248 CONSERVATION OF GROUND WATER 



requires delineation of the entire hydrologic unit involved 

 and abandonment of the separate categories of rights. 



If the present classification of "watercourses" in many in- 

 stances cuts jaggedly through waters of a single hydrologic 

 unit, the other principal class of surface waters goes to the op- 

 posite extreme. The surface waters not in watercourses, com- 

 monly grouped as "diffused surface waters," may include visi- 

 ble waters from a great variety of sources: standing water from 

 precipitation which has not yet infiltrated into the ground or 

 which cannot enter the ground because of impermeability of 

 the surface layer; overland flows which may either seep into 

 the OTound elsewhere or enter a recognized "watercourse"; 

 the discharge from ground-water reservoirs at springs or seeps; 

 water in sloughs or escaped flood waters in "watercourses" 

 that have been too narrowly delimited in their definition; 

 marshes and bogs formed by ground water where the water 

 table rises to the surface; waters discharged by streams into 

 the closed basins of the West, which will be dissipated even- 

 tually by evaporation. Here certainly is a hodgepodge class, 

 necessitated doubtless by the meagerness of hydrologic knowl- 

 edge in bygone days but eligible for retirement in the light 

 of present knowledge. 



The empirical classification of ground waters is still less 

 workable than that for surface waters. Court decisions and 

 statutes have commonly classified ground waters as (1) definite 

 underground streams and (2) percolating waters. If the char- 

 acteristics of "definite underground streams" include the tur- 

 bulent flow that characterizes practically all surface streams, 

 this class becomes a small one indeed, suitable only for cav- 

 ernous limestones, some organic soils, and certain volcanic 

 rocks. If on the other hand laminar flow through porous mate- 

 rials is included, the class will embrace all ground-water res- 

 ervoirs as fast as the requirements of the word "definite" can 

 be met by scientific investigation to delineate their boundaries. 

 The class was drawn to be exclusive, however, for the burden 

 of proof was placed upon the person who asserts that a "defi- 

 nite underground stream" exists. This was a very high wall 



