Water and Pollution Control Department

Understanding The Predictions

Information |  Information During a Flood |  Ames Flood Frequency
Flood Prediction Process   |   Understanding Prediction Numbers
Actions to Take in Flood Event  |   June 18, 1998 Flood event

The numbers provided by city staff or given over the radio correspond to the depth of water in the river. The depth is accurate for the specific site only! The predictive models used by the water plant engineers are based on a flow of water in the river, usually in cubic feet per second (cfs). The depth of the water varies based on the shape of the river basin. Where the river channel narrows, the depth of water for a given flow rate will be higher than in a location where the river is wider.

The flood prediction model estimates peaks for several locations in the basin. It is important to understand that a prediction of 14 feet on the Skunk River north of Ames is very different from a peak of 14 feet on the south side of town. If you live in a flood-prone area, you should listen carefully to the predictions and know in advance what levels may threaten your home or business.

City staff have compiled a list of past flood levels and the properties that were impacted. When using these lists, it is important to remember that every flood event is unique. The flood level at which a property is impacted can vary depending on the combined interaction of multiple streams, multiple rainfalls, log jams, and a variety of other situations. There are three lists shown below. Each of the lists corresponds to a specific United States Geological Survey (USGS) river gauge.

Projected Flooding Levels based on the
Squaw Creek at Lincoln Way Gage Readings*
Current USGS Gage Reading - Squaw Creek at Ames

Revised July 13, 1999

Gage Reading, ft	Discharge cfs	Affect	Notes
1.1	0	Dry conditions
2.5	250	Average flow
6.5	2340	Below banks
8.5±	3420	Bank full
9.0	3700	Minor flooding	Low-lying fields flooded, but no structures threatened
10.4	4470	1204 S 4th St; Riverside Manor yard field behind Quality Motors	Brookside park threatened
12.0	5850	428 Stonehaven Drive, apts.	Notify Cy-ride; Veenker golf course shed
13.0	7484	S. 4th Street bridge;bottom of Happy Joe's wall; Century Theatre surrounded/ bowling alley parking	Evacuate Riverside Manor (if prediction for >14+ feet); 6" below park sign in Stuart Smith park
13.2	7835	S. 5th Street apts
13.3	8015	6th & Brookside water over road thru RR underpass	August 1993 high water level
13.8	8952	Tall Timber & Willow Run apts
14.0	9346	Water over South Duff
14.4	10170	Timbercreek & Plumwood apts
15.0	11550		July 17, 1993 high water level
15.1	11710	Scheman & Hilton Coliseum	June 1975 high water level
15.3	12180		June 1996 high water level
15.5	12650		June 1990 high water level
15.8	13390	Water over Lincoln Way and Elwood
16.4	14960	Maple/Willow/Larch
17.1	16920	ISU Rec Center
17.3	17510	Stange Road overtopped
18.5	24300		July 9, 1993 high water level

Projected Flooding Levels based on the
South Skunk River at Ada Hayden Heritage Park Gage Readings*
Current USGS Gage Reading - South Skunk River near Ames

Revised July 13, 1999

Gage Reading, ft	Discharge, cfs	Affect	Notes
1.7	0	Dry
3.2	250	Average flow
6.0	2120	Below banks
7.5 +/-	3620	Bank full
8.0	4084	Minor flooding	Low-lying fields flooded, no structural damage
8.5	4566	Water out-of-bank at River Valley park
9.2	5271		June 1975
10.5	6667	E. Lincoln Way businesses east of S. Duff affected	June 1990
11.7	8074	Sondrol Ave.; S. 5th Street closed	July 17, 1993
12.7	9270	General Filter- Arrasmith Trail
14.2	11130	Freel Drive residences	July 9, 1993; August 1993
15.0	12300	Sargent Metal- Arrasmith Trail
15.9	14000	Water over E. 13th Street	June 1996

Projected Flooding Levels based on the
South Skunk River at US Highway 30 Gage Readings*
Current USGS Gage Reading - Skunk River below Squaw Creek

Revised July 13, 1999

Gage Reading, ft	Discharge, cfs	Affect	Notes
9.5	0	Dry
11.8	434	Average flow
15.5	2002	Below banks
19.0 +/-	4374	Bank full
20.0	5200	Minor flooding
21.1	6396	Water over S. 16th Street
21.4	6846	Oriole Street Residences
22.4	8750	Kriz-Davis Co.; Shaffer Auto Body
22.8	9935	Shady Grove Trailer park	Southbound lane S. Dayton exit
23.6	13330		June 1990
23.7	13840		July 17, 1993
23.9	14900		June 1975
24.1	16020		Hwy 30 between Dayton & Duff concern for Duff
24.5		Water over I-35 south of Hwy 30
25.2	23520	Heart of Iowa Coop; Harmon Glass	Motels along S. Dayton affected
25.3	23920		August 1993
25.5+/-	~26000	Water over Hwy 30	June 1996; July 9, 1993

*These levels are estimated based on best projections and recalled observations. However, variations of +/- 0.5 feet may also result in flood impacts at these and other locations due to a variety of factors and the inaccuracies associated with modeling predictions. Furthermore, numerous flood mitigation activities (buyouts, flood walls, relocations, etc.) have occurred since the historic 1993 and 1996 flood events which may have altered the potential flooding impact.