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

Abstract

Measurement 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 threepoint 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.

User-focused evaluation of National Ecological Observatory Network streamflow estimates

“…Manual measurements of streamflow used to construct NEON’s rating curves were collected via acoustic Doppler current profilers (ADCP) 23 , conservative salt tracer releases 24 , and flow meter measurements 25 . It is important to note, each of these methods are used under different conditions and are subject to unique types of error, see citations for details on how the methods are used to calculate streamflow.…”

River Flow Measurements Utilizing UAV-Based Surface Velocimetry and Bathymetry Coupled with Sonar

“…The river cross-section is typically divided into subsections (see Figure 1). In each subsection, the water depth and average flow velocity are measured to obtain the water discharge [7,8]. Another commonly used traditional flow monitoring method is the establishment of a rating curve between the water level and the streamflow in order to indirectly estimate the discharge by real-time water level measurement measures [9].…”