Wet Soil Conditions in Illinois

[June 20, 2015]  CHAMPAIGN – Higher than normal rainfall across most of the state has led to wet soil conditions, according to Jennie Atkins, Water and Atmospheric Resources Monitoring (WARM) Program Manager at the Illinois State Water Survey, Prairie Research Institute, University of Illinois.

Soil moisture levels were higher than normal in mid-June, averaging 0.37 water fraction by volume (wfv) at 2 inches on June 14, or 39 percent above the long-term average. Levels steadily increased in the second week of June with additional rainfall. Similar increases were seen at depths of 4 and 8 inches. No significant changes occurred at 20-inch or greater depths, though soil moisture levels remained high.

Rains over the weekend did not, on average, significantly increase soil moisture levels. However, impacts were seen at individual locations, particularly in northern Illinois. Freeport in Stephenson County received 3.07 inches of rain June 11 – 14, resulting in a 54 percent increase in 2-inch soil moisture levels and 88 percent increase in the 4-inch levels. Similar increases were observed at St. Charles in Kane County where levels increased 54 and 44 percent at 2 and 4 inches, respectively, after 2.48 inches of rainfall.

Soil temperatures in mid-June were also higher than the long-term average. Statewide soil temperatures at 4 inches under bare soil averaged 78.1 degrees F, 4.8 degrees above the long-term average. Similar numbers were seen with temperatures under sod with averages of 77.0 degrees at 4 inches and 74.7 degrees at 8 inches, 4.0 and 2.8 degrees above the long-term average, respectively.

The Illinois State Water Survey’s WARM Program collects hourly and daily weather and soil information at 19 stations across the state. Daily and monthly summaries can be found at the WARM website http://www.isws.illinois.edu/ warm/  and in the Illinois Water and Climate Summary http://www.isws.illinois.edu/warm/ climate.asp.   Maps of soil temperatures and moisture levels can also be found at the WARM website.

[Lisa Sheppard, Illinois State Water Survey]