RAINFALL-RUNOFF MODEL ACCURACY FOR AN EXTREME FLOOD

Relatively little is known about the accuracy of conceptual rainfall-r unoff model simulations of extreme floods. A case study is used to eva luate the accuracy of runoff model simulations of the 100-year flood o f July 1, 1978 on the Kickapoo River (drainage area = 690 km(2)), in s outhwest Wisconsin. The accuracy of a simple and quick analysis is com pared to that of an elaborate, labor-intensive analysis. The more elab orate modeling approach produces more accurate results, although signi ficant errors for the peak discharge and runoff volume are observed in both approaches. The potential sources of uncertainty in the results are evaluated. Error in the precipitation data used for calibrating th e model appears to be the primary source of uncertainty.