Open-channel flow rate measurement estimation using videos

Abstract

Reliable data on river flow rates are the basis for the operation and planning of many water management systems. However, flow rate measurements in open-channel flows are complex, time-consuming, and often economically expensive. Conventional measurement techniques - propeller-type current meters, acoustic and electromagnetic methods, etc. - rely on the estimation of physical quantities by the means of special hardware components, which have not been able to follow the development tempo of software technology throughout the recent decades. Adequate alternatives to traditional approaches could be found with image-processing methods, which analyze the free-surface motion of the open-channel flow. The results represent the free-surface velocity flow field, which can then be used in conjunction with appropriate expressions to estimate the flow rate. The main advantages of such an approach are: 1) low cost, 2) simple and fast data acquisition, and 3) a large and growing number of available methods and software tools. However, the low degree of standardization of the newly developed methods is a considerable obstacle for their expansion beyond the research domain. This study summarizes the most important steps of their workflow, from the preparations for field data acquisition to the data processing for flow rate measurement. Particular attention is paid to the description and analysis of applicability of available methods and software tools in various field conditions.