60 The Inexhaustible Resource of Technology 



tution and improved utilization, raw materials for our civilization can 

 be obtained for a long period in the future . . ." ^^ 



I believe a similar conclusion may be reached in respect to our 

 water resources. Water, unlike minerals and the mineral fuels, is a 

 renewable resource. Thanks to the automatic operation of the hydro- 

 logic cycle, our supply is continuously, but not always uniformly, re- 

 plenished by rainfall. Although three-quarters of the precipitation 

 which falls is returned to the atmosphere by evapotranspiration and 

 only one-quarter is currently available for man's use, we are in this 

 country using only one-fifth of this smaller available amount. And of 

 this one-fifth that we do use, approximately one-half is applied to 

 what are regarded as nonconsumptive uses — that is, this amount is 

 subject, within certain limits, to repeated reuse. Hence in the broadest 

 sense, our water resources are not only renewed by natural processes 

 but, in theory at least, the use of about one-half of them is subject to 

 almost unUmited expansion. 



A number of the papers given at the 1908 conference expressed 

 concern over the continued adequacy of our supply of water. Irriga- 

 tion, water power, and inland waterways appear to have been con- 

 sidered as requiring the preservation of our water resources, and pro- 

 tection of a forest cover seems to have been considered the major 

 factor in such a preservation. Curiously enough, little attention was 

 given to industrial supplies, which now represent about half of the 

 present water use. Nor was there recognition of the nonconsumptive 

 character of the water-power use. 



We still have problems of adequate supplies of water, although the 

 use pattern is significantly different from that of fifty years ago. And 

 as the drought in the Southwest of a year ago made dramatically 

 clear, water shortages may have a devastating effect upon the econ- 

 omy of a community or region. Luna Leopold, however, in a recent 

 illuminating discussion of Water and the Conservation Movement, 

 makes clear that our current problems of water surpluses or shortages, 

 serious as they may be locally, are basically not problems of conser- 

 vation so much as they are of economics. Except for the problems that 

 arise through our desire to preserve portions of the original environ- 



-^ Thomas B. Nolan, "The Outlook for the Future — Non-renewable Re- 

 sources," Economic Geology, Vol. 50 (1955), p. 7. 



