The heavy rainfall across the Midwest in recent weeks has increased the risk of flooding on the Illinois and Mississippi Rivers. Rainfall totals were highest in western Illinois, northern Missouri, much of Iowa, southeastern Minnesota, and western Wisconsin, and ranged from 6 to 12 inches in the last 30 days. See the MRCC map below.
The National Weather Service produces forecasts of river levels based on current conditions and precipitation over the next 24 hours. At Quincy Lock and Dam, the Mighty Mississippi River is expected to be in “major” flood by sometime Thursday (first graph). See the latest forecast for this site here.
It is a similar story on the lower Illinois River. The current and forecasted river stage at Hardin, IL (second graph) shows that the river will reach “major” flood stage by next Monday. See the latest forecast for this site here. Of course, more rainfall in coming days will change these forecasts.
On Saturday, the US Corps of Engineers began releasing water from Lake Carlyle (east of St. Louis), which flows down the Kaskaskia River into the Mississippi River near Thebes. They kept the water level higher than usual on Lake Carlyle this fall, in anticipation of this move. As the article below states, it’s a short-term measure.
And for you drought history buffs, during the 1988 drought Governor Thompson (Illinois) suggested increasing flow out of Lake Michigan and down the Illinois River to aid in navigation on the Mississippi River. Stan Changnon discussed this in an article on the 1988 drought and it’s impacts on the barge and railroad industries. The abstract of that article summarizes the situation:
The drought of 1988 rated as one of the nation’s worst in the past 100 years, resulting in a myriad of impacts and responses. A notable, largely unexpected impact involved stoppages of barge traffic on the lower Mississippi River during June and July, a result of shallow areas produced by record low flows and shoaling. The barge industry hauls 45% of all bulk commodities (grains, coal, petroleum) shipped in the central United States. The low flows were a result of the unusually large areas extent of drought conditions across most of the Mississippi Basin, which comprises 40% of the continental United States. Most 1987 months had been relatively warm and dry, minimizing moisture in the soils and shallow ground water. Then deficient snowmelt (due to low winter snow-falls) and record low spring 1988 precipitation combined to produce the record low flows along much of the Mississippi River.
Most responses to the drought came in a crisis mode and included concentrated dredging to open channels, government enforced reductions in barge loads and in numbers of barges per tow, tripled barge shipping rates, and shifts in transportation modes. The barge industry suffered a 20% income loss. The total losses to the barge industry coupled with higher costs for shipping were $1 billion. The Illinois Central Railroad, which parallels the major blocked waterways, used a climate prediction to anticipate the low flows 3 months in advance. They leased additional cars to help handle the increased shipments transferred from barges and made a sizable profit. A response proposed by Illinois and shippers—a temporary increase in the water diverted from lake Michigan to raise the levels on the lower Mississippi River—was met with strong objections by other lake states and Canada. The federal government declined the proposal, but the sizable controversy it engendered reflects the growing sensitivity to water resources issues in the Great Lakes Basin and is also illustrative of problems to be expected from a drier future climate (as hypothesized by certain global climate models as a result of ever-increasing trace gases in the atmosphere). This case study illustrates the value of using seasonal climate predictions of limited skill, and the need for better near real-time climatic data, including information about physical impacts of current climatic conditions.