• catchment hydrology;
  • climate variability;
  • landscape structure;
  • modeling;
  • topography;
  • transfer function

Attempts to predict future water availability are muddled by the tendency of the hydrologic system's key drivers, weather and watershed topography, to change across space and time. Interannual climate variability, land use change, and watershed shape alter how water moves through a catchment as it flows from rain and snow to streamflow. For municipalities whose climate forecast includes a dramatic change in the quantity, distribution, or timing of precipitation, this uncertainty leads to worries about future water security. The key to assuaging those fears lies in understanding how different physical and climate variables influence the watershed's runoff ratio—the proportion of precipitation that makes it to the stream—and response time—how long it takes a volume of water to move through the catchment.