Overview of the April-May Southern Illinois Flood
Record rainfall along the Ohio River Valley, nearly 300 percent of normal precipitation, in conjunction with snowmelt across the upper Midwest, caused record flooding along the Ohio and lower Mississippi Rivers this spring. At the confluence of the Ohio and Mississippi Rivers, the above-average water flow of each combined to cause the Ohio River to crest at a record level at Cairo, the Mississippi River to inundate the lower half of Alexander County, and the Corps of Engineers to utilize the Birds Point Floodway for only the second time since its inception.
Heavy rainfall in the month of April, most of it coming in the last 10 days of the month, led to flooding on several other rivers in southern Illinois: Big Muddy River, Cache River, Embarras River, Kaskaskia River, Little Wabash River, Skillet Fork, and the Wabash River. As shown in the NWS precipitation map below, the southern portion of Illinois experienced rainfall amounts for the month of April in the 10-20 inch range. All of that rainfall led to flooding in numerous communities which led to damaged structures, evacuations, and road closures. Thousands of acres of farmland were also flooded.
New Stage Records were set at several gages:
- Ohio River at Cairo: 61.72 ft 5/2/2011
- Ohio River at Smithland L&D TW: 54.89 ft 5/6/2011 *Newer gage with a short period of record
- Wabash River at Mt. Carmel: 34.02 ft 5/3/2011
- Big Muddy River at Plumfield: 34.68 ft 5/4/2011
- Big Muddy River at Murphysboro: 40.46 ft 5/3/2011
Preliminary Damage assessments conducted jointly by federal, state, and local officials after the flood estimated the cost for the Individual Assistance program at $13, 274,712. The total number of residences impacted was 955, of which 109 were destroyed, 348 suffered major damage, 377 suffered minor damage, and 121 were affected. Another 87 businesses suffered flood damages also.
In June, Federal officials approved a declaration finding 14 southern Illinois counties to be disaster areas. The counties of Alexander, Franklin, Gallatin, Hardin, Jackson, Lawrence, Massac, Perry, Pope, Pulaski, Randolph, Saline, White, and Williamson were included. An additional seven counties: Hamilton, Jefferson, Marion, Union, Washington and Wayne were included for the Public Assistance program only. Later in June, Wabash County was added to the presidential disaster declaration for both programs.
In the first three weeks since the original federal declaration was approved on June 7, approximately 1,000 people have applied for federal assistance.
OWR During The Flood Event
The Office of Water Resources provided information to IEMA (generally twice a day) regarding impacts to communities and facilities from current and projected flood stages. This information was in the form of flood inundation maps that show the aerial extent of current and forecasted flooding, maps and tables identifying the amount of freeboard available at leveed areas and non-leveed communities, identification of potential areas of concern resulting from sand boils, levee slumps, excessive interior seepage and other potential levee/floodwall failures, and identification of actual levee failures or overtopping of levees.
We provided back checking and confirmation of field reports provided to IEMA from various sources using our field personnel and other technical contacts. We provided daily briefings regarding flood stages and precipitation to other state agencies on numerous conference calls arranged by the Governor's staff. We set highwater marks at various locations that will be used in post-flood evaluations. We provided technical assistance to IDNR legal staff pertaining to the issue of whether the New Madrid floodway in Missouri should have been used.
Federal Disaster Counties
Flooding began when the Lower Cache River overflowed its banks. With the rising Mississippi River backwatering up the Cache cutoff, floodwater caused by all of the heavy rains could not drain out of the system. The communities of Olive Branch, Tamms, and Unity were all experiencing flooding. In Olive Branch, over 50 homes were flooded. Highwater marks set by OWR personnel were approximately 3 ft above the ground.
The Mississippi River was also flooding the southern portion of the county. Dogtooth Island was completely inundated flooding out the small communities of Miller City and Willard. On May 2 the Lens Small levee breached and overtopped at several locations. A Highwater mark set by OWR personnel was approximately 4.85 ft above the ground in Willard.
In Cairo, the high water on the Ohio River caused seepage under the levee and created a large sand boil and a second smaller boil along the northern portion of town near 34th St. Along Commercial Street in downtown, several sink holes formed necessitating the closure of the street. A mandatory evacuation order was given for Cairo. As noted earlier the Ohio River gage crested at 61.72 ft, 2.21 ft higher than the previous record. As shown in the stage hydrograph plot below, when the New Madrid Floodway was opened on May 2, the stage reduction at Cairo was approximately 1.85 ft.
Floodwaters from the Upper Cache River and from the Ohio River (backwater up the Post Creek Cutoff) were flowing through the Karnak levee breach into the lower Cache River and causing problems for the communities of Karnak, Ullin, and Tamms. In Tamms, the Cache River didn't directly flood the village, but rather with the high stages on the Cache the village had to keep their flap gates closed and therefore couldn't drain the interior storm water by gravity. Tamms had to pump out their interior storm water. With the large amounts of rainfall at the end of April, the pumps couldn't keep up and the center section of town along their drainage ditch flooded several homes. A Highwater mark set by OWR personnel was approximately 4.6 ft above the ground
The extended period of highwater on the lower Mississippi River has continued to cause flood problems for East Cape Girardeau. Interior drainage has caused flooding to some structures and threatened to close IL Rte 146. East Cape Girardeau is included in the Wolf Lake Drainage & Levee District, but there are no pumpstations to alleviate the interior drainage. Their gravity drains help during low water times. Several christifoli pumps have been pumping nonstop to reduce the interior flood threat.
Floodwater from the Wabash River was flowing overland and emptying into the Saline River watershed before making its way back to the Ohio River. The entire town of Junction, in the path of the overland flow, was flooded as well as most of IL Rte 1 through Gallatin Co. In Junction over 30 structures were affected by floodwater, some with water nearly to the top of the first floor windows. During the flood event approximately 2/3 of Old Shawneetown was flooded, but not from a failure of the levee protecting the town from the Ohio River. The primary cause of flooding was from interior drainage problems and seepage either through or under the levee. The highwater mark set by OWR personnel was 3.6 ft above the ground. The town of New Haven sits just above the Junction of the Little Wabash River and Wabash Rivers. The east side of town was completely inundated by floodwaters. At least 50 homes were flooded and another 30 plus outbuildings and or other similar structure types. Down near the public boat ramp, the highwater mark set by OWR personnel was 7 ft above the ground.
A few homes along the riverfront in Elizabethtown experienced structural flooding, as did several along an unnamed creek on the west side of town, (backwater from the Ohio River.) The sewage system flooded causing a voluntary evacuation order to be given. The highwater mark set by OWR personnel was 3.6 ft above the ground.
The Grand Tower Levee along the Big Muddy River experienced some slumping issues and a gate failure. A significant amount of rock and sandbags were dumped along the base of the gate structure to help stop the leaking pipe. The levee has a history of slumping. Plastic and sandbags were used to cover new slumps, (as shown in the picture ) to help prevent additional erosion. In Murphysboro, the Big Muddy River set a new stage record and caused flooding to homes, businesses, and the riverside park on the west side of town. The trailer park upstream of IL Rte 13 and businesses along Amusement Park Dr were flooded. A group of homes on the right bank downstream of IL Rte 13 were flooded as well. A Highwater mark set by OWR personnel was approximately 2.9 ft above the ground at a church located near the IL Rte 127 bridge.
On May 3, the Cross Levee ( also referred to as the Russell-Allison Levee) breached in three locations along the Embarras River near it's junction with the Wabash River. Floodwaters flowed through the breaches floodin the entire community of Westport and causing significant road way and agricultural flooding. This levee also breached during the 2008 flood.
In Joppa, two homes near the intersection of Main St and North Ave were significantly flooded by the Ohio River. Another home located to the west on Main St had to sandbag their home to prevent flooding. A highwater mark set by OWR personnel measured 4.1 ft above the ground. At Metropolis, flooding by the Ohio River damaged more than 100 homes and additional garages and outbuildings. Flood-fighting efforts included filling more than 400,000 sandbags. The casino and accompanying hotel were shut down for over a month due to flooding. Several homes along third street west of the downtown area were impacted by floodwaters, damaging some and isolating others. On the east side of downtown along 2nd St and 3Rd St, homes experienced flooding. On the east side of Metropolis, the Ohio River backwatered up a Creek and flooded the WoodHaven subdivision. The ring levee constructed of sandbags could not prevent the floodwater from causing damages. In Brookport the only a few structures were flooded due to interior drainage problems. While there was concern over the integrity of the levee protecting Brookport, the levee held.
The homes along Halltown Rd, outside of the Golconda levee were flooded with several feet of water as the Ohio River caused backwater flooding along Miller Creek.
Floodwaters from the Upper Cache River and from the Ohio River (backwater up the Post Creek Cutoff) were flowing through the Karnak levee breach into the lower Cache River and causing problems for the communities of Karnak, Ullin, and Tamms. In Karnak, the Cache River didn't directly flood the village, but rather with the high stages on the Cache they had to keep their flap gates closed and therefore couldn't drain the interior storm water by gravity. Karnak had to pump out their interior storm water. With the large amounts of rainfall at the end of April, the pumps couldn't keep up and the center section of town along their drainage ditch flooded several homes.
In Ullin, the Cache River, located on the south side of town caused flood issues for residents living near the creek. A tributary running through the middle of town, Indian Camp Creek, also created some flood problems.
In Carmi, Both IL Rte and Rte 14 were closed at the river bridge on the east side of town. . More than a dozen homes were flooded. This flood event was the second highest event recorded at the gage. Flooding would have been substantially worse if it were not for the buyouts along the east side of town by the river. Emma, located on the Little Wabash River, approximately 15 homes were flooded. All roads leading to Emma were flooded completely isolating the community. The village of Maunie, along the Wabash River, experienced significant flooding as seen in the photo. Well over half of the town, at least 50 or more structures were flooded. With all the surrounding roads flooded, the only access was by boat. The highwater mark set by OWR personnel was 2.77 ft above the ground.