How high is the Big Sioux River Near Castlewood,sd right now?

The Big Sioux River Near Castlewood,sd is currently flowing at 101 cubic feet per second with a gage height of 5.38 feet, based on the most recent USGS instantaneous reading.

Is the flow on the Big Sioux River Near Castlewood,sd normal for this time of year?

Current flow is classified as normal for June 11. Today's discharge is at the 51th percentile compared to the long-term historical record at this gauge.

Is the Big Sioux River Near Castlewood,sd at flood stage?

No — the gage height is 3.62 feet below the NWS flood-stage threshold of 9.0 feet.

What is the historical median flow for the Big Sioux River Near Castlewood,sd on June 11?

The long-term median discharge for this date is 98 cfs based on USGS daily statistics. The 10th–95th percentile range historically is 7 to 498 cfs.

Where is the Big Sioux River Near Castlewood,sd stream gauge located?

The Big Sioux River Near Castlewood,sd stream gauge is operated by the USGS in Hamlin County, SD on the Big Sioux River. USGS site number 06479525 (coordinates 44.7315, -97.0447).

Big Sioux River Near Castlewood,sd

USGS Site No: 06479525 • Big Sioux River • Hamlin County, SD

Big Sioux River Near Castlewood,sd on the Big Sioux River is currently at 101 cfs (Normal — 51th percentile for this date) . Gage height: 5.38 ft.

Reading from 1 week ago

↑ Upstream on Big Sioux River

Big Sioux River Below Watertown, SD

Downstream on Big Sioux River ↓

Big Sioux River Near Bruce, SD

101

CFS Discharge

5.38

Gage Height (ft)

Normal

Flow Condition

Normal

Flood Status

Historical Percentile Comparison

Today's discharge compared to the long-term record for June 11 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.

Percentile	Label	CFS Threshold	Today's Flow
10th	Very Low threshold	7
25th	Low threshold	26
50th (Median)	Normal (median)	98
75th	High threshold	220	Today: 101 cfs
95th	Very High threshold	498

30-Day Hydrograph

Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.

10th–95th historical Day-of-year median Recent discharge

30-Day Flow History

Date	Discharge (CFS)	Gage Ht (ft)
May 28, 2026	107	5.43
May 27, 2026	111	5.46
May 26, 2026	107	5.43
May 25, 2026	116	5.50
May 24, 2026	126	5.59
May 23, 2026	130	5.62
May 22, 2026	98	5.35
May 21, 2026	98	5.35
May 20, 2026	107	5.42
May 19, 2026	109	5.45
May 18, 2026	100	5.38
May 17, 2026	79	5.20
May 16, 2026	84	5.24
May 15, 2026	94	5.32
Apr 20, 2026	167	5.87
Apr 19, 2026	181	5.97
Apr 18, 2026	201	6.11
Apr 17, 2026	213	6.20
Apr 16, 2026	214	6.21
Apr 15, 2026	214	6.21
Apr 14, 2026	206	6.15
Apr 13, 2026	205	6.15
Apr 12, 2026	194	6.07
Apr 11, 2026	193	6.06
Apr 10, 2026	199	6.10
Apr 9, 2026	216	6.23
Apr 8, 2026	214	6.21
Apr 7, 2026	216	6.23
Apr 6, 2026	205	6.14
Apr 5, 2026	201	6.12

Station Information

USGS Site No: 06479525
State: SD
County: Hamlin County
Coordinates: 44.7315, -97.0447
Drainage Area: 1,096 mi²
Datum (ft): 1,668.5
HUC Code: 10170201

View on USGS NWIS →

Flood Stage Thresholds

Action Stage: 8.0 ft
Flood Stage: 9.0 ft
Moderate Flood: 11.0 ft
Major Flood: 16.0 ft

Currently 3.62 ft below flood stage.

Recent Extremes

Max discharge: 1,450 cfs

Jul 29, 2025
Min discharge: 36 cfs

May 14, 2025
Days at flood stage: 14

Computed from the local daily-values archive.

Nearby Gauges

Big Sioux River Below Watertown, SD
8.0 mi · 21 cfs

Low
Hidewood Creek Near Estelline SD
10.3 mi

Unknown
Willow Creek Near Watertown,sd
12.9 mi · 0 cfs

Unknown
Big Sioux River at Watertown,sd
15.4 mi · 73 cfs

Normal
Big Sioux River Near Bruce, SD
19.8 mi · 205 cfs

Normal