West Fork San Juan River
Streamflow, conditions and background by watershed segment. Data through November 1, 2026.
Where it is
Segments are the HUC8 watersheds the gauges sit in, numbered upstream to downstream. Use the buttons to switch between the state and the river.
- 1Upper San Juan
- river and reservoirs
- gauge
About the West Fork San Juan River
This report follows 17 miles (27 km) of the West Fork San Juan River, all within the Upper San Juan watershed segment. At the lower end of the report the river drains about 89 square miles. Downstream of the mapped reach it flows into the San Juan River. Named tributaries joining it here include the Cimarron Creek. 3 gauges with at least 26 weeks of daily flow cover 1935 to 2026.
From the archive: NHDPlus river network, WBD watersheds, NHD waterbodies, TIGER urban areas and the report's gauges.
From the headwaters down
Each watershed segment in order, with last week's flow rated against the same week in 1991–2020.
Segment 1: Upper San Juan
No data last week.
Median conductance 56 µS/cm in the 1990s. Rain over the last 3 months: 248% of normal.
Reservoirs
No reservoir with 500 acre-feet or more of storage on this river in the National Inventory of Dams.
Sources
Numbered sources for the statements above, as they were read when the page was prepared.