The Entergy facility is a boiling water reactor with a rated core thermal power level of 1912 MW, providing a gross electrical output of 620 MW. The facility draws water from the Connecticut River into a cooling system that varies from open cycle once through, cooling tower cooling to a closed cycle recirculating cooling tower configuration. Heated water from the cooling water system is discharged to the Connecticut River.

 The facility has two mechanical draft cooling towers. The CWIS as well as the thermal discharge outfall is located on the west side of the Connecticut River in Vernon Pool, an impoundment created by Vernon Dam.

 The Agency of Natural Resources administers the federal CWA in Vermont  Any discharge of pollutants to state waters require a (NPDES) discharge permit  Heat is a pollutant  Entergy is required to have a NPDES permit for the thermal discharge to the Connecticut River

 CWA 316(a) – the thermal discharge effluent limit must be more stringent than necessary to assure the protection and propagation of the balanced, indigenous population (BIP) of shellfish, fish and wildlife in the receiving waters.  CWA 316(b) - the location, design, construction and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact.  Implementing federal regulations

316b focuses on the impacts of the CWIS  Entrainment – occurs when the cooling towers draw in aquatic organisms  Impingement – occurs when the flow of water traps aquatic organisms against grills or screens as the water is drawn into the CWIS.  Both result in injury or death of aquatic organisms.

 10 VSA Chapter 47  The Vermont Water Quality Standards, Section 3- 01B.1.b – The total increase from the ambient temperature due to all discharges and activities shall not exceed 1°F for cold water habitat except as provided in d.  Section 3-01B.1.d – The Secretary may set higher temperature limits if: 1)The discharge complies with all applicable provisions of the VWQS 2)A mixing zone of 200 feet is not adequate 3)After taking into to account the interaction of thermal effects and other wastes, the temperature will not result in thermal shock or prevent the full support of uses in the receiving waters.

Under the VWQS, the following are designated protected uses in the Connecticut River:  Aquatic Biota, Wildlife, and Aquatic Habitat  Aesthetics  Public water supply  Irrigation of crops and other agricultural uses  Swimming and other primary contact recreation  Boating, fishing and other recreational uses

The permit allows Entergy to discharge heated water to the Connecticut River. The permit sets thermal effluent limitations during specific time periods. Compliance with the temperature limits is measured at a downstream compliance point at Station 3 (approximately 1.5 miles downstream from the discharge) as compared to ambient as measured at Station 7 (located approximately 3.5 miles upstream of the discharge).

 The permitted discharge flow is up to 543 MGD and Entergy withdraws in excess of 125 MGD, actual intake flow for cooling purposes. The facility has not run the cooling towers year round since successful 316(a) and (b) demonstrations were made in 1978 (winter period) and 1991 (summer period).

The temperature limits for the period of October 15 through May 15 are as follows:  The temperature at Station 3 shall not exceed 65°F.  The rate of change of temperature at Station 3 shall not exceed 5°F per hour. The rate of change of temperature shall mean the difference between consecutive hourly average temperatures.  The increase in temperature above ambient at Station 3 shall not exceed 13.4°F.

The increase in temperature above ambient at Station 3 shall not exceed the limits set forth below: Station 7 (upstream)Increase in Temperature Above Ambient at Station 3: Above 63°F2°F >59°F, ≤63°F3°F ≥55°F, ≤59°F4°F Below 55°F5°F

Station 7 Temperature:Increase in Temperature Above Ambient at Station 3: Above 78°F2°F >63°F, ≤ 78°F3°F >59°F, ≤63°F4°F ≤59°F5°F The permit sets a temperature cap of 85° F at Station 3.

The permit includes effluent limits and monitoring frequencies from each discharge point. The permit also requires monitoring in the Connecticut River. The purpose of the Connecticut River monitoring regime was to assure that the discharges did not violate the Clean Water Act and applicable Vermont Water Quality Standards. The annual monitoring regime focuses primarily on the fish and other aquatic biota that inhabit the Connecticut River in and around the vicinity of Vernon.

 The discharge permit was renewed by the Agency in On September 30, 2005, Entergy applied for renewal of its discharge permit. The permit expired on March 31, Because Entergy submitted a timely application for renewal on which the Agency has not yet made a final decision, in accordance with 3 V.S.A. §814, Entergy may continue to operate under the terms and conditions of the expired permit. The Agency is currently working on the renewal permit.

On February 20, 2003, ENVY applied for an amendment to its 2001 discharge permit. The application essentially requested a §316(a) variance for an additional 1°F increase in thermal discharge during the period of May 16 through October 14. On March 30, 2006, the Agency amended the 2001 permit, granting the request for an increase during the June 16 – October 14 time period and denying the request for the May 16 – June 15 time period.

 The Agency’s permit amendment was appealed to the Environmental Court. The Court issued a final decision on November 24, 2008 substantially affirming the Agency’s permit decision. The Environmental Court’s decision was subsequently appealed to the Vermont Supreme Court. The Supreme Court’s decision was issued on December 18, 2009.

 The federal 316b rules have been the subject of protracted litigation in the federal courts in Riverkeeper vs EPA.  The US Supreme Court issued a decision in  EPA published draft rules on April 20,  EPA issued two Notices of Data Availability in June 2012 regarding impingement mortality limitations and the preliminary results of surveys of households' willingness to pay for incremental reductions in fish mortality.  The deadline for the final 316b rule is June 27, 2013.

 Once a tentative decision has been made, the Agency must notify the public, EPA, and affected states.  After a minimum of 30 days public notice and opportunity for a public informational hearing, the agency issues a permit decision and a response summary.  The permit decision may be appealed to the Environmental Division of Superior Court