Rivermatics

2 USGS Streamgages · Colorado River system

Big Sandy River flows and levels

Big Sandy River is gauged at 2 USGS streamgages in Wyoming, each tracked by Rivermatics. The mainstem runs about 143 miles (230 km) from headwaters to outlet. It drains into the Colorado River system. Drainage area at the gauges ranges from 315 square miles at Big Sandy River near Farson, WY up to 1,485 at Big Sandy River at Gasson Bridge, near Eden, WY. The gauged reach falls about 459 feet, from 6,808 feet down to 6,349. Rivermatics issues a daily machine-learned 14-day flow outlook for every one of them.

Gauges on this river, upstream to downstream

Ordered by drainage area, which is how far down the river each gauge sits. April and July figures are long-term median daily flows for that month from the USGS record — historical normals, not a forecast and not today's reading.

USGS streamgages on this river, ordered upstream to downstream
Gauge State Drainage sq mi Elevation ft April p50 cfs July p50 cfs Forecast
Big Sandy River near Farson, WY WY 315 6,808 49.4 132.9 14-day
Big Sandy River at Gasson Bridge, near Eden, WY WY 1,485 6,349 58.3 78.4 14-day

Typical flow by month at Big Sandy River at Gasson Bridge, near Eden, WY

The furthest-downstream gauge on this river, so the fullest flow it carries here. Long-term daily discharge percentiles from the USGS record (up to 35 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 12.2 28.7 42.9
February 13.1 29.6 44.6
March 29.4 52.7 166
April 30.7 58.3 198.5
May 22.2 50.1 158.6
June 27.1 72.4 407.3
July 27.3 78.4 219.1
August 28.3 75 107
September 28 72.9 97.2
October 27.3 57.7 82.3
November 26.8 48.3 70.4
December 14.5 35.6 54.4

All values in cubic feet per second (cfs).

Common questions

When does the Big Sandy River run highest?
July, on the long-term record at Big Sandy River at Gasson Bridge, near Eden, WY — the furthest-downstream gauge Rivermatics tracks on this river. Median daily flow there is about 78.4 cfs that month, against 28.7 cfs in January, the lowest. Upstream gauges peak on their own schedule; the table on this page gives April and July for each.
How many gauges are on the Big Sandy River?
Rivermatics tracks 2 USGS streamgages on the Big Sandy River, across Wyoming. Each has its own page with the site's full flow record and monthly normals. The river may carry other gauges that publish neither daily values nor discharge statistics; those are not tracked here.
Is there a flow forecast for the Big Sandy River?
Yes, at 2 of the 2 gauges. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on each basin's observed flows, weather and snowpack, and issues a daily outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on each gauge's live screen.
What river system is the Big Sandy River part of?
The Big Sandy River drains into the Colorado River system — it is a tributary somewhere in that chain, following the flowpath down to its terminal river. Rivermatics builds this from the USGS/geoconnex reference-mainstem network rather than from names.
Can I use Big Sandy River data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Other rivers in the Colorado River system

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