The Water of Leith is Edinburgh's main river, flowing through the heart of the city and out to sea via the Firth of Forth. It has severely flooded several times, causing substantial damage. The City of Edinburgh awarded a £11.5 million flood prevention scheme to tackle the problem.

Flood Control International was contracted by Lagan Construction to provide a range of flood barriers and gates as part of the project which extends along a 2.5km stretch of the Water of Leith.

Their job was to design, manufacture and install 2 lift hinge flood gates, 2 heavy duty bi-fold flood gates, 3 window shutters and 9 separate demountable flood barrier systems. The flood prevention scheme officially opened on May 31st 2013.

The challange was to produce engineered flood defences that formed a coherent flood prevention scheme. Also, the demountable flood barriers had to be connected to listed building which meant that no wall fixings could be used in their design. Most challanging of all was the requirement for a pair of bi-fold heavy duty flood gates across a level threshold that allowed for a 7 tonne impact load. This has never been done before.

The gates are 6m wide by 2.5m high.

The bespoke design required the use of hydraulic lifting hinges to allow the gates to operate over a dead level roadway. The bi-fold mechanism was chosen so that when in the stored position the gates have a reduced footprint.

Part of the installation process was to undertake installation time tests and full height water tests on all the flood control barriers and gates. Installation time tests were achieved at 70 square metres per hour, and all the barriers and gates achieved the full height water test.

Bi-fold Heavy Duty Flood Gate Testing

Bearing in mind that these bi-fold flood gates are over 2.5m high, testing these vast 2 tonne gates to full height required significant effort.

Some 90 tonnes of dumpy bag sand was used to hold the water against the gates.
The gates have to form a seal against a level threshold to allow for pedestrian and vehicle access.

Flood Barrier Storage

The storage requirements for the removable flood barriers resulted in the need to provide storage in situ, or on dedicated road trailers for quick deployment of the kit to each location.
In situ flood barrier storage comprised specially design secure panels ensuring that the equipment is out of view.