Heavy downpours are often brief and local and can fill pipelines in some areas for brief periods of time. Accordingly, the solution is to dam up excess water elsewhere in the system during the required period of time. In other words, use areas with sufficient capacity as a temporary reservoir.
The solution works in the vast majority of downpour situations and does not require investment in large pipelines or basins. All that is needed is to control the flow with appropriate flow regulators.
Proper flow control is defined as discharge which quickly reaches its maximum level and remains at or below this level. This is the level of discharge that can be handled without difficulty after the flow regulator downstream in the system.
Generally, the purpose of a flow regulator is to protect the lower (downstream) part of the pipelines against overloading and flooding. The flow regulator's specific property is that it allows a predetermined maximum amount of liquid per time unit to flow further downstream in the pipeline, regardless of the variation of inlet volume and water level just before the regulator.
To safeguard against clogging and minimise the need for operation and maintenance, the flow regulator should not have any moving parts. In addition, it should have the biggest possible cross sectional throughput area to minimise the resistance to normal daily drainage needs and to avoid clogging.