Alamo Dam is located in west-central Arizona. The dam is on the Bill Williams River approximately 39 miles upstream from the river's confluence with the Colorado River at Lake Havasu. Alamo Dam and Lake is a multiple-purpose facility providing the following benefits: flood control, water supply and conservation, recreation, and fish and wildlife enhancement.
Alamo Dam was authorized by the Flood Control Act of 1937 (Public Law 75-406, 28 August 1937, as amended). The initial proposal for the project was contained in House Document No. 625, 78th congress, 2nd Session, dated April 11, 1944.
The current approved water control manual (WCM) for Alamo Dam and Lake is dated October 2003.
The Bill Williams River is one of the Nation's ecological treasures. More information can be found on the Bill Williams River Website developed by the Bill Williams River Corridor Steering Committee.
ALAMO DAM AND RESERVOIR
MOHAVE and LA PAZ COUNTIES, ARIZONA
PERTINENT DATA - March 2022
Primary Objective / Secondary Objectives
Flood Control
Fish & Wildlife, Recreation
Additional Project Authorizations
Water Supply
Hydropower
Construction Completion
June 1968
Stream System
Bill Williams River
Lower Colorado River
Drainage Area
4,770
mi2
Significant Upstream Flood Control Facilities
None
DSAC Rating
4
Reservoir:
Elevation
NGVD 1929
+ 2.34 ft =
NAVD 1988
Outlet Invert Elevation2
980.0
ft
982.3
Original Streambed Elevation2
982.0
984.3
Intake Invert Elevation2
990.0
992.3
Recreation pool
1,070.0
1,072.3
Target Elevation4
1,125.0
ft
1,127.3
Water Conservation pool
1,160.4
ft
1,162.7
Spillway crest
1,235.0
ft
1,237.3
Top of dam
1,265.0
ft
1,267.3
Area1
Recreation pool
925
acres
Target Elevation4
3,665
acres
Conservation Storage6
5,698
acres
Spillway crest
13,251
Top of dam
17,079
acres
Capacity1, Gross
Recreation pool
17,912
af
Target Elevation4
138,979
af
Conservation Storage6
304,169
af
Spillway crest2
992,847
af
Top of dam
1,447,484
af
Allowance for sediment (100-year)2
200,000
af
Dam
Type:
Rolled Earthfill
Height above original streambed
283
ft
Top length
975
ft
Top width
30
ft
Outlets Works
Gate Type:
Tandem, vertical slide, hydraulic lift
Gates
Number -- Dimensions
Service (downstream)
Three - 5.5'W x 8.5'H
ft
Emergency (upstream)
Three - 5.5'W x 8.5'H
ft
Low-flow bypass (around Service Gate #3)
1 - 18" diameter
ftKnife valve, Installed August 2012
Maximum Discharge capacity
112
cfs
Minimum Water Surface Elevation to initiate operation
1002.3
ft
1,004.6
Conduit (Conduit limits outflow capacity)
12
ft, dia
Intake / Outlet invert elevations
990.0 / 980.0
ft
992.3 / 982.3
Total Conduit length
1,290
ft
Maximum Hydraulic capacity at spillway crest2
8,700
cfs
Spillway
Type:
Detached Concrete Ogee Weir on left under Associated Rd.
Crest length (excavated in rock saddle on right-side of dam)2
100
ft
Original design surcharge2
24.6
ft
Revised PMF freeboard5
dam overtops
0
ft
Reservoir Design Flood ➜
Original2
Resived SPP3
Duration
7
days
7
Total volume
422,000
af
613,000
Inflow peak
317,000
cfs
389,000
Outflow peak
7,000
cfs
7,100
Maximum water surface elevation
1215.2 (1217.5 NAVD)
ft
1232.5 (1234.8 NAVD)
Spillway Design Flood ➜
Original2
Resived PMP5
Duration (Inflow)
3
days
4
Total volume
893,000
af
1,136,300
Inflow peak
580,000
cfs
859,900
Outflow peak
49,000
cfs
302,000
Maximum water surface elevation
1,259.6 (1,261.9 NAVD)
ft
1283.5 (1285.8 NAVD)5
Historic Maximums
Date
Local Datum
NAVD 1988
Maximum water surface elevation
2/23/1980
1207.33
ft
1,209.67
Maximum water impoundment1 (68% full)
2/23/1980
672,756
af
Maximum 1-hr inflow
2/20/1993
103,800
cfs
Maximum outflow
3/26/1993
7,000
cfs
1. Based on: aerial survey November 2016 and bathymetric survey October 2017 - computed June 2019. 1a. Based on composite surveys of 1963/68/85 - computed June 1993.
2. DM#3 General Design for Alamo Reservoir, April 1964.
3. Interim Report, H&H Review, Design Features of Existing Dams for Alamo & Whitlow Dams, March 1986
4. Alamo Dam and Lake Water Control Manual, October 2003
5. Maximum water surface elevation is 17 feet above top of dam and likely results in dam failure. Routing assumes infinite dam height.
6. Conservation Storage volume has no sponsor, is unallocated and is utilized to maximize project benefits