USGS research to help industry pros better quantify groundwater resources in MN
With the help of new research conducted by the U.S. Geological Survey, water resource managers are able to quantify critical groundwater resources and assess the sustainability of long-term water use in the state of Minnesota.
May 18, 2015 -- With the help of new research conducted by the U.S. Geological Survey (USGS), in partnership with the Minnesota Pollution Control Agency, water resource managers are now able to quantify critical groundwater resources and assess the sustainability of long-term water use in the state of Minnesota.
USGS scientists recently estimated annual rates of potential recharge, or the natural replenishment of groundwater, over 15 years across Minnesota. According the study, the statewide mean annual potential recharge rate from 1996 to 2010 was 4.9 inches per year (in/yr). Recharge rates increased from west to east across the state, and April generally had the highest potential recharge.
Improved estimates of recharge are necessary because approximately 75 percent of drinking water and 90 percent of agricultural irrigation water in Minnesota are supplied from groundwater. "Resource managers in Minnesota can use this study to help inform water use or water conservation guidelines throughout the state," said USGS scientist and lead author of the report, Erik Smith.
To maintain a stable supply of groundwater, recharge rates must be high enough to compensate for water that is lost to streams, lakes and other surface-water bodies, or removed for uses such as agriculture. The scientists used data about daily precipitation, minimum and maximum daily temperatures, land cover, and soil to model Minnesota's recharge rates.
During the study period, mean annual potential recharge estimates across the state ranged from less than 0.1 to 17.8 in/yr. Other findings include:
- The highest annual mean recharge estimate across the state was 7 inches in 2010, and the lowest mean recharge estimate was 1.3 inches in 2003.
- Some of the lowest potential recharge rates occurred in the Red River of the North Basin in northwestern Minnesota, generally between 1 and 1.5 in/yr.
- The highest potential recharge rates were in northeastern Minnesota and the Anoka Sand Plain in central Minnesota.
- Eighty-eight percent of the mean annual potential recharge rates transpired between 2 and 8 in/yr.
- April had the greatest monthly mean at 30 percent of the yearly recharge.