Lake Mead National Recreation Area is a unique freshwater diving area. Here are a few tips when deciding to dive at Lake Mead.
Visibility on both lakes fluctuates throughout the year. During the months from October to April, visibility is usually good (20 feet to 50 feet). From May to September, algae growth is stimulated by warmer water temperatures which results in reduced visibility (30 feet to less than one foot, depending on location and depth). Visibility also varies with depth — the deeper you go the darker it is — and this is particularly pronounced in the summer months when the thermocline formed by warmer surface waters is present.
The first distinct thermocline usually occurs near 30 to 40 feet in depth. From surface level to a depth of 30 feet, the temperature may range from 70°F to 82°F, and this layer supports the majority of algae growth. The second distinct thermocline usually is found near a depth of 60 feet. Between 30 and 60 feet the temperature ranges from 70°F to 60°F with less algae present due to cooler water. Below 60 feet, the water temperature is 60°F to 52°F. At this depth the water is usually clear but much darker in summer than in winter due to the dissipation of the light caused by the presence of algae in the warmer water above. During the winter there is usually no thermocline, with the entire water column in the low 50 degrees.
Where rivers or streams flow into Lake Mead, visibility is poor year round due to high silt content or excessive algae growth. Examples are: Iceberg Canyon where the Colorado River flows into Lake Mead; north of Overton Beach where the Virgin and Muddy Rivers flow into Lake Mead; and Las Vegas Bay near the terminus of Las Vegas Wash. The reverse is true, however, from Hoover Dam to mid-way between Willow Beach and Eldorado Canyon. The colder water released from Hoover Dam (52°F-55°F) provides clear water and good visibility throughout the year.
Most of the currents in Lake Mead and Lake Mohave are slow and undetectable. From Hoover Dam to mid-way between Willow Beach and Eldorado Canyon, however, the current ranges from 3 to 12 miles per hour. This current is variable, depending on the volume of water released from Hoover Dam and the water level in Lake Mohave. At Ringbolt Rapids, the speed of the water may reach 16 miles per hour on weekdays.
Information courtesy of Lake Mead National Recreation Area