Virginia Administrative Code › Title 9 - ENVIRONMENT › Agency 25 - STATE WATER CONTROL BOARD › Chapter 31 - VIRGINIA POLLUTANT DISCHARGE ELIMINATION SYSTEM (VPDES) PERMIT REGULATION › Part II - Permit Applications and Special VPDES Permit Programs › Section 9VAC25-31-165 - Requirements applicable to cooling water intake structures

Current through Register Vol. 40, No. 24, July 15, 2024
A. Definitions.
				  The following definitions apply specifically to this section:
"Annual mean flow" means the average of daily flows over a
					 calendar year.
"Closed-cycle recirculating system" means a system
					 designed, using minimized makeup and blowdown flows, to withdraw water from a
					 natural or other water source to support contact and/or noncontact cooling uses
					 within a facility. The water is usually sent to a cooling canal or channel,
					 lake, pond, or tower to allow waste heat to be dissipated to the atmosphere and
					 then is returned to the system. (Some facilities divert the waste heat to other
					 process operations.) New source water (make-up water) is added to the system to
					 replenish losses that have occurred due to blowdown, drift, and
					 evaporation.
"Cooling water" means water used for contact or noncontact
					 cooling, including water used for equipment cooling, evaporative cooling tower
					 makeup, and dilution of effluent heat content. The intended use of the cooling
					 water is to absorb waste heat rejected from the process or processes used, or
					 from auxiliary operations on the facility's premises. Cooling water that is
					 used in a manufacturing process either before or after it is used for cooling
					 is considered process water for the purposes of calculating the percentage of a
					 new facility's intake flow that is used for cooling purposes.
"Cooling water intake structure" means the total physical
					 structure and any associated constructed waterways used to withdraw cooling
					 water from state waters. The cooling water intake structure extends from the
					 point at which water is withdrawn from the surface water source up to, and
					 including, the intake pumps.
"Design intake flow" means the value assigned (during the
					 facility's design) to the total volume of water withdrawn from a source water
					 body over a specific time period.
"Design intake velocity" means the value assigned (during
					 the design of a cooling water intake structure) to the average speed at which
					 intake water passes through the open area of the intake screen (or other
					 device) against which organisms might be impinged or through which they might
					 be entrained.
"Entrainment" means the incorporation of all life stages of
					 fish and shellfish with intake water flow entering and passing through a
					 cooling water intake structure and into a cooling water system.
"Estuary" means a semi-enclosed body of water that has a
					 free connection with open seas and within which the seawater is measurably
					 diluted with fresh water derived from land drainage. The salinity of an estuary
					 exceeds 0.5 parts per thousand (by mass) but is typically less than 30 parts
					 per thousand (by mass).
"Existing facility" means any facility that is not a new
					 facility.
"Freshwater river or stream" means a lotic (free-flowing)
					 system that does not receive significant inflows of water from oceans or bays
					 due to tidal action. For the purposes of this section, a flow-through reservoir
					 with a retention time of seven days or less will be considered a freshwater
					 river or stream.
"Hydraulic zone of influence" means that portion of the
					 source water body hydraulically affected by the cooling water intake structure
					 withdrawal of water.
"Impingement" means the entrapment of all life stages of
					 fish and shellfish on the outer part of an intake structure or against a
					 screening device during periods of intake water withdrawal.
"Lake or reservoir" means any inland body of open water
					 with some minimum surface area free of rooted vegetation and with an average
					 hydraulic retention time of more than seven days. Lakes or reservoirs might be
					 natural water bodies or impounded streams, usually fresh, surrounded by land or
					 by land and a man-made retainer (e.g., a dam). Lakes or reservoirs might be fed
					 by rivers, streams, springs, and/or local precipitation. Flow-through
					 reservoirs with an average hydraulic retention time of seven days or less
					 should be considered a freshwater river or stream.
"Maximize" means to increase to the greatest amount,
					 extent, or degree reasonably possible.
"Minimize" means to reduce to the smallest amount, extent,
					 or degree reasonably possible.
"Natural thermal stratification" means the
					 naturally-occurring division of a water body into horizontal layers of
					 differing densities as a result of variations in temperature at different
					 depths.
"New facility" means any building, structure, facility, or
					 installation that meets the definition of a "new source" or "new discharger"
					 and is a greenfield or stand-alone facility that commences construction after
					 January 17, 2002, and uses either a newly constructed cooling water intake
					 structure, or an existing cooling water intake structure whose design capacity
					 is increased to accommodate the intake of additional cooling water. A
					 greenfield facility is a facility that is constructed at a site at which no
					 other source is located, or that totally replaces the process or production
					 equipment at an existing facility. A stand-alone facility is a new, separate
					 facility that is constructed on property where an existing facility is located
					 and whose processes are substantially independent of the existing facility at
					 the same site. New facility does not include new units that are added to a
					 facility for purposes of the same general industrial operation (for example, a
					 new peaking unit at an electrical generating station).
"Ocean" means marine open coastal waters with a salinity
					 greater than or equal to 30 parts per thousand (by mass).
"Source water" means the water body from which the cooling
					 water is withdrawn.
"Thermocline" means the middle layer of a thermally
					 stratified lake or reservoir. In this layer, there is a rapid decrease in
					 temperatures.
"Tidal excursion" means the horizontal distance along the
					 estuary or tidal river that a particle moves during one tidal cycle of ebb and
					 flow.
"Tidal river" means the most seaward reach of a river or
					 stream where the salinity is typically less than or equal to 0.5 parts per
					 thousand (by mass) at a time of annual low flow and whose surface elevation
					 responds to the effects of coastal lunar tides.
B. Cooling water intake structures for new
				  facilities.
1. Applicability.
a. This section applies to a new facility if
				  it:
(1) Is a point source that uses or
				  proposes to use a cooling water intake structure;
(2) Has at least one cooling water intake
				  structure that uses at least 25% of the water it withdraws for cooling purposes
				  as specified in subdivision 1 c of this subsection; and
(3) Has a design intake flow greater than two
				  million gallons per day (MGD).