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South River near Ackworth

Highest listed crest 32.85 ftFlood stage 29.0 ft87 crests since 1930

The South River near Ackworth crested at major flood stage 2 times among the 87 crests the National Weather Service lists from 1930 to 2025. The highest, 32.85 ft on July 5, 1981, was major flooding, 3.85 feet above flood stage.

The gauge

Highest listed crest
32.85 ft
July 5, 1981; 32,700 cubic feet per second
Flood stage
29.0 ft
Major flooding from 32.0 ft
Crests at major
2
70th of 203 gauges in Iowa
Most recent flood crest
June 25, 2015
31.87 ft, moderate flooding
Location
Warren County
Near Indianola (4.5 mi), Norwalk (14.8 mi)

Flood stages

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

Flood categories, South River near Ackworth
Action stage26.09Apr 18, 2013The level at which the NWS or its partners begin to take action
Flood stage (minor)29.03Sep 10, 2014Minimal or no property damage, but possibly some public threat
Moderate flood stage30.04Jun 25, 2015Some inundation of structures and roads near the stream
Major flood stage32.02Jul 16, 1982Extensive inundation of structures and roads

Every listed crest

87 crests from 1930 to 2025. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the South River near Ackworth, 1930 to 2025 010203040ft Flood stage 29.0 ftMajor 32.0 ft Jun 1, 1930: 24.50 ft, below flood stage; 30,000 cubic feet per secondAug 11, 1940: 8.30 ft, below flood stage; 1,770 cubic feet per secondJun 9, 1941: 20.60 ft, below flood stage; 13,400 cubic feet per secondNov 1, 1941: 18.70 ft, below flood stage; 9,480 cubic feet per secondMay 15, 1943: 15.10 ft, below flood stage; 6,130 cubic feet per secondMay 22, 1944: 19.70 ft, below flood stage; 10,900 cubic feet per secondApr 16, 1945: 19.60 ft, below flood stage; 11,800 cubic feet per secondJun 19, 1946: 20.00 ft, below flood stage; 12,600 cubic feet per secondJun 5, 1947: 24.60 ft, below flood stage; 34,000 cubic feet per secondMar 15, 1948: 16.00 ft, below flood stage; 8,900 cubic feet per secondJun 25, 1949: 17.80 ft, below flood stage; 11,000 cubic feet per secondMay 9, 1950: 20.10 ft, below flood stage; 15,200 cubic feet per secondMay 26, 1951: 18.84 ft, below flood stage; 13,100 cubic feet per secondJun 22, 1952: 21.83 ft, below flood stage; 16,600 cubic feet per secondJun 10, 1953: 20.65 ft, below flood stage; 16,200 cubic feet per secondApr 25, 1954: 13.70 ft, below flood stage; 7,100 cubic feet per secondJul 10, 1955: 12.02 ft, below flood stage; 5,500 cubic feet per secondAug 18, 1956: 7.69 ft, below flood stage; 2,350 cubic feet per secondApr 3, 1957: 9.01 ft, below flood stage; 3,130 cubic feet per secondJul 2, 1958: 14.43 ft, below flood stage; 6,040 cubic feet per secondMay 22, 1959: 22.81 ft, below flood stage; 13,700 cubic feet per secondMar 30, 1960: 22.60 ft, below flood stage; 18,100 cubic feet per secondFeb 18, 1961: 19.80 ft, below flood stage; 11,400 cubic feet per secondMar 19, 1962: 25.53 ft, below flood stage; 12,300 cubic feet per secondApr 29, 1963: 20.82 ft, below flood stage; 7,260 cubic feet per secondJun 23, 1964: 16.90 ft, below flood stage; 4,480 cubic feet per secondMar 17, 1965: 25.47 ft, below flood stage; 12,100 cubic feet per secondMay 15, 1966: 25.58 ft, below flood stage; 12,100 cubic feet per secondJun 12, 1967: 25.35 ft, below flood stage; 11,500 cubic feet per secondApr 23, 1968: 14.87 ft, below flood stage; 3,810 cubic feet per secondJul 18, 1969: 28.20 ft, action stage; 15,200 cubic feet per secondAug 8, 1970: 27.46 ft, action stage; 14,500 cubic feet per secondOct 9, 1970: 22.00 ft, below flood stage; 9,200 cubic feet per secondAug 6, 1972: 24.98 ft, below flood stage; 12,000 cubic feet per secondFeb 2, 1973: 27.35 ft, action stage; 14,400 cubic feet per secondJun 10, 1974: 29.07 ft, minor flooding; 19,500 cubic feet per secondJun 27, 1975: 21.73 ft, below flood stage; 9,060 cubic feet per secondApr 24, 1976: 24.34 ft, below flood stage; 11,800 cubic feet per secondAug 26, 1977: 26.99 ft, action stage; 15,800 cubic feet per secondApr 18, 1978: 24.17 ft, below flood stage; 11,600 cubic feet per secondApr 25, 1979: 16.68 ft, below flood stage; 4,880 cubic feet per secondJun 15, 1980: 24.31 ft, below flood stage; 11,900 cubic feet per secondJul 5, 1981: 32.85 ft, major flooding; 32,700 cubic feet per secondJul 16, 1982: 32.00 ft, major flooding; 26,000 cubic feet per secondDec 28, 1982: 21.47 ft, below flood stage; 10,300 cubic feet per secondApr 30, 1984: 23.15 ft, below flood stage; 10,900 cubic feet per secondJun 24, 1985: 18.08 ft, below flood stage; 5,700 cubic feet per secondJul 12, 1986: 21.42 ft, below flood stage; 8,630 cubic feet per secondAug 27, 1987: 29.55 ft, minor flooding; 19,900 cubic feet per secondNov 28, 1987: 15.50 ft, below flood stage; 3,670 cubic feet per secondSep 9, 1989: 11.87 ft, below flood stage; 1,800 cubic feet per secondJun 17, 1990: 31.25 ft, moderate flooding; 38,100 cubic feet per secondApr 19, 1991: 26.93 ft, action stage; 19,200 cubic feet per secondSep 16, 1992: 26.77 ft, action stage; 14,600 cubic feet per secondJul 6, 1993: 30.02 ft, moderate flooding; 32,200 cubic feet per secondMar 4, 1994: 15.44 ft, below flood stage; 4,100 cubic feet per secondMay 8, 1995: 17.89 ft, below flood stage; 5,670 cubic feet per secondMay 10, 1996: 26.04 ft, action stage; 20,800 cubic feet per secondMay 7, 1997: 22.10 ft, below flood stage; 13,400 cubic feet per secondMar 30, 1998: 25.91 ft, below flood stage; 21,700 cubic feet per secondApr 16, 1999: 16.44 ft, below flood stage; 8,330 cubic feet per secondJun 25, 2000: 16.60 ft, below flood stage; 6,580 cubic feet per secondMay 13, 2001: 22.13 ft, below flood stage; 13,800 cubic feet per secondMay 11, 2002: 13.20 ft, below flood stage; 3,360 cubic feet per secondJun 25, 2003: 18.18 ft, below flood stage; 8,400 cubic feet per secondAug 4, 2004: 19.18 ft, below flood stage; 9,660 cubic feet per secondMay 13, 2005: 17.10 ft, below flood stage; 7,130 cubic feet per secondAug 14, 2006: 14.26 ft, below flood stage; 4,260 cubic feet per secondMay 7, 2007: 28.42 ft, action stage; 20,900 cubic feet per secondJul 29, 2008: 31.57 ft, moderate flooding; 35,700 cubic feet per secondApr 27, 2009: 25.21 ft, below flood stage; 20,800 cubic feet per secondJul 20, 2010: 25.91 ft, below flood stage; 22,500 cubic feet per secondMay 25, 2011: 25.82 ft, below flood stageApr 15, 2012: 19.35 ft, below flood stage; 10,100 cubic feet per secondApr 18, 2013: 27.38 ft, action stage; 26,300 cubic feet per secondSep 10, 2014: 29.91 ft, minor flooding; 31,100 cubic feet per secondJun 25, 2015: 31.87 ft, moderate flooding; 34,800 cubic feet per secondDec 14, 2015: 24.27 ft, below flood stage; 17,800 cubic feet per secondApr 5, 2017: 16.87 ft, below flood stage; 7,120 cubic feet per secondSep 4, 2018: 15.63 ft, below flood stage; 5,730 cubic feet per secondMay 28, 2019: 24.06 ft, below flood stage; 17,700 cubic feet per secondMar 20, 2020: 19.43 ft, below flood stage; 9,870 cubic feet per secondApr 8, 2021: 18.36 ft, below flood stage; 8,540 cubic feet per secondMay 3, 2022: 15.24 ft, below flood stage; 5,170 cubic feet per secondFeb 27, 2023: 11.45 ft, below flood stage; 2,470 cubic feet per secondMay 20, 2024: 22.68 ft, below flood stage; 14,500 cubic feet per secondAug 7, 2025: 25.49 ft, below flood stage; 19,200 cubic feet per second Highest, 32.85 ft, Jul 5, 1981 19401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, South River near Ackworth 1930s: 0 1940s: 0 1950s: 0 1960s: 0 1970s: 1 1980s: 3 3 1990s: 2 2000s: 1 2010s: 2 2020s: 0 1930s1940s1950s1960s1970s1980s1990s2000s2010s2020s
  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

The 50 highest of 87 listed crests.

Highest listed crests, South River near Ackworth
1Jul 5, 198132.85+3.85Major32,700
2Jul 16, 198232.00+3.00Major26,000
3Jun 25, 201531.87+2.87Moderate34,800
4Jul 29, 200831.57+2.57Moderate35,700
5Jun 17, 199031.25+2.25Moderate38,100
6Jul 6, 199330.02+1.02Moderate32,200
7Sep 10, 201429.91+0.91Minor31,100
8Aug 27, 198729.55+0.55Minor19,900
9Jun 10, 197429.07+0.07Minor19,500
10May 7, 200728.42−0.58Action20,900
11Jul 18, 196928.20−0.80Action15,200
12Aug 8, 197027.46−1.54Action14,500
13Apr 18, 201327.38−1.62Action26,300
14Feb 2, 197327.35−1.65Action14,400
15Aug 26, 197726.99−2.01Action15,800
16Apr 19, 199126.93−2.07Action19,200
17Sep 16, 199226.77−2.23Action14,600
18May 10, 199626.04−2.96Action20,800
19Mar 30, 199825.91−3.09Below flood stage21,700
20Jul 20, 201025.91−3.09Below flood stage22,500
21May 25, 201125.82−3.18Below flood stage—
22May 15, 196625.58−3.42Below flood stage12,100
23Mar 19, 196225.53−3.47Below flood stage12,300
24Aug 7, 202525.49−3.51Below flood stage19,200
25Mar 17, 196525.47−3.53Below flood stage12,100
26Jun 12, 196725.35−3.65Below flood stage11,500
27Apr 27, 200925.21−3.79Below flood stage20,800
28Aug 6, 197224.98−4.02Below flood stage12,000
29Jun 5, 194724.60−4.40Below flood stage34,000
30Jun 1, 193024.50−4.50Below flood stage30,000
31Apr 24, 197624.34−4.66Below flood stage11,800
32Jun 15, 198024.31−4.69Below flood stage11,900
33Dec 14, 201524.27−4.73Below flood stage17,800
34Apr 18, 197824.17−4.83Below flood stage11,600
35May 28, 201924.06−4.94Below flood stage17,700
36Apr 30, 198423.15−5.85Below flood stage10,900
37May 22, 195922.81−6.19Below flood stage13,700
38May 20, 202422.68−6.32Below flood stage14,500
39Mar 30, 196022.60−6.40Below flood stage18,100
40May 13, 200122.13−6.87Below flood stage13,800
41May 7, 199722.10−6.90Below flood stage13,400
42Oct 9, 197022.00−7.00Below flood stage9,200
43Jun 22, 195221.83−7.17Below flood stage16,600
44Jun 27, 197521.73−7.27Below flood stage9,060
45Dec 28, 198221.47−7.53Below flood stage10,300
46Jul 12, 198621.42−7.58Below flood stage8,630
47Apr 29, 196320.82−8.18Below flood stage7,260
48Jun 10, 195320.65−8.35Below flood stage16,200
49Jun 9, 194120.60−8.40Below flood stage13,400
50May 9, 195020.10−8.90Below flood stage15,200

Other gauges in Warren County

Flood gauges in Warren County
Indianola23.025.55 ft, Jun 6, 20080
Norwalk22.025.33 ft, Jun 17, 19900

Warren County: every hazard · River floods across the country · Iowa

NOAA National Water Prediction Service, gauge AKWI4, 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.