ECONOMICS OF WATER SOURCES 327 
having practically no population. I use the term ‘‘oasis economy”’ 
to describe the situation. 
There are social and economic consequences of this oasis econ- 
omy which, time permitting, could be further explored. As an ex- 
ample of a minor sociological consequence I shall cite the restric- 
tion in dwelling environment offered in the oasis economy. In the 
humid regions the degree of urbanization, being high in the center 
of the metropolitan areas, gradually decreases toward the periph- 
ery, typically reaching the rural level before beginning to rise 
again as the outskirts of the next city are approached. This gradual 
change allows the dweller in those regions a wide variety of 
choices in balancing the rural and the urban in his dwelling en- 
vironment. Not so in the arid lands, for example the Southwest. 
Here, although it is true that the degree of urbanization decreases 
outward from the center of the city, at the city boundary, namely 
at the termination of water, gas, and other utility services, there 
is a very abrupt transition to a completely rural environment. 
Thus the dweller in the arid regions has essentially only two 
choices; either urban residential living or semi-isolated, ranch 
type, in many cases supplying his own water, gas, and even power. 
Oasis Economy and Advancing Technology 
It should be pointed out that solutions such as are discussed in 
this volume on prospects for additional water resources are solu- 
tions which may intensify the oasis economy rather than alleviate 
it. Any solution which increases the availability of water at one 
spot, possibly at the expense of another spot, will aggravate the 
situation. Technical advances will be made in water supply and 
transportation of water, and most of these, if only for efficient 
utilization, will intensify the oasis economy. For that reason it 
should be stressed, especially for the engineers, that the better use 
of present resources and the better adaptation of plants and ani- 
mals present possibilities for eliminating the oasis economy and 
making arid lands generally available for habitation as we of the 
western world understand the normal pattern of land use. I make 
this point particularly because it happens that the solution to 
additional water resources lies so largely in applied research and 
engineering, whereas the solution to better use of present resources 
