Temperature Summary


Save Lake Almanor website

Under the December 2000 Rock Creek-Cresta Relicensing Settlement Agreement (FERC Project #1962) PG&E is required to maintain water temperatures of 20 degrees Celsius (68 degrees Fahrenheit) or less in the Feather River between Rock Creek Dam and Cresta Power House "to the extent that Licensee (PG&E) can reasonably (emphasis added) control such temperatures".  Section 1 of the RC-C Settlement Agreement contemplates that the temperature could be controlled by installing a Thermal Curtain in front of the Prattville Intake structure in Lake Almanor to force colder water to be drawn from a cold water layer that is located deeper in the lake during much of the year.  A reduction in water temperature in the Feather River is expected to result in an improved fishery habitat downstream of Lake Almanor.


The proposed modification would result in a 770 foot x 900 foot Thermal Curtain constructed around the Prattville Intake.  While it is not anticipated that more water would be released than is released now, the modified intake would result in up to 50 % of the cold water in Lake Almanor being released during the summer months.  In addition to Lake Almanor, PG&E is considering installing Thermal Curtains in Butt Valley reservoir.   Overall, the modifications could result in a total cost of $50-$60 million to PG&E that would ultimately be passed on to PG&E's ratepayers.


The Project 2105 Committee is very concerned that the release of cold water could result in:

  • harm to the Lake Almanor fishery

  • harm to the Butt Lake fishery
  • temperature changes in Lake Almanor that may cause detrimental effects on food chain availability, dissolved oxygen concentrations, and thermocline elevations
  • possible detrimental effects on fish spawning and fish passage between Lake Almanor and Butt Lake
  • possible decrease in lake levels if additional water releases are needed to help control Feather River water temperatures
  • an 18 month delay in obtaining the final Project 2105 FERC license in order to complete the CEQA and NEPA process to assess the construction impact

Because of the possible detrimental environmental impacts, the large construction costs, visual impacts and negative impacts on boating, the Project 2105 Committee is opposed to constructing Thermal Curtains.  The Committee will continue to participate in the 2105 Licensing Group to work toward a reasonable alternative in controlling the water temperatures downstream of Lake Almanor.


Public Meetings


Several public meeting to discuss the temperature issue have been held in Chester.  The next 2105 Licensing Group meeting will held on September 22 2005 in Chico.  Times, locations, and agendas of future meeting are located here.  Local citizens are concerned about the Thermal Curtain and have sent many letters to state agencies and FERC opposing the Thermal Curtain.