Well depth gauge11/8/2022 ![]() ![]() Porcelain enameled iron has been the standard material for staff gauges for years. Marine organisms in particular can be difficult to remove once they become established. Waiting to inspect and clean the gauge may make it harder in the long run to remove any accumulation on the gauge. Best practice is to clean and inspect a staff gauge every time a site in visited – whether the gauge is used during the visit or not. In a normal application, the staff gauge should be located upstream of the weir at least 3-4 times the maximum anticipated head, H max, due to this drawdown effect.īiological growth, vegetative mater, scum, scale, and other debris can all collect / grow on the indicating face of a staff gauge. The reason for this is that the surface of the water draws down as it approaches the weir crest. They are not – and should not be assumed to be – entirely accurate. Etched on, screwed to, or otherwise located on the weir plate, staff gauges in these instances are intended only for general level measurements. In weirs it is not uncommon to see a staff gauge mounted on the weir face itself. Stilling wells may be particularly useful if foam or surface turbulence is present in the main body of the flume. ![]() However, if a stilling well exists (or can be added) a staff gauge could be located there also. In flumes, the point of measurement is dictated by the flume type and size and here the location selection is usually only left / right in the flume. For Trapezoidal and RBC flumes, the gauges may or may not be direct read as the sidewalls are not vertical. Stafff gauges in flumes with vertical walls ( Parshall, HS / H / HL, Cutthroat, and Montana) are all direct read. Direct read gauges correct for sidewall geometry, while indirect read gauges require some adjustment be applied to the gauge reading. When reading a staff gauge at a new site, thought shoudl be given as to whether the gauge is a direct read or not. Thought should be given when planning an installation as the method (and personnel) required for meter calibration. More than one otherwise good installation has been compromised by poor flow meter / staff gauge placement. Gauges should be placed where they can be quickly read and compared against the flow meter's reading. In natural channels and streams this may be difficult as other factors may affect where the gauge is put (most notably site access).įor flumes and weirs, the location of the gauge may either help or hinder the calibration of a flow meter. #Well depth gauge free#Where possible, staff gauges should be located in a part of a steam or channel where the water is relatively free of turbulence. Rulers or other devices repurposed as staff gauges typically do not have this user-friendly characteristic. Higher end gauges will provide an indication at the top of the scale and/or along the side of the scale as to the units of measurement. some combination of Imperial depth, SI depth, and flow units). Some gauges may be in a dual scale format (i.e. ![]() Unless otherwise indicated, the assumption is that the graduations on a staff gauge are in feet, 1/10-feet, and 1/100-feet increments. Usually, even in well conditioned flows, there is some amount of surface ripple or turbulence present. Water rarely flows in a nice, tranquil manner. Although they should not be solely relied on when more precise level measurement devices are available, staff gauges allow operators to quickly gauge the relative level of water and then proceed with other duties. Staff ("Head" or "Level") Gauges provide a quick, visual indication of the level of water in a channel, flume, or weir. ![]()
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