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Hydrograph River at a Glance Download
Willow Brook at Old Redwood Highway Bridge Stage (ft)Observed: 31.54 ft at 9:16PM Sep 19, 2023Observed: 31.54 ft at 10:15PM Sep 19, 2023Observed: 31.54 ft at 11:13PM Sep 19, 2023Observed: 31.54 ft at 12:11AM Sep 20, 2023Observed: 31.54 ft at 1:10AM Sep 20, 2023Observed: 31.54 ft at 2:08AM Sep 20, 2023Observed: 31.54 ft at 3:06AM Sep 20, 2023Observed: 31.54 ft at 4:05AM Sep 20, 2023Observed: 31.57 ft at 5:03AM Sep 20, 2023Observed: 31.54 ft at 6:01AM Sep 20, 2023Observed: 31.54 ft at 7:00AM Sep 20, 2023Observed: 31.54 ft at 7:58AM Sep 20, 2023Observed: 31.54 ft at 8:56AM Sep 20, 2023Observed: 31.54 ft at 9:55AM Sep 20, 2023Observed: 31.54 ft at 10:53AM Sep 20, 2023Observed: 31.54 ft at 11:51AM Sep 20, 2023Observed: 31.54 ft at 12:50PM Sep 20, 2023Observed: 31.54 ft at 1:48PM Sep 20, 2023Observed: 31.54 ft at 2:46PM Sep 20, 2023Observed: 31.57 ft at 3:45PM Sep 20, 2023Observed: 31.54 ft at 4:43PM Sep 20, 2023Observed: 31.54 ft at 5:41PM Sep 20, 2023Observed: 31.57 ft at 6:40PM Sep 20, 2023Observed: 31.54 ft at 7:38PM Sep 20, 2023Observed: 31.54 ft at 8:36PM Sep 20, 2023Observed: 31.54 ft at 9:35PM Sep 20, 2023Observed: 31.54 ft at 10:33PM Sep 20, 2023Observed: 31.54 ft at 11:31PM Sep 20, 2023Observed: 31.54 ft at 12:30AM Sep 21, 2023Observed: 31.54 ft at 1:28AM Sep 21, 2023Observed: 31.54 ft at 2:26AM Sep 21, 2023Observed: 31.54 ft at 3:25AM Sep 21, 2023Observed: 31.57 ft at 4:23AM Sep 21, 2023Observed: 31.54 ft at 5:21AM Sep 21, 2023Observed: 31.54 ft at 6:20AM Sep 21, 2023Observed: 31.54 ft at 7:18AM Sep 21, 2023Observed: 31.54 ft at 8:16AM Sep 21, 2023Observed: 31.54 ft at 9:15AM Sep 21, 2023Observed: 31.54 ft at 10:13AM Sep 21, 2023Observed: 31.54 ft at 11:11AM Sep 21, 2023Observed: 31.57 ft at 12:10PM Sep 21, 2023Observed: 31.54 ft at 1:08PM Sep 21, 2023Observed: 31.54 ft at 2:06PM Sep 21, 2023Observed: 31.54 ft at 3:05PM Sep 21, 2023Observed: 31.54 ft at 4:03PM Sep 21, 2023Observed: 31.57 ft at 5:01PM Sep 21, 2023Observed: 31.54 ft at 6:00PM Sep 21, 2023Observed: 31.54 ft at 6:58PM Sep 21, 2023Observed: 31.54 ft at 7:56PM Sep 21, 2023Observed: 31.54 ft at 8:55PM Sep 21, 2023Observed: 31.54 ft at 9:53PM Sep 21, 2023Observed: 31.54 ft at 10:51PM Sep 21, 2023Observed: 31.54 ft at 11:50PM Sep 21, 2023Observed: 31.54 ft at 12:48AM Sep 22, 2023Observed: 31.54 ft at 1:46AM Sep 22, 2023Observed: 31.54 ft at 2:45AM Sep 22, 2023Observed: 31.54 ft at 3:43AM Sep 22, 2023Observed: 31.54 ft at 4:41AM Sep 22, 2023Observed: 31.54 ft at 5:40AM Sep 22, 2023Observed: 31.54 ft at 6:38AM Sep 22, 2023Observed: 31.54 ft at 7:36AM Sep 22, 2023Observed: 31.57 ft at 8:35AM Sep 22, 2023Observed: 31.54 ft at 9:33AM Sep 22, 2023Observed: 31.54 ft at 10:31AM Sep 22, 2023Observed: 31.54 ft at 11:30AM Sep 22, 2023Observed: 31.57 ft at 12:28PM Sep 22, 2023Observed: 31.57 ft at 1:26PM Sep 22, 2023Observed: 31.54 ft at 2:25PM Sep 22, 2023Observed: 31.57 ft at 3:23PM Sep 22, 2023Observed: 31.54 ft at 4:21PM Sep 22, 2023Observed: 31.54 ft at 5:20PM Sep 22, 2023Observed: 31.57 ft at 6:18PM Sep 22, 2023Observed: 31.57 ft at 7:16PM Sep 22, 2023Observed: 31.57 ft at 8:15PM Sep 22, 2023Observed: 31.54 ft at 9:13PM Sep 22, 2023Observed: 31.54 ft at 10:11PM Sep 22, 2023Observed: 31.54 ft at 11:10PM Sep 22, 2023Observed: 31.54 ft at 12:08AM Sep 23, 2023Observed: 31.54 ft at 1:06AM Sep 23, 2023Observed: 31.54 ft at 2:05AM Sep 23, 2023Observed: 31.54 ft at 3:03AM Sep 23, 2023Observed: 31.54 ft at 4:01AM Sep 23, 2023Observed: 31.54 ft at 5:58AM Sep 23, 2023Observed: 31.57 ft at 6:56AM Sep 23, 2023Observed: 31.54 ft at 7:55AM Sep 23, 2023Observed: 31.57 ft at 8:53AM Sep 23, 2023Observed: 31.54 ft at 9:51AM Sep 23, 2023Observed: 31.52 ft at 10:50AM Sep 23, 2023Observed: 31.54 ft at 11:48AM Sep 23, 2023Observed: 31.54 ft at 12:46PM Sep 23, 2023Observed: 31.57 ft at 1:45PM Sep 23, 2023Observed: 31.54 ft at 2:43PM Sep 23, 2023Observed: 31.57 ft at 3:41PM Sep 23, 2023Observed: 31.54 ft at 4:40PM Sep 23, 2023Observed: 31.54 ft at 5:38PM Sep 23, 2023Observed: 31.54 ft at 6:36PM Sep 23, 2023Observed: 31.54 ft at 7:35PM Sep 23, 2023Observed: 31.54 ft at 8:33PM Sep 23, 2023Observed: 31.54 ft at 9:31PM Sep 23, 2023Observed: 31.54 ft at 10:30PM Sep 23, 2023Observed: 31.54 ft at 11:28PM Sep 23, 2023Observed: 31.54 ft at 12:26AM Sep 24, 2023Highest Observation: 31.59 ft at 1:25AM Sep 24, 2023Observed: 31.54 ft at 2:23AM Sep 24, 2023Observed: 31.54 ft at 3:21AM Sep 24, 2023Observed: 31.54 ft at 4:20AM Sep 24, 2023Observed: 31.54 ft at 5:18AM Sep 24, 2023Observed: 31.57 ft at 6:16AM Sep 24, 2023Observed: 31.54 ft at 7:15AM Sep 24, 2023Observed: 31.54 ft at 8:13AM Sep 24, 2023Observed: 31.54 ft at 9:11AM Sep 24, 2023Observed: 31.54 ft at 10:10AM Sep 24, 2023Observed: 31.54 ft at 11:08AM Sep 24, 2023Observed: 31.54 ft at 12:06PM Sep 24, 2023Observed: 31.57 ft at 1:05PM Sep 24, 2023Observed: 31.54 ft at 2:03PM Sep 24, 2023Observed: 31.54 ft at 3:01PM Sep 24, 2023Observed: 31.54 ft at 4:00PM Sep 24, 2023Observed: 31.54 ft at 4:58PM Sep 24, 2023PTMC1(plotting HGIRR) Graph Created (9:00PM Sep 24, 2023)ObservedLatest observed value: 31.54 ft at 4:58 PM PDT 24-Sep-2023. Flood Stage is 40.7 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 Old Redwood Highway Bridge. 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: 44.3
Moderate Flood Stage: 43
Flood Stage: 40.7
Action Stage: 40.7
Low Stage (in feet): -9999

Historic Crests
Currently none available.

Recent Crests
Currently none available.

Low Water Records
Currently none available.
Zoom Level:14
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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
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44.3 Major Flood Stage. Water level has reached by bottom of the bridge soffit.
43.9 Flood waters flowing down Redwood Way at Old Redwood Highway.
43.2 Water levels are above bankfull and begin flowing through upstream businesses, including passing through the old lumber company's parking lot.
43 Moderate Flood Stage. A local detention basin may begin to release water onto North McDowell Blvd. Ext.
42.3 Water begins to flow across Ely Road at the railroad track near Old Redwood Highway. Holm Road begins to flood and water ponds on North McDowell at the Post Office.
41.7 City of Petaluma will notify the City Manager and evaluate the need to activate the Emergency Operations Center.
40.7 Action Stage. NWS and City of Petaluma will be closely monitoring the situation. NWS will issue an urban/small stream advisory if not already issued.
About This Location Collapse

Latitude: 38.279722° N, Longitude: 122.669444° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame		 Gauge Height Flood Stage Uses
NWS stage 0 ft 40.7 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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