In interpretation and use of basic hydrological data as basis for planning any public works for conservation or control of water, there is great need for a careful and thorough analysis of the precipitation‐runoff relations. Moreover, when such relations may have been worked out for one particular basin, experience has shown that extreme caution must be used in any attempt to apply these relations to another basin even though superficially the latter may appear to be comparable with respect to physiography, meteorological conditions, and all of the other elements which contributed to the relations established for the first basin.