First Flush definition

First Flush means within the first 30 minutes of the formation of a discrete storm water discharge.
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First Flush means the initial or early stages of stormwater runoff from a storm event which commonly delivers a disproportionately large amount of previously accumulated pollutants due to the rapid rate of runoff. The first flush is defined in the City of Cookeville Stormwater Management Design Guidelines.
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First Flush. , means the transport of solids in a combined sewer system that:
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Examples of First Flush in a sentence

  • First flush retention (retention of the first ½ inch of rainfall) shall be provided for all newly disturbed and impervious surfaces.

  • First flush water captured from the compost maturation area goes to the leachate treatment pond land is reused in the composting process.

  • The water quality, or first flush volume can be computed by the following equation Vff = 3,630 * C * A Where:Vff = First flush volume, post-development (in cubic feet) C = Post-development runoff coefficientA = Drainage area tributary to detention basin (in acres) In order to qualify for the maximum 10 percent credit, water quality detention basins must be designed to the Vff volume for the entire property and must demonstrate a 75 percent removal of TSS.

  • First flush diverters direct the initial pulse of stormwater runoff away from the storage tank.

  • First flush retention shall be provided in Low Impact Development practices distributed throughout the site.

  • First flush was excluded in the tank behavioral model, given that the use, type and volumetric behaviour of filtration devices is highly variable.

  • First flush sample collection occurs at the onset of the rainy season, typically October or November.

  • Dual drainage system: First flush captured in street catch basins and discharged to adjacent vegetated swale or gravel shoulder, high flows connect directly to storm water conveyance system.

  • First flush devices safeguard the quality of water captured in a rainwater tank.

  • First flush shall be to remove debris and bigger particles from the system without operation of the pumps.


More Definitions of First Flush

First Flush effect means that the timing of a rainfall event and the volume of run-off generated affects the concentrations of contaminants present. However, the total amount of each substance deposited on surfaces and that eventually ends up in the run-off will, over a sufficiently long period (e.g. a year), be more or less the same (except perhaps in the case of spills). This means that the total load of contaminants discharged into the receiving environment by urban run-off over that same period will be, approximately the same, whether they are all discharged in a small number of intense rainfall events or a longer period of prolonged rainfall.
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First Flush means a method for the removal of sediment and debris from the collection
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First Flush means a method for the removal of sediment and debris from the collection surface by diverting initial rainfall from entry into the storage unit.
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First Flush means the delivery of a disproportionately large load of pollutants in surface runoff during the early parts of storms due to the rapid runoff of accumulated pollutants.
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Related to First Flush

  • Double Phase Aerosol Air Freshener means an aerosol air freshener with the liquid contents in two or more distinct phases that requires the product container be shaken before use to mix the phases, producing an emulsion.

  • Single Phase Aerosol Air Freshener means an aerosol air freshener with the liquid contents in a single homogeneous phase and which does not require that the product container be shaken before use.

  • Air kerma means kerma in a given mass of air. The unit used to measure the quantity of air kerma is the Gray (Gy). For X-rays with energies less than 300 kiloelectronvolts (keV), 1 Gray of absorbed dose is delivered by 114 roentgens (R) of exposure.

  • Freeboard means a factor of safety usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, blockage of bridge or culvert openings, and the hydrological effect of urbanization of the watershed.

  • Uppermost aquifer means the geologic formation nearest the natural ground surface that is an aquifer, as well as lower aquifers that are hydraulically interconnected with this aquifer within the facility's property boundary.

  • Crane means any self-propelled vehicle to which has been permanently mounted or attached any crane, whether or not such vehicle was originally a truck, tractor, or other type of motor vehicle or was designed and built as a complete crane unit. However, the word "crane," as herein defined, shall not be construed to mean any truck or other vehicle equipped with or to which has been affixed any device used for the purpose of providing a means for towing other vehicles.

  • LOT FRONTAGE means lot frontage as defined in Town's Zoning By-law No. 1136 (1987), as amended, or any successor thereto.

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  • Heliport means an aerodrome or a defined area on a structure intended to be used wholly or in part for the arrival, departure and surface movement of helicopters;

  • Chimney means a construction by means of which a flue is formed for the purpose of carrying products of combustion to the open air and includes a chimney stack and the flue pipe.

  • River means a flowing body of water or a portion or tributary of a flowing body of water, including streams, creeks, or impoundments and small lakes thereon.

  • Soda fountain means a place especially equipped

  • Rock means the body of consolidated or partially consolidated material composed of minerals at or below the land surface. Rock includes bedrock and partially weathered rock that is hard and cannot be dug with hand tools. The upper boundary of rock is "saprolite," "soil," or the land surface.

  • Falconry means the sport of taking quarry by means of a trained raptor.

  • JetBrains or “We” means JetBrains s.r.o., having its principal place of business at Xx Xxxxxxxxx XX 0000/00, Xxxxxx, 00000, Xxxxx Xxxxxxxx, registered in the Commercial Register maintained by the Xxxxxxxxx Xxxxx xx Xxxxxx, Xxxxxxx X, Xxxx 00000, ID. No.: 265 02 275.

  • B-BBEE means broad-based black economic empowerment as defined in section 1 of the Broad-Based Black Economic Empowerment Act;

  • Green means products, materials, methods and processes certified by a “Green Authority” that conserve natural resources, reduce energy or water consumption, avoid toxic or other polluting emissions or otherwise minimize environmental impact.

  • Spring means a source of water where an aquifer comes in contact with the ground surface.

  • Shutter means a device attached to the tube housing assembly which can intercept the entire cross sectional area of the useful beam and which has a lead equivalency not less than that of the tube housing assembly.