ACCURACY AND CONSISTENCY OF WATER‐CURRENT MIETERS¹

Abstract

The measurement of discharge in natural streams requires hydrographers to use accurate meters that have consistent performance among meters of the same model. This paper presents the results of an investigation into the accuracy and consistency of four models of current meters‐Price Type‐AA, Price Pygmy, Marsh McBirney 2000, and Swoffer 2100. Test results for six meters of each model are presented. Variation of meter performance within a model is used as an indicator of consistency, and percent velocity error that is computed from a measured reference velocity is used as an indicator of meter accuracy. Velocities measured by each meter are also compared to the manufacturer's published or advertised accuracy limits. The investigation found the Price models to be more accurate and consistent than the other models. The Price models met their respective accuracy limits over the range of test velocities better than the other models. The Marsh McBirney model usually measured within its accuracy specification. The Swoffer meters did not meet the stringent Swoffer accuracy limits for all the velocities tested. The Swoffer model had accuracies similar to the Price Type‐AA model when individual meter rating equations were computed and used. Every model tested had meters that did not meet manufacturer accuracy limits. Because current meters are not consistently accurate within a model, hydrographers should periodically check meters against a velocity standard.

A comparison of fibre‐optic distributed temperature sensing to traditional methods of evaluating groundwater inflow to streams

“…The integrated software of the FlowTracker ADV helped to identify some of these possible sources of error, but the general discharge uncertainty measurements generated by both the USGS statistical method and the ISO method appear to have underestimated the true uncertainty. This is consistent with previous work that found current meters performed poorer than their respective manufacturers published accuracy limits (Fulford, 2001). Perhaps a finer measurement spacing and further clearing of macrophyte growth would have provided more accurate discharge estimates, but both of these activities can be treacherous within a deep, fast flowing large stream.…”

“…There are several well‐known field techniques available with which to evaluate groundwater inflows to streams, each with particular strengths and scale applicability. Other researchers have compared and contrasted many of these traditional techniques (Zellweger, 1994; Fulford, 2001; Kalbus et al , 2006; Soupir et al , 2009), but we compare three of the most widely used with the new distributed temperature sensing (DTS) heat tracing method in a large stream influenced by contaminated groundwater to assess the repeatability, practicality, and spatial resolution of discharge estimates.…”

Underwater artificial lateral line flow sensors

“…Flow sensing is an essential technology for marine sciences. Now, there are existing many technologies to measure flow field, such as wheel flow meter (Fulford 2001), pressure probe, hot-wire anemometry (Bleckmann et al 2014), acoustic Doppler velocimetry (ADV), particle image velocimetry (Kitzhofer et al 2011) and so 1 3 2 Morphology and biophysics of the fish lateral line…”

A Comparative Study of Stream‐Gaging Techniques for Low‐Flow Measurements in Two Virginia Tributaries1

“…Comparisons of some methods have been performed by various researchers (Fulford et al. , 1994; Thibodeaux, 1994; Fulford, 2001); however, none cover the broad range of technologies currently employed to measure low flows.…”

“…Fulford (2001) compared four types of current meters, the Price Type‐AA, Price Pygmy, Marsh McBirney 2000, and Swoffer 2100, and six of each type for variation of meter performance within each type and percent velocity error. Steady flow velocities, ranging from 0.25 to 8.0 ft/s, were tested.…”