NASA Photos Reveal Why Cities Are Running Dry
By Chris Baskind in Environment
In terms of economic development, Las Vegas’ growth is an amazing success. But as a quarter century of satellite images show, sprawl comes at a high price.
A new series of NASA Landsat 5 images taken of the Las Vegas area over a 25-year period dramatically illustrates why some cities are finding it difficult to keep up with water demands.
While Las Vegas is an extreme case — it’s located in the middle of a desert — freshwater shortages are continuing to afflict growing population centers everywhere. Atlanta, for instance, is in an area hardly known for its aridity. But in the autumn of 2007, a combination of high demand and a multi-year drought pushed Atlanta to the edge, causing shortages and requiring residents to take emergency conservation measures. Rainfall in 2008 raised Lake Lanier’s levels from record lows, city leaders continue to juggle the area’s thirst against future growth.
Like Atlanta, Las Vegas has traditionally relied on a nearby lake to meet its freshwater needs. But the area’s rapid urbanization has far outstripped Lake Mead’s ability to provide, forcing the city to undertake a multi-billion dollar project to pipe in water from distant sources. Las Vegas’ sprawl is apparent from the series of Landsat photos, acquired by NASA at five-year intervals.
The first image, taken before the construction of Interstate 215 to the city’s southwest, shows Las Vegas prior to the explosive growth it has experienced over the past two decades:
Las Vegas satellite image: 1984 (NASA Landsat image)
In successive images, Las Vegas creeps westward. Green spaces disappear to development and water demand. Of particular note is the increased density near the city’s core: The dark shapes which appear center right are the shadows of high-rise buildings.
Las Vegas satellite image: 1989 (NASA Landsat image)
Las Vegas satellite image: 1994 (NASA Landsat image)
Las Vegas satellite image: 1999 (NASA Landsat image)
Las Vegas satellite image: 2004 (NASA Landsat image)
Las Vegas satellite image: 2009 (NASA Landsat image)
In addition to the new water supply project, Las Vegas has moved aggressively to curb its collective thirst. The city has embraced active metering, water-smart building codes, and has even begun paying residents to tear out water-intensive lawns and landscaping. But other areas with similar problems haven’t been so proactive. In Mexico City, the drawdown of its local aquifers is so complete that it has geological faulting, and large urbanized areas have sunk up to twenty feet.
The United States currently consumes 148 trillion gallons of freshwater annually. At least 36 states are already facing significant water challenges, from California and the Southwest, through Florida and Georgia, and extending to upstate New York and the Great Lakes region. In these regions, conservation efforts are already underway. Whether it will be enough to guarantee their growth — or even sustain existing populations — is still up for debate.
For downloadable, high-resolution images of Landsat 5’s visual surveys, see 25 Years of Growth in Las Vegas (NASA).
PDF-
Evelyn
-
Uncle B