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Arizona Water Atlas Volume 7: Lower Colorado River Planning Area Water Atlas

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Lower Colorado River Planning Area Water Atlas

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Butler Valley

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Gila Bend

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Lower Gila

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McMullen Valley

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Ranegras Plain

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San Simon Wash

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Tiger Wash

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Western Mexican Drainage

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The Lower Colorado River Planning Area is composed of eleven groundwater basins in southwestern Arizona. The planning area contains the driest and hottest portions of the State.  Large expanses of federal lands consisting of military reservations, wildlife refuges and national monuments are located in the planning area. Elevations range from over 7,700 feet in the Baboquivari Mountains along the southeastern boundary of the planning area to about 70 feet at the Colorado River where it enters Mexico.  All of Yuma County and most of La Paz County (91% of the county) are contained within the planning area as well as portions of Maricopa (38%), Pima (43%) and Yavapai (1%) counties.  Five Indian reservations including the Cocopah, Colorado River Indian Tribes (CRIT), Gila Bend, Fort Yuma-Quechan and Tohono O’odham are located within the planning area.  One of the planning area basins, Harquahala, has been designated as an irrigation non-expansion area (INA) due to insufficient groundwater to provide a reasonably safe supply for irrigation.

Although much of the planning area is relatively sparsely populated, there are several major population centers, particularly in the Yuma area.  The 2000 Census planning area population was approximately 194,100 with basin populations ranging from less than 10 in the Tiger Wash Basin to almost 153,000 in the Yuma Basin. Yuma is the largest community with over 91,000 residents in 2006.  Other population centers include Fortuna Foothills and San Luis located near Yuma, Parker/Parker Strip, Ajo, Gila Bend and Quartzsite.

During 2001-2005 an average of over 2,899,700 acre-feet of water was used annually in the planning area for agricultural, municipal and industrial uses (cultural water demand) – approximately 42% of the state’s total demand during that period. Of the total planning area demand, approximately 964,670 acre-feet was well pumpage, 1,934,390 acre-feet was surface water diversions from the Colorado River, Gila River and the Central Arizona Project and about 680 acre-feet was effluent reuse.  The agricultural demand sector was by far the largest with approximately 2,835,100 acre-feet of demand a year – 98% of the total demand.  Average annual municipal sector demand was about 51,000 acre-feet a year (AFA) and industrial demand was about 13,560 AFA.

Planning area San Simon Wash Cultural Water Demand Western Mexican Drainage Cultural Water Demand Lower Gila Cultural Water Demand Yuma Cultural Water Demand Gila Bend Cultural Water Demand Harquahala Cultural Water Demand McMullen Valley Cultural Water Demand Tiger Wash Cultural Water Demand Butler Valley Cultural Water Demand Ranegras Plain Cultural Water Demand Parker Cultural Water Demand


Information on specific topics for each groundwater basin in the Lower Colorado River Planning Area can be found in the menu to the right. 

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Parker Dam
Agriculture in Yuma Basin