CRITICAL RULE CURVES -- A set of curves that define reservoir elevations that must be maintained to ensure that firm energy requirements can be met under the most adverse historical streamflow conditions. Critical rule curves are derived for all four years in the critical period. They are used to guide reservoir operation for power.

CRITICAL WATER PERIOD -- The "Worst Case" water condition under which the region's hydropower resource would generate the least amount of energy (about 12,500 aMW, as compared to 16,600 aMW in an average year). The definition of critical water is based on the lowest water condition on record (August 1928 to February 1932) measured at The Dalles Dam.

CUBIC FEET PER SECOND (CFS) -- A measurement of water flow representing one cubic foot of water moving past a given point in one second.

CURTAILMENT -- A temporary, mandatory load reduction under emergency conditions taken after all possible conservation and load management measures, and prompted by problems of meeting baseload rather than an upswing or peak.

DEMAND-SIDE -- When looking at the entire electric system as a whole, the portion that determines the amount of demand (furnaces, motors, lights, etc.).

DEMAND-SIDE MANAGEMENT (DSM) -- Strategies for reducing consumption by influencing when and how customers use electricity. Demand-side management includes such things as conservation programs and incentives for switching electricity use from mid-day to evening.

DEREGULATION -- The loosening of federal and state laws and regulations that govern the generation, transmission and distribution of electricity.

DIRECT CURRENT (DC) -- An electrical current in which the electrons flow continuously in one direction. Direct Current is used in specialized applications in commercial electric generation, transmission and distribution systems.

DIRECT SERVICE INDUSTRY (DSI) -- An industrial customer that buys power directly from BPA. Most Direct Service Industries are aluminum factories.

DISCHARGE -- Volume of water flowing at a given time, usually expressed in cubic feet per second.

DISTRIBUTION SYSTEM -- The system that transports electricity from the substation to customers. At Snohomish County PUD, the distribution system carries power at 12,500 volts.

DRAFT -- Release of water from a reservoir storage, usually measured in feet of reservoir elevation.

DRAWDOWN -- The distance that the water surface of a reservoir is lowered from a given elevation as water is released from the reservoir. Also refers to the act of lowering reservoir levels.

EDISON ELECTRIC INSTITUTE (EEI) -- An organization that represents the interests of investor-owned utilities in the United States.

END USE -- A term referring to the final use of energy. In the aggregate, it is used the same as demand. In more detailed use, it often refers to specific energy services, such as space heating.

ELECTRIC CONSUMERS PROTECTION ACT OF 1986 -- declared that municipal preferences would not apply in FERC relicensing decisions. It also required FERC to give equal consideration to environmental concerns, such as protecting fish and wildlife and enhancing recreation and conservation, as well as energy concerns, in making licensing and relicensing decisions.

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