Coastal and Estuarine Processes
A very large body of information exists for the Thames Estuary. This includes an assessment of Sediment Budget undertaken by IECS in 1993.
Water quality monitoring comprises largely monitoring by the Environment Agency under various EC Directives, which in turn is limited to selected locations with varying frequencies. Some sampling was undertaken in 2001 as part of studies for the London Gateway Environmental Statement. Although some data exists, comprehensive information is not available for the estuary, particularly with respect to suspended sediment concentrations which have the most potential to be affected by maintenance dredging.
Sediment quality data have largely been collected as part of London Gateway Environmental Statement, PLA dredging license applications and, on occasion, FEPA disposal licence applications. Data is therefore available for both the subtidal and selected intertidal areas of the estuary.
There is a good coverage of data available for the Thames Estuary on marine ecology. Comprehensive surveys have been carried out within the last five years, including intensive grab surveys and large scale biotope mapping. It is therefore considered that the marine ecology can be well characterised from these sources.
With regard to ornithology, data collected as part of the WeBS scheme provides an excellent coverage of bird data for the intertidal areas of the estuaries. Data also exists from selected studies such as the London Gateway Environmental Statement. It is considered that the existing level of bird count data is at present sufficient for detecting any adverse effects on the SPA (if they occur). However, as WeBS information may occasionally have incomplete data set, the adequacy of the data should be monitored as part of the cross-cutting functions of the Dredging Liaison Group, the adequacy reviewed as part of the ongoing update of the Baseline document, and additional surveys should be undertaken where appropriate.