Quad Cities, IA/IL

Weather Forecast Office

Review of The 2008 Flood

Overview

In June of 2008 historic river flooding occurred across much of eastern Iowa. The setup for flooding began almost a year prior as a long term wet pattern primed the area for floods. Well above normal rain fell in the fall of 2007, heavy snow fell during the winter months, and then rains of 3 to 7 inches above normal for April kept soils saturated throughout the area. Portions of northeast Iowa observed soil moisture greater than 125 percent of normal. With soil conditions conducive to extreme runoff and rivers already running high going into June, the wet pattern continued with record rainfall through the first half of June. This water swelled the rivers with record levels observed throughout much of eastern Iowa causing extreme impacts to many cities and rural communities, county and state infrastructure, agricultural land, etc.

Oakville, IA
June 2008

Cedar Rapids, IA
June 13, 2008
Courtesy: Iowa HSEMD/CAP

Before the Flood
The Flood
Photos
Radar & Rainfall Maps
2008 River Crest Levels
Environment
Additional Information

Conditions Before the Flood


Fall 2007 Rainfall 5 to 10 Inches	Winter 2007-08 Snowfall 40 - 60 Inches	Winter 2007-08 Snowfall 1.5 to 2.5 Times Above Normal	Spring 2008 Rainfall 10 - 20 Inches


Mid Feb. 2008 Snow Depth	April 2008 Rainfall	April 2008 River Levels	May 2008 Soil Moisture Content

The 2008 Flood

June 2008

With extremely wet soils and rivers already running high, two heavy rainfall events occurred in early June. These events saw the rain turn almost completely into runoff as saturated soils left no storage for the water. The first event was June 4th and 5th, where the axis of heavy rain fell from central Iowa into southern and central Wisconsin. The second event was June 8th and 9th. While much of eastern Iowa observed at least an inch, the areas that were the most wet across the northeast quadrant were hit with another 1.50 to 3.00 inches. Because of all of this rain, by June 12, 2008 record flooding was already occurring or expected for many eastern Iowa rivers.

The Flash Flood of June 12-13, 2008

Record flooding was ongoing on many rivers in eastern Iowa by June 12th. Then, another significant heavy rainfall event occurred the night of June 12^th and morning of June 13^{th. The axis of the heavy rain in this event fell on top of the}already record flood moving down the Cedar and Iowa River basins. This flash flood raised river levels significantly and was a key contributor to the crest at Cedar Rapids being over 11 feet above the previous record.

One measure of the magnitude of the flooding was that the staff gage in Vinton, IA was raised to be able to read higher levels, and the water in Cedar Rapids was so high, it overflowed the streamgage. The United States Geological Survey (USGS) was able to take a few manual measurements, but due to the gage loss, real-time information on river stages and flow was minimal.

Columbus Junction to the Mississippi River

The Iowa and Cedar Rivers meet at Columbus Junction, IA. At this point the crests from both rivers hit at nearly the same time, and the combined river flow going down the lower part of the Iowa River was nearly twice that which occurred during the Great Flood of 1993. Several levees breeched in this stretch of the river, but the most notable being the levee just west of the city of Oakville. Water that moved through this levee failure flooded the entire town.

From the entry of the Iowa River into the Mississippi River, the extreme amounts of water also caused record flooding on the Mississippi River as 1993 flood levels were passed from the Keithsburg, IL area through Burlington, IA.


Vinton, IA	Palo, IA	Iowa City, IA

Photos Courtesy of the Civil Air Patrol


Cedar River June 13, 2008	Cedar Rapids Bridge June 16, 2008	Cedar Rapids Bridge June 16, 2008


Cedar River June 13, 2008	Coralville Spillway	Cedar - Iowa Confluence


Columbus Junction	Oakville Breach	Oakville

Radar/Rainfall Maps

Cedar Rapids Rainfall Graph June 2 to June 15 2008

Regional Rainfall June 1-15 2008

June 5 Interactive Radar Loop	June 8 Interactive Radar Loop	June 12 Interactive Radar Loop

2008 River Crest Levels

The Flood of 2008 resulted in record flooding along the length of the Cedar, much of the Iowa, and parts of the Wapsipinicon and Mississippi rivers. The new record crests ranged from just under one half foot at Keithsburg, IL to over 11 feet at Cedar Rapids, Iowa.

Anamosa Hydrograph

Cedar Rapids Hydrograph

Conesville Hydrograph

Iowa City Hydrograph

Wapello Hydrograph

Location	Flood Stage	Previous Record Level	2008 Crest Level
Mississippi River
New Boston	15	25.90 - 7/09/1993	25.20 - 6/17/2008
Keithsburg	14	24.15 - 7/09/1993	24.49 - 6/17/2008
Gladstone	10	21.54 - 7/10/1993	22.46 - 6/17/2008
Burlington	15	25.10 - 7/10/1993	25.73 - 6/17/2008
Keokuk	16	27.58 - 7/10/1993	26.95 - 6/17/2008
Gregory Landing	15	28.49 - 7/09/1993	27.60 - 6/18/2008

Wapsipinicon
Anamosa	14	22.90 - 7/21/1968	26.18 - 6/13/2008
De Witt	11	14.19 - 6/17/1990	14.13 - 6/16/2008

Cedar
Vinton	15	19.30 - 3/30/1961	24.70 - 6/12/2008
Cedar Rapids	12	20.00 - 3/18/1929*	31.12 - 6/13/2008
Conesville	13	17.11 - 4/06/1993	23.40 - 6/15/2008

Iowa
Marengo	14	20.31 - 7/19/1993	21.38 - 6/12/2008
Iowa City	22	28.52 - 8/10/1993	31.53 - 6/15/2008
Lone Tree	15	22.94 - 7/07/1993	23.10 - 6/15/2008
Columbus Junction	19	28.30 - 7/07/1993	32.30 - 6/15/2008
Wapello	20	29.53 - 7/07/1993	32.15 - 6/14/2008