This month, the National Oceanic and Atmospheric Administration confirmed what many people already knew – 2012 was the warmest year on record for the lower 48 contiguous states.
NOAA also reports that 2012 was the 10th driest year in Illinois since record keeping in the state began in 1895.
“(DeKalb County was) down 12.55 inches from normal (precipitation levels),” said Gilbert Sebenste, staff meteorologist at Northern Illinois University. DeKalb County received 24.24 inches of rain and melted snow last year – 34 percent less than the average of 36.79 inches.
Dry weather meant a rough harvest for farmers; corn yields for 2012 were down 34 percent from the previous year. The drought was the topic of two talks at the Northern Illinois Farm Show, and farmers and non-farmers alike are concerned as the 2013 growing season approaches.
The Cause
“What happened is that last year we were in a La Nina,” Sebenste said of the long-term weather system that prevailed over much of the continental United States. “The waters off the central Pacific Ocean were cooler than normal. It may not sound like it, but that has a serious effect on the weather.”
A high pressure system over the central U.S. forced the jet stream to steer storm systems that would normally have hit the Midwest north into Canada or south into the Gulf of Mexico.
Surface Water
The most obvious effect of the drought for many DeKalb County residents is the drop in water levels in rivers, streams, ponds and lakes. Steve Bock said his farm pond at Honey Hill Orchard in Waterman is one-half its usual depth.
“It is fed from a creek which is tied into field tiles that normally are still running,” he said.
Beyond small bodies of water like farm ponds, low surface waters can have more disastrous effects. Barge traffic on the Mississippi River carries millions of tons of corn and soybeans from the Great Plains to the Gulf of Mexico each year and brings other commodities like fertilizer north from the Gulf.
The river has fallen low enough to prompt the U.S. Army Corps of Engineers to warn that it soon could become unnavigable to most barge traffic.
Agriculture would be among the sectors affected by barge traffic interruptions, said Joe White, who farms near Elburn and serves as president of the Kane County Farm Bureau.
Without barge traffic, the grain would have to be transported by trucks and trains, which are costlier and could lead to higher supermarket prices. Farmers could also pay up to 25 percent more for fertilizer, White said, judging by early quotes some farmers have gotten on delivery by ground transportation.
Aquifers
Fortunately, aquifers do not react quickly to changes in surface precipitation and underground water levels are not a cause for concern.
“We do monthly tests on our aquifers where we measure the static water table level,” said Bryan Faivre, assistant director of public works for the city of DeKalb. “I haven’t seen any change from drought and the water table has been relatively stable.”
The city maintains nine wells of varying depths.
“The general rule is that the deeper the aquifer, the less it will react on a short-term basis,” said professor Collin Booth, chair of the geology department at NIU. Nonetheless, some of the shallower aquifers Booth has studied “in the later part of 2012 were the lowest thing we have seen in a few years,” he said. Aquifers are normally recharged by winter and spring precipitation.
“If we have another spring like we had last year, we will have some problems,” he said.
Planting Season
Russ Higgins, commercial agriculture educator for the University of Illinois Extension, spoke at the farm show about ways the drought may affect farming practices in 2013. Drought-stricken plants did not use as much nitrogen last year as they normally would, he said, leaving more water-soluble nitrogen in the soil than usual. He said farmers should test their soil nitrogen levels carefully before applying fertilizer this spring.
Higgins encouraged farmers to reduce the number of tillage trips they make in their fields, but noted that there is little else they can do to prepare for another possible year of drought.
“We are encouraging producers not to overreact,” he said. “But there is really not a lot they can do about the weather. We are going to hope that 2013 is going to be better.”
Forecast for 2013
Sebenste said that the La Nina system lasted longer than usual last year, but neither La Nina or El Nino will be factors in the weather systems over Illinois this year, which is cause for guarded optimism. Though he said much of DeKalb County is in a “moderate drought,” that is less severe than other parts of the country that remain in severe, extreme, or exceptional droughts.
“We are not out of this drought by any means,” Sebenste told an audience at the DeKalb County Farm Bureau last week. After La Nina “it will take a while for the atmosphere to reset and get back to normal weather patterns.”
Sebenste said some weather models predict slightly higher-than-average precipitation for DeKalb County this spring, but he remains cautious, noting that unforeseen events like hurricanes and tropical storms can change the jet stream’s long-term pattern in a matter of days.
“Even the best computer models did not predict the 2012 drought,” he said.
Shaw Media reporter Jonathan Bilyk contributed to this article.
