Dredging Impact Assessment and Monitoring Services Barnegat Bay Dredged Holes Geotechnical Testing In the early 1960s material for beach repair/replenishment projects was taken from the back bays (as opposed to ocean sites). These projects often created unnaturally deep holes within the bay. Excessive depths within the holes act as a sink for organic material often creating poor water quality conditions near the bottom (low dissolved oxygen). These sites were selected as a fast track restoration project by USACE. As part of other studies documenting the poor biological conditions in the holes, Versar was contracted to develop a data base on the geotechnical attributes of the sediments within two holes near the township of Harvey Cedars, New Jersey. The data were used to predict the behavior of material if the holes were filled with material dredged from the intracoastal waterway. Versar supervised the collection and laboratory analysis of sediment cores taken within each hole and assessed the potential movement and consolidation of material that may occur after placement. Versar also developed a dredging plan and provided recommendations of how to place material in the holes to minimize impact to living resources in the project area. Dredged holes in the estuary with poor biological conditions were identified as a fast track restoration project by USACE. Versar was contracted to develop a data base on the benthic invertebrate community condition within the dredged holes. A series of grab samples were taken in the deepest portion of the holes, along the slopes of the holes, and in nearby shallow water reference areas. Surveys were conducted during the spring and summer seasons. Benthic data indicated that the dredged holes had much lower densities and number of species relative to shallower habitats. The study also included adult fish surveys in the holes relative to shallow water reference areas. The importance of the holes as fish habitat was evaluated by sampling with otter trawls and gills nets during the summer season. Fish surveys were also conducted in the early winter to investigate whether the holes were used as overwintering areas for resident fish. Water quality within the holes was measured with a moored data logging instrument for a two week period during the summer months. These data were used to evaluate the length and severity of the low dissolved oxygen events in the holes. ecological assessment | watershed managment | environmental compliance | power plant assessment | about versar | client showcase | publications | careers | site map | search | contact us | home © 2001 by Versar, Inc.