Water Resources Research Center, University of Minnesota
Newsletter or Bulletin
We examined the sensitivity of Minnesota's water resources to predicted climate changes due to global wanning. Statistical models, for the current climate, of the relationship between seasonal moisture surplus (Thornthwaite water budget method) and seasonal river discharge were built for nine watersheds in Minnesota. Global Climate Model predicted temperature changes and precipitation ratios were used to adjust the observed climatic record. The moisture surplus values were recalculated for this doubled C02 world and became the predictor variables in the statistical models.
The results indicate a general and substantial decrease in river discharge. However, there is great spatial variation in the magnitude of the decrease. Mean annual discharge decreases ranged from 0.3% for the St. Louis River to 18% for the Blue Earth River. The individual annual discharges were about evenly split between increases and decreases for the St. Louis River while there were only four years (out of 47) with increased discharge for the Blue Earth River. All nine basins showed increased discharge during the first season (three months) of the year largely because increased temperatures shifted the snow melt period to an earlier month. The second season (April through June) had most extensive and largest decreases. In the third season (July through September) decreases were large (13% to 31 %) for the southern and central river basins but were modest (2% to 7%) for the northern basins. During the last three months of the year, five basins had increased discharge and four basins, especially the Mississippi at both Anoka and St. Paul, had decreases. Thus, the southern and central portions of Minnesota would experience substantial decreases in discharge but the northern third of the state would see only modest decreases.
Baker, Donald G. Newman, Lynn E. Skaggs, Richard H. 1992. Effects of Climate Variability and "Greenhouse Effect"--Scenarios on Minnesota's Water Resources. Water Resources Research Center.
Water Resources Research Center
Baker, Donald G.; Newman, Lynn E.; Skaggs, Richard H..
Effects of Climate Variability and "Greenhouse Effect"--Scenarios on Minnesota's Water Resources.
Water Resources Research Center, University of Minnesota.
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