About this river
Big Sioux River is a 47.9 mile river near Sodaks Marina in South Dakota. Streamflow is measured at the USGS gauge Big Sioux River near Brookings, SD (site 06480000). The National Hydrography Dataset places it at stream order 6. Reach geometry comes from the USGS National Hydrography Dataset.
Typical flow by month
1954 to 2026
Big Sioux River typically runs highest in April, at a median 429 cfs, and lowest in February, at 21 cfs. The highest flow on record for any single day is 31,200 cfs, in 1969.
| Month | Typical (cfs) | Usual range (cfs) | Relative level |
|---|---|---|---|
| January | 24 | 6.1 to 94 | |
| February | 21 | 5.7 to 90 | |
| March | 243 | 49 to 596 | |
| April | 429 | 150 to 1,260 | |
| May | 386 | 136 to 936 | |
| June | 297 | 96 to 862 | |
| July | 165 | 53 to 530 | |
| August | 86 | 27 to 299 | |
| September | 66 | 20 to 205 | |
| October | 76 | 25 to 220 | |
| November | 71 | 28 to 208 | |
| December | 47 | 12 to 134 |
Typical is the median of each month’s daily median values, and the usual range runs from the median 25th to the median 75th percentile, across about 72 years of record. Statistics published by the US Geological Survey for Big Sioux River near Brookings, SD (site 06480000). Conditions on any given day can fall well outside the usual range. Check the current reading before you go.
Boat access nearby
2 mapped launches sit in the mapped area of Big Sioux River, all of them public access. Ramp data comes from the USGS national boat-ramp inventory.
Embed this gauge on your site
Paste this snippet anywhere, an outfitter page, a club site, a trip report, to show Big Sioux River's live streamflow, water level and 7-day trend. It reads the USGS gauge directly, updates itself, and links back here.
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