Science Source

Stream flow in Minnesota: Indicator of climate change

Studies stream flow records (up to the year 2002) from 36 USGS gauging stations in five major river basins of Minnesota
Finds that trends differed significantly from one river basin to another, and became more accentuated for shorter time windows
Detects periodicity in the trends for the Red River of the North, the Mississippi River, and the Minnesota River basins for six of the statistics studied
Finds that peak flow due to snowmelt, typically the highest flow in each year, appears to be the only streamflow statistic that has not changed at a significant rate
Finds that peak flows due to rainfall events in the summer are increasing, as well as the number of days with higher flows (high flow days)
Finds that increases in low flow (base flow) in summer and in winter have been significant
Finds that wetter summers and more frequent snow melt events due to warmer winters are the likely cause
Concludes that stream flows in Minnesota reflect observed changes in precipitation with increases in mean annual precipitation, a larger number of intense rainfall events, more days with precipitation and earlier and more frequent snowmelt events