Habitat Development Field Investigations Windmill Point Marsh Development Site, James River, Virginia. Appendix F. Environmental Impacts of Marsh Development with Dredged Material: Sediment and Water Quality. Volume II. Substrate and Chemical Flux Characteristics of a Dredged Material Marsh.

摘要

This volume is the second of a two-volume appendix presenting the results of chemical and sedimentological studies conducted at a dredged material marsh development site located near Windmill Point, on the tidal freshwater James River, 16 km below Hopewell, Virginia. Sediment and water quality studies conducted before, during, and shortly following dredged material disposal for marsh site construction are presented in Volume I. This volume presents results of substrate sediment studies conducted at the marsh development site and a natural reference marsh 6, 18, and 24 months after site construction. It also compares the physical and chemical transport characteristics of the two marshes based upon monitoring tidal water quality conditions 18 and 24 months following habitat development. Sediment cores were collected and processed using techniques designed to document horizontal and vertical physical and chemical gradients and allow comparisons between sampling periods. Temperature, pH, redox potential, water and volatile solids content, particle size composition, mineralogy, cation exchange capacity, and interstitial and total concentrations of nutrients, carbon, and metals were studied. Metal associations with organic, easily and moderately reduceable and residual sediment phases were also examined.