Painted Rock Dam

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Reservoir information
Painted Rock Dam
Photo taken during period of high runoff, with the resultant reservoir nearly full
Official name	Painted Rock Dam
Impounds	Gila River
Creates	Painted Rock Reservoir
Locale	Southwestern Arizona
Maintained by	United States Army Corps of Engineers
Length	4,780 feet (1,460 m)
Height	181 feet (55 m)
Construction began	18 Jan 1960
Opening date	25 July 1957
Construction Cost	$13,670,000
Capacity	2,491,700 acre feet (3,073,500,000 m³)
Geographical Data
Coordinates	33°4′22″N 113°0′56″W / 33.07278, -113.01556

The Painted Rock Dam is an earthfill embankment dam located west of Gila Bend, Arizona. It is primarily used for flood control purposes.

[edit] Description

The Painted Rock Dam was constructed during a 3 year period from 1957-1960 by the United States Army Corps of Engineers to help control seasonal floods on the lower reaches of the Gila River. The river had no significant impediments between the Colorado River and the Coolidge Dam hundreds of miles upstream. As the river receives several tributaries, including the Hassayampa, Agua Fria rivers, and most importantly the Salt River and its major tributary, the Verde River. Due to a relatively large watershed of 50,800 square miles (132,000 km²), more than half of which is unregulated, the flood threat to small farming communities downstream on the Gila River is large, and seasonal flooding of these areas prior to the construction of the dam was significant.^[1]

The area surrounding the dam has also hosted a number of historical events. The Butterfield Overland Mail route passed through the area, as did the path followed by the Mormon Battalion. Evidence of both can be found, as well as the expedition of Juan Bautista De Anza in 1774. Inscriptions made by these groups can be found in various sites in the region. Near the dam site, there is also a campground maintained by the Bureau of Land Management that showcases a number of prehistoric petroglyphs, indicating human involvement in the region long predating Western influence.^[2]

Painted Rock Reservoir
Location	Arizona
Coordinates	33°4′22″N, 113°0′56″W
Lake type	reservoir
Primary inflows	Gila River
Primary outflows	Gila River, evaporation
Catchment area	50,800 sq mi (132,000 km²)
Basin countries	United States
Surface area	53,200 acres (215 km²) (maximum)
Max. depth	181 ft (55 m)
Water volume	2,491,700 acre·ft (3.0735 km³) (maximum)
Surface elevation	661 ft (201 m)

[edit] Painted Rock Reservoir

The Painted Rock Reservoir is an artificial reservoir impounded by the Painted Rock Dam. The reservoir, with a maximum storage capacity of 2,491,700 acre feet (3,073,500,000 m³), has the potential to be the largest reservoir completely within the borders of the state of Arizona, but due to the fact that the lake is almost entirely a flood control project, the lake is generally dry.

In 2005, heavy runoff filled the reservoir to record levels, swelling the lake to become the second largest by area in the state of Arizona, trailing only Theodore Roosevelt Lake. However, extremely high levels of pesticides, particularly the now-banned DDT, had built up in the farmlands upstream from the reservoir in the decades prior and accumulated in the lake during the flood. The extreme toxicity of the lake rendered it unsuitable for recreational uses and public access to both the lake and the dam was restricted.^[3] Similar runoff had filled the lake previously in 1993 and 1980, and in each instance the lake lasted only a few months before emptying due to evaporation and release downstream.