North Anna Waste Heat Treatment Facility

North Anna Waste Heat Treatment FacilityCooling Lagoons

North Anna Power Station uses water from Lake Anna to condense steam back to water inside the station. The water is returned to the lake slightly warmer than when it was taken. The discharged water cools in a series of private cooling lagoons, known as the Waste Heat Treatment Facility (WHTF).

When North Anna is in full operation, approximately 2,000,000 gallons of water pass through the station per minute.


Lake Anna was developed to provide cooling water for North Anna and is 17 miles long, 1 1/2 miles wide, and offers 200 miles of shoreline. Download a brochure on Lake Anna.

Harmful Algae Blooms identified in the Waste Heat Treatment Facility

Lake Anna Conditions

Lake Anna's water level and temperature readings are updated once each weekday. The temperature is measured in water being drawn directly from the main lake into the station's intake. The lake level is based on feet above sea level as measured at the main dam.

Date Temperature (deg. F) Lake Level (ft.)
7/13/2020 87 249.7

WHTF Water Temperatures

Discharge Water 

By design, the temperature of the discharge water is typically 14 degrees warmer than the intake water. Intake temperatures can fluctuate with seasons or weather conditions. The current temperature of the discharge water is presented below as it initially leaves the station.

Lagoons 2 and 3

Calculated water temperatures for WHTF Lagoons 2 & 3 in the vicinity of the dikes are also shown below. These predicted values are based on historical observations and are provided for the period of primary recreational use (May 1 - October 31) as this is typically the period with the highest water temperatures and greatest recreational use. Individuals choosing to use the lagoons for recreational purposes should consider these temperatures in relation to health risk information contained on the Virginia Department of Health's website

The temperature values are calculated using the actual measured discharge temperature and equations that express the historical relationship between the discharge temperature and temperatures measured at a single location in each lagoon. The calculated lagoon temperatures are provided as an indication of the predicted temperatures that are expected to occur in the lagoons given the measured discharge temperature.

Date Time Discharge Temp
(deg F)
Lagoon 2 Temp
(deg F)
Lagoon 3 Temp
(deg F)
Jul 14 0500 101 96 93
Jul 14 0445 101 96 93
Jul 14 0430 101 96 93
Jul 14 0415 101 96 93
Jul 14 0400 101 96 93
Jul 14 0345 101 96 93
Jul 14 0330 101 96 93
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