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Big Sioux River near Castlewood

Highest listed crest 13.19 ftFlood stage 9.0 ft48 crests since 1977

The Big Sioux River near Castlewood crested above flood stage 29 times among the 48 crests the National Weather Service lists from 1977 to 2025. The highest, 13.19 ft on April 7, 1997, was moderate flooding, 4.19 feet above flood stage. 8 other gauges on the Big Sioux River crested above flood stage within a week of it, 2 at their own highest listed crest.

The gauge

Highest listed crest
13.19 ft
April 7, 1997; 4,300 cubic feet per second
Flood stage
9.0 ft
Major flooding from 16.0 ft
Crests at major
0
29 above flood stage
Most recent flood crest
July 29, 2025
11.44 ft, moderate flooding
Location
Hamlin County
Near Watertown (13.4 mi)

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Big Sioux River near Castlewood
Action stage8.07Apr 10, 2021The level at which the NWS or its partners begin to take action
Flood stage (minor)9.013Jun 1, 2022Minimal or no property damage, but possibly some public threat
Moderate flood stage11.016Jul 29, 2025Some inundation of structures and roads near the stream
Major flood stage16.00—Extensive inundation of structures and roads

Every listed crest

48 crests from 1977 to 2025. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Big Sioux River near Castlewood, 1977 to 2025 46810121416ft Flood stage 9.0 ftMajor 16.0 ft Jun 16, 1977: 10.33 ft, minor flooding; 1,090 cubic feet per secondMar 31, 1978: 11.10 ft, moderate flooding; 1,740 cubic feet per secondApr 13, 1979: 11.23 ft, moderate flooding; 1,440 cubic feet per secondJun 5, 1980: 8.80 ft, action stage; 617 cubic feet per secondJul 22, 1981: 7.60 ft, below flood stage; 368 cubic feet per secondMar 31, 1982: 8.62 ft, action stage; 380 cubic feet per secondApr 1, 1983: 7.26 ft, below flood stage; 302 cubic feet per secondJun 16, 1984: 10.68 ft, minor flooding; 1,160 cubic feet per secondMar 19, 1985: 11.14 ft, moderate flooding; 1,830 cubic feet per secondMar 30, 1986: 11.73 ft, moderate flooding; 2,250 cubic feet per secondMar 25, 1987: 7.88 ft, below flood stage; 517 cubic feet per secondMar 2, 1988: 7.60 ft, below flood stage; 200 cubic feet per secondMar 25, 1989: 9.81 ft, minor flooding; 400 cubic feet per secondJun 17, 1990: 6.53 ft, below flood stage; 260 cubic feet per secondJun 22, 1991: 10.93 ft, minor flooding; 1,270 cubic feet per secondJun 19, 1992: 9.15 ft, minor flooding; 657 cubic feet per secondMar 28, 1993: 11.39 ft, moderate flooding; 1,500 cubic feet per secondMar 16, 1994: 11.21 ft, moderate flooding; 1,200 cubic feet per secondMar 13, 1995: 11.37 ft, moderate flooding; 1,940 cubic feet per secondMar 14, 1996: 11.65 ft, moderate flooding; 1,300 cubic feet per secondApr 7, 1997: 13.19 ft, moderate flooding; 4,300 cubic feet per secondApr 1, 1998: 9.98 ft, minor flooding; 978 cubic feet per secondJun 10, 1999: 7.79 ft, below flood stage; 430 cubic feet per secondJun 26, 2000: 5.34 ft, below flood stage; 111 cubic feet per secondApr 8, 2001: 12.27 ft, moderate flooding; 3,070 cubic feet per secondAug 21, 2002: 9.63 ft, minor flooding; 837 cubic feet per secondMar 16, 2003: 9.63 ft, minor flooding; 750 cubic feet per secondJul 3, 2004: 6.24 ft, below flood stage; 199 cubic feet per secondJun 11, 2005: 7.20 ft, below flood stage; 346 cubic feet per secondMar 11, 2006: 8.33 ft, action stage; 450 cubic feet per secondMar 20, 2007: 10.65 ft, minor flooding; 1,410 cubic feet per secondJun 13, 2008: 8.27 ft, action stage; 505 cubic feet per secondMar 24, 2009: 11.28 ft, moderate flooding; 1,760 cubic feet per secondMar 15, 2010: 11.98 ft, moderate flooding; 1,770 cubic feet per secondMar 23, 2011: 12.29 ft, moderate flooding; 2,270 cubic feet per secondMar 13, 2012: 7.40 ft, below flood stage; 328 cubic feet per secondJun 24, 2013: 9.02 ft, minor flooding; 661 cubic feet per secondJun 22, 2014: 6.97 ft, below flood stage; 323 cubic feet per secondMar 13, 2015: 8.75 ft, action stage; 300 cubic feet per secondAug 12, 2016: 6.93 ft, below flood stage; 299 cubic feet per secondFeb 20, 2017: 8.60 ft, action stage; 673 cubic feet per secondApr 23, 2018: 10.93 ft, minor flooding; 1,450 cubic feet per secondMar 28, 2019: 12.39 ft, moderate floodingApr 3, 2020: 9.53 ft, minor flooding; 812 cubic feet per secondApr 10, 2021: 8.37 ft, action stage; 529 cubic feet per secondJun 1, 2022: 10.70 ft, minor flooding; 1,180 cubic feet per secondApr 13, 2023: 11.64 ft, moderate flooding; 2,030 cubic feet per secondJul 29, 2025: 11.44 ft, moderate flooding; 1,490 cubic feet per second Highest, 13.19 ft, Apr 7, 1997 19801990200020102020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Big Sioux River near Castlewood 1970s: 3 1980s: 4 1990s: 8 8 2000s: 5 2010s: 5 2020s: 4 1970s1980s1990s2000s2010s2020s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

Highest listed crests, Big Sioux River near Castlewood
1Apr 7, 199713.19+4.19Moderate4,300
2Mar 28, 201912.39+3.39Moderate—
3Mar 23, 201112.29+3.29Moderate2,270
4Apr 8, 200112.27+3.27Moderate3,070
5Mar 15, 201011.98+2.98Moderate1,770
6Mar 30, 198611.73+2.73Moderate2,250
7Mar 14, 199611.65+2.65Moderate1,300
8Apr 13, 202311.64+2.64Moderate2,030
9Jul 29, 202511.44+2.44Moderate1,490
10Mar 28, 199311.39+2.39Moderate1,500
11Mar 13, 199511.37+2.37Moderate1,940
12Mar 24, 200911.28+2.28Moderate1,760
13Apr 13, 197911.23+2.23Moderate1,440
14Mar 16, 199411.21+2.21Moderate1,200
15Mar 19, 198511.14+2.14Moderate1,830
16Mar 31, 197811.10+2.10Moderate1,740
17Jun 22, 199110.93+1.93Minor1,270
18Apr 23, 201810.93+1.93Minor1,450
19Jun 1, 202210.70+1.70Minor1,180
20Jun 16, 198410.68+1.68Minor1,160
21Mar 20, 200710.65+1.65Minor1,410
22Jun 16, 197710.33+1.33Minor1,090
23Apr 1, 19989.98+0.98Minor978
24Mar 25, 19899.81+0.81Minor400
25Aug 21, 20029.63+0.63Minor837
26Mar 16, 20039.63+0.63Minor750
27Apr 3, 20209.53+0.53Minor812
28Jun 19, 19929.15+0.15Minor657
29Jun 24, 20139.02+0.02Minor661
30Jun 5, 19808.80−0.20Action617
31Mar 13, 20158.75−0.25Action300
32Mar 31, 19828.62−0.38Action380
33Feb 20, 20178.60−0.40Action673
34Apr 10, 20218.37−0.63Action529
35Mar 11, 20068.33−0.67Action450
36Jun 13, 20088.27−0.73Action505
37Mar 25, 19877.88−1.12Below flood stage517
38Jun 10, 19997.79−1.21Below flood stage430
39Jul 22, 19817.60−1.40Below flood stage368
40Mar 2, 19887.60−1.40Below flood stage200
41Mar 13, 20127.40−1.60Below flood stage328
42Apr 1, 19837.26−1.74Below flood stage302
43Jun 11, 20057.20−1.80Below flood stage346
44Jun 22, 20146.97−2.03Below flood stage323
45Aug 12, 20166.93−2.07Below flood stage299
46Jun 17, 19906.53−2.47Below flood stage260
47Jul 3, 20046.24−2.76Below flood stage199
48Jun 26, 20005.34−3.66Below flood stage111

The worst floods along the Big Sioux River

For this gauge's highest crests, the other gauges on the Big Sioux River that crested above flood stage within a week.

April 7, 1997: 13.19 ft here, moderate flooding

March 28, 2019: 12.39 ft here, moderate flooding

March 23, 2011: 12.29 ft here, moderate flooding

  • AkronIA · Mar 26, 2011 · 20.39 ft · Major
  • Dell RapidsSD · Mar 24, 2011 · 15.63 ft · Major
  • WatertownSD · Mar 23, 2011 · 12.56 ft · Major
  • FlandreauSD · Mar 25, 2011 · 1,543.85 ft · Moderate
  • Sioux Falls N. Cliff AvenueSD · Mar 25, 2011 · 21.53 ft · Moderate
  • BrookingsSD · Mar 24, 2011 · 13.33 ft · Moderate
  • BruceSD · Mar 28, 2011 · 12.16 ft · Moderate · its highest
  • WatertownSD · Mar 23, 2011 · 10.30 ft · Minor

Gauges on the Big Sioux River

Flood gauges sharing the river's name, linked within 80 miles of one another.

Flood gauges on the Big Sioux River
CantonSD1,235.01,248.35 ft, Jun 22, 20243
Dell RapidsSD1,481.01,490.00 ft, Sep 13, 20192
FlandreauSD1,540.01,545.29 ft, Sep 13, 20191
HawardenSD20.539.92 ft, Jun 22, 20244
AkronIA16.027.35 ft, Jun 22, 202424
FairviewSD1,202.01,213.14 ft, Sep 14, 20190
Lake KampeskaSD21.022.40 ft, Mar 15, 20100
Lake Poinsett Inlet/OutletSD1,654.01,657.60 ft, Apr 5, 20112
Sioux CitySD32.044.90 ft, Jun 23, 20241
Sioux Falls I-90SD12.018.91 ft, Sep 14, 20191
Sioux Falls N. Cliff AvenueSD16.026.08 ft, Sep 14, 20190
Sioux Falls Western AvenueSD8.016.90 ft, Mar 14, 20194
TrentSD1,495.01,501.42 ft, Sep 13, 20192
Watertown Broadway AvenueSD10.513.67 ft, Apr 6, 19971
Watertown Sioux Conifer RoadSD9.011.18 ft, Apr 13, 20230
WatertownSD11.013.13 ft, Apr 2, 19975
BrandonSD1,304.01,313.53 ft, Sep 14, 20192
BrookingsSD9.014.77 ft, Apr 9, 19690
BruceSD8.012.16 ft, Mar 28, 20110
Castlewood this gaugeSD9.013.19 ft, Apr 7, 19970
Dell RapidsSD12.016.70 ft, Sep 13, 201910
EganSD1,516.51,524.20 ft, Sep 12, 20192
EstellineSD1,644.01,647.03 ft, Jun 30, 20250
FlorenceSD8.09.70 ft, Apr 13, 20236
JeffersonIA31.044.50 ft, Jun 24, 20242
RichlandIA1,117.01,128.70 ft, Jun 23, 20245
WatertownSD10.012.33 ft, Apr 7, 20012

Other gauges in Hamlin County

Flood gauges in Hamlin County
Lake Poinsett Inlet/Outlet1,654.01,657.60 ft, Apr 5, 20112
Estelline1,644.01,647.03 ft, Jun 30, 20250

Hamlin County: every hazard · River floods across the country · South Dakota

NOAA National Water Prediction Service, gauge CSWS2, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.