Posted on November 14, 2016
New techniques for dredging the River Parrett are being tested this November and December, as Somerset Rivers Authority seeks cheaper and better ways of maintaining tidal rivers.
Three weeks of trials are being carried out between Westonzoyland Pumping Station and Burrowbridge to see how effective water injection dredging and agitation dredging can be at getting silt moving down to Bridgwater Bay and preserving the River Parrett’s capacity.
Some locals in Burnham-On-Sea believe the new techniques could lead to extra silt gathering in the estuary at Burnham, creating new sand banks and building up local beaches over time.
The techniques being trialled for Somerset Rivers Authority are water injection dredging and agitation dredging – two ways to keep silt moving downstream on an outgoing tide when the water can carry it away.
The vessel being used on the Parrett for the work is called Borr. Having been delivered to Dunball Wharf in halves, then re-assembled, the Borr is now set to motor upstream through Bridgwater on Saturday night (12th November).
Three weeks of trials are due to start on Monday 14th November, in conjunction with detailed monitoring before, during and after. Along the trials section, there is 150% more silt than there was in April and in places, four times as much, says the SRA.
Work therefore carries on from where 2.2km of maintenance dredging was finished earlier this year by the Parrett Internal Drainage Board for the SRA. That dredging, and the trials, aim to maintain the 8km of river dredged in 2014.
Cllr John Osman, SRA chairman, said this week: “This is the first time that such trials have been done on the Parrett in conjunction with a long-term programme of detailed monitoring.”
“Potentially, new methods offer Somerset big benefits: done at the right times, in the right places, they could be much cheaper, more effective, and better for the environment, local residents and farmers.”
The trials are being delivered for the SRA by the Parrett Internal Drainage Board with contractors Van Oord.
Source: Burnham-On-Sea
