Evaluation of discharge measurements methods in a natural river of low or middle flow using an electromagnetic flow meter

Abstract

AbstractMeasurement of river discharge should be accurate, as it is key environmental data and essential for hydrologic simulations, regardless of whether the flow is high, medium, or low. Herein, conventional methods based on velocity measurements at different depths (i.e., one‐point method, two‐point method, and three‐point method) are evaluated with a method using a surface velocity index and a method based on the entropy theory to estimate river discharge. All the methods were implemented to calculate the discharge of Agios Germanos River, located in Northern Greece, based on 2 years of measurement. Considering that the uncertainty in flow measurement is decreasing by increasing the number of velocity measurements points (EN ISO, 2007), in this work, the reference method is the conventional three‐point method. Results show that the other two conventional methods (the one‐point and the two‐point) estimate the discharge with an error of about 3%, while the error of the other two methods ranges between 11 and 14%. Nevertheless, the nonconventional methods could be considered acceptable and could be used safely to minimize time and subsequently, the cost of field measurements.