There are varying storage capacity elevations for water levels at Lake Mead. The U.S. Bureau of Reclamation (BOR) measures the reservoir’s storage and operational capacities at the following elevations:
Lake Mead Operational Levels
Top of Dam - Maximum designed water-surface elevation
Full Pool - Operational Capacity
SNWA Intake No. 1 - Dam intake tower's upper gates
Inactive Pool - Minimum elevation for power generatiom
Dead Pool - Lowest water outlet, Dam intake towers' lower gates
Dead Storage- No water can be released downstream of Hoover Dam
When BOR releases weekly and monthly hydrology data, they are reporting on what is commonly known as “live storage capacity,” which ranges in elevations from 895 feet to 1,219.6 feet. Water elevations ranging from 1,219.6 feet up to 1,229.0 feet is referred to as “full pool” and represents the Dam’s exclusive flood control space, as the Colorado River naturally fluctuates over time.
Water elevation of 950.0 feet, or 8% of live capacity, is the minimum level of water needed to generate power at Hoover Dam. Water elevations between 950.0 feet to 895.0 feet is considered “inactive pool” because water can be released from the dam downstream but does not generate hydropower. Water capacity at 895.0 feet elevation is considered “dead pool,” which is when downstream releases from Hoover Dam are no longer possible.
Measuring the Capacity of Lake Mead
In 1935, BOR and the Soil Conservation Service mapped the nearly formed Lake Mead’s topography in order to calculate the reservoir’s storage capacity. This study resulted in an estimated capacity of over 31 million acre-feet of water at an elevation of 1,221.4 feet.
Since 1935, sedimentation build up and shifts due to river flow over time has decreased the capacity of the reservoir.
A number of subsequent studies have been conducted to determine its current storage capacity and to support long-term planning and modeling for the lake’s operational and economic future.Subsequent ground surface measurements include bathymetric studies conducted from 1948 to 1949, 1963 to 1964, and in 2001.
In late 2009, BOR acquired LiDAR (combination of Light and Radar) data for elevations of emerging shorelines at and below 1,230 feet elevation, which were published in 2011.
The most recent sedimentation study indicated that the capacity of Lake Mead increased between 1964 and 2001 because the soil at the bottom of the lake had compacted over time. BOR is currently working on an updated bathymetry study at Lake Mohave at the southern end of the Lake Mead National Recreation Area.
Area and Capacity of Lake Mead (2010)
Area of Lake
Total Capacity of Lake
Capacity of Lake
Maximum designed water-surface elevation
Crest of drum gates on spillway (raised)
Permanent crest of spillway sill
Intake tower, upper gates
Intake tower, lower cylinder gate entrance liners
From U.S. Bureau of Reclamation (2011) 1Reclamation reports live capacity and percent of live capacity in all public documentation.