Glossary L – R

A - F | G - K | L - R | S - Z
LANDSCAPE A heterogenous land area with interacting ecosystems that are repeated in similar form throughout.
LEVEEAn embankment constructed to prevent a river from overflowing.
LIFE CYCLE Various stages an animal passes through from egg fertilization to death.
LIMNOLOGY The study of lakes, ponds and streams.
LITTORAL ZONE The region of land bordering a body of water.
LOAD The amount of electric power or energy delivered or required at any specified point or points on a system. Load originates primarily at the energy-consuming equipment of customers.
LOAD SHAPING The adjustment of storage releases so that generation and load are continuously in balance.
LOCKA chambered structure on a waterway closed off with gates for the purpose of raising or lowering the water level within the lock chamber so ships can move from one elevation to another along the waterway.
LOW-HEAD DAM A dam at which the water in the reservoir is not high above the turbine units.
MACROINVERTEBRATE Invertebrates visible to the naked eye, such as insect larvae and crayfish.
MACROPHYTES Aquatic plants that are large enough to be seen with the naked eye.
MAINSTEM The principal river in a basin, as opposed to the tributary streams and smaller rivers that feed into it.
MEGAWATT (MW) A megawatt is one million watts, a measure of electrical power.
MEGAWATT-HOUR (MWH)A unit of electrical energy which equals one megawatt of power used for one hour.
MID-COLUMBIAThe section of the Columbia River from its junction with the Snake River up to Grand Coulee Dam.
MID-COLUMBIA DAMS Dams owned by the mid-Columbia Public Utility Districts. They include Wells, Rocky Reach, Rock Island, Wanapum and Priest Rapids dams.
MIGRATING Moving from one area of residence to another.
MILLOne tenth of a cent. The cost of electricity is often expressed in mills per kilowatt-hour. (25 mills = 2.5 cents).
MINIMUM FLOW LEVEL The level of stream flow sufficient to support fish and other aquatic life; to minimize pollution; or to maintain other instream uses such as recreation and navigation.
MINIMUM OPERATING POOL The lowest water level of an impoundment at which navigation locks can still operate
MITCHELL ACT The Mitchell Act of 1938 (Public Law No. 75-502, 16 U.S.C. 755), which authorizes federal funds for hatchery construction and operation within the Columbia River Basin.
MITIGATING MEASURES Modifications of actions that (1) avoid impacts by not taking a certain action of parts of an action; (2) minimize impacts by limiting the degree or magnitude of the action and its implementation; (3) rectify impacts by repairing, rehabilitating, or restoring the affected environment; (4) reduce or eliminate impacts over time by preservation and maintenance operations during the life of the action; or (5) compensate for impacts by replacing or providing substitute resources or environments.
MITIGATION The act of alleviating or making less severe. Generally refers to efforts to alleviate the impacts of hydropower development to the Columbia Basins salmon and steelhead runs.
MIXED STOCK A stock whose individuals originated from commingled native and non-native parents; or a previously native stock that has undergone substantial genetic alteration.
MONITOR To systematically and repeatedly measure conditions in order to track changes.
MORTALITY The number of fish lost or the rate of loss.
MULTIPURPOSE PROJECT A project designed for irrigation, power, flood control, municipal and industrial, recreation, and fish and wildlife benefits, in any combinations of two or more (contrasted to single-purpose projects serving only one need).
MUNICIPAL UTILITYA utility owned and operated by a city.
NAMEPLATE RATINGThe output capacity of a generating device as designated by the manufacturer. The nameplate is usually attached to the individual machine.
NATIONAL ENERGY POLICY ACT OF 1992A law aimed at increasing efficiency in the electric utility industry by enhancing competition in generation. It opens up transmission access in an unprecedented fashion by giving the Federal Energy Regulatory Commission authority to order utilities to provide transmission to other utilities, federal power marketing agencies or anyone else generating electric energy for sale.
NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) OF 1969A law requiring agencies to consider the environmental impacts of major federal actions and to prepare environmental impact statements (EISs) which discuss these impacts and weigh alternatives. The law also requires public participation in the EIS process.
NATAL STREAM Stream of birth.
NATIVE SPECIES A species of fish indigenous to a specific state.
NATIVE STOCK An indigenous stock of fish that has not been substantially affected by genetic interactions with non-native stocks or by other factors, and is still present in all or part of its original range.
NATURAL PRODUCTION Spawning, incubating, hatching and rearing fish in rivers, lakes and streams without human intervention.
NATURALLY SPAWNING POPULATIONS Populations of fish that have completed their entire life cycle in the natural environment and may be the progeny of wild, hatchery or mixed parentage.
NET PEN A fish rearing enclosure used in lakes and marine areas.
NITROGEN SUPERSATURATION A condition of water in which the concentration of dissolved nitrogen exceeds the saturation level of water. Excess nitrogen can harm the circulatory system of fish.
NITROGEN SUPERSATURATIONA condition of water in which the concentration of dissolved nitrogen exceeds the saturation level of water. Excess nitrogen can harm the circulatory systems of fish.
NONFIRM ENERGY Energy available when water conditions are better than the worst historical pattern; generally such energy is sold on an interruptible (nonguaranteed) basis. Sometimes called secondary energy.
NON-POWER OPERATING REQUIREMENTSOperating requirements at hydroelectric projects that pertain to navigation, flood control, recreation, irrigation, and other non-power uses of the river.
NORTHWEST POWER PLANNING COUNCIL/ACTThe Northwest Power Planning Council was created in 1981 in accordance with the Northwest Power Act of 1980. The Council is a regional planning agency composed of eight members, two each from the states of Idaho, Montana, Oregon and Washington. Members are appointed by state governors and confirmed by state legislatures. The Council's primary responsibilities are 1) to develop a program to "protect, mitigate, and enhance fish and wildlife damaged by hydroelectric development in the Columbia River Basin; 2) to develop a 20-year regional conservation and electric power plan; and 3) to provide for broad public participation in its planning processes. The Council is not a part of BPA nor a federal agency funded by BPA rates.
NORTHWEST POWER POOLThe Northwest Power Pool is an association of generating utilities serving the Northwestern United States, British Columbia and Alberta. Members include the Bonneville Power Administration, the U.S. Army Corps of Engineers, the Bureau of Reclamation and all public and investor-owned utilities with generating resources. The association dates to 1942, when the United States government directed utilities to coordinate operations in support of wartime production. Activities of the Power Pool are determined by three committees. One deals with coordination of operations, the second with transmission issues and the third with administration of the Pacific Northwest Coordination Agreement of 1964. The agreement is a plan for coordinating hydropower generation and determining load carrying capability in the Columbia River Basin.
NORTHWEST POWER POOL COORDINATING GROUPMade up of BPA, the Corps, Reclamation, and public utilities in the Northwest and British Columbia and Alberta. The group's primary functions are administering the Pacific Northwest Coordination Agreement and participating in Northwest Power Pool Committee activities.
NUTRIENT CYCLING Circulation or exchange of elements such as nitrogen and carbon between nonliving and living portions of the environment.
NUTRIENT DEPLETION Detrimental changes on a site in the total amount of nutrients and/or their rates of input, uptake, release, movement, transformation, or export.
OFFPEAK HOURS Period of relatively low demand for electrical energy, as specified by the supplier (such as the middle of the night).
OFF-SITE MITIGATION The improvement in conditions for fish or wildlife species away from the site of a hydroelectric project that had detrimental effects on fish and/or wildlife, as part or total compensation for those effects. An example of off-site mitigation is the fish passage restoration work being conducted in the Yakima River Basin for the detrimental effects caused by mainstem hydroelectric projects.
OPERATING LIMITS Limits or requirements that must be factored into the planning process for operating reservoirs and generating projects. (Also see operating requirements, below.)
OPERATIONAL LOSSES The direct wildlife losses caused by the day-to-day fluctuations in flows and reservoir levels resulting from the operation of the hydrosystem.
OPERATING REQUIREMENTS Guidelines and limits that must be followed in the operation of a reservoir or generating project. These requirements may originate in authorizing legislation, physical plant limitations, or other sources.
OPERATING RULE CURVE A curve, or family of curves, indicating how a reservoir is to be operated under specific conditions and for specific purposes.
OPERATING YEAR The 12-month period from August 1 through July 31.
OUTAGES Periods, both planned and unexpected, during which the transmission of power stops or a particular power-producing facility ceases to provide generation.
PACIFIC SALMON TREATY A treaty signed by the United States and Canada in 1984 that governs the harvest of certain salmon stocks in the commercial fisheries of Alaska, Canada and the western continental United States.
PACIFIC NORTHWEST COORDINATION AGREEMENTA binding agreement among BPA, the Corps, Reclamation, and the major generating utilities in the Pacific Northwest that stemmed from the Columbia Treaty. The Agreement specifies a multitude of operating rules, criteria, and procedures for coordinating operations of the system for power production. It directs operation of major generating facilities as though they belonged to a single owner.
PACIFIC NORTHWEST ELECTRIC POWER PLANNING CONSERVATION ACT OF 1980Established the Northwest Power Planning Council to prepare a regional power plan that provides an adequate, efficient, economical and reliable power supply and to develop a program to protect, mitigate and enhance the fish and wildlife of the Columbia River Basin. The act also enabled BPA to acquire the output of raw resources to meet future load growth, established priorities for BPA resource aquistition, set terms of the Residential Exchange, and outlined ratemaking provisions for the agency.
PACIFIC NORTHWEST UTILITIES CONFERENCE COMMITTEE (PNUCC)PNUCC represents the three constituencies in the Northwest energy community: public utilities, investor-owned utilities, and direct service industries. PNUCC provides a forum where its diverse membership can share information and views and work toward consensus on a variety of power and environmental issues that impact resource stability and future energy development.
PASSAGE The movement of migratory fish through, around, or over dams, reservoirs and other obstructions in a stream or river.
PEAK LOAD The maximum electrical demand in a stated period of time. It may be the maximum instantaneous load or the maximum average load within a designated period of time.
PENSTOCK A pipeline or conduit designed to withstand pressure surges leading from a forebay or reservoir to power-producing turbines, or pump units.
PHOTOVOLTAICThe direct conversion of sunlight to electric energy through the effects of solar radiation on semi-conductor materials.
PIT TAGS Passive Integrated Transponder (PIT) tags are used for identifying individual salmon for monitoring and research purposes. This miniaturized tag consists of an integrated microchip that is programmed to identify individual fish. The tag is inserted into the body cavity of the fish and decoded at selected monitoring sites.
PLANKTON Minute floating forms of microscopic plants and animals in water which cannot get about to any extent under their own power. They form the important beginnings of food chains for larger animals.
PLUME The area of the Pacific Ocean that is influenced by discharge from the Columbia River, up to 500 miles beyond the mouth of the river.
POOL A reach of stream that is characterized by deep low velocity water and a smooth surface.
POWER BROKERA company that acts as an agent in the sale of electricity from the company that generates the power to the company or customer that wants to buy the power.
POWERHOUSE A primary part of a hydroelectric dam where the turbines and generators are housed and where power is produced by falling water rotating turbine blades.
POWER MARKETERA company that purchases electricity from one company and then sells that electricity to another company or customer.
POWER PEAKING The generation of electricity to meet maximum instantaneous power requirements; usually refers to daily peaks.
PREDATION Hunting and killing another animal for food.
PUBLIC POWER COUNCIL (PPC)Formed in 1966, PPC represents and advocates the common legal and technical interests of the Northwest's consumer-owned utilities. PPC interacts with BPA, the Northwest Power Planning Council and other regional and national groups on subjects including BPA rate proceedings and power marketing policies, public preference issues, power supply planning, conservation, legislative concerns, and related issues. Offices are located in Portland.
PUBLIC UTILITY REGULATORY POLICIES ACT OF 1978 (PURPA)Federal law that requires utilities to purchase electricity from qualified independent power producers at a price that reflects what the utilities would have to pay for the construction of new generating resources (see avoided cost). Portions of the act were designed to encourage the development of small-scale cogeneration and renewable resources.
PUBLIC UTILITY A private business organization, subject to government regulation, that provides an essential commodity or service, such as water, electricity, transportation, or communications, to the public.
PUBLIC UTILITY DISTRICT (PUD) A government unit established by voters of a district to supply electric or other utility service.
PUMPED STORAGE PLANT A hydroelectric power plant which generates electric energy to meet peak load by using water pumped into a storage reservoir during off-peak periods.
PREFERENCEPriority granted by the Federal Power Act that grants public bodies and cooperatives priority access to federal power.
PUBLICLY OWNED UTILITYA utility that is owned by the public, rather than by stockholders. Snohomish County PUD, Seattle City Light and Tacoma City Light are all publicly owned utilities.
RAPIDS A reach of stream that is characterized by small falls and turbulent high velocity water.
REARING The juvenile life stage of anadromous fish spent in freshwater rivers, lakes and streams before they migrate to the ocean.
RECOVERY RESTORATION The reestablishment of a threatened or endangered species to a self-sustaining level in its natural ecosystem (i.e., to the point where the protective measures of the Endangered Species Act are no longer necessary).
RECREATIONAL FISHERY (OR HARVEST) A fishery limited to use of certain gear types (usually rod and reel) where fish can only be used for personal consumption (not sold) or must be released unharmed.
REDDSSpawning nests made in the gravel beds of rivers by salmon and steelhead.
REFILLThe annual process of filling a reservoir; also refers to the point at which the hydro system is considered full from the seasonal snowmelt runoff.
RELIABILITYFor a power system, a measure of the degree of certainty that the system will continue to meet load for a specified period of time.
RENEWABLE RESOURCEA power source that is continuously or cyclically renewed by nature. In the Northwest Power Act, a resource that uses solar, wind, hydro, geothermal, biomass or similar sources of energy.
RESERVE CAPACITY Generating capacity used to meet unanticipated demands for power or to generate power in the event normal generating resources are not available.
RESIDENT FISH Occupying headwater reaches; may disperse locally, but generally considered non-migratory.
RESERVOIR A body of water collected and stored in an artificial lake behind a dam.
RESERVOIR ELEVATIONSThe levels of the water stored behind dams.
RESERVOIR STORAGE The volume of water in a reservoir at a given time.
RESIDENT FISH Fish that spend their entire life cycle in freshwater. In the Northwest, resident fish includes landlocked anadromous fish (e.g., white sturgeon, kokanee and coho), as well as traditionally defined resident fish species.
RESIDENT FISH SUBSTITUTIONS The enhancement of resident fish to address losses of salmon and steelhead in those areas permanently blocked to anadromous (ocean-migrating) fish as a result of hydroelectric dams.
RIFFLE A reach of stream that is characterized by shallow, fast moving water broken by the presence of rocks and boulders.
RIPARIAN Living on or adjacent to a water supply such as a riverbank, lake, or pond. Of, on, or pertaining to the bank of a river, pond, or lake.
RIPARIAN HABITAT Habitat along the banks of streams, lakes or rivers.
RIPRAP A layer of large uncoursed stones, broken rock, boulders, precast blocks, bags of cement, or other suitable material generally placed in random fashion on the upstream and downstream faces of embankment dams, stream banks, on a reservoir shore, on the sides of a channel, or other land surfaces to protect them from erosion or scour caused by current, wind, wave, and/or ice action.
RIVER MILES Miles from the mouth of a river; for upstream tributaries, from the confluence with the main river.
RULE CURVES Water levels, represented graphically as curves, that guide reservoir operations.
RUNA general term referring to upriver migration of anadromous fish over a particular time and area - often composed of multiple individual breeding stocks.
RUNOFF Water that flows over the ground and reaches a stream as a result of rainfall or snowmelt.
RUN-OF-THE-RIVER DAMSHydroelectric generating plants that operate based only on available streamflow and short-term storage (hourly, daily, or weekly).
1) Snohomish County P.U.D.:
2) The Columbia River System: The Inside Story A 1991 publication from the U.S. Bureau of Reclamation, U.S. Army Corps of Engineers and Bonneville Power Administration
3) Public Power Fundamentals, a 1995 publication from the Public Power Council
4) Northwest Power Planning Council 2001 Columbia Basin Fish and Wildlife Program Description
5), 2001 Glossary of Terms
6) Bureau of Reclamation, Glossary of Hydropower Terms