Monthly Water Resource Summary

August, 2023

Precipitation

August 2023 precipitation for the state of Indiana was slightly above normal, with average temperatures slightly below normal. The statewide monthly precipitation average was 108 percent of normal. The overall monthly temperature average for Indiana was 72.2 degrees Fahrenheit or 0.5 degrees below normal.

Five of the nine climate divisions received above or much above normal precipitation for August (see Percent of Normal Precipitation Table). Climate Division 7 (SW) received the highest (153.9) percentage of normal precipitation for the month, while Climate Division 3 (NE) received the lowest (64.6) percentage.

Precipitation for the year to date (2023) ranges from 91.4% to 112.0% through August. For the Water Year 2023, all nine climate divisions received below normal precipitation, ranging from 78.8% to 98.6%. Over the longer duration (from September 2021-August 2023) six of the nine climate divisions have received slightly below normal precipitation ranging from 92.4% for Climate Division 4 (WC) to 102.7% for Climate Division 7 (SW).

The 12-month SPI indices shows Climate Division 6 (EC) in the “moderately dry” category; with the remaining climate divisions in the “near normal” category.  The 6-month, 3-month, and 1-month SPI indices shows Climate Division 8 (SC) in the “moderately wet” category; with the remaining climate divisions in the “near normal” category.

• Table of recent precipitation compared to normal for each climatic division of the state.
• Standardized Precipitation Index (SPI) drought maps for the state for current month.
• Explanation of Standardized Precipitation Index (SPI)

U. S. Drought Monitor

For August 29, 2023, the U.S. Drought Monitor shows small portions of northeast, northwest, and west-central Indiana are experiencing “Abnormally Dry” conditions, while the rest of the state is not experiencing drought conditions. The U.S. Seasonal Drought Outlook predicts drought conditions to develop for all of Indiana, except the eastern third and along the Ohio River by the end of November 2023.

• State Map
• Latest U.S. Drought Monitor Map for the United States 
• Learn more about the U.S. Drought Monitor 

Streamflow

In August 2023, all the streams included in drought reporting since 1999 had below normal to much below normal streamflow. Muscatatuck River near Deputy had the lowest mean monthly flow at 32%, and the White River near Centerton had the highest mean monthly flow at 97%.

Detailed Information on Streamflow

Lake Michigan

On September 1, 2023, the Lake Michigan-Huron forecasted water level was one inch below the measurement taken on August 1, 2023, and 3 inches below the measurement taken on September 1, 2022. On August 31, 2023, the Michigan-Huron level was 579.66 feet, which is about 36 inches above the lowest recorded monthly mean level for August set in 1964. Comparison of August monthly mean water levels to the long-term (1918-present) average shows Lakes Michigan-Huron water levels were about 5 inches above the average. All Lake Michigan-Huron data are referenced to the International Great Lakes Datum 1985.

The Lake Michigan-Huron water level is forecast by the U.S. Army Corps of Engineers to fall 3 inches over the next month.

Reservoirs

On August 31, 2023, the water levels for seven of the eight reservoirs monitored by the U.S. Army Corps of Engineers were at or above the normal pool elevation. The deviation from normal pool ranged from -0.95 feet (Salamonie) to +2.06 feet (Roush).

Two of the three reservoirs monitored by Citizens Water, Eagle Creek and Morse were above their respective normal pool elevations as of August 31, 2023. The deviation from normal pools ranged from -0.03 feet (Geist) to +0.45 feet (Eagle Creek).

Groundwater Levels

As of September 1, 2023, new water level data is available for all nine wells currently monitored. Of the nine wells monitored, data indicates that water levels are below to well below normal for Laporte 9, Fulton 7, Lagrange 2, Vigo 7, Morgan 4, Randolph 3, and Posey 3. Groundwater levels are near normal for 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:
http://waterdata.usgs.gov/in/nwis/current/?type=gw

• Detailed information on groundwater levels

Acknowledgments
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)

Streamflow:
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