What is BUDS?
The Beneficial Use of Dredged Sediment, or ‘BUDS’, is the process of using dredged material in a manner that will benefit society and the natural environment, in this case for coastal flood protection and habitat restoration.
Most sediment dredged from ports and harbours for navigational purposes is disposed of offshore, with only a very small proportion (<1%) used nationally for restoring declining habitats, despite the significant flood protection and wider benefits such schemes can provide.
Why is the material being dredged from Harwich Harbour?
Ports and harbours have an important and legal role to play in providing safe navigation for global shipping within the UK’s ports, through which over 95% of the UK’s imports and exports pass. Dredging of the Harwich Harbour outer approach channel is necessary to maintain navigational depths, ensuring safe navigation of vessels into and out of the harbour.
How will the project be funded?
The project is one of three projects in Essex to be funded through the Environment Agency’s £25m Natural Flood Management which seeks to reduce flood risk to communities whilst providing additional wider benefits to nature and society across England.
What are the benefits?
In addition to the creation and replenishment of 6.7 Ha of vegetated shingle beach habitat for beach-nesting birds, the proposed schemes will contribute to the protection of 25km of coastal flood defence. It will also help to protect 240 Ha of coastal saltmarsh, 406 Ha of coastal floodplain grazing marsh and towards the protection of 289 residential and commercial properties in West Mersea and Tollesbury.
Additionally, it will protect European Native and Pacific Oyster layings in West Mersea Harbour and boat moorings in West Mersea Harbour and Tollesbury Marina.
What will it look like?
From the ground it will look like an extension of naturally formed vegetated shingle beach habitat in the area and so will be in keeping with the natural environment.
The Beneficial Use of Dredged Sediment, or ‘BUDS’, is the process of using dredged material in a manner that will benefit society and the natural environment, in this case for coastal flood protection and habitat restoration.
Most sediment dredged from ports and harbours for navigational purposes is disposed of offshore, with only a very small proportion (<1%) used nationally for restoring declining habitats, despite the significant flood protection and wider benefits such schemes can provide.
Why is the material being dredged from Harwich Harbour?
Ports and harbours have an important and legal role to play in providing safe navigation for global shipping within the UK’s ports, through which over 95% of the UK’s imports and exports pass. Dredging of the Harwich Harbour outer approach channel is necessary to maintain navigational depths, ensuring safe navigation of vessels into and out of the harbour.
How will the project be funded?
The project is one of three projects in Essex to be funded through the Environment Agency’s £25m Natural Flood Management which seeks to reduce flood risk to communities whilst providing additional wider benefits to nature and society across England.
What are the benefits?
In addition to the creation and replenishment of 6.7 Ha of vegetated shingle beach habitat for beach-nesting birds, the proposed schemes will contribute to the protection of 25km of coastal flood defence. It will also help to protect 240 Ha of coastal saltmarsh, 406 Ha of coastal floodplain grazing marsh and towards the protection of 289 residential and commercial properties in West Mersea and Tollesbury.
Additionally, it will protect European Native and Pacific Oyster layings in West Mersea Harbour and boat moorings in West Mersea Harbour and Tollesbury Marina.
What will it look like?
From the ground it will look like an extension of naturally formed vegetated shingle beach habitat in the area and so will be in keeping with the natural environment.
2022 beach recharge at Old Hall Point. Photo by Jim Pullen
How will the sediment be delivered?
The sediment will be delivered to the receptor sites on the ebb of a high tide by the same large dredging vessel that will dredge the sediment from Harwich Harbour. The sediment itself will be delivered one of two ways: either by ‘rainbowing’, where the sediment is hydraulically projected through the air to the receptor sites or using a floating or fixed pipeline to transport the sediment from the vessel.
Hasn’t this been done before? Why are you doing it again?
Successful BUDS schemes were delivered in the Blackwater Estuary in the 1990's by the Environment Agency and more recently by the Mersea Harbour Protection Trust in 2022. The newly proposed schemes are an extension of this work and will see the delivery of schemes at Tollesbury Wick, Old Hall Point and Cobmarsh Island. The previously delivered sand and gravel beaches at Old Hall Point and Cobmarsh Island will be raised to provide greater flood defence benefit and to create additional bird nesting areas. The new scheme at Tollesbury Wick will provide additional protection to the coastal flood defences and protect residential and commercial properties in Tollesbury.
Will it affect public spaces?
During delivery, the dredging vessel will transit between the dredging site and the Blackwater Estuary and so will have some impact on marine traffic. Waterway users will be informed of the operation through a notice to mariners and its location prior to deployment in order to minimise impacts and to notify users of the potential for disturbance. It is not expected that the proposed works will have an impact on terrestrial public spaces.
Will the sediment silt up the creeks?
The sand and gravel beach recharge undertaken by the Environment Agency in the 1990s and by Mersea Harbour Protection Trust in 2022 has demonstrated material remains relatively in-situ once deposited. Monitoring of previous schemes has demonstrated that, once placed, the beaches respond to natural tidal forcings by reprofiling and slowly migrating inland whilst providing protection to exposed saltmarsh.
The proposed schemes looks to reduce coastal erosion of mudflat that can result in excess sediment silting up creeks and smothering oyster beds.
Will it affect marine life?
Due to the low speed of the dredging vessels, marine mammals are unlikely to be directly impacted by dredging operations or deposition of sediment. Any plumes arising during sediment placement are expected to be localised which will minimise impact on marine ecosystems and wildlife.
Will it affect important fishery species such as oysters?
Sediment will be deposited on the ebb of a high tide to ensure any sediment plumes are drawn away from the oyster layings in the creeks and into the main channel of the Blackwater Estuary by the falling tide. Turbidity (cloudiness) of the water column adjacent to the receptor sites will be monitored during placement of sediment to ensure suspended sediment remains within tolerable limits. The proposed schemes aim to help provide additional protection to the oyster beds and reduce erosion of mudflat which will have an overall positive impact on the beds.
Will I be able to land my boat on them?
Bird nesting areas on the proposed beaches will be cordoned off as required during the breeding season (April – August), however, landing will be permitted in designated areas, away from vulnerable nesting sites. We request that signage is respected and where breeding birds have been disturbed invertedly to back away carefully from the nest.
Why have the gulls taken over recent beach recharge in the Mersea Quarters?
The RSPB on behalf of the MHPT project have been carrying out bird surveys since 2015 and every year since 2018 to monitor the populations of breeding birds around the Mersea quarters. It is a reasonably complex picture with changes in both numbers, species and distribution around this area. Large gull numbers (Herring gull and Lesser Black backs) have increased since 2015, from 41 to 86 in 2024 (with a peak of 116 in 2023, however, this is still below the peak of 139 in 2011 when 97 pairs nested on Cob Marsh Island).
The recent changes have largely been driven by the increase in nesting pairs on Packing Marsh Island, where we do not propose to carry out any recharge on this occasion. The remainder of the sites carried out in 2021 have not been colonised by large gulls, although it should be said that the recharge at Cobmarsh will protect the saltmarsh which hosts a Herring gull colony.
Success is equally mixed, with most success coming from Packing Marsh and the Barges adjacent to Cobmarsh, Cobmarsh island is less successful due to flooding of nests (something this project will not be able to prevent). Going back further, since 2011 Herring gulls have been slowly increasing in the estuary by around 30% indicating that an increase in gulls was already occurring before the recent recharge work.
Will you cull the gulls?
Herring gulls are a red listed species and have suffered a 50% decline since 1969-70. Annual monitoring suggests that further declines have occurred since Seabird 2000 and the results from the recent Seabirds Count (2015–21) are expected to confirm the severity of this decline in coastal breeding Herring Gulls (JNCC 2022) (as per the BTO/JNCC). As mentioned above, only one historical recharge location has seen an increase in nesting herring gull. We are therefore hopeful that, although gull numbers may continue to increase on Packing Marsh and the Barges, the work proposed by this project will not be the cause of this. Estuaries are best looked at, at a landscape level and we are hopeful that by providing more locations where gulls may not necessarily colonise, we will be providing a home for terns, ringed plovers and other beach nesting birds, not just large gulls.
What about an increased amount of bird guano in the water leading to lower water quality?
Although large gulls may have increased in the last decade, it is likely that actual numbers of nesting birds in the estuary have decreased. Most notably when we compare black-headed gull survey counts with historic data. This shows that this species has declined at their usual breeding sites within the estuary by 86% since 2000. The main driver of water quality in the Blackwater is likely to be agricultural and sewage run-off from the hinterland surrounding the estuary and these inputs will dwarf any impacts that breeding gulls may have. Indeed, protection of saltmarsh by the project will prevent additional release of sediment currently captured by the saltmarsh and might have a small but positive effect on water quality in the estuary.
Why is the proposed recharge only protecting your own reserves?
The Tollesbury Wick and Old Hall peninsulas are a vital wave break from the prevailing westerly winds that affect Mersea Harbour. Without them Mersea would be exposed to many more damaging waves. In addition, if those sea walls breach during a storm there will be a catastrophic release of extra water during each tide that will have serious detrimental impacts for the harbour.
How can I influence or feed into the project?
If you have any further questions or concerns, please contact our project email address: [email protected]
Further details of the proposals can be found on our project information sheet. We are extremely keen to meet with local groups and industries during the project’s development to seek opinion and insight. To maximise awareness, it would be fantastic for locals to share their knowledge of the project around their community
The sediment will be delivered to the receptor sites on the ebb of a high tide by the same large dredging vessel that will dredge the sediment from Harwich Harbour. The sediment itself will be delivered one of two ways: either by ‘rainbowing’, where the sediment is hydraulically projected through the air to the receptor sites or using a floating or fixed pipeline to transport the sediment from the vessel.
Hasn’t this been done before? Why are you doing it again?
Successful BUDS schemes were delivered in the Blackwater Estuary in the 1990's by the Environment Agency and more recently by the Mersea Harbour Protection Trust in 2022. The newly proposed schemes are an extension of this work and will see the delivery of schemes at Tollesbury Wick, Old Hall Point and Cobmarsh Island. The previously delivered sand and gravel beaches at Old Hall Point and Cobmarsh Island will be raised to provide greater flood defence benefit and to create additional bird nesting areas. The new scheme at Tollesbury Wick will provide additional protection to the coastal flood defences and protect residential and commercial properties in Tollesbury.
Will it affect public spaces?
During delivery, the dredging vessel will transit between the dredging site and the Blackwater Estuary and so will have some impact on marine traffic. Waterway users will be informed of the operation through a notice to mariners and its location prior to deployment in order to minimise impacts and to notify users of the potential for disturbance. It is not expected that the proposed works will have an impact on terrestrial public spaces.
Will the sediment silt up the creeks?
The sand and gravel beach recharge undertaken by the Environment Agency in the 1990s and by Mersea Harbour Protection Trust in 2022 has demonstrated material remains relatively in-situ once deposited. Monitoring of previous schemes has demonstrated that, once placed, the beaches respond to natural tidal forcings by reprofiling and slowly migrating inland whilst providing protection to exposed saltmarsh.
The proposed schemes looks to reduce coastal erosion of mudflat that can result in excess sediment silting up creeks and smothering oyster beds.
Will it affect marine life?
Due to the low speed of the dredging vessels, marine mammals are unlikely to be directly impacted by dredging operations or deposition of sediment. Any plumes arising during sediment placement are expected to be localised which will minimise impact on marine ecosystems and wildlife.
Will it affect important fishery species such as oysters?
Sediment will be deposited on the ebb of a high tide to ensure any sediment plumes are drawn away from the oyster layings in the creeks and into the main channel of the Blackwater Estuary by the falling tide. Turbidity (cloudiness) of the water column adjacent to the receptor sites will be monitored during placement of sediment to ensure suspended sediment remains within tolerable limits. The proposed schemes aim to help provide additional protection to the oyster beds and reduce erosion of mudflat which will have an overall positive impact on the beds.
Will I be able to land my boat on them?
Bird nesting areas on the proposed beaches will be cordoned off as required during the breeding season (April – August), however, landing will be permitted in designated areas, away from vulnerable nesting sites. We request that signage is respected and where breeding birds have been disturbed invertedly to back away carefully from the nest.
Why have the gulls taken over recent beach recharge in the Mersea Quarters?
The RSPB on behalf of the MHPT project have been carrying out bird surveys since 2015 and every year since 2018 to monitor the populations of breeding birds around the Mersea quarters. It is a reasonably complex picture with changes in both numbers, species and distribution around this area. Large gull numbers (Herring gull and Lesser Black backs) have increased since 2015, from 41 to 86 in 2024 (with a peak of 116 in 2023, however, this is still below the peak of 139 in 2011 when 97 pairs nested on Cob Marsh Island).
The recent changes have largely been driven by the increase in nesting pairs on Packing Marsh Island, where we do not propose to carry out any recharge on this occasion. The remainder of the sites carried out in 2021 have not been colonised by large gulls, although it should be said that the recharge at Cobmarsh will protect the saltmarsh which hosts a Herring gull colony.
Success is equally mixed, with most success coming from Packing Marsh and the Barges adjacent to Cobmarsh, Cobmarsh island is less successful due to flooding of nests (something this project will not be able to prevent). Going back further, since 2011 Herring gulls have been slowly increasing in the estuary by around 30% indicating that an increase in gulls was already occurring before the recent recharge work.
Will you cull the gulls?
Herring gulls are a red listed species and have suffered a 50% decline since 1969-70. Annual monitoring suggests that further declines have occurred since Seabird 2000 and the results from the recent Seabirds Count (2015–21) are expected to confirm the severity of this decline in coastal breeding Herring Gulls (JNCC 2022) (as per the BTO/JNCC). As mentioned above, only one historical recharge location has seen an increase in nesting herring gull. We are therefore hopeful that, although gull numbers may continue to increase on Packing Marsh and the Barges, the work proposed by this project will not be the cause of this. Estuaries are best looked at, at a landscape level and we are hopeful that by providing more locations where gulls may not necessarily colonise, we will be providing a home for terns, ringed plovers and other beach nesting birds, not just large gulls.
What about an increased amount of bird guano in the water leading to lower water quality?
Although large gulls may have increased in the last decade, it is likely that actual numbers of nesting birds in the estuary have decreased. Most notably when we compare black-headed gull survey counts with historic data. This shows that this species has declined at their usual breeding sites within the estuary by 86% since 2000. The main driver of water quality in the Blackwater is likely to be agricultural and sewage run-off from the hinterland surrounding the estuary and these inputs will dwarf any impacts that breeding gulls may have. Indeed, protection of saltmarsh by the project will prevent additional release of sediment currently captured by the saltmarsh and might have a small but positive effect on water quality in the estuary.
Why is the proposed recharge only protecting your own reserves?
The Tollesbury Wick and Old Hall peninsulas are a vital wave break from the prevailing westerly winds that affect Mersea Harbour. Without them Mersea would be exposed to many more damaging waves. In addition, if those sea walls breach during a storm there will be a catastrophic release of extra water during each tide that will have serious detrimental impacts for the harbour.
How can I influence or feed into the project?
If you have any further questions or concerns, please contact our project email address: [email protected]
Further details of the proposals can be found on our project information sheet. We are extremely keen to meet with local groups and industries during the project’s development to seek opinion and insight. To maximise awareness, it would be fantastic for locals to share their knowledge of the project around their community
