Feb 28, 2007

Stream flow in Minnesota: Indicator of climate change

by
Eric V. Novotny and Heinz G.Stefan
,
Journal of Hydrology
  • 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