Demographics: Population of the Sonoran Desert

Population Centers and Patterns of Growth

There are six population centers of over 250,000 people in the Sonoran Desert Region (Table 5). Three of these cities are in the U.S. and three in Mexico. Three grew by more than a third in the ten years from 1990 to 2000. Given their size, this meant that in even the smallest, slowest growing city, Obregón, the population increased by over 30,000. While the largest city, Phoenix, and adjacent Mesa had to provide homes and infrastructure for an additional 438,000 people during the 1990s. That figure is nearly as many people as currently live within the city limits of Tucson, AZ.

Although larger cities show a greater growth in absolute numbers, in general, the most rapid growth is being seen in smaller urban areas adjacent to major cities such as Phoenix and Tucson (Table 6). For example, Marana, whose population grew by a factor of 5 and Oro Valley whose population more than tripled are small amenity rich sites close to Tucson. Gilbert, Goodyear, Chandler, Apache Junction, and Scottsdale are either adjacent to or near Phoenix. Other rapidly growing cities such as Imperial, La Quinta and Palm Desert in California and Lake Havasu City in Arizona can attribute a large amount of their growth to an influx of retirees. (For a listing of Core Counties in the U.S. portion of the Sonoran Desert, and Sonoran Desert cities in California and Arizona, see Table A, Table B, Table C, and Table D respectively).

The number of people in a population does not translate directly into the amount of impact that population has on the environment. Per capita consumption of resources including land is needs to be considered. The population of a smaller city of affluent people, such as Palm Desert, California may have a greater impact than a much larger one in which a high proportion of the population have lower incomes.

Population Centers in Mexico

The three largest population centers in Sonora also include the two most rapidly growing (Table 7). The capitol, Hermosillo, is both the largest and fastest growing city with San Luis Río Colorado, third in population, grew by nearly a third in the past decade. San Luis is sister city to Yuma and sits on the US-Mexico border. Obregón the second largest city in Sonora and dependent on agricultural and industrial production, grew relatively slowly. The slower rate of growth might be attributed to the city's distance, 526 km, from the U.S. border (http://www.obregon.gob.mx/info.htm). Caborca, also primarily an agricultural/industrial city closer to the border grew more rapidly than did Obregón. Puerto Penasco's growth can be attributed to its location on the Sea of Cortez. With the closing of the waters north of Puerto Penasco to commercial fishing in 1994 when the Pinacate International Biosphere Reserve was created, approximately half of its economy now is related to tourism http://www.synergytours.com/rocky1.htm.

With the exceptions of Mexicali, Baja California and Comondú, Baja California Sur, cities in the Baja Peninsula portion of the Sonoran Desert are small. Mexicali is the border city paired with Calexico, California and is Baja California's capital. Mexicali is home to 170 maquiladoras employing over 48,000 of the city's over half million residents (http://www.dot.ca.gov/dist11/border/ports.html). Comondú, lies in a region noted for its biodiversity and relies heavily on tourism. By 2000, the population had grown to nearly 64,000.