Information Notes 3 - Beneficial Use / Research and Monitoring / Managing Maintenance Dredging

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Beneficial Use
Research and Monitoring
Managing Maintenance Dredging

Beneficial Use

Government policy encourages the beneficial use of dredged material rather than its disposal. In the Thames Estuary, the great majority of dredged material is either retained within the sedimentary system using water injection dredging, or taken to a beneficial use site at either Rainham, Essex or Cliffe, Kent. These sites are managed by the RSPB for nature conservation with the dredged material placement being a key part of the continuing successful function of the sites.

In addition to these beneficial use initiatives, the PLA is working with other agencies through the Thames Estuary Partnership to identify any further uses of dredged material. Berth holders must consider the eventual fate of the sediment from their berths when making a dredging licence application.

Research & Monitoring

The environmental effects of dredging are a subject of extensive and ongoing research throughout the world. Where specific concerns are identified, the PLA will work with berth operators and other stakeholders in designing and undertaking appropriate research to address the issue(s). The PLA will also promote research and monitoring programmes to inform and enhance its decision-making.

Managing Maintenance Dredging

Once the necessary information is in place, should the environmental assessment of an individual licence application identify concerns, the PLA will consider the use of conditions on the licence to place constraints or monitoring requirements on the operation. Some examples of existing constraints are given below:

• Dredging to be carried out on the ebb tide.
• Water quality monitoring operation to be carried out to monitor dissolved oxygen, suspended solids, zinc, mercury etc.
• Dredging methodology to ensure minimal losses of suspended solids to the marine environment.

Further, dredging licences will always carry a requirement to undertake pre- and post-bathymetric surveys of the dredged area.

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