MATTOLE RIVER

Last Updated: April 14, 2026

Total streamflow across the Mattole River was last observed at 993 cfs, and is expected to yield approximately 1,970 acre-ft of water today; about 74% of normal. Average streamflow for this time of year is 1,339 cfs, with recent peaks last observed on 2023-03-14 when daily discharge volume was observed at 38,900 cfs.

Maximum discharge along the river is currently at the Mattole R Nr Petrolia Ca reporting a streamflow rate of 778 cfs. This is also the highest stage along the Mattole River, with a gauge stage of 12.67 ft at this location. This river is monitored from 2 different streamgauging stations along the Mattole River, the highest being situated at an altitude of 599 ft, the Mattole R Nr Ettersburg Ca.

Get the latest River Levels, Streamflow, and Hydrology for in River flows across 2 streamgages of the Mattole River


15-Day Long Term Forecast


River Details

Last Updated 2026-04-14
Discharge Volume 1,970 ACRE-FT
Streamflow 993.0 cfs
Past 24 Hours: -532.0 cfs (-34.89%)
Percent of Normal 74.18%
Maximum 38,900.0 cfs
2023-03-14
Seasonal Avg cfs
       
River Streamflow Levels
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Streamgauge Streamflow Gauge Stage 24hr Change (%) % Normal Minimum (cfs) Maximum (cfs) Air Temp Elevation
Mattole R Nr Ettersburg Ca
USGS 11468900 		215 cfs 10.07 ft -35.82
Mattole R Nr Petrolia Ca
USGS 11469000 		778 cfs 12.67 ft -34.62
Seasonal Discharge Comparison
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Maximum Streamflow Discharge
Streamflow Elevation Profile

Historically, the Mattole Valley was home to the indigenous Mattole people who lived along the river for thousands of years. The river is unique in that it is one of the few undammed rivers left in California, allowing for a relatively natural flow regime. The Mattole River watershed provides critical habitat for threatened and endangered species, including coho and Chinook salmon, steelhead trout, and the Pacific lamprey. There are no major reservoirs or dams on the river, and the water is primarily used for agriculture and recreational purposes such as fishing, swimming, and river rafting.