3. Flow observations and forecasts

3.1 Flowmeter stations

In addition to precipitation observations, a number of tools are also available for measuring the flow of natural or managed runoff (rivers, canals, diversions, etc.). Depending on the location and purpose of the measurement, flow can be measured directly or indirectly.

Direct measurements consist of point surveys, carried out using a method known as "velocity field exploration". Flow velocity is measured at various points in the study section, then related to the wetted section area to determine the flow rate. Surface velocity can also be captured using video tools. These techniques are often costly, as they require special equipment (reels, poles) and qualified personnel. For these reasons, flow is generally estimated indirectly using...