Iowa Flood Information

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The USGS provides practical, unbiased information about the Nation's rivers and streams that is crucial in mitigating hazards associated with floods.  This site provides information about flooding that has occurred in Iowa.

Real-time information on floods in Iowa is available throught the USGS National Water Information System (NWIS).

A map of Iowa gages currently at high-flow or flood conditions can be found here. Click on a site to get a summary of conditions, view the current hydrograph, or see a chart of how the current stage compares with historical peak flows and floods. Animations of current and historical high-flow and flood events (by date) are also available.

A table of current discharge measurements and historical peaks for all real-time streamgages in Iowa is also available. You can use the USGS WaterAlert service to receive an email or text alert if a particular streamgage exceeds a user-specified gage height or discharge value.

In addition to reports documenting floods in Iowa, reports on historical floods across the Nation can be found at the USGS Flood Information Page.

 

The Effects of Missouri River Mainstem Reservoir System Operations on 2011 Flooding Using a Precipitation-Runoff Modeling System Model

In 2011, the Missouri River Mainstem Reservoir System (Reservoir System) experienced the largest volume of flood waters since the initiation of record-keeping in the nineteenth century. The high levels of runoff from both snowpack and rainfall stressed the Reservoir System's capacity to control flood waters and caused massive damage and disruption along the river. The flooding and resulting damage along the Missouri River brought increased public attention to the U.S. Army Corps of Engineers (USACE) operation of the Reservoir System.

To help understand the effects of Reservoir System operation on the 2011 Missouri River flood flows, the U.S. Geological Survey Precipitation-Runoff Modeling System was used to construct a model of the Missouri River Basin to simulate flows at streamgages and dam locations with the effects of Reservoir System operation (regulation) on flow removed. Statistical tests indicate that the Missouri River Precipitation-Runoff Modeling System model is a good fit for high-flow monthly and annual stream flow estimation. A comparison of simulated unregulated flows and measured regulated flows show that regulation greatly reduced spring peak flow events, consolidated two summer peak flow events to one with a markedly decreased magnitude, and maintained higher than normal base flow beyond the end of water year 2011. Further comparison of results indicate that without regulation, flows greater than those measured would have occurred and been sustained for much longer, frequently in excess of 30 days, and flooding associated with high-flow events would have been more severe. (October 6, 2014)

Summary of U.S. Geological Survey Reports Documenting Flood Profiles of Streams in Iowa, 1963-2012

This report summarizes 47 U.S. Geological Survey flood-profile reports that were published for streams in Iowa during a 50-year period from 1963 to 2012. Flood events profiled in the reports range from 1903 to 2010. The report summarizes flood-profile measurements, changes in flood-profile report content throughout the years, streams that were profiled in the reports, the occurrence of flood events profiled, and annual exceedance-probability estimates of observed flood events. A total of 94 stream reaches have been profiled in U.S. Geological Survey flood-profile reports. Floods were profiled for June flood events for 18 different years, followed by July flood events for 13 years, May flood events for 11 years, and April flood events for 9 years. Multiple large flood events exceeding the 2-percent annual exceedance-probability discharge estimate occurred at 37 of 98 selected streamgages during 1960-2012. Five large flood events were recorded at two streamgages in Ames during 1990-2010 and four large flood events were recorded at four other streamgages during 1973-2010. Results of Kendall's tau trend-analysis tests for 35 of 37 selected streamgages indicate that a statistically significant trend is not evident for the 1963-2012 period of record; nor is an overall clear positive or negative trend evident for the 37 streamgages. (June 25, 2014)

Streamflow Characterization and Summary of Water-Quality Data Collection during the Mississippi River Flood, April through July 2011

From April through July 2011, the U.S. Geological Survey collected surface-water samples from 69 water-quality stations and 3 flood-control structures in 4 major subbasins of the Mississippi River Basin to characterize the water quality during the 2011 Mississippi River flood. Most stations were sampled at least monthly for field parameters suspended sediment, nutrients, and selected pesticides. Samples were collected at daily to biweekly frequencies at selected sites in the case of suspended sediment. Hydro-carbon analysis was performed on samples collected at two sites in the Atchafalaya River Basin to assess the water-quality implications of opening the Morganza Floodway. Water-quality samples obtained during the flood period were collected at flows well above normal streamflow conditions at the majority of the stations throughout the Mississippi River Basin and its subbasins. (October 30, 2013)

Methods for Estimating Annual Exceedance-Probability Discharges for Streams in Iowa, Based on Data through Water Year 2010

A statewide study was performed to develop regional regression equations for estimating selected annual exceedance-probability statistics for ungaged stream sites in Iowa. The study area comprises streamgages located within Iowa and 50 miles beyond the State’s borders. Annual exceedance-probability estimates were computed for 518 streamgages by using the expected moments algorithm to fit a Pearson Type III distribution to the logarithms of annual peak discharges for each streamgage using annual peak-discharge data through 2010. The estimation of the selected statistics included a Bayesian weighted least-squares/generalized least-squares regression analysis to update regional skew coefficients for the 518 streamgages. Low-outlier and historic information were incorporated into the annual exceedance-probability analyses, and a generalized Grubbs-Beck test was used to detect multiple potentially influential low flows. Also, geographic information system software was used to measure 59 selected basin characteristics for each streamgage.

Regional regression analysis, using generalized least-squares regression, was used to develop a set of equations for each flood region in Iowa for estimating discharges for ungaged stream sites with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, which are equivalent to annual flood-frequency recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively. A total of 394 streamgages were included in the development of regional regression equations for three flood regions (regions 1, 2, and 3) that were defined for Iowa based on landform regions and soil regions. (May 9, 2013)

Summary: Rivers in eastern Iowa are in moderate flood stage after 2-3 inches of rain on snow pack and frozen ground

Crews from the Eastern Field Unit of the USGS Iowa Water Science Center went into the field on Sunday March 10th to measure high flow and repair river orifice lines damaged by high flow. Eastern Iowa received 2-3" of rain starting late Saturday and through the day Sunday; this rain fell on the snow pack and frozen ground in this area of the state. Multiple crews went into the field Sunday to measure high flow and repair river orifice lines that were damaged by the high flow. Rivers in the Iowa, lower Des Moines, Cedar, Skunk, Upper Mississippi, and Turkey/Maqouketa Basins are above flood stage. Crews are out again today measuring high flow and continue to repair orifice lines damaged by the high flow. Multiple highwater measurements will be made and repairs have been and or will be made to 6 gages. (November 3, 2013)

When Floods Hit, the USGS is There

As flooding continues in parts of Missouri, Iowa, Illinois, Wisconsin, Michigan, and Indiana due to heavy rainfall over the past seven days, the U.S. Geological Survey is maintaining its response efforts and preparing for continued flooding in the Northern Plains and upper Midwest.

So far this spring, USGS streamgages have measured approximately 17 peaks of record, and numerous flood peaks that have been the largest in more than 50 years. The USGS will be in flood response mode for the next several days as flooding continues down the Wabash and White Rivers in Indiana, the Illinois River in Illinois, and along the middle Mississippi River.

The USGS is also ready to deploy field crews to the Red River of the North Basin in North Dakota and Minnesota as air temperatures rise above freezing and snowmelt begins, and has installed seven rapid deployment gages at locations in the basin where streamflow data is needed but otherwise unavailable. Runoff and subsequent flooding is expected to begin this weekend, especially in Fargo, N.D., and Oslo, Minn. (April 25, 2013)

Summary: Flooding in Eastern and South Central Iowa

Flooding continues and expand in eastern and south central Iowa with 23 streamgages above NWS flood stage and 6 streamgages above NWS major flooding levels. Crews continue to make discharge measurements and in some locations are having a difficult time accessing the streamgages due to flooded roadways. Multiple crews are out measuring streamflow and over road flow at several sites. Thirty high-flow measurements have been made since Wednesday afternoon with a number of check measurements made to confirm shifts; discharge measurements have also been made at 9 crest stage gages since the flooding began.

Old Man's Creek near Iowa City, IA 05455100 has had a temporary orifice line installed due to damage from the high flows. The Hach Nitratax real-time nitrate sensor at this site was lost when debris and high flow damaged the river line and nitrate sensor installation.

Communities in the flooding area continue to assess damage including a mudslide on the campus of the University of Iowa. Maximum 24 hr rainfall total occurred in North Liberty, Ia which recorded 8.3 inches in 24 hours.

Johnson County sees as much as 8 inches of rain (April 19, 2013)

Flood of August 11-16, 2010, in the South Skunk River Basin, Central and Southeast Iowa

This report provides a description of the watershed, the thunderstorms, the flooding, and a profile of high-water marks measured at 20 locations along the South Skunk River. (October 31, 2012)

Bayesian WLS/GLS Regression for Regional Skewness Analysis for Regions with Large Crest Stage Gage Networks

This paper summarizes methodological advances in regional log-space skewness analyses that support flood-frequency analysis with the log Pearson Type III (LP3) distribution. A Bayesian Weighted Least Squares/Generalized Least Squares (B-WLS/B-GLS) methodology that relates observed skewness coefficient estimators to basin characteristics in conjunction with diagnostic statistics represents an extension of the previously developed B-GLS methodology. B-WLS/B-GLS has been shown to be effective in two California studies. B-WLS/B-GLS uses B-WLS to generate stable estimators of model parameters and B-GLS to estimate the precision of those B-WLS regression parameters, as well as the precision of the model. The study described here employs this methodology to develop a regional skewness model for the State of Iowa. (July 2, 2012)

Floods of July 23-26, 2010, in the Little Maquoketa River and Maquoketa River Basins, Northeast Iowa

Minor flooding occurred July 23, 2010, in the Little Maquoketa River Basin and major flooding occurred July 23-26, 2010, in the Maquoketa River Basin in northeast Iowa following severe thunderstorm activity over the region during July 22-24. A breach of the Lake Delhi Dam on July 24 aggravated flooding on the Maquoketa River. Rain gages at Manchester and Strawberry Point, Iowa, recorded 72-hour-rainfall amounts of 7.33 and 12.23 inches, respectively, on July 24. The majority of the rainfall occurred during a 48-hour period. Within the Little Maquoketa River Basin, a peak-discharge estimate of 19,000 cubic feet per second (annual flood-probability estimate of 4 to 10 percent) at the discontinued 05414500 Little Maquoketa River near Durango, Iowa streamgage on July 23 is the sixth largest flood on record. (January 23, 2012)

Has the Magnitude of Floods Across the USA Changed With Global CO2 Levels?

An increase in flood magnitudes remains one of the most anticipated impacts of climate change. Land and water resource managers are asking questions about how to estimate future flood risks and develop effective flood mitigation strategies for the future. A new report published by U.S. Geological Survey scientists in the Hydrologic Sciences Journal looks at this potential linkage using historical records looking back 127 years through 2008 at 200 locations across the United States. (November 16, 2011)

Year of The Flood

Devastating floods across much of the U.S. were severe and unrelenting during the spring and summer of 2011. When floods happen, USGS crews are among the first-responders. Often working in dangerous conditions, USGS scientists measure streamflow and river levels, repair and install streamgages, measure water quality and changes in sediment flow, and assess river changes. From flood forecasts to difficult decisions about flood management, science is critical for flood preparations and response. (September 1, 2011)

USGS Notes Flood's Quirks

Omaha World-Herald story on the USGS and the Missouri River Flood (July 11, 2011)

Six New Streamflow Gages Available for Flood Forecasting

USGS recently installed six rapid-deployment streamgages to monitor flooding in the Missouri River basin. Four of the streamgages are located in Council Bluffs, two each on Mosquito Creek and Indian Creek. Another is located on Willow Creek near Logan, and the final is located near the intersection of Interstate 29 and State Highway V near Hamburg. Equipment installed at the sites include a non-contact radar sensor and data collection platform that records the height of the water surface at 15-minute intervals. The data are transmitted hourly via satellite and made available to the public via NWISWeb. The streamgages are operated in cooperation with the Omaha District of the U.S. Army Corps of Engineers. For more information, contact the Iowa Water Science Center at (319) 337-4191.

06610502 Indian Creek at Sylvan Drive at Council Bluffs, IA

06610504 Indian Creek at US Highway 275 at Council Bluffs, IA

06610645 Mosquito Creek at Yellow Pole Road at Council Bluffs, IA

06610658 Mosquito Creek upstream of I-29 at Council Bluffs, IA

403514095393101 Missouri River Overflow at I-29 near Hamburg, IA
(June 28, 2011)

Increased Discharge Measurements of Streamgages Located on the Missouri River

In response to flooding on the Missouri River, USGS is currently making weekly discharge measurements at streamgages located at Sioux City, Iowa, and at Decatur, Blair, Omaha, Plattsmouth, Nebraska City, Brownville, and Rulo, Nebraska. Discharge measurements are made three times per week on the Missouri River at Yankton, South Dakota. The data collected in the field are used to verify the current stage-discharge rating for each streamgage, and are also used by the National Weather Service and the U.S. Army Corps of Engineers in support of river forecasting and gate operations. For more information, contact the Central Midwest Water Science Center in Iowa City, Iowa r at (319) 337-4191. (June 28, 2011)