The maximum mean daily discharge occurring in a stream during a given flood event.
- Browse Related Terms: ADI, Antecedent flood, Base Flood, Base flood plain, Daily Flood Peak, Designated frequency flood, Flood frequency, Hydrologic Model, Lowland Flooding, Moderate frequency flood, Partial-Duration Flood Series, RFD
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Any artificial barrier which impounds or diverts water. The dam is generally hydrologically significant if it is:
- 25 feet or more in height from the natural bed of the stream and has a storage of at least 15 acre-feet.
- Or has an impounding capacity of 50 acre-feet or more and is at least six feet above the natural bed of the stream.
- A barrier built across a watercourse to impound or divert water. A barrier that obstructs, directs, retards, or stores the flow of water. Usually built across a stream. A structure built to hold back a flow of water. See afterbay dam, ambursen dam, arch dam, buttress dam, check dam, coffer dam, concrete dam, crib dam, detention dam, diversion dam, double curvature arch dam, earth dam, embankment dam, gabion dam, gravity arch dam, gravity dam, hollow gravity dam, hydraulic fill dam, industrial waste dam, masonry dam, mine tailings dam, multiple arch dam, multipurpose dam, overflow dam, precast dam, prestressed dam, regulating dam, rockfill dam, roller-compacted concrete dam, rubble dam, or saddle dam.
A barrier built, usually across a watercourse, for impounding or diverting the flow of water.
- Browse Related Terms: Dam, Regulating dam (reregulating dam), Reregulation dam., Tailrace.
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Catastrophic event characterized by the sudden, rapid, and uncontrolled release of impounded water.
- Catastrophic type of failure characterized by the sudden, rapid, and uncontrolled release of impounded water. It is recognized that there are lesser degrees of failure and that any malfunction or abnormality outside the design assumptions and parameters which adversely affect a dam's primary function of impounding water could be considered a failure. Such lesser degrees of failure can progressively lead to or heighten the risk of a catastrophic failure. They are, however, normally amenable to corrective action.
- Browse Related Terms: Base safety condition (BSC), Dam Failure, Dam safety deficiency, Dam safety issue, failure, Level of protection (LOP), Low hazard, Population at risk (PAR), Probability of failure, Risk Assessment, Significant hazard, Warning time (WT)
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- A flood hydrograph resulting from a dam breach prepared for a specific location downstream from the dam.
- Browse Related Terms: Breach, Breach hydrograph, Dam failure hydrograph, Design water level, Flood boundary, Inundation Area, Inundation map, Jokulhlaup, Stoping, Travel Time
- The excavated surface or undisturbed material upon which a dam is placed.
- Browse Related Terms: Backfill, Backfill concrete, Borrow, Borrow areas, Borrow pits, Cutoff Trench, Cutoff trench (keyway), Dam foundation, Embankment Dam (Fill Dam), Embankment dam or fill dam, Exploit, Fill Dam, Payline, Pipe trench, Pit run gravel, Refill, Sand backfill, Select material, Slurry trench, Uncompacted backfill, Unsuitable material, Wastebank
- A physical condition capable of causing the sudden uncontrollable release of reservoir water by partial or complete failure of a dam, appurtenant structure, or facility.
- Browse Related Terms: Base safety condition (BSC), Dam Failure, Dam safety deficiency, Dam safety issue, failure, Level of protection (LOP), Low hazard, Population at risk (PAR), Probability of failure, Risk Assessment, Significant hazard, Warning time (WT)
- Dam safety related issues and concerns are those which, if not adequately addressed could/would:
1 - Lead to a failure or malfunction reulting in an uncontrolled release of stored water that would place the downstream population potentially at risk or;
2 - Compromise the agency's ability to detect developing adverse dam performance and prudently respond to that performance.
- Browse Related Terms: Base safety condition (BSC), Dam Failure, Dam safety deficiency, Dam safety issue, failure, Level of protection (LOP), Low hazard, Population at risk (PAR), Probability of failure, Risk Assessment, Significant hazard, Warning time (WT)
- The person responsible for the daily or routine operation and maintenance activities of a dam and its appurtenant structures. The dam tender commonly resides at or near the dam.
- Browse Related Terms: Dam tender, Earthwork, essential element, Gated spillway, Incident command system, Landfill, Logbook (operating log), Maintenance management system, OML, Posted operating instructions, Remote operation, Reservoir regulation (or operating) procedure, Review of Operation and Maintenance (RO&M), Standing Operating Procedures (SOP), Supervisory control
- Resistance which reduces vibration by energy absorption.
- Browse Related Terms: conservation, Damping, Efficiency, EGL, EPACT, Federal Power Commission (FPC), FERC, Firm energy (power), Ground motion, Hypocenter, Kinetic Energy, Magnitude, Nonfirm commercial energy, Pollution, Potential Energy
- The ratio of the actual damping to the critical damping, critical damping being the minimum amount of damping which prevents free oscillatory vibration.
- Browse Related Terms: activity, Air-space ratio, Air-void ratio, Average degree of consolidation, Coefficient of compressibility, compression, Damping ratio, Density of Snow, Detonation, Effective Porosity, expansion, Porosity, Relative density, Scale, Snow Density, Specific Gravity, Storage Equation, Void ratio, Vortex
- Electronic equipment device that gathers digital and analog data from monitoring devices and remotely relays that data to a central computer for interpretation and archiving.
- Browse Related Terms: Area Wide Hydrologic Prediction System (AWHPS), Automated Tone Dial Telephone Data Collection System (ATDTDCS), base station, Basin runoff model, Centralized Automated Data Acquisition System (CADAS), Computer base station, Cooperative Observer, Data collection platform, Data Collection Platform (DCP), E-19a, Abridged Report on River Gage Station, File Transfer Protocol (FTP), GOES Data Collection System (DCS), Ground receive sites, Hydromet, Integrated Flood Observing and Warning System (IFLOWS), LARC (Limited Automatic Report Collector), Limited Automatic Remote Collector (LARC), National Environmental Satellite, Data, and Information Service (NESDIS), NWSRFS V5.0, or Version 5 (National Weather Service River Forecast Model Version 5), Stage II Precipitation Processing, Standard Hydrologic Exchange Format (SHEF)
An electronic device that connects to a river or rainfall gage that records data from the gage and at pre-determined times transmits that data through a satellite to a remote computer.
- Browse Related Terms: Area Wide Hydrologic Prediction System (AWHPS), Automated Tone Dial Telephone Data Collection System (ATDTDCS), base station, Basin runoff model, Centralized Automated Data Acquisition System (CADAS), Computer base station, Cooperative Observer, Data collection platform, Data Collection Platform (DCP), E-19a, Abridged Report on River Gage Station, File Transfer Protocol (FTP), GOES Data Collection System (DCS), Ground receive sites, Hydromet, Integrated Flood Observing and Warning System (IFLOWS), LARC (Limited Automatic Report Collector), Limited Automatic Remote Collector (LARC), National Environmental Satellite, Data, and Information Service (NESDIS), NWSRFS V5.0, or Version 5 (National Weather Service River Forecast Model Version 5), Stage II Precipitation Processing, Standard Hydrologic Exchange Format (SHEF)
The Software System that supports RFC gateway functions.
- Browse Related Terms: ADMS, Advanced Decision Support System (ADSS), Alert (Automated Local Evaluation in Real Time), ASAPTRAN, DATACOL, DATANET, Geographic Information System (GIS), Hydrometeorological Automated Data System (HADS), Paleoflood data, SHEFPARS
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Hydrologic Data Network Analysis Software
- Browse Related Terms: ADMS, Advanced Decision Support System (ADSS), Alert (Automated Local Evaluation in Real Time), ASAPTRAN, DATACOL, DATANET, Geographic Information System (GIS), Hydrometeorological Automated Data System (HADS), Paleoflood data, SHEFPARS
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- DataWeb is an electronic presentation of the Bureau of Reclamation's Project Data book and contains historical, statistical, and technical information on the projects of the Bureau of Reclamation.
- Browse Related Terms: Arable land, Authorized Reclamation project, BEA, BIA, BLM, BOM, BOR, BRAIN, Bureau of Land Management (BLM), Bureau of Reclamation (USBR, Reclamation, BOR), DataWeb, Full irrigation service land, Public involvement plan, Publications, Recreation, Supplemental irrigation service land, Water Measurement Manual, Wilderness resource
- Any level surface taken as a plane of reference from which to measure elevations.
- Browse Related Terms: Datum, Elevation, Gage Datum, Gage Height, Gage height (G.H.), Gage Zero, Gauge height, Hypsography, River Gage Datum, Stage, Station, Water surface elevation (stage)
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Often abbreviated as SDF. See Second-Day Feet.
- Browse Related Terms: Cfs-Day, Cubic Feet per Second, Cubic feet per second (cfs or ft3/s), Cubic Feet per Second (CFS), Cubic foot per second (cfs or ft3/s), Day-Second Feet, Foot-Pound, Foreshore, Infiltration Rate, Permeability Coefficient, Pressure head, Pumping Head, Second foot (sec-ft), Second-Day Feet
- - design basis earthquake.
- Browse Related Terms: Capable fault, DBE, Design basis earthquake (DBE), Design response spectra, Earthquake, Maximum credible earthquake (MCE), Maximum design earthquake (MDE), Operating basis earthquake (OBE), Safety Evaluation Earthquake (SEE), Seismic evaluation criteria, Soil classification, Synthetic earthquake
- Davis Dam (Laughlin, NV).
- Browse Related Terms: BCD, Camber, DD, Dike, Diversion capacity, Downstream face, Earth Dam or Earthfill Dam, Flood Wave, Fluctuating flows, Gabion dam, Hydraulic fill structure, Impoundment, Irrigation check, Overtopping, Pond, Rolled Earth Dam, Saddle dam, Seepage collar, Tailings dam., Toe Drain (or Outfall), Toe of Dam, Toe of Dam (Upstream and Downstream), Top of dam., Upstream face
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Delineated areas of the marine environment where human access is restricted or where specific activities or uses are regulated for reasons other than conservation or natural or cultural resource management.
- Browse Related Terms: Aquatic Protected Area, Area, Critical Habitat, De Facto MPA, Marine Managed Area, Marine Managed Areas (MMA) Inventory, Marine Protected Area, Marine Resource Areas, Multiple-Use MPAs, National Oceanic and Atmospheric Administration (NOAA), Permanence of Protection, Place-Based Management