The Solent Forum
Working in partnership for the future
There is a strong desire amongst Solent Forum members to find solutions to the many barriers which are preventing the effective use of dredged material to augment Solent intertidal sites and provide other benefits associated with restoration work (especially enhanced coastal protection). To find solutions, in 2017 the Solent Forum convened a project group of interested parties and initiated the BuDS Solent project. A final report provides a summary of the work that was undertaken from 2017 to 2024 under Phases 1 to 3. One final outcome of these first 3 phases, was that the MMO were unable to proceed with the Marine Licence application. The concern was not with the activity itself, but the practicalities of overseeing the multiple conditions and monitoring commitments which would have accompanied a multi donor disposal site. Phase 4 commenced in 2025 and will seek to repurpose the Marine Licence Application for a two donor benefical reuse project at a disposal site in Lymington. This phase will be overseen by the project group and which is chaired by the Solent Forum.
Following several successful trials, since 2014 Lymington Harbour Commission has been placing up to 10,000 tonnes of sediment dredged from the harbour each year within a bay at the exposed seaward edge of the saltmarsh. The purpose was to create a sacrificial reef that will shelter the marsh behind from wind wave action and provide a source of sediment to ‘feed’ the marsh in the immediate vicinity. By August 2023 surveys showed that an area of mud of around 17,000m² had been raised by around 1.5m in height and its presence was slowing down erosion of the marsh behind.
While the technique described above has been successful at reducing erosion to the saltmarsh behind, the barges cannot get mud high enough in the tidal frame for new saltmarsh to grow. LHC worked with partners Land & Water / Earth Change, a marine contractor specialising in environmental enhancement projects, and Hampshire and Isle of Wight Wildlife Trust to trial a new technique to move a significant quantity of the previously placed and consolidated sediment higher up the tidal frame onto adjacent lower lying areas of decaying saltmarsh. The aim is to raise the trial area to the same level as supports the surrounding healthy high marsh to encourage new high marsh growth.
In December 2023, the Marine Management Organisation granted Lymington Harbour Commissioners a ten-year licence to trial new techniques and in 2024 the Environment Agency awarded the Commissioners grant funding from the DEFRA Water Improvement Fund to trial the new technique in August and September 2024. While the trial did not move as much sediment as was hoped due to difficult ground conditions contributing to equipment issues, and an unseasonably windy period, the technique showed considerable promise and a number of lessons were learned that will improve results for future schemes, see Beneficial Use of Dredged Sediment to Improve Boiler Marsh, Lymington: Review of restoration activities and monitoring undertaken for the first trial campaign in 2024.The trial area will be monitored until autumn 2025, view the monitoring report.
This handbook is a practical guide for those interested in beneficially using dredged sediment for estuarine and coastal habitat restoration. It has been written with a broad audience in mind, not just specialists in the field. It is hoped that it will be of value for a range of individuals and organisations including policy makers, nature conservation bodies, local communities or anyone interested, or involved in, dredging, coastal management and ecosystem restoration. Page 11 of the handbook sets out the current barriers to beneficial use.
This mapping platform was produced for the UK Beneficial Use Working Group (BUWG). It was created to help identify where dredged sediment can be used beneficially (e.g. for shoreline adaptation, flood protection and/or coastal habitat restoration). To achieve this, this platform collates the best available data and maps to answer the following questions:
This ‘data-viewer’ also includes links to useful resources (e.g. guidance documents, case example websites). This information was brought together to enhance collaboration and communication between partnerships that want to use the dredge sediment resource beneficially., dredging specialists and organisations which regulate and advise on this sector.
The Nab Tower is currently the main dredge disposal site in the Solent (indigo box in the map above). It is 11.5km from the coast. Recent quantities of disposed dredgings are shown below (source: Dredge Sediment Resource Data Platform).
There is a much smaller disposal site at the Needles (yellow box in the map), the total Dry Tonnage for 2012-2022 was 5,834.3 and the total Metric Wet Tonnage for 2012-2022 was 10,829.0 (source: Dredge Sediment Resource Data Platform).
The dredging of marine sediment could theoretically result in the entrainment of a wide variety of animals, plants and any other organisms, such as pathogens, that are in/on the seabed (benthic species) or suspended in water (pelagic species). Larvae, eggs, algal spores and other immature stages must be considered, along with mature individuals. Natural England commissioned an evidence review on the risk from navigational dredging and disposal activities as a pathway of introduction and spread for non-native species (NNS). This was to understand the survival rates of species from dredging activity and through disposal, particularly for coastal inshore beneficial use/beneficial placement disposal sites as well as understand the subsequent (if any) risk to statutory protected sites and the wider seas.
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