||Uncertainty Analysis of Runoff Estimates from a Runoff Contour Map.
Rochelle, B. P. ;
Stevens, D. L. ;
Church, M. R. ;
||Corvallis Environmental Research Lab., OR. ;NSI Technology Services Corp., Corvallis, OR. ;Eastern Oregon State Coll., La Grande.
Water pollution ;
Mathematical models ;
Regional planning ;
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The US EPA in cooperation with the USGS conducted an analysis to quantify the uncertainty associated with interpolating runoff to specific sites using a runoff contour map. The authors interpolated runoff to 93 gaged watersheds from a runoff contour map using: (1) hand interpolation to the watershed outlet, (2) a computer interpolation to the watershed outlet, and (3) hand interpolation to the watershed centroid. The authors compared the interpolated values to the actual gaged values and found that there was a bias in the average interpolated value for runoff estimated at basin outlets, with interpolated values being less than the actual. The authors found no significant difference between the hand interpolation method and the computer interpolation method except that the computer method tended to have higher variability due to factors inherent to the software used. There were no strong spatial correlations or regional patterns in the runoff interpolations, which indicates that there are no regional biases introduced in the development of the contour map. The authors determined that they could estimate runoff, on the average within approximately 15% of the measured value using the three methods.