Water terms starting with P

215 terms

Plastic limit The water content corresponding to an arbitrary limit between the plastic and the semisolid state of consistency of a soil; water content at which a soil…
Plastic soil A soil that exhibits plasticity.
Plasticity A phenomenon used to describe a cell that is capable of becoming a specialized cell type of different tissue.
Plasticity index Numerical difference between the liquid limit and the plastic limit.
Playa Flat areas that contain seasonal or year-to-year shallow lakes that often evaporate, leaving minerals behind.
Plot A forest area defined by its condition.
Plumb Exactly vertical; at right angles to the horizontal.
Plumb Bob A pointed weight hung from a string. Used for vertical alignment.
Plunge pool A natural or artifically created pool that dissipates the energy of free-falling water.
Pluvial In hydrology, anything that is brought about directly by precipitation.
Ply One of several layers of fabric or of other strength-contributing material.
Pneumatic Powered or inflated by compressed air.
Pneumatic Gate (Rubber Gate or Bladder Gate) A tubular flexible gate anchored to a foundation or inside a pipe that is operated by filling with air under pressure.
Point Discharge Instantaneous rate of discharge, in contrast to the mean rate for an interval of time.
Point Precipitation Precipitation at a particular site, in contrast to the mean precipitation over an area.
Point source Any discernible, confined, or discrete conveyance from which pollutants are or may be discharged, including, but not limited to, any pipe, ditch, channel…
Pollutant Any inorganic or organic substance that contaminates air, water or soil. Generally, any substance introduced into the environment that adversely affects…
Pollution A resource that is out of place. Generally, the presence of matter or energy whose nature, location or quantity produces undesired environmental effects.
Polyvinyl Chloride (PVC) A type of plastic used to make pipe and fittings for water distribution and irrigation.
Pond A small lake. Water impounded by a diversion dam.
Pondage (1) The holding back of water for later release for power development above the dam of a hydroelectric plant to (a) equalize daily or weekly fluctuations…
Ponding In flat areas, runoff collects, or ponds in depression and cannot drain out. Flood waters must infiltrate slowly into the soil, evaporate, or be pumped…
Ponding (or flooding) A method for compacting soil using water added after the soil is in place until free water stands on the surface.
Pool A deep area of a stream between rapids or where the current is slow.
Pool Height The height of the water behind a dam. (Various datums may be used and various pool heights may be used, e.g., conservation pool, flood control pool, etc.)
Population the totality of items or units of material under consideration.
Population at risk (PAR) The population potentially affected by flood waters as a result of large operational releases or dam failure.
Population density Number of cells or individuals per unit. The unit could be an area, or a volume of medium.
Pore A small to minute opening or interstice in a rock or soil.
Pore Pressure The interstitial pressure of fluid (air or water) within a mass of soil, rock, or concrete.
Pore spaces The open areas, or spaces, in soil, sediments, and rocks that are filled by air or water.
Pore-water pressure Internal hydrostatic pressure in an embankment caused by the level of water in the reservoir acting through pressure-transmitting paths between soil…
Porosity The ratio of the volume of void space to the total volume of an undisturbed sample.
Portal An opening into a tunnel.
Positive pressure Pressure within a pipe that is greater than atmospheric pressure.
Posted operating instructions Operations and maintenance instructions taken from the Standing Operating Procedures (SOP) that pertain to the mechanical features in the immediate area…
Potable water Water that is suitable for drinking, as defined by local health officials.
Potential dam safety deficiency A condition that currently does not significantly affect the safety of the dam, but is capable of becoming a dam safety deficiency; for example…
Potential Energy Energy available due to position.
Potential evapotranspiration Rate at which water, if available, would be removed from soil and plant surfaces.
Potential spill An accident or other circumstances which threatens to result in discharge of oil or other hazardous substances.
Pounds per square inch (psi or lb/in2) A pressure designation for pounds per square inch. May be pounds per square inch gage (psig) or absolute (psia).
Powder factor (explosives factor) A term expressing the amount of explosives used to break a quantity of rock. Normal units for the powder factor are lb/yd3 or kg/m3; however, lb/ton and…
Power Authority to do. One has the power to do something if he is of legal age. Also, used as "powers," the term refers to authority granted by one person to…
Power demand Rate at which electric energy is required and delivered to or by a system over any designated period of time.
Power factor The ratio of real to total power. In alternating-current power transmission and distribution, the cosine of the phase angle between the voltage and…
Power pool Two or more interconnected electric systems which operate as a single system to supply power to meet combined load requirements.
Powerplant Structure that houses turbines, generators, and associated control equipment.
Powerplant capacity The capacity for powerplants is the nameplate rating in kW (kilowatts) and generally includes only the main generating units, except for very large plants…
Precast dam A dam constructed mainly of large precast concrete blocks or sections.
Precipitation The total measurable amount of water received in the form of snow, rain, drizzle, hail, and sleet.
Precipitation Processing System The WSR-88D system that generates 1-hour running, 3-hourly, and running storm total precipitation accumulations.
Predominant period The period(s) at which maximum spectral energy is concentrated.
Preference Priority access to Federal power by public bodies and cooperatives.
Preference customers Publicly owned systems and non-profit cooperatives which, by law, have preference over investor-owned systems for purchase of power from Federal projects.
Prescribed elevation The elevation as called out or dictated in notes, drawings or specifications paragraphs.
Pressure The load divided by the area over which it acts.
Pressure Gage A device for registering the pressure of solids, liquids, or gases. It may be graduated to register pressure in any units desired.
Pressure Head The amount of force or pressure created by a depth of one foot of water.
Pressure Relief Pipes Pipes used to relieve uplift or pore-water pressure in a dam foundation or in the dam structure.
Prestressed dam A dam, the stability of which depends in part on the tension in steel wires, cables, or rods that pass through the dam and are anchored into the…
Price Current Meter A current meter with a series of conical cups fastened to a flat framework through which a pin extends.
Primacy The responsibility for ensuring that a law is implemented, and the authority to enforce a law and related regulations.
Primary (or Principal) Spillway The spillway which would be used first during normal inflow and flood flows.
Primary excavation Digging in undisturbed soil, as distinguished from rehandling stockpiles.
Primary production Creation of organic matter by photosynthesis.
Prime See Subprime
Principal organizations Federal, State, and local agencies or departments or executive offices having major or lead roles in emergency planning and preparedness for emergency…
Prior appropriation A doctrine of water law that allocates the right to use water on a first-come first-serve basis.
Private sector Industry, volunteer, quasi-governmental, etc., having a role in emergency planning and preparedness.
Probabilistic Quantitative Precipitation Forecast (PQPF) A form of QPF (see below) that includes an assigned probability of occurrence for each numerical value in the forecast product.
Probability The chance that an event occurs. It is usually expressed as a percent. Zero percent denotes impossibility, while 100% denotes certainty.
Probability of failure Likelihood that, given the loading event and failure mode, the structure responds with the necessary adverse occurrences to ultimately result in…
Probability of load Likelihood that a certain loading event (static, seismic, hydrologic, other) occurs at a structure site.
Probable maximum flood (PMF) (maximum probable flood, MPF) The largest flood that may reasonably be expected to occur at a given point on a stream from the most severe combination of critical meteorologic and…
Probable maximum precipitation (PMP) Theoretically, the greatest depth of precipitation for a given duration that is physically possible over a given size storm area at a particular…
Production The process of delivering to another party, or making available for that partys review, documents deemed responsive to a discovery request.
profile A sectional view showing grades and distances, usually taken along the centerline.
Profundal Deepest part of the ocean or lake where light does not penetrate. This layer usually has fewer nutrients, more silt, and fewer organisms than the surface.
Programmatic environmental impact statement (PEIS) An environmental impact statement that addresses a proposal to implement a specific policy, to adopt a plan for a group of related actions, or to…
Project A single financial entity which can be composed of several units or divisions, integrated projects, or participating projects.
Project Hazardous Waste Coordinator (PHWC) Individual designated by the Area Manager to coordinate records and maintain proper management of hazardous wastes on each project; acts as primary…
Project-use energy This is intended to cover primarily power and energy used for project operations such as pumping or other miscellaneous uses.
Project-use power Power for main conveyance pumping, designated drainage pumping and other designated miscellaneous electric loads directly associated with the operation of…
Property Protection Measures that are undertaken usually by property owners in order to prevent, or reduce flood damage.
Proratable water That portion of the total water supply available under provisions of sections 18 and 19 of Civil Action No.
Protection For purposes of the National System of MPAs, must have existing laws or regulations that are designed and applied to afford the site with increased…
Protective Action An action or measure taken to avoid or reduce exposure to a hazard.
Protective action decision making (recommendations) The process whereby local authorities select one of more actions to protect threatened populations.
Psychological value. See Social value.
Public affairs officer The dam operating organization's designated person responsible for public affairs.
Public Alert and Notification System The system for obtaining the attention of the public and providing appropriate emergency information.
Public information officer (public relations officer) The person on the emergency management team who is in charge of public information affairs.
Public involvement Process of obtaining citizen input into each stage of development of planning documents. Citizen input is required in all environmental impact statements.
Public involvement plan Document that presents the procedural plans of the Bureau of Reclamation to inform and gather information from project beneficiaries and the general…
Public land order An action on Federal lands to withdraw it from public use for a specified purpose.
Public Utilities Commission (Public Service Commission) The state regulatory agency that governs retail utility rates and practices and, in many cases, issues approvals for the construction of new generation…
Public Utility Holding Company Act (PUHCA) Federal legislation, enacted in 1935, which regulates the corporate structure and financial operations of certain utility holding companies.
Public Utility Regulatory Policies Act (PURPA) A federal law requiring a utility to buy the power produced by a qualifying facility at a price equal to that which the utility would otherwise pay if it…
Publications Books, manuals, and publications of the Bureau of Reclamation may be obtained from the National Technical Information Service (NTIS), U.S.