Delaware Administrative Code
Title 7 - Natural Resources and Environmental Control
5000 - Division of Watershed Stewardship
7400 - Watershed Assessment Section
7404 - TMDLs for Zinc in the Red Clay Creek
Section 7404-2.0 - Amended Total Maximum Daily Load (TMDL) Regulation for Zinc in the Red Clay Creek, Delaware

Article 1. The TMDL for zinc in the Red Clay Creek shall be 55.93 pounds per day, measured as total zinc.

Article 2. The combined mass loading of zinc to the Red Clay Creek from NVF Yorklyn's permitted discharge 002 (i.e., WLA002), plus the mass loading of zinc to the Red Clay Creek from contaminated groundwater beneath the NVF Yorklyn property (i.e., LAg.w.) shall not exceed 25.17 pounds of zinc per day, measured as total zinc.

Article 3. The load allocation of zinc originating from upstream of Yorklyn (i.e., LAup) shall not exceed 25.17 pounds of zinc per day, measured as total zinc.

Article 4. The margin of safety (MOS) for the TMDL listed in Article 1 has been set at 5.59 pounds of zinc per day, measured as total zinc. This MOS represents 10% of the TMDL and accounts for uncertainties in the overall TMDL analysis.

Article 5. DNREC has determined with a reasonable degree of certainty that water quality standards for zinc will be met in the Red Clay Creek once the mass loading requirements of Articles 1 through 3 are met.