CNRFC - Hydrology - Observed River/Reservoir Conditions

SAN LORENZO RIVER - BIG TREES (BTEC1)

Latitude: 37.04º N	Longitude: 122.07º W	Elevation: 227 Feet
Location: Santa Cruz County in California		River Group: Central Coast

Monitor Stage: 14.0 Feet

Flood Stage: 16.5 Feet

Observed Data Credit
	Raw streamflow data is provided by the US Geological Survey (USGS). View USGS Data for this station location.

Historical Stage/Flow Data
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2025	6,470	15.69	Feb 13, 2025
2024	5,220	14.69	Feb 4, 2024
2023	20,500	24.54	Jan 9, 2023
2022	5,600	16.06	Dec 13, 2021
2021	1,750	9.11	Jan 28, 2021
Historical High Stage/Flow Events (Period of Record - Oct 1936 to Present)* - Ranked by Flow
1956	30,400	22.55**	Dec 23, 1955
1982	29,700	28.85	Jan 5, 1982
1940	24,000	21.10**	Feb 27, 1940
2023	20,500	24.54	Jan 9, 2023
1986	19,800	21.22	Feb 17, 1986
1998	19,400	24.04	Feb 03, 1998
* Low flow partially regulated by Loch Lomond Reservoir since 1961, and inflatable fiber dam located 500 ft upstream from gauge. Many small diversions upstream from station for domestic supply.
** Unknown old datum.

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Official 7 Day National Weather Service Forecast (CAZ512)

rest of Tonight: Showers likely and a slight chance of thunderstorms late in the evening, then a chance of rain after midnight. Lows in the upper 40s. Southwest winds 5 to 15 mph.

Saturday: A chance of rain in the morning, then showers likely and a slight chance of thunderstorms in the afternoon. Highs in the 50s. South winds 10 to 20 mph with gusts to around 40 mph.

Saturday Night: A chance of thunderstorms in the evening. Showers. A slight chance of thunderstorms after midnight. Lows in the mid 40s. Southwest winds 10 to 20 mph with gusts to around 40 mph.

Sunday: Showers in the morning. A chance of thunderstorms. Showers likely in the afternoon. Highs in the 40s to upper 50s. Southwest winds 10 to 20 mph with gusts to around 35 mph.

Sunday Night: Mostly cloudy. A chance of rain. Lows in the mid 40s. Southwest winds 10 to 15 mph and becoming west around 5 mph after midnight. Chance of rain 40 percent.

Monday: Partly cloudy. A slight chance of rain. Highs in the lower 50s to mid 60s.

Monday Night through Wednesday: Mostly clear. Lows in the mid 40s. Highs in the mid 50s to upper 60s.

Wednesday Night: Partly cloudy. Lows in the mid 40s.

Thursday through Friday: Mostly clear. Highs in the upper 50s to lower 70s. Lows in the mid 40s.

Flood Impacts
21.76 Feet	Major Flooding. At approximately 21.76 feet discharge in the San Lorenzo River is approximately 15,000 cfs. Major flooding in the Felton Grove neighborhood occurs at this stage, with roadways several feet deep and waters inundating the approaches to the Felton Covered Bridge. Felton Covered Bridge Park begins to experience widespread flooding at shallow depths. At 15,000 cfs, the City of Santa Cruz downstream will experience more serious flooding. The flood wave may take 2-3 hours to reach Santa Cruz.
19.5 Feet	Moderate Flooding. The St. Bernard Street area in Paradise Park is under several feet of water, with below grade floodplain infrastructure several feet deeper. St. Augustine Avenue neighborhood in Paradise Park begins to flood. Flooding imminent or already occurring in the Felton Grove neighborhood. Ground stories, first floors, and garages flooded. Felton Covered Bridge Park begins to flood.
16.5 Feet	Minor Flooding. Flooding is either imminent or already occurring in Paradise Park, with initial flooding in the St. Bernard Street area.
14.0 Feet	Monitor Stage. Stage can rise rapidly on the San Lorenzo River, up to several feet per hour. Approximately 2.5 feet below flood levels in Paradise Park and approximately 5.5 feet below flood stage in Felton Grove.

Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS San Francisco Bay Area-Monterey Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.

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