Climatologist: Iowa 'vulnerable' to continuing drought
State in worse situation than a year ago, despite above-normal winter precipitation
“Vulnerable” is the word most often used by climatologist Brian Fuchs to describe the prospects of a second straight drought year in Iowa.
“We’re in a worse situation than we were a year ago, and we will be talking about drought issues again in 2013,” said Fuchs, who works at the National Drought Mitigation Center in Lincoln, Neb.
Although precipitation in Iowa has been slightly above normal this winter, “that is not a drought breaker, given the deficits at the end of 2012,” he said.
State Climatologist Harry Hillaker agreed Monday that the recent return to normal precipitation levels does not signal an end to the drought.
“It’s hard to know the long-term implications because this is the driest time of the year. The critical months, from March onward, will tell us a lot more about the status of the drought,” he said.
“If we fall below normal in the March through May period, we will have missed our best chance to catch up,” said Tim Hall, coordinator of the Governor’s Drought Task Force, which on Feb. 7 issued its most recent Water Summary Report.
Hall said declining ground water is the task force’s greatest current concern.
In parts of northwest Iowa, where concentrated livestock feeding operations place year-round demand on water supplies, shallow ground water is lower now than it was in the depths of summer and 7 ½ feet lower than it was a year ago, Hall said.
“Many Iowa cities that depend on shallow aquifers for drinking water are dusting off their water conservation plans,” he said.
In Cedar Rapids, which draws much of its water from shallow wells, the water department last month diverted water from the Cedar River into an 8-foot-deep channel designed to recharge a shallow aquifer that feeds city wells.
Fuchs said Iowa’s drought status is much worse now than it was a year ago.
About 54 percent of the state is in severe, extreme or exceptional drought, which compares with 24 percent of the state a year ago, he said.
While only one-third of the state fell under any drought classification a year ago, the entire state does now, he said.
Fuchs said the state gets progressively drier from east to west, prompting him to predict a central Iowa demarcation line separating more favorable growing conditions in Eastern Iowa from less favorable conditions in the west.
Recent rains, heavy is some areas, ran quickly off frozen ground, doing little if anything to replenish subsoil moisture.
That runoff, however, improved stream flows to normal levels in most parts of Iowa and to above-normal levels in far southeast Iowa, according to the Feb. 7 Water Summary Report.
Dan Christiansen, a hydrologist with the U.S. Geological Survey in Iowa City, cautioned that winter stream flows can be deceptive because ice dams and other anomalies can distort gauge readings.
Recent runoff in Iowa and other Midwest states has alleviated low flows that had been disrupting barge traffic on the Mississippi River below St. Louis, according to Hillaker.
Lake levels continue to drop, with Saylorville Lake, an impoundment of the Des Moines River in central Iowa, standing Monday at more than 6 feet lower than its normal pool.
Both Hillaker and Fuchs said it is hard to get a handle on subsoil moisture because accurate data is scarce.
“We know for sure that shallow wells and aquifers are lower than they were a year ago,” Hillaker said.Low-water-related winter fish kills have not materialized, in part because clear ice with little snow cover has allowed sufficient light penetration to support oxygen-producing vegetation, Department of Natural Resources fisheries biologist Paul Sleeper said.