IWA Comments on Bridgwater Tidal Barrier Options15 December 2016
IWA West Country Branch has submitted to the Environment Agency (EA) its comments regarding the location and gate design for the proposed Bridgwater Tidal Barrier in Somerset.
Seven possible locations originally proposed for the barrier have been shortlisted by EA to two, of which IWA prefers the location alongside the A38 and upstream of Dunball Wharf (site 4). A tidal barrier at this site will require multiple gates which IWA considers will ease maintenance, as one gate at a time can be raised above the high tide level for this purpose. The other location, adjacent to Express Park (site 5), is proposed to have just a single gate, thus denying the maintenance benefits of multiple gates. IWA’s concerns regarding site 5 would be addressed if the Environment Agency decides to adopt multiple gates for a tidal barrier at this location.
IWA favours the use of rising sector gates (similar to the Thames Barrier) which would enable the penning of water above the barrier at the ‘half-tide’ level on certain occasions during the year and thus enhance navigation on the River Parrett above the tidal barrier as far as the River Tone. This would also facilitate the reopening of the Barge Lock at Bridgwater Docks to link the River Parrett with the Docks and hence the Bridgwater & Taunton Canal. IWA considers that the other option proposed by the Environment Agency of a vertical lift gate (similar to the Hull Barrier) would not readily lend itself to penning at the half-tide level and is therefore unlikely to provide a suitable alternative. IWA is aware that the Environment Agency is currently evaluating the ability of a modified vertical lift gate to provide ‘half-tide’ penning and awaits the results of this work.
IWA is also pressing for the public right of navigation, which exists on the River Parrett from Bridgwater Bar to well upstream of Langport, to be maintained during the period of construction by providing for navigation through the temporary bypass channel that will be built as part of the tidal barrier scheme. Furthermore, unless the tidal barrier includes navigation gates, IWA has requested that when the bypass channel is decommissioned land is reserved for a lock and approach channels to be built in the future to enable navigation when the tidal barrier is closed.
Bob Abbott, Chairman of IWA West Country Branch, said “The key benefit of our proposals is to enable penning between 1 March and 31 October every year thus bringing enhanced navigation to the River Parrett and the ability to access Bridgwater Docks. This will bring more leisure, recreation and tourism to Bridgwater and the Somerset Levels, thus helping with their regeneration”.