Short Cuts in Hydrology

In Queensland, Australia, a general rainfall-runoff relationship has been found useful when applied to rainfall zones in a catchment, rather than to the mean rainfall over the entire catchment. When, for different sizes of storage at a given site, regulated flow-mean annual discharge is plotted against storage capacity-mean annual discharge, the resultant lines for storages on different streams exhibit a pattern that appears to be partly accounted for by the mean storage depth (which affects the significance of evaporation loss) and the minimum 3-yr discharge (which is an indication of the critical demand on the storage). In many cases, mean catchment width appears to be an important factor in relation to unitgraph peak discharge. When examining the frequency pattern of minor floods, mean annual runoff, as well as catchment area, appears to be significant.