colorado river delta basemap
community | data | history | publication list | partners
Aerial Photos

The Basemap

Developing a GIS

IBWC Graphs

Ground Photos

Imaging Requirements

Developing a Basemap

Remote Sensing

Satellite Images

Techniques for Mapping

Vegetation Mapping

The Basemap Area

   "The Colorado grows grapes in New Mexico, brews beer in Colorado, raises minnows in Utah, floats rafts in Arizona, lights jackpots in Nevada, nurses elk in Wyoming, freezes ice for California, sweetens cantaloupes in Mexico" (Carrier, 1991). The Colorado River begins at elevations of 14,000 ft. on the continental spine of the Rockies near Mammoth Glacier in Rocky Mountain National Park and in Wyoming's Wind River Range where the Green River feeds into the Colorado. The Colorado has the greatest elevational drop in North America and carves the mile-deep Grand Canyon. Only the seventh longest in the U.S., it runs for 1,450 miles, but the volume (15 maf./yr.) is only a fraction of that of the Columbia (92-maf/yr.) or Mississippi (400 maf/yr.). It is also the most silty (380,000 tons/day are moved downstream) and one of the saltiest (carrying 9 million tons a year) (World River Review, 1997). Federally-owned, it as been nearly regulated out of existence: the river has scores of reservoirs, diversion dams and pumping stations, hundreds of miles of aquedects and tunnels, thousands of miles of canals, and 30 hydroelectric plants (Bureau of Reclamation, 1999).

   Near Yuma, on the border of Arizona and Mexico, the Colorado River backs up behind Imperial Dam, which takes more than 20% of the water, the single largest chunk of the river, and flows through the All American Canal about 80 miles west of California's Imperial Valley (BoR, 1999). The Valley receives only three inches a year in rainfall (NOAA, 1996); hence, the valley's 500-million acres of farmland would revert to desert without the 2.9 million acre-ft. of water drawn from the Canal (Pontius, 1997; Bureau of Reclamation, 1999). The Canal crosses the Imperial Sand Dunes and 15% (70,000 acre-ft./yr.) soaks into the sand, while another 1 maf. of water runs off and beneath the Valley's irrigated, productive fields (Pontius, 1997; Bureau of Reclamation, 1999). Altogether, 700 prosperous farmers generate about a billion dollars a year in produce, grain, and livestock; and they have a senior right to the river's water (Pontius, 1997). However, the land is so salty and the river water is so saline due to being extracted, evaporated from the reservoirs, passed over the natural salt beds, and poured through soil that was once the bottom of an ancient sea, it takes extra water, poured through the soil, to flush salt away from roots (Carrier, 1991). Pipes buried 1-5 meters feet deep carry the excess salty water away through 1,400 miles of pipeline carrying drainage to rivers that empty into the briny Salton Sea (Glenn et al., 1996). More efficient irrigation methods, like the drip system, are replacing these older methods of irrigation.

   Based on Bureau of Reclamation statistics, Carrier (1991) describes the following: The California cities that receive 33% of their municipal water from a 242 mile Colorado River Aquaduct receive a billion gallons of water/day. The Arizona aqueduct system, umbilical cord amongst the Saguaro cacti, slows the depletion of groundwater pumped from deep wells. The Bureau of Reclamation spent $3.5 billion on the aqueduct network, which includes the Central Arizona Project (CAP) that stretches 335 miles from Lake Havasu to central Arizona farms, Indian reservations, industries and cities, ending in Tucson (taking 1.5 maf./yr.). A pump house at CAP draws 1 billion gallons/day of water for southern California and carries water for ten tribes of Native Americans. It is not covered and not protected from evaporation; comparably, the evaporation rate off Lake Powell is such that the lake decreases by 5 feet annually.

   Not counting evaporation losses, nearly a half-trillion gallons of water a year is drawn from the river, so cartographers no longer draw the Colorado River as a vibrant blue line. Furthermore, the Bureau of Reclamation helped build a coal plant near Page, Arizona so farmers can subsidize economically, which taints the air over the Grand Canyon and the Navajo Reservation (Carrier, 1991).

    The last of the Colorado River is pushed into Canal Central below Morelos Dam in Mexico, south of Yuma, and the riverbed becomes shallow enough to wade across. There are 15,000 or so farmers living in the delta area and they only farm 80% of their land because only 66% is irrigable (Sonora, Mexico) (INEGI, 2000a,b). The rest of the water is for industrial or urban use, which is needed for cities like Tijuana, Mexicali, and San Luis Rio Colorado. At least they have profits to off set the cost of buying water (Calbreath, 1998 in Garcia-Hernandez, 2001). In 1997, Tijuana increased employment by 14% seven times faster than in San Diego, California, due to offshore manufacturing plants (the maquiladora industry). On the U.S. side, agriculture draws 80-90% of the Colorado River's water (in Mexico, agriculture is the primary consumer of water). Just as the economic struggle in the U.S. is between the irrigators and power interests, in Mexico, other Mexican industries (municipalities and factories) are fighting for their share (Coronado, 1999).

home | community | data | history | publication list | partners | site map | staff