The Hart-Miller Island Exterior Monitoring Program

Aerial Photograph of Hart-Miller Island
In 1983, Hart-Miller Island Confined Disposal Facility (HMI) was constructed to contain sediments dredged from Baltimore Harbor and its approaches.  HMI is located in the upper Chesapeake Bay at the mouth of Back River, northeast of Baltimore Harbor.  Construction of HMI began by building a dike connecting the remnants of Hart and Miller Islands and encompassing an open-water area of approximately 1,100 acres.  Completed in 1983, the dike is approximately 29,000 feet long and is divided into North and South Cells by a 4,300 foot interior cross-dike.  Placement of dredged material within HMI began with dike completion and concluded in December 2009.

Environmental Monitoring

Under section 404(b&c) of the Clean Water Act (1987), entitled “Permits for Dredged or Fill Material”, permits for dredged material disposal can be denied if it is determined that: “the discharge of such materials into such area will have an unacceptable adverse effect on municipal water supplies, shellfish beds and fishery areas (including spawning and breeding areas), wildlife, or recreational areas.”   In accordance with this federal mandate and as a special condition of the State Wetlands License 72-127(R), a long-term compliance monitoring program was implemented in 1981 to assess the effects of HMI on local water quality and biota.  Results from the monitoring are used to detect changes from baseline environmental conditions established in the area surrounding HMI, and to guide decisions regarding possible operational changes and remedial actions.  Starting in 1995, the Maryland Department of the Environment assumed programmatic oversight of the HMI Exterior Monitoring Program from the Maryland Department of Natural Resources.

Exterior Monitoring Reports

Below are links to PDF versions of the HMI exterior monitoring reports. The first report listed includes preliminary data of HMI prior to the start of the exterior monitoring reports. For stakeholders interested in downloading the actual monitoring data, please visit EPA’s Storet Web Page.  Once there, click on “Results by Project”, and select the organization ID “MDEDAT01” or “MDEDAT01_WQX”. 



Contact Information

For questions or comments concerning these reports, please contact John Backus at or 410-537-3947.​​

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