Physical, Chemical and Biological Effects of Dredging in the Thames River (CT) and Spoil Disposal at the New London (CT) Dumping Ground.
Abstract
The Impact of Dredging Operations on Suspended Material Transport in the Lower Thames River Estuary were confined to an area within 300 to 500 yards of the operating dredge and barge, produced an increase in total suspended load within the estuary that was small in comparison to that produced by typical aperiodic storm events, and caused no major alterations in mass transport within the estuary. Field surveys of the Thames River hydrography, phytoplankton, and trace metal concentrations in water, sediment and shellfish suggested that effects of dredging on primary production were spatially and temporally limited. The highest concentrations of nickel, lead, cadmium and mercury in water samples were observed before or during dredging, while copper was highest after dredging but were generally higher upriver. Sediment levels of these five metals, plus zinc and organic carbon, increased in an upriver direction. Dredging-related changes in trace metal body burdens in shellfish but were difficult to separate from normal seasonal variations. No gross pathology was detected in the shellfish. The physical oceanography of the disposal area showed that turbidity was higher in bottom waters than near the surface and was not restricted to the vecinity of the spoil pile. Maximum transport was in the east/west direction with highest values occurring during the ebbtide.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1977
- Accession Number
- ADA044164
Entities
Organizations
- National Marine Fisheries Service