Secchi disk definition

Secchi disk means a tool that is used to measure the transparency of lake water. A Secchi disk is an eight-inch weighted disk on a calibrated rope, either white or with quadrants of black and white. To measure water transparency with a Secchi disk, the disk is viewed from the shaded side of a boat. The depth of the water at the point where the disk reappears upon raising it after it has been lowered beyond visibility is recorded.
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Secchi disk means a device for measuring water clarity that consists of a circular weighted disk painted in flat black and white in alternating quarters that is suspended on an incremented rope or line.
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Secchi disk means a 30 cm diameter circular disk used to measure the transparency of water by being lowered into the water column until no longer visible;
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Examples of Secchi disk in a sentence

  • Three parameters are the most important measures of eutrophication in most New York lakes: total phosphorus, chlorophyll a (estimating the amount of algae), and Secchi disk transparency.

  • Field measurements include water depth, water temperature, and Secchi disk transparency.

  • It also affects the length of the recreational season Secchi Disk Transparency (m) Conductivity (µmho/cm) pH Color (true) (platinum color units) Phosphorus (total, mg/l) Nitrogen (nitrate, ammonia, and total (dissolved), mg/l) Chlorophyll a (µg/l) Calcium (mg/l)Determined by measuring the depth at which a black and white disk disappears from sight, the Secchi disk transparency estimates the clarity of the water.

  • An algal bloom is defined as a planktonic growth of algae which causes Secchi disk transparency to be less than 2.0 meters.

  • Public bathing beach and lakes – Secchi disk depth >1.2 meters (> 4’) (minimum of three samples representing critical period).

  • Public bathing beach and lakes - Secchi disk depth <1.2 meters (< 4’) (minimum of three samples representing critical period).

  • Secchi disk depth was measured monthly at station PR-3 and used for the TSI calculation.

  • Water transparency can also be unexpectedly lower in shallow lakes, due to influences from the bottom (or the inability to measure the maximum water clarity due to the visibility of the Secchi disk on the lake bottom).

  • They are helpful for measuring transparency in situations where the stream is too shallow for the Secchi disk to be practical and for running waters where flow is too fast that the Secchi disk cannot remain vertical.

  • Three parameters are the most important measures of eutrophication in most New York lakes: total phosphorus, chlorophyll a (measuring algal standing crop), and Secchi disk transparency.


More Definitions of Secchi disk

Secchi disk means a 200 mm. circular plate which has opposite quarters painted gloss white and black.
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Secchi disk means a 200-mm ( 7 7/8 inches) circular plate which has opposite quarters of the same face painted gloss white and black.
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Related to Secchi disk

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  • Best available control technology or “BACT” means an emissions limitation, including a visible emissions standard, based on the maximum degree of reduction for each regulated NSR pollutant which would be emitted from any proposed major stationary source or major modification which the reviewing authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such source or modification through application of production processes or available methods, systems, and techniques, including fuel cleaning or treatment or innovative fuel combination techniques for control of such pollutant. In no event shall application of best available control technology result in emissions of any pollutant which would exceed the emissions allowed by any applicable standard under 567—subrules 23.1(2) through 23.1(5) (standards for new stationary sources, federal standards for hazardous air pollutants, and federal emissions guidelines), or federal regulations as set forth in 40 CFR Parts 60, 61 and 63 but not yet adopted by the state. If the department determines that technological or economic limitations on the application of measurement methodology to a particular emissions unit would make the imposition of an emissions standard infeasible, a design, equipment, work practice, operational standard or combination thereof may be prescribed instead to satisfy the requirement for the application of best available control technology. Such standard shall, to the degree possible, set forth the emissions reduction achievable by implementation of such design, equipment, work practice or operation and shall provide for compliance by means which achieve equivalent results.