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The Chairman invited feedback on the Harbour Study which had been presented to the Committee at its meeting on 23 February 2023.
Councillor Cook summarised feedback from the Working Harbour working group. The group recommended that the South Pier be replaced with a rock armour breakwater as recommended by Royal Haskoning. The group had also discussed the use of the North Wall and the possibility of dredging, and asked that research be done to determine what business could be accommodated at the North Wall. With regards to dredging, the group asked that the material on the river bed be sampled should dredging be needed in the future, but that dredging should not go ahead at this point.
The Chairman gave feedback on behalf of the Southwold Harbour Investment Programme working group who also recommended that works begin on the South Pier as soon as possible, and that a business case be prepared for the North Wall.
Mr Musgrove agreed with the comments from the Committee's working groups and added that it would be prudent to sample sediment on the riverbed when works on the South Pier were taking place as this would lower costs.
Mr Pickles commented that the material in the river bed might be possible to use for the building of the south pier, and whether using some of this material but not dredging the whole bed could be considered. Mr Musgrove stated that any removal of sediment would require a dredging license.
Mr Flunder, Chairperson of the Stakeholder Advisory Group, commented that the group had expressed concern about there not being culverts in the replacement South Pier structure. There was anecdotal evidence that a solid South Pier had negatively affected the channel, and there was feeling that if culverts were not installed this would happen again.
The Chairman commented that the original structure was solid, and asked if a rock breakwater would have the same effect on the channel as a solid structure. Mr Musgrove and Mr Pickles commented that whilst a rock breakwater was a solid structure, it was not a solid structure with a flat surface and so it would effectively dissipate wave action in the channel. More detailed modelling could be done at the design stage to ensure that the rocks that made up the structure would be placed to produce the right conditions in the Harbour.
Councillor Cook commented commented that at this stage costs should not be prohibitive but the focus should be on the right structure to create the right conditions in the harbour.
Mr Gladwell, a member of the Advisory Group, stated that the windows in the current structure also created a Venturi effect and as a result siltation in the channel was greatly reduced, it was not clear if a more solid structure would have this impact. Mr Gladwell also expressed concern that none of the models were based on a north-westerly wind, as it was during these conditions when issues occurred.
The Chairman agreed that final designs should include detailed modelling, especially with regards to siltation and the impact of north-westerly winds, taking into account local knowledge from the advisory group members.
Mr Flunder commented that the advisory group were also keen to see works happen further upstream to help prevent flooding. The Chairman commented that the Harbour was restricted in what it could do upstream as this area was not included in Harbour lands. The Chairman referred to the success of works in the Alde where improvements had been made with the involvement of landowners and other public bodies, and stated that this model should be copied in the Blyth estuary. The Harbour could be involved in these works but could not lead on them, as ultimately it was prohibited in spending money in this area. With regards to work in the Harbour, care would be taken to ensure that works did not exacerbate issues upstream.
The Committee were in agreement that works on the South Pier to replace the current structure with a breakwater should go ahead, and asked that a report be received at the July meeting to confirm options for the replacement of the structure. The Committee also asked that final options should include detailed modelling taking into account local knowledge.