River Waveney

The River Waveney has numerous flood defences and water level control structure throughout its length. We monitor water levels at these sites through a telemetry network which is controlled and data is utilised by our flood incident duty officers.

The Environment Agency does not control or own all such structures on the river as, for example, some sites are in private ownership such as mills.

Historically, a lot of investment has taken place on the Waveney to install electrically automated sluice gates.  These gates operate on pre-determined trigger levels so we can use live river level data to trigger a gate to open or close in reaction to rising water levels during flood or low flow periods.  All river channels have a maximum capacity of water which can be conveyed before water levels exceed the height of the river banks and spill into the natural floodplain.  When the quantity of water that inflows to the river system is high enough and the river capacity exceeded then flooding will be experienced.  In some cases intense pockets of rainfall and storms mean that this can occur quite rapidly and on other occasions it can happen over many days of moderate rainfall amounts which build to eventually cause water to spill out of the channel onto the floodplain.

The Waveney is generally one of our river systems where levels can take many hours/days to build and react to localised flooding to fields and floodplain.  In some instances the influence of the tidal river system in Broadland can cause river waters to be artificially held back due to storm surges pushing and holding tidal waters high up in the Broadland river network precluding normal drainage of the fluvial river network - this is more of a problem at the lower end of the Waveney, for example round the Ellingham area.

Pete Roberts

Asset Performance Team Manager (Environment Agency)