Jan 1, 2014

Impact of Climate Variability on Runoff in the North-Central United States

by
Karen R. Ryberg; Wei Lin, M.ASCE; and Aldo V. Vecchia
,
ASCE Library
  • States that large changes in runoff in the north-central United States have occurred during the past century, with larger floods and increases in runoff tending to occur from the 1970s to the present
  • States that the attribution of these changes is a subject of much interest
  • Uses long-term precipitation, temperature, and streamflow records to compare changes in precipitation and potential evapotranspiration (PET) to changes in runoff within 25 stream basins
  • The basins studied were organized into four groups, each one representing basins similar in topography, climate, and historic patterns of runoff
  • Precipitation, PET, and runoff data were adjusted for near-decadal scale variability to examine longer-term changes
  • A nonlinear water-balance analysis shows that changes in precipitation and PET explain the majority of multidecadal spatial/temporal variability of runoff and flood magnitudes, with precipitation being the dominant driver
  • Historical changes in climate and runoff in the region appear to be more consistent with complex transient shifts in seasonal climatic conditions than with gradual climate chang