I 



OUR WATER SUPPLY— MEINZER 3Q5 



EMERGENCE OF HYDROLOGY AS A RECOGNIZED SCIENCE 



The hydrologic cycle, being of major scientific and practical interest, 

 has received the study of a large number of scientists, most of whom 

 have not called themselves hydrologists. In this country the Weather 

 Bureau long ago established a comprehensive and systematic program 

 that has resulted in the accumulation of a great amount of base data 

 on precipitation and other weather conditions, the value of which 

 is beyond estimation. The Geological Survey has developed a 

 thorough technique for gaging streams and has accumulated a remark- 

 able body of systematic and exact data on stream flow. By sys- 

 tematic work through many years it has also made substantial 

 achievements in the chemical analysis of the natural waters, in a 

 general survey of the ground-water conditions, and in the development 

 and application of quantitative methods in ground-water investigation. 



In addition to the work of these two scientific bureaus of the 

 Federal Government, there has been a vast amount of work by a great 

 number of governmental and private agencies and individuals that 

 has contributed in many ways to the base data and to the methods 

 and principles of hydrology. Thus, many hydraulic engineers have 

 devoted much of their time not to engineering work at all but to scien- 

 tific research relating to the natural waters; thus, also, many other 

 scientists, such as soil scientists, agronomists, geologists, botanists, 

 and foresters, have made distinct contributions to hydrology. There 

 has, however, been a lack of coordination, and developments have 

 been made which have had unfavorable effects that were not foreseen 

 because the scientists and engineers concerned did not have an ade- 

 quate appreciation of the unity and complexity of the hydrologic 

 cycle. 



In recent years there has arisen a wholesome recognition of hydrol- 

 ogy as a comprehensive science, and a general effort has been made to 

 correlate the different aspects of the subject. This trend has found 

 expression and stimulus in the organization, 6 years ago, of the section 

 of hydrology of the American Geophysical Union. More recently 

 an attempt has been made through the efforts of the Mississippi 

 Valley Committee, the National Resources Committee, the State 

 planning boards, and other agencies to evaluate objectively the mani- 

 fold works of man that have affected the hydrologic cycle at some 

 point and to attain a clearer perspective for the future. Thus, progress 

 has been made in an appreciation of the sensitivity of our water supply 

 to many complex controls. Looking to the future, we must insist that 

 engineering works or other developments shall be undertaken only 

 after their hydrologic consequences have been fully studied, and we 

 must resolutely set ourselves the task of building a science of hydrology 

 that will be adequate for the responsibilities that are involved. 



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