USE OF WEIGHTED INTEGRAL VARIABLES TO DETERMINE THE RELATION BETWEEN RAINFALL INTENSITY AND STORM FLOW AND PEAK FLOW GENERATION

Hewlett's (1977) work using his storm flow separation technique has established that peak rainfall intensities have little predictive value in the determination of storm flow depth or storm peak flow from small upland streams emanating from forested catchments. A logical inference is that storm rainfall intensities have little influence on either the volume of storm flow or peak flow. To obtain additional information a variant of the technique was applied to excellent records from two separate, steep, upland catchments in southern Australia. The catchments were regarded as having quite distinct rainfall response characteristics by hydrologists. Antecedent flow, storm rainfall, and measures of maximum rainfall intensity were supplemented by weighted integrals of rainfall intensity. Regression analysis showed that knowledge of maximum intensities gave little increase in predictive ability over storm rainfall.