Case ref: MLA/2019/00495
Licence ref: L/2020/00009/1

Case summary

Main content

Project description

Project title

Project background

Tidal movements create a build up of sediment within the river Mersey approach to Canning Half Tide Dock. This silt needs to be moved from the lock gate entrance, to ensure that navigation in and out of the dock is not restricted/prevented and to prevent a hazard to navigation that can develop if silt prevents the lock gates sitting on the concrete cill. Several deep drafted craft access and exit the Liverpool South Docks (including Albert Dock) via Canning Half Tide Dock. Without dredging, this would affect future maritime events e.g. Tall Ships Races / Regattas.
This work has been carried out for very many years, either once or twice a year. Prior to 2019, this work was undertaken by the Harbour Authority (under their exemption from requiring a Marine Licence). In 2019 the Canal & River Trust undertook the work under an MMO exemption, as the volume was <500m3. The 2019 hydrographic survey indicates that a higher volume of silt needs to be moved (~1600m3) in February / March 2020 (when the work is planned) therefore a marine licence is required. The dredging is a hydrodynamic dredging process which does not involve "disposal of" the sediment. The method will involve a dredger at low tide to disturb the compacted silt before using a plough, when the tie comes, to relocate the silt away from the entrance. The attached survey shows that the height of the silt quickly drops away, therefore the silt is only ploughed into the deeper water immediately adjacent to the lock gate approaches. A works information package for the Feb/March 2020 work is attached. This application is to put in place a Marine Licence until March 2023 that allows the Trust to dredge each year (either once or twice/year) to maintain the required navigational depth at the dock entrance.

Programme of works

The work needs to be done each year, either once or twice a year.

We would like the licence to allow us to undertake this routine dredging maximum of twice a year within the following months: once in January to March and once in August to November (inclusive). These months were agreed with Natural England (email correspondence uploaded below).

There will always be a minimum of 2 months between each campaign (i.e. there will be no dredging in the months of December and January or April - July).

The exact timings of each dredging activity depend on how quickly silt builds up in front of the gates and the tides. When dredging starts, the work takes 1 week to complete.

As this is a routine job we would like the licence to allow this dredging until 31st March 2023.

Other information

Applicant details

Mrs Karen Jackson / 07917185840 / karen.jackson@canalrivertrust.org.uk
CANAL AND RIVERS TRUST / Canal & River Trust, Red Bull Wharf, Congleton Road South, Church Lawton, Stoke-on-Trent, ST7 3AP / ST7 3AP

Date application submitted

Date application validated

Date initial decision made

Status