- Dam type: Reinforced concrete multiple dome and buttress, similar to
multiple arch and buttress
- Location: 31 miles east of Globe, Arizona
- Watercourse: Gila River
- Reservoir: San Carlos
- Original construction: 1924-28
- Modified: 1992-94
- Total storage to El. 2511: 910,000 acre-ft
- Hydraulic height: 220 ft
- Total spillway capacity at El. 2557: 295,170 cfs
- Dam crest capacity at El. 2557: 163,590 cfs
- Outlet works capacity at El. 2511: 5,000 cfs
- Drainage area: 12,870 sq mi
- HMR: N/A
- PMF: 1987 Summer Type
- Volume: 2,143,000 acre-ft over 17 days
- Peak inflow: 800,000 cfs
- Maximum water surface: 2557 ft
- Foundation: Precumbrian granite is most widely exposed unit. Ten rock
units have been identified along with faults in the dam site.
Coolidge Dam is a multiple-dome concrete structure. The dam was designed and
constructed, and is owned and operated, by the Bureau of Indian Affairs (BIA), and was
completed in 1928. The dam consists of three domes, which are supported by
massive buttresses on 100-foot centers. Two uncontrolled ogee crest spillways
are concrete lined and located on each abutment.
In 1990 the BIA requested that the Bureau of Reclamation mitigate an
identified safety of dams issue associated with the probable maximum flood
overtopping and failing the dam. The modification included a stability buttress
placed on the left abutment and overtopping protection placed on both abutments.
Of note, this overtopping protection consisted of concrete blocks placed with
joints at 20-foot centers each way and with a 2.5-foot minimum thickness.
Reinforcement was placed in the top face of the blocks and extends through
the joints. Waterstops were placed in all of the joints and anchor bars and
drains were constructed in each placement; armor-stone was added in the
channel to prevent popping (hydraulic jacking) and eroding of rock immediately
downstream of the dam; and concrete lining was placed on the floors of both
spillways to prevent erosion of the existing deteriorated concrete. These
modifications were made between 1992 and 1994.
Alkali Aggregate Reaction
Reclamation Arizona Dams
How much water is being released from Coolidge Dam right now?
1992 Satelite image of Coolidge Dam
Bureau of Reclamation, Department of the Interior