Reports
Cox Creek Dredge Material Containment Facility exterior monitoring: sedimentary environment 2007
2008, Hill, J.M.
File Reports, Coastal and Estuarine Geology, File Report 2008-03
Executive Summary
The Cox Creek site is a dredged material containment facility (DMCF) located in Baltimore Harbor. The Cox Creek DMCF is a site which was in operation in the 1960’s through 1984, which has been reactivated. A limited amount of material was accepted in 2005 – 2007. The site is an upland disposal site anchored to land, with a diked containment area projecting into the Harbor. Dredged material from Baltimore Harbor is the primary material designated for placement at the site. Use of the site will prevent overboard disposal of dredged sediment and accept material that would in the past be sent to the Hart-Miller Island Dredge Material Containment Facility (HMI - DMCF). HMI-DMCF is to be closed at the end of 2009.
A total of 10 sites were sampled to monitor the effects of reactivation and operation of the containment facility. Nine (9) monitoring sites adjacent to the area with 1 site designated as reference site. EA Engineering, Science and Technology (EA) collected the samples and the Maryland Geological Survey (MGS) was responsible for analyses and interpretation of the data. The samples were collected late October 1 – 3, 2007. Samples consisted of undisturbed sediments collected at the sediment-water interface.
The data showed:
- No statistically significant change from the 2006 baseline study.
- Sediments are fine grained. The sediments have slightly higher Sand content than sediments further into the Harbor. However the average Clay content for the area is ~20% , comparable to samples from previous studies in Baltimore Harbor.
- Based on the total Nitrogen (N) content of the sediment the area is consistent with the overall Harbor area with a consistent input of organic matter from primary production. However , the area around Cox Creek area has a higher Terrigenous Carbon (C) input, being closer to the main stem of the Bay and other sources of non-reactive/Terrigenous C.
- Cadmium (Cd), Manganese (Mn), and Nickel (Ni) are within background levels found for the Northern Chesapeake Bay.
- Trace metals in the study area follow the general pattern seen in the 1994 - 1997 Baltimore Harbor study. However based on the enrichment distribution maps and elevated values greater than in the previous study; the facility appears to be a source of Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), and Zinc (Zn) to the external sedimentary environment.
- The reference site is not representative of the area, both physically and chemically. Its use as an indicator of external input to the area will need to be determined by future monitoring in the area.
