It is now necessary to protect sensitive sites upstream and downstream of networks.
Article 92-3 of the French Water Act of 3 January 1992 makes it mandatory to :
- Controlling rainwater and run-off
- Flood protection
- Pollution control.
Several parameters need to be taken into account when regulating flow:
- The constancy of the leakage flow: Fascicule 77-284 (the technical instruction relating to urban drainage networks) states that a flow can be considered ‘constant if it does not vary by more than 10% as a function of the head of water’.
- The intake surface of the incoming flow: For the same flow rate and head of water, a traditional nozzle (e.g. a pipe) will have an intake surface area 2 to 3 times smaller than a flow regulator or controller, increasing the risk of clogging and, consequently, flooding.
- Device maintenance: Devices with moving parts should be avoided in wastewater systems.
