Alamo Dam

Alamo Dam

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 2016

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   372 acres  
  Target Elevation4   826 acres  
  Water Conservation pool   1084 acres  
  Spillway crest        
  Top of dam   1154 acres  
 Capacity, Gross Allocated2      
  Recreation pool 5,000 24,372 af  
  Target Elevation4   160,546 af  
  Water Conservation pool 230,000 321,716 af  
  Spillway crest2 Flood control 608,000 995,300 af  
  Top of dam   1,451,300 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  
Spillway2 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 PMP3
  Duration (Inflow)   3 days 3
  Total volume   893,000 af 1,390,000
  Inflow peak   580,000 cfs 820,000
  Outflow peak   49,000 cfs 418,000
  Maximum water surface elevation   1,259.6 (1,261.9 NAVD) ft 1282.1 (1284.4 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 March 1963, bottom survey May 1968 & bathymetric resurvey October 1985 (elevations 990-1120) - computed June 1993
2. DM#3 General Design for Alamo Reservoir, April 1964. The space allocation is based on a reservoir volume of 1,043,000 af at spillway crest.
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.