Traffic Analysis: Volume, Density, Capacity, time means speed, space mean speed and travel time | Civil Works and Solutions

Definitions

Acronyms and Abbreviations

• AAR: After Action Report
• ADAS: Automated Data Acquisition System
• AEP: Annual Exceedance Probability
• AFP: Annualised Failure Probability
• ALL: Annualised Loss of Life
• ANCOLD: Australian National Committee on Large Dams
• ASCE: American Society of Civil Engineers
• BDS: British Dam Society
• BIS: Bureau of Indian Standards
• BRE: Building Research Establishment
• CDSO: Central Dam Safety Organisation
• CWC: Central Water Commission
• DDMA: District Disaster Management Authority
• DDMS: Dam Deformation Monitoring System
• DG set: Diesel Generator set
• DRIP: Dam Rehabilitation and Improvement Project
• DSRP: Dam Safety Review Panel
• DTM: Digital Terrain Model
• EAP: Emergency Action Plan
• EDA: Energy Dissipation Arrangement
• GPS: Global Positioning System (uses GPRS for data transmission like browsing the web)
• HM works: Hydro-Mechanical works
• ICE: Institution of Civil Engineers
• ICOLD: International Commission on Large Dams
• LIDAR: Light Detection and Ranging
• OED: Overflow Embankment Dam
• PAR: Population at Risk
• PC: Personal Computer
• RCCD: Rolled Compacted Concrete Dam
• RMU: Remote Monitoring Unit
• SDSO: State Dam Safety Organisation
• SOI: Survey of India
• SPANCOLD: Spanish National Committee on Large Dams
• SPCBs: State Pollution Control Boards
• SPM: Suspended Particulate Matter
• SPMU: State Project Management Unit
• SPS: Safeguards Policy Statement
• SYI: Sediment Yield Index
• ToR: Terms of Reference
• tph: Ton per hour
• ULB: Urban Local Bodies
• UNESCO: United Nations Educational, Scientific and Cultural Organization
• USACE: United States Army Corps of Engineers
• USBR: United States Bureau of Reclamation
• UTPCC: Union Territory Pollution Control Committee
• UV: Ultraviolet
• WB: World Bank
• WCED: World Commission on Environment and Development
• WMO: World Meteorological Organization

General Dam and Safety Related Terms

• Abutment: The part of the valley side against which the dam is constructed. The left and right abutments are defined with the observer looking downstream from the dam. An artificial abutment can be a concrete gravity section constructed to take the thrust of an arch dam where there is no suitable natural abutment.
• Acceptable Risk: A broadly acceptable risk is generally one that may be considered negligible and properly controlled. However, risks associated with dams are rarely classified into this category due to the huge destructive potential of this infrastructure.
• Abrasion Erosion: Damage caused by the abrasive effects of waterborne silt, sand, gravel, rocks, ice, and other debris rolling and grinding against a concrete surface. It is recognized by the smooth, worn-appearing concrete surface.
• Appurtenant Work: Structures associated with the dam.
• Basin: The area of land that drains to a particular river, or the main river on which the dam is built.
• Baseline Data: An initial set of observations or measurements used for comparison; a starting point.
• Calibration: A comparison between a known measurement (the standard) and the measurement using the specific instrument.
• Compaction: A mechanical action that increases the density by reducing the voids in a material.
• Compliance Assessment: An activity undertaken to determine whether a regulated party's activity/operation complies with a statute, regulation, authorization, or Code of Practice. This process educates the regulated party on legislative requirements and identifies current or potential non-compliance, including inspections, reviews, and audits.
• Cracks: An incomplete separation into one or more parts with or without space between.
  • Fine cracks: Generally less than 0.5 mm in width.
  • Medium cracks: Between 0.5 mm and 2 mm in width.
  • Wide cracks: Over 2 mm in width.
• Dam Hazard Potential Classification: A system for dams that is simple, clear, concise, and adaptable to the current system, providing straightforward definitions that can be applied uniformly by all central and state dam safety agencies and readily understood by the public.
• Deterministic Methodology: A method in which the chance of occurrence of the variable involved is ignored and the method or model used is considered to follow a definite law of certainty, not probability.
• Diaphragm Wall (membrane): A sheet, thin zone, or facing made of an impervious material such as concrete, steel, wood, or plastic.
• Discharge: Refers generally to the outflow and is used as a measure of the rate at which a volume of water passes a given point. This term can describe the flow of water from a pipe or a drainage basin.
• Discolouration: Departure of colour from that which is normal or desired.
• Factor of Safety: The ratio of the available shear strength to the minimum shear stress required to maintain equilibrium.
• Length of Navigation Locks (Metre): The length of the main lock chamber.
• Lining: With reference to a canal, tunnel, shaft, or reservoir, a coating of asphaltic concrete, reinforced or unreinforced concrete, shotcrete, rubber or plastic to provide water tightness, prevent erosion, reduce friction, or support the periphery of the outlet pipe conduit.
• O&M Manual: A detailed written document of procedures and protocols for ensuring that a dam is operated and maintained properly and timely to avoid further health deterioration and extend service life of these assets.
• Sand Pocket: Part of concrete containing sand without cement.
• Segregation: The differential concentration of the components of mixed concrete, resulting in non-uniform proportions in the mass.
• Stability: The condition of a structure or a mass of material when it is able to support the applied stress for a long time without suffering any significant deformation or movement that is not reversed by the release of the stress.
• Streambanks: The natural boundaries (not the flood boundaries) of a stream channel. Right and left banks are named facing downstream.
• Structural Joint: A joint constructed where movement of a part of a structure due to temperature or moisture variations, settlement, or any other cause, would result in the harmful displacement of adjoining structural components.
• Subarea/Sub-basin: A portion of a watershed divided into homogenous drainage units that can be modeled for purposes of determining runoff rates. These subareas/sub-basins have distinct boundaries, as defined by the topography of the area.

Dam Components and Systems

• End Sill: An upright obstruction usually located at the downstream end of a stilling basin. It can be solid or dentate and is used to reduce the length of the stilling basin by creating additional tailwater depth and to provide for scour control.
• Energy Dissipater: Any device constructed in a waterway to reduce or destroy the energy of fast-flowing water (also referred to as Terminal Structure).
• Energy Dissipating Valve: A generic term for regulating valves designed to dissipate flow energy. For terminal structures, this valve is located at the downstream end and often discharges freely into the atmosphere.
• Entrance Channel: A channel which conveys water from the reservoir to the control.
• Outlet Works: A dam appurtenance that provides release of water (generally controlled) from a reservoir. It is also defined as a combination of structures and equipment required for the safe operation and control of water released from a reservoir to serve various purposes, or a series of components located in a dam through which normal releases from the reservoir are made, or a device to provide controlled releases from a reservoir, or a pipe that lets water out of a reservoir, mainly to supply downstream demands.
• Sluice: A conduit, fitted with a gate, for carrying water at high velocity.
• Spillway: A hydraulic structure that passes normal (operational) and/or flood flows in a manner that protects the structural integrity of the dam and/or dikes. It is also defined as a structure over or through which flow is discharged from a reservoir.
• Spillway, Tunnel: A tunnel used as an outlet channel for a side channel spillway.
• Splitter Wall: A wall parallel to the direction of flow in a chute or stilling basin that separates flows released from different sources as a means of energy dissipation.
• Spray Lining: The application of cement mortar or epoxy resin against the inside walls of an existing conduit, using a revolving spray head moved through the conduit.

Flood Management Terms

• Auxiliary Spillway: A spillway that complements the capacity of the service spillway to discharge the total Project Design Flood (or Check Flood).
• Check Flood / Project Design Flood: The maximum flood event to be supported by the project without incurring a failure of the project such as embankment overtopping. It is commonly the PMF or a variation of that concept.
• Design Flood: The flood, which is normally computed based on probability analyses of hydrologic data, and which must be discharged without impairing the normal operation of the project.
• Emergency Spillway: A supplementary discharge organ that would enter into operation if either the incoming flood is greater than the flood for which the Service and the Auxiliary spillways combined can take care of, or if the normal capacity of these structures is harmed by an unusual event.
• IDF (Inflow Design Flood) / SDF (Spillway Design Flood): These acronyms refer to the Inflow Design Flood or Spillway Design Flood.
• PMF (Probable Maximum Flood): Refers to the Probable Maximum Flood.

Sediment Management Terms

• Adaptive Measures: Actions to mitigate the impacts of sedimentation, without directly handling the sediment. They can be structural or non-structural.
• Drawdown Flushing: Entails opening a low-level outlet to completely empty the reservoir, thereby scouring sediment deposits.
• Empty Flushing: The same as drawdown flushing.
• Sequential Flushing: Occurs when two or more reservoirs in series are flushed simultaneously. Flow is released from an upper reservoir to scour sediment from the lower one, with the operation planned so that sediment released from the upper reservoir(s) passes through the downstream reservoirs with minimal deposition.