Discussion of “The relation of geology to dry weather stream flow in Ohio”

The concepts presented in this paper are of great value to the ground‐water hydrologist. They indicate one way to analyze and conveniently use the vast accumulation of stream‐flow records collected by governmental agencies as a tool for geophysical reconnaisance. To be usable as a method of geophysical prospecting for ground water, stream‐flow records must first be transformed into flow‐duration curves. Then, by means of the 90 per cent index, chosen by Cross, or other, more suitable indices, the ground‐water storage characteristics of the surficial deposits of drainage basins can readily be determined. Where there is good indication of extensive groundwater storage, it is probable that large supplies of ground water can be developed for use.