In Tanks, Basins, and Wells: Volume is calculated by the PLC or SCADA system using the Level measurement and the known dimensions and geometry of the structure (e.g., Volume = Cross-Sectional Area x Level).
In Pipes and Channels: Volume is the integral of Flow over time (e.g., Total Volume = ∑(Flow Rate x Time Interval)). This is how water companies measure the total volume abstracted from a river, supplied to a town, or discharged from a treatment works.
Key System for Volume Reporting: SCADA and Telemetry
The raw data from all the sensors above is fed into Programmable Logic Controllers (PLCs) and Remote Telemetry Units (RTUs).
This data is then transmitted via radio, cellular (GSM/4G/5G), or fibre networks to a central SCADA (Supervisory Control and Data Acquisition) system.
The SCADA system performs the volume calculations, logs the data for regulatory reporting (e.g., to the Environment Agency), and provides real-time visibility and control to operators.
Common SCADA/Telemetry Providers: Schneider Electric, Siemens, ABB, Rockwell Automation, and bespoke systems from companies like Atlas.
Government Agencies (Environment Agency)
The EA doesn’t typically install permanent monitors for public water supply. Their role is regulatory and investigative. They use monitoring to:
Verify Compliance: Check the self-monitoring data provided by water companies against their permits.
Environmental Investigation: Monitor river levels, flows, and quality to assess the impact of abstractions and discharges.
Flood Warning: Monitor rainfall, river levels, and tidal data.
For this, they use a network of their own monitoring equipment, often similar to that listed above, but with a focus on environmental rather than process applications:
Flow: Acoustic Doppler Current Profilers (ADCP) for river surveys, flumes, and weirs with level sensors.
Level: Radar and pressure transducers for river and groundwater level monitoring.