Accurately Measuring and Gauging Streamflow

Why measure streamflow?

Streamflow measurement is an essential practice for understanding and managing water resources. Flow, defined as the volume of water passing through a given cross-section of a river, is a key variable in hydrometry. It is calculated by multiplying the cross-sectional area by the flow velocity.

Difference between water level and flow

Water level is simply the distance between the water surface and a fixed reference point, whereas flow provides a more complete picture by incorporating flow velocity. This distinction matters: while water level may be sufficient for public safety purposes, only flow measurement allows for the detailed analyses needed to calibrate hydrological and hydraulic models or to carry out hydrogeomorphological studies.

The importance of stream gauging and hydrometric stations

Stream gauging is a method used to take point measurements of a river’s flow and water level, often using hydrometric stations. These stations collect accurate data through a range of instruments (pressure sensors, acoustic devices, etc.), making it possible to track seasonal variations and analyze the impact of factors such as precipitation, snowmelt and climate change.

At Avizo, our experts follow a rigorous protocol for every gauging: selecting an appropriate river section, using an ADCP (Acoustic Doppler Current Profiler) for accurate measurement, and collecting repeated data to ensure reliability. This methodical approach is essential to delivering high-quality results.

Why choose continuous flow measurement?

Measuring flow continuously offers significant advantages. The longer a data series, the more it can reveal hydrological fluctuations over time. This information is critical, especially during periods of hydrological change driven by urbanization, agriculture or climate change.

For a municipality or organization, the benefits include:

• Optimizing investments in existing water level monitoring stations
• Accurately calibrating hydrological and hydraulic models
• Achieving overall savings by avoiding repeated estimates for each new project

Conclusion

Whether through spot gauging or continuous measurement, knowing the flow of watercourses is fundamental to engineering projects and water resource management. At Avizo, we put our expertise to work for you to strengthen your decision-making and ensure the success of your initiatives.