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South Branch Ralston Creek at Iowa City

Highest listed crest 10.50 ftFlood stage 7.0 ft68 crests since 1962

The South Branch Ralston Creek at Iowa City crested above flood stage 49 times among the 68 crests the National Weather Service lists from 1962 to 2021. The highest, 10.50 ft on July 14, 1962, was minor flooding, 3.50 feet above flood stage.

The gauge

Highest listed crest
10.50 ft
July 14, 1962
Flood stage
7.0 ft
No major stage set
Crests at major
0
49 above flood stage
Most recent flood crest
October 6, 2018
9.64 ft, minor flooding
Location
Johnson County
Near Iowa City (1.2 mi), Coralville (5.7 mi), North Liberty (8.3 mi)

Flood stages

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

Flood categories, South Branch Ralston Creek at Iowa City
Action stage6.08May 3, 2021The level at which the NWS or its partners begin to take action
Flood stage (minor)7.049Oct 6, 2018Minimal or no property damage, but possibly some public threat

Every listed crest

68 crests from 1962 to 2021. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the South Branch Ralston Creek at Iowa City, 1962 to 2021 24681012ft Flood stage 7.0 ft Jul 14, 1962: 10.50 ft, minor floodingJun 22, 1964: 3.47 ft, below flood stage; 126 cubic feet per secondSep 21, 1965: 8.15 ft, minor flooding; 780 cubic feet per secondJun 9, 1966: 7.59 ft, minor flooding; 492 cubic feet per secondJun 7, 1967: 8.78 ft, minor flooding; 859 cubic feet per secondMay 26, 1968: 4.67 ft, below flood stage; 184 cubic feet per secondJul 8, 1969: 8.52 ft, minor flooding; 677 cubic feet per secondSep 17, 1970: 7.40 ft, minor flooding; 510 cubic feet per secondJul 10, 1971: 6.20 ft, action stage; 292 cubic feet per secondJul 17, 1972: 9.47 ft, minor flooding; 1,070 cubic feet per secondAug 6, 1972: 7.71 ft, minor flooding; 578 cubic feet per secondApr 20, 1973: 7.65 ft, minor flooding; 564 cubic feet per secondApr 28, 1974: 7.58 ft, minor flooding; 548 cubic feet per secondMar 19, 1975: 4.07 ft, below flood stage; 136 cubic feet per secondApr 24, 1976: 4.13 ft, below flood stage; 140 cubic feet per secondAug 15, 1977: 7.51 ft, minor flooding; 534 cubic feet per secondJun 28, 1978: 7.89 ft, minor flooding; 680 cubic feet per secondJul 9, 1978: 7.28 ft, minor flooding; 540 cubic feet per secondSep 16, 1978: 7.38 ft, minor flooding; 510 cubic feet per secondJul 11, 1979: 7.49 ft, minor flooding; 530 cubic feet per secondJun 14, 1980: 4.28 ft, below flood stage; 152 cubic feet per secondJun 15, 1981: 6.58 ft, action stage; 385 cubic feet per secondJun 15, 1982: 7.25 ft, minor flooding; 490 cubic feet per secondJul 18, 1982: 8.10 ft, minor flooding; 666 cubic feet per secondDec 2, 1982: 7.00 ft, minor flooding; 441 cubic feet per secondJun 22, 1984: 4.06 ft, below flood stage; 142 cubic feet per secondOct 18, 1984: 5.84 ft, below flood stage; 275 cubic feet per secondJun 30, 1986: 7.13 ft, minor flooding; 452 cubic feet per secondJul 8, 1986: 8.19 ft, minor flooding; 689 cubic feet per secondAug 8, 1988: 6.54 ft, action stage; 378 cubic feet per secondAug 3, 1989: 6.10 ft, action stage; 340 cubic feet per secondJun 17, 1990: 7.79 ft, minor flooding; 542 cubic feet per secondMay 29, 1991: 5.09 ft, below flood stage; 240 cubic feet per secondJul 15, 1992: 5.74 ft, below flood stage; 301 cubic feet per secondJul 5, 1993: 8.89 ft, minor flooding; 834 cubic feet per secondJul 24, 1993: 7.05 ft, minor flooding; 421 cubic feet per secondAug 10, 1993: 9.43 ft, minor flooding; 994 cubic feet per secondAug 16, 1993: 8.40 ft, minor flooding; 704 cubic feet per secondJun 13, 1994: 5.12 ft, below flood stage; 243 cubic feet per secondJun 25, 1995: 6.56 ft, action stage; 384 cubic feet per secondApr 8, 1999: 7.24 ft, minor floodingJun 6, 2006: 5.62 ft, below flood stageJun 3, 2008: 7.61 ft, minor floodingJul 21, 2008: 7.40 ft, minor floodingJul 11, 2009: 6.97 ft, action stageJun 15, 2010: 8.14 ft, minor floodingJun 23, 2010: 7.59 ft, minor floodingJul 22, 2011: 7.07 ft, minor floodingApr 14, 2012: 7.03 ft, minor floodingMay 3, 2012: 9.48 ft, minor floodingJun 26, 2013: 7.30 ft, minor floodingJun 30, 2014: 9.40 ft, minor floodingJul 12, 2014: 7.73 ft, minor floodingSep 10, 2014: 7.18 ft, minor floodingMay 5, 2015: 7.61 ft, minor flooding; 807 cubic feet per secondJun 22, 2016: 7.92 ft, minor flooding; 873 cubic feet per secondAug 12, 2016: 7.99 ft, minor flooding; 888 cubic feet per secondSep 7, 2016: 7.33 ft, minor floodingSep 22, 2016: 7.10 ft, minor floodingJul 21, 2017: 7.64 ft, minor floodingAug 2, 2017: 7.10 ft, minor floodingJun 21, 2018: 8.30 ft, minor floodingAug 28, 2018: 8.22 ft, minor floodingSep 5, 2018: 7.96 ft, minor floodingSep 25, 2018: 7.67 ft, minor floodingOct 6, 2018: 9.64 ft, minor floodingJun 9, 2020: 6.87 ft, action stageMay 3, 2021: 6.57 ft, action stage Highest, 10.50 ft, Jul 14, 1962 197019801990200020102020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, South Branch Ralston Creek at Iowa City 1960s: 5 1970s: 10 1980s: 5 1990s: 6 2000s: 2 2010s: 21 21 2020s: 0 1960s1970s1980s1990s2000s2010s2020s
  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 68 listed crests.

Highest listed crests, South Branch Ralston Creek at Iowa City
1Jul 14, 196210.50+3.50Minor—
2Oct 6, 20189.64+2.64Minor—
3May 3, 20129.48+2.48Minor—
4Jul 17, 19729.47+2.47Minor1,070
5Aug 10, 19939.43+2.43Minor994
6Jun 30, 20149.40+2.40Minor—
7Jul 5, 19938.89+1.89Minor834
8Jun 7, 19678.78+1.78Minor859
9Jul 8, 19698.52+1.52Minor677
10Aug 16, 19938.40+1.40Minor704
11Jun 21, 20188.30+1.30Minor—
12Aug 28, 20188.22+1.22Minor—
13Jul 8, 19868.19+1.19Minor689
14Sep 21, 19658.15+1.15Minor780
15Jun 15, 20108.14+1.14Minor—
16Jul 18, 19828.10+1.10Minor666
17Aug 12, 20167.99+0.99Minor888
18Sep 5, 20187.96+0.96Minor—
19Jun 22, 20167.92+0.92Minor873
20Jun 28, 19787.89+0.89Minor680
21Jun 17, 19907.79+0.79Minor542
22Jul 12, 20147.73+0.73Minor—
23Aug 6, 19727.71+0.71Minor578
24Sep 25, 20187.67+0.67Minor—
25Apr 20, 19737.65+0.65Minor564
26Jul 21, 20177.64+0.64Minor—
27Jun 3, 20087.61+0.61Minor—
28May 5, 20157.61+0.61Minor807
29Jun 9, 19667.59+0.59Minor492
30Jun 23, 20107.59+0.59Minor—
31Apr 28, 19747.58+0.58Minor548
32Aug 15, 19777.51+0.51Minor534
33Jul 11, 19797.49+0.49Minor530
34Sep 17, 19707.40+0.40Minor510
35Jul 21, 20087.40+0.40Minor—
36Sep 16, 19787.38+0.38Minor510
37Sep 7, 20167.33+0.33Minor—
38Jun 26, 20137.30+0.30Minor—
39Jul 9, 19787.28+0.28Minor540
40Jun 15, 19827.25+0.25Minor490
41Apr 8, 19997.24+0.24Minor—
42Sep 10, 20147.18+0.18Minor—
43Jun 30, 19867.13+0.13Minor452
44Sep 22, 20167.10+0.10Minor—
45Aug 2, 20177.10+0.10Minor—
46Jul 22, 20117.07+0.07Minor—
47Jul 24, 19937.05+0.05Minor421
48Apr 14, 20127.03+0.03Minor—
49Dec 2, 19827.000.00Minor441
50Jul 11, 20096.97−0.03Action—

Other gauges in Johnson County

Flood gauges in Johnson County
Coralville11.016.36 ft, Jun 17, 19900
Oxford10.016.05 ft, Jul 1, 20140
Iowa City23.531.53 ft, Jun 15, 20082
Iowa City12.018.61 ft, Jul 1, 20140
Iowa City9.015.61 ft, Aug 10, 19930

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

NOAA National Water Prediction Service, gauge IACI4, 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.