The Department invites public comment on an amended proposal to clean-up Operable Unit 2 (OU 2) of the Hessler Property Site located at 401 Garasches Lane and 610 South Market Street Wilmington. The Site was heavily filled with construction waste and other debris and most recently used as a lay-down and storage area for steel products. OU-2 is approximately 4.50 acres, located on tax parcel 26-057.00-05, and consists of the shallow and deep soils. The groundwater beneath OU-2, and the associated sediment and groundwater located in the ditch beneath and adjacent to OU-2 will be considered as OU-3. The original Proposed Plan and Final Plan for OU-2 only applied to the shallow soils (0-2 ft. below ground surface (bgs). Additionally, a Delaware Department of Transportation (DelDOT) owned right-of-way (ROW) will be acquired and combined with the OU-2 portion of the Site.
The proposed remedy will require the following:
On OU 2: Install a surface cap consisting of at least two feet of DNREC-approved clean fill or impervious material (e.g. buildings, asphalt, or concrete). Pervious areas of OU-2 are to be limited to 20% or less of the Site’s surface area, recording an environmental covenant restricting digging and the use of groundwater, and submittals for DNREC’s approval of a Contaminated Materials Management Plan and a Long Term Stewardship Plan;
On OU-3: Install a cap consisting of a culvert, concrete liner, or other impervious surface over the ditch portion of the Site that will prevent human contact to contaminated sediment but not impede the drainage way of the existing ditch, In addition, require placement of a reactive material liner system or similar DNREC-approved treatment system, to be included as a part of the culvert design to treat contaminated groundwater that may travel along a preferential pathway in the base of the culvert system and discharge further downstream., recording an environmental covenant restricting digging and the use of groundwater, and submittals for DNREC’s approval of a Contaminated Materials Management Plan and a Long Term Stewardship Plan.
Details of the Amended Proposed Plan are available online at: www.nav.dnrec.delaware.gov/DEN3/
The comment period ends on July 13, 2020. For additional information, please contact Kristen Thornton, Project Manager at (302) 395-2650 or via email at Kristen.Thornton@delaware.gov.