In the past 100 years, humans have tended to concentrate on the dry side of the climatic spectrum
[in regions with less than 800 mm of annual precipitation].
Drier climates are generally healthier than more humid climates.
Example: Southern California.
Thus, the need for Hydraulic Engineering, which seeks to move
water from a region with more than average precipitation but with few people,
to a region with lesser precipitation but with more people.
Example: Compare Northern California with Southern California.
Map of California population density
