 Water starts flowing across Stony Point Road south of Leisure Lake and begins flowing towards Highway 101 around/into the intersection of Petaluma Boulevard North and Stony Point Road. Water begins flowing across Rainsville Road but passable as an emergency exit for Leisure Lake (City of Petaluma Policies and Procedures).
38.7 Stony Point Road south of Leisure Lake flooded and should be closed.
37.4 Minor Flood Stage. NWS issues a Flash Flood Warning if not already issued. Waters reach edge of Stony Point Road south-bound lane.
34.7 City of Petaluma Manager notified. City of Petaluma evaluates need to open Emergency Operations Center.
33.7 Action Stage. NWS and City of Petaluma monitoring gage readings closely. City of Petaluma Fire Chief, Watch Commander, and Water Resources and Conservation Director notified.
About This Location Collapse

Latitude: 38.274444° N, Longitude: 122.676944° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 37.7 ft Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps
Vertical Datum Elevation
(gauge height = 0)
Elevation
(gauge height = flood stage)
Elevation information source
NAVD88 Not Available Not Available Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps
NGVD 29 Not Available Not Available Older USGS topographic maps, NGVD29 benchmarks
MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks
Other Not Available Not Available  
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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.
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Page last modified: 2-Nov-2020 7:27 PM
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