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Cost and Accuracy Comparisons
Mechanical Current Meter System with AquaCalc Versus Other Point Velocity Discharge Systems
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Secchi Discs
Secchi Discs are designed for the measurement of the relative turbidity and clarity of a body of water. This disc is constructed of PVC and is finished in alternating black and white quadrants of acrylic paint. The disc operates as such: the disc is lowered into the water on a graduated line. The depth at which the disc is no longer visible is recorded. The disc is then raised, and a recording of the depth at which the disc reappears should be made. The mean of these two recordings is considered to be the limit of visibility. Although the disc is unable to provide an actual measure of light penetration, it is useful in providing a rough index of visibility for comparative purposes available in a kit that includes a weighted, 20 cm (8") diameter Secchi disc with black and white quadrants, 50 feet calibrated Kevlar line on foam spool, and instructions.