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	3,560	13.25	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: Mostly cloudy. A chance of rain late in the evening, then a slight chance of rain after midnight. Lows in the upper 40s. Southeast winds 10 to 20 mph.

Friday: Mostly cloudy. A slight chance of rain. Highs in the 50s. South winds 10 to 20 mph with gusts to around 40 mph.

Friday Night: Breezy, rain. Lows in the lower 50s. Southeast winds 10 to 20 mph increasing to south 20 to 30 mph after midnight. Gusts up to 45 mph.

Saturday: Rain in the morning, then showers and a slight chance of thunderstorms in the afternoon. Highs in the mid 50s. South winds 10 to 20 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon.

Saturday Night: Rain in the evening, then showers and a slight chance of thunderstorms after midnight. Lows in the lower 50s. South winds 10 to 20 mph with gusts to around 35 mph.

Sunday: Rain. Highs in the mid 50s.

Sunday Night through Monday Night: Rain likely. Lows in the upper 40s. Highs in the lower to mid 50s.

Tuesday: Mostly cloudy in the morning then becoming partly cloudy. A slight chance of rain. Highs in the 40s to upper 50s.

Tuesday Night: Mostly cloudy. Patchy fog. A chance of rain. Lows in the mid 40s.

Wednesday and Wednesday Night: Mostly cloudy. A chance of rain. Highs in the 40s to upper 50s. Lows in the lower 40s.

Thursday: Mostly cloudy in the morning then becoming partly cloudy. A chance of rain and a slight chance of snow. Highs in the upper 40s to mid 50s.

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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