BHC Reveals Dredging and Saltmarsh Creation Project
Brightlingsea Harbor Commissioners (BHC) has announced formal plans for a long term dredging and saltmarsh creation program designed to improve and maintain harbor depths and regenerate the vital intertidal saltmarshes in Brightlingsea Creek.
The build up of mud is a natural occurrence and dredging is therefore one of BHC’s key responsibilities.
Such dredging requires careful planning, complex survey work, liaison with commercial and leisure stakeholders, local residents and other interest groups, plus detailed consultation with organisations such as the Environment Agency, the Marine Management Organisation and the Center for Environment, Fisheries and Aquaculture Science.
The erosion of the inter tidal salt marshes that surround the harbor is also of major concern to BHC.
Following extensive consultation with experts in the field in both the UK and Europe, plans are being drawn up for the spoil from harbor dredges to be used in a major regeneration program for the saltmarshes.
Coincidental to BHC’s own dredging plans, during 2015 the owners of Brightlingsea’s Waterside Marina, which lies within the harbor, put forward proposals for dredging the marina and creating a barrier wall around it.
The plans were not acceptable to BHC or many harbor users, so following discussion between BHC and the marina owners, it was agreed that BHC would assist in identifying a more acceptable dredging solution for the marina.
Following additional consultation/survey work a plan has been agreed with the marina owners that will ensure the marina dredge becomes a cohesive element of the program and that the work will be overseen by BHC.
The areas covered by BHC’s own dredging plan will mainly produce heavy mud waste, whilst the material to be removed from the marina is a lighter silt. Further surveys including complex hydrodynamic modelling, a Habitats Regulations Assessment and an Environment Impact Assessment have been undertaken which identify that a sediment dispersal program is the optimum system for extracting the material from the marina.
The conclusions of the modelling and assessments on the effects of the proposed marina dredge are:
- That there will be no siltation of the main navigation channel;
- That sedimentation upon the oyster beds within the Colne is negligible whether dispersing on the ebb or flood;
- That there is minimal, if any, disturbance to wildlife (including fish), flora and fauna during dredging operations;
- That a flood dispersal is more beneficial to the saltmarshes, and therefore the habitat and designated areas, than an ebb dispersal;
- That a flood dispersal will see some siltation on the Town Hard, Smack Dock and between Olivers’ Wharf and Morgan Marine. There may be some siltation on the oyster beds being used in the North and South Channel and BHC will work with the operator to mitigate any effect.
- A key part of the program will be monitoring; in particular, the amount of siltation and the concentration of sediment within the water. It is intended to employ an independent consultant to conduct the monitoring. The marina dredge will allow data to be gathered that will be invaluable in determining the final plans for the more extensive and complex harbor dredge.
The main harbor dredge is expected to commence in late 2016 and will be preceded by the marina dredge in early 2016. The timetable will be carefully planned to minimize disruption to harbor users, whilst at the same time maximizing the potential for rejuvenation of the saltmarshes.