Case studies

In watercourse monitoring, continuous measurement of the water level is not sufficient to directly determine the flow rate. To obtain this value, it is necessary to establish a reliable level–flow relationship, based on field measurements and survey data.

In the analyzed case, a hydrometric station was installed near a bridge, consisting of a radar water level sensor positioned under the arch and oriented toward the water surface. This allows continuous level measurement without direct contact with the fluid.

To define the level–flow relationship, point measurements of flow velocity were carried out using area velocity instrumentation, allowing the hydraulic behavior of the channel to be characterized.

A key step is the channel cross-section survey, necessary to describe the channel geometry. The collected data allow reconstruction of the section profile and calculation of the wetted area as a function of the water level.

The measurements show a non-uniform velocity distribution:

• left bank: approximately 143 mm/s
• right bank: approximately 30 mm/s
• radar sensor location: near-zero velocity

The data are transmitted to a remote monitoring web platform, enabling continuous access and the progressive development of more accurate rating curves.

This approach transforms a simple level measurement into a complete flow calculation system, essential for hydraulic, environmental applications and drainage network management.