Hydro-Logic is now part of Hydro International.

Uncertainty Analysis

Understanding uncertainty in flow measurement is as challenging as it is useful, as there are numerous factors that can affect the uncertainty. Different methods, instruments and site conditions can produce significant variance in the expected uncertainty range. For example, the accuracy of water level measurement, how representative the sampled velocity is and the calibration range can all have a significant bearing on overall measurement uncertainty.

HLS are able to undertake uncertainty analysis and the provide uncertainty estimates for a wide range of flow measurement techniques and monitoring applications. Our clients have found these to be of significant benefit particularly when deciding how much confidence to put on their data records and where to focus improvements. Our experience is that clients are often surprised at how significant measurement uncertainties can be, particularly at extreme high or low flows when the data is often of greatest importance.

Further details of the standard approach to uncertainty estimation in hydrometry are provided in a joint European and International Standard:- PrCEN ISO/TS 25377:2007 – Hydrometric Uncertainty Guide (HUG). This document was prepared with the aid of Stewart Child, Senior Consultant at HLS.

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