208 THE FUTURE OF ARID LANDS 
conditions, somewhat along the lines suggested by Russell’s 
climatic year concept (7). 
It seems evident from the foregoing that the establishment of 
boundary lines implies an investigation of the internal structure 
of the area to be delimited. The interpretation of regional differ- 
ences and local patterns brought to light in the course of such an 
investigation, a routine task for the geographer, prepares a val- 
uable framework for regional planning. Having an area compar- 
able in size to that of France or Spain, the Nordeste could be 
expected to include several greatly contrasted natural landscapes. 
As already indicated, the region does indeed present considerable 
topographic and climatic diversity. There can be no single devel- 
opment scheme here, and any long-range program should aim to 
extract all possible advantages from the variety of existing con- 
ditions. This calls for optimum use of every single tract of land 
and a combined development of all resources. The required in- 
ventory and appraisal of the possibilities offered by the environ- 
ment furnishes the planner with a basis to judge the claims of 
competing uses. It also enables him to obtain a better perspective 
in the appraisal (or reappraisal) of the significance of what may be 
no more than one-sided solutions for the problems of the region. 
Water Storage 
The traditional approach to the question of insuring a perma- 
nent provision of water in the Northeast rests essentially on the 
construction of large surface storage reservoirs. Elsewhere, I have 
indicated some of the limitations of this solution as applied to the 
region (11). However, since it is customary to point to the bene- 
fits which the establishment of large reservoirs have brought to 
lands of even more acute moisture deficiencies, I should like to 
refer to yet another phase of the geographers’ work, the compara- 
tive study of widely separated geographical regions. Although the 
Nordeste, in respect to certain elements or element complexes, 
may be bracketed in the same general type as other arid and semi- 
arid lands, an examination of some notable differences shows the 
region to be unique in many respects. One example will suffice 
here. With a single exception, all its streams rise in the dry zone 
