WATERSHED MODEL CALIBRATION AND VALIDATION: THE HSPF EXPERIENCE

Model calibration and validation are necessary and critical steps in any model application. For most all watershed models, calibration is an iterative procedure of parameter evaluation and refinement, as a result of comparing simulated and observed values of interest. Model validation is in reality an extension of the calibration process. Its purpose is to assure that the calibrated model properly assesses all the variables and conditions which can affect model results, and demonstrate the ability to predict field observations for periods separate from the calibration effort.