Monthly Water Resource Summary

May, 2018


For May 2018, Indiana’s precipitation was generally below normal, with average temperature above normal. The statewide monthly precipitation average was 67.4 percent of normal. The overall monthly temperature average for Indiana was 70.1 degrees Fahrenheit or 8.7 degrees above normal.

Two of the nine climate divisions received above normal precipitation for the month of May. The north-central climate division received the highest (116.8) percentage of normal precipitation for the month; the central climate division received the lowest (42.7) percentage of normal precipitation.

For the year to date, all nine climate divisions have received above normal to well above normal precipitation, ranging from 101.9 percent of normal for the east-central climate division to 122.9 percent of normal for the north-central climate division. For the 2018 water year, which began October 1, 2017, total precipitation is near or above normal for all the nine climate divisions (99.2% to 120.6% percent of normal). Beginning January 2017, all nine climate divisions have received above normal precipitation. These range from 100.3 percent in the southwestern division to 118.7 percent for the northeastern division.

The Standardized Precipitation Index (SPI) long-term 12-month indices shows the northwestern and north-central climate divisions in the “moderately wet” category with the remaining climate divisions in the “near normal” category. The SPI for the 6-month and 3-month indices shows all climate division in the “near normal” category.  The SPI for the 1-month indices shows the central and east-central climate divisions in the “moderately dry” category and the remaining climate divisions in the “near normal” category. 

U. S. Drought Monitor

For the period ending May 29, 2018, the U.S. Drought Monitor shows a small area of “abnormally dry” conditions in the southwest part of the state. The U.S. Seasonal Drought Outlook predicts no drought conditions for the state through the end of August 2018.


Of the twelve streams included in drought reporting since 1999, two had stream flows near to above normal. The Kankakee River at Shelby had the highest mean monthly flow at 121% and the Muscatatuck River near Deputy had the lowest mean monthly flow at 18%.

Detailed Information on Streamflow

Lake Michigan

The Lake Michigan-Huron water level for June 1, 2018 was four inches above the measurement taken on June 1, 2017, and four inches above the measurement reported on May 1, 2018.  On May 31, 2018 the Michigan-Huron level was 580.60 feet, which is approximately 48 inches above the lowest recorded monthly mean level for May set in 1964. Comparison of May monthly mean water levels to the long-term (1918-present) average shows Lakes Michigan-Huron water levels were approximately 17 inches above the average. All Lake Michigan-Huron data are referenced to the International Great Lakes Datum 1985.

The U.S. Army Corps of Engineers predicts the Lake Michigan-Huron water level to rise about three inches over the next month.


On June 1, 2018, the water levels for seven of the eight Indiana reservoirs monitored by the U.S. Army Corps of Engineers were above normal pool elevation. The deviation from normal pools ranged from 0.7 feet below (Salamonie) to 4.9 feet above (Patoka). 

The water levels of all three reservoirs monitored by Citizens Energy Group (Morse, Geist and Eagle) were above their respective normal pool elevations as of June 4, 2018.  The deviation from normal pools ranged from 0.06 feet (Morse) to 1.27 feet (Eagle Creek).

Groundwater Levels

As of May 31, 2018 new water level data was available for all nine wells currently monitored.  Of the nine wells monitored, data indicate the groundwater levels for LaGrange 2 and Vigo 7 are above normal for their respective mean monthly level. The mean monthly groundwater level is near normal for LaPorte 9 and below normal for Fulton 7, Morgan 4, Randolph 3, Posey 3, Harrison 8 and Clark 20. 

Real-time data are available for all nine observation wells. The real-time information may be accessed on the following U.S. Geological Survey website:

This report has been compiled from Division of Water data and from information supplied by the following:

Precipitation data:
National Oceanic and Atmospheric Administration, National Weather Service, Midwestern Regional Climate Center

Standardized Precipitation Index (SPI):
National Drought Mitigation Center (NDMC) and Western Regional Climate Center (WRCC)

U.S. Geological Survey and State of Indiana cooperative program

Lake Michigan level data:
U.S. Army Corps of Engineers, Detroit District

Reservoir data:
U.S. Army Corps of Engineers, Louisville District

Groundwater level data:
U.S. Geological Survey and State of Indiana cooperative program

Temperature data:
Midwestern Regional Climate Center and Indiana State Climate Office, Purdue University