Ebley Flood Gates – An Explanation
Staff at the Cotswold Canals Trust Visitor Centre at Wallbridge in Stroud have recently received a number of enquiries regarding the flood defence works at Ebley Mill and Frome Gardens.
The usual questions are… “Why is it necessary? – How will it work and when?”
The Canal Project engineers have provided reassuring answers.
In the event of heavy rainfall, surface water runoff will cause the water level to rise in the canalised river section of the canal, including the pound from Dudbridge Lower Lock to Ryeford Double Lock.
In order to protect properties from flooding, the Ebley Flood Gate structure is being constructed at Ebley Mill. See top picture right.
So, in a flood event the flood gates will be closed at Ebley, preventing the water level from rising detrimentally between Ebley and Ryeford.
Holding back the flood water at this point will cause excess flood water to ‘back up’ the pound to the overflow weir (between Ebley Mill and the confluence weir) where it will be automatically diverted back into the river Frome. See middle picture right.
Canal Flow Redirected
The overall effect is that the excess flood flow is directed away from residential properties to protect them from flooding and keeps the hazardous high flood flows out of the canal and within the river.
Once in a Hundred Years
The Ebley Flood Gates have been designed using a detailed hydraulic model and will protect properties from a 1 in 100 year flood event, including adjustments for climate change.
To keep the structure in keeping with the canal restoration, the gates will appear similar to a set of lock gates, although there will be only one set of gates.
The picture right is an extract from the engineers plan drawings.