Rivermatics

USGS Streamgage 06481000

Big Sioux River near Dell Rapids, SD

Big Sioux River near Dell Rapids, SD is USGS streamgage 06481000 in South Dakota, monitoring river discharge in hydrologic subbasin 10170203. It sits on the Big Sioux River, alongside 16 other gauges Rivermatics tracks on the same river. It drains a watershed of about 3,927 square miles. Discharge records at this site go back to 1948. Typical flow runs near 257.4 cfs in July and 619.8 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

View live conditions & forecast →

Gauge details

State
South Dakota
Drainage area
3,927 sq mi
Gauge elevation
1,463 ft
Subbasin (HUC-8)
10170203
Coordinates
43.79047, -96.74533
USGS site number
06481000
Records begin
1948-05-01 (78 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Big Sioux River near Dell Rapids, SD. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
103 118 139
91.6 110 139
86.1 106 136
83.6 105 142
79.7 102 142
80.8 105 157
90 125 231
92 136 262
88 135 281
84.2 131 290
79.4 125 280
74.2 117 264
72.4 114 240
71.6 111 223

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 78 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 5.6 33.2 225.9
February 5.1 40.2 375.3
March 31.1 326.8 2,173.6
April 118.9 619.8 4,453.7
May 81.6 521.5 2,396.1
June 52.9 434.3 2,208.7
July 33.5 257.4 1,641.9
August 18.3 132.8 1,020.5
September 14.9 91.5 707.5
October 16 98.3 738.8
November 20.1 89.5 586.3
December 12 64.1 368.2

All values in cubic feet per second (cfs).

Common questions

When does Big Sioux River near Dell Rapids, SD normally run highest?
April, on the long-term record. The median daily flow that month is about 619.8 cfs, against 33.2 cfs in January, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Big Sioux River near Dell Rapids, SD?
It depends on the month. In January, half of days historically fall near 33.2 cfs, with the middle 80% of days between 5.6 and 225.9 cfs. The month-by-month table on this page gives the full range.
How long has Big Sioux River near Dell Rapids, SD been measured?
Discharge records at USGS site 06481000 begin in 1948, about 78 years, covering roughly 9,080 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Big Sioux River near Dell Rapids, SD?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow 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 the live gauge screen. Open live conditions to see the current outlook.
Where is Big Sioux River near Dell Rapids, SD?
The gauge sits at 43.79047, -96.74533, in South Dakota, in hydrologic subbasin 10170203, at an elevation of about 1,463 feet, draining roughly 3,927 square miles.
Can I use Big Sioux River near Dell Rapids, SD 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.

Upstream and downstream on the Big Sioux River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Big Sioux River in full.

Other gauges in this subbasin