The Horse Mesa Dam is a concrete thin arch dam

Arch dam

An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...

 located Northeast of Phoenix, Arizona

Phoenix, Arizona

Phoenix is the capital, and largest city, of the U.S. state of Arizona, as well as the sixth most populated city in the United States. Phoenix is home to 1,445,632 people according to the official 2010 U.S. Census Bureau data...

. The dam is 660 feet (201.2 m) long, 300 feet (91.4 m) high and was built between 1924-27. The dam includes three conventional hydroelectric generating units totaling 32 megawatts (MW) and a pumped-storage unit with a capacity of 97 MW. The dam forms Apache Lake

Apache Lake (Arizona)

Apache Lake is one of four artificial reservoirs created along the Salt River in central Arizona as part of the Salt River Project. The lake is located near the Apache Trail about 65 miles northeast of Phoenix. Apache Lake was formed by Horse Mesa Dam which was completed in 1927...

 as it slows the passage of the Salt River

Salt River (Arizona)

The Salt River is a stream in the U.S. state of Arizona. It is the largest tributary of the Gila River. The river is about long. Its drainage basin is about large. The longest of the Salt River's many tributaries is the Verde River...

. It is located downstream from the Theodore Roosevelt Dam

Theodore Roosevelt Dam

Theodore Roosevelt Dam is a dam on the Salt River located northeast of Phoenix, Arizona. The dam is high and forms Theodore Roosevelt Lake as it impounds the Salt River. Originally built between 1905 and 1911, the dam was renovated and expanded in 1989-1996. The dam is named after then-President...

 and upstream of Mormon Flat Dam

Mormon Flat Dam

The Mormon Flat Dam is a dam on the Salt River located Northeast of Phoenix, Arizona. The dam is 380 feet long, 224 feet high and was built between 1923-25. The Dam is named after nearby Mormon Flat, a place where LDS settlers from Utah stopped to camp. There are two hydroelectric generating units...

.