Re:How did we create a society where we can’t afford to live...
by dredmorbius on Wednesday October 25, 2017 @08:55AM
(#15549627)
In terms of locally-available water, it really pretty much is. As is almost all of the U.S. starting a couple hundred miles west of the Mississippi River and the Pacific, the Northwest excepted.
San Francisco itself has next to no indigenous lakes or (fresh)waterways. Lake Merced, Laguna Honda, and Mountain Lake. A handful of springs. Already in the 19th century, water was in limited supply and brought in from the Peninsula. Much of San Francisco (the Richmond and Sunset districts) were sand dunes. The part that wasn't was in large part wetlands (Marina, Financial District, SoMa, Bayview).
Rainfall ranges from about 12 in (30 cm) in a dry year to about 30 in (75 cm) in wet, but that's strongly concentrated in the winter months, meaning you need a large amount of water storage for the summer (and, again: no lakes).
If you look at a population density map of the U.S., or one with higher levels of detail showing urbanisations, you note that the pattern devolves from very regular in the east to almost a desert-island scattering in the west. Much of that is accounted for by water availablility, and the water shadow of cities. Look at the map below, which shows the Colorado River, and realise that Los Angeles's watershed reaches very nearly to Denver. In many ways, it is effectively preventing any other cities from emerging throughout that region (not that several haven't tried).
San Francisco itself has next to no indigenous lakes or (fresh)waterways. Lake Merced, Laguna Honda, and Mountain Lake. A handful of springs. Already in the 19th century, water was in limited supply and brought in from the Peninsula. Much of San Francisco (the Richmond and Sunset districts) were sand dunes. The part that wasn't was in large part wetlands (Marina, Financial District, SoMa, Bayview).
Rainfall ranges from about 12 in (30 cm) in a dry year to about 30 in (75 cm) in wet, but that's strongly concentrated in the winter months, meaning you need a large amount of water storage for the summer (and, again: no lakes).
If you look at a population density map of the U.S., or one with higher levels of detail showing urbanisations, you note that the pattern devolves from very regular in the east to almost a desert-island scattering in the west. Much of that is accounted for by water availablility, and the water shadow of cities. Look at the map below, which shows the Colorado River, and realise that Los Angeles's watershed reaches very nearly to Denver. In many ways, it is effectively preventing any other cities from emerging throughout that region (not that several haven't tried).
http://www.ancientrails.com/wp-content/uploads/2014/10/US_Po...
A precipitation average map shows very nearly the same distribution. (Not precisely, of course, but close.)
https://i.pinimg.com/originals/88/51/cc/8851cc3ed4f7e048b217...