Delaware’s Section 303(d) Waters and Data Solicitation

Division of Watershed Stewardship

Start Date: June 4, 2020
End Date: July 10, 2020

This notice announces the availability and opportunity to comment on the Delaware Department of Natural Resources and Environmental Control’s Tentative Determination for Delaware’s 2020 Section 303(d) List and the supporting Documents for the determinations.

Section 303(d) of the Federal Clean Water Act and implementing regulations (40 CFR 130.7) require each state to identify and prioritize water quality limited segments still requiring Waste Load Allocations/Load Allocations (WLAs/LAs) and Total Maximum Daily Loads (TMDLs) within its boundaries.  A water quality limited segment is a waterbody or portion of a waterbody (e.g., a length of river, an area of an estuary, a pond or wetland, etc.) in which water quality does not meet applicable water quality standards and/or is not expected to meet applicable water quality standards even after the application of technology-based effluent limitations required by sections 301(b) and 306 of the Clean Water Act.  A TMDL specifies the maximum allowable loading of a pollutant or thermal energy to a waterbody and allocates that loading or thermal energy to contributing point and nonpoint sources such that water quality standards can be attained.  TMDLs may involve a single point source or multiple sources (e.g., point sources and nonpoint sources).  In the case where both point and nonpoint sources are involved, the loading allocated to the point source(s) is referred as the “Wasteload Allocation (WLA)” and the loading assigned to the nonpoint sources (including natural background loading) is called the “Load Allocation (LA).”  Depending upon the nature of the water quality problem, TMDLs may be established for geographic areas that range in size from large hydrologic units containing many watersheds to relatively small, individual water body segments.

Today’s notice is limited to the listing of water quality limited segments and their priority.  This notice does not address individual WLAs/LAs and TMDLs.  Such WLAs/LAs and TMDLs are made available for public review and comment under separate public notice.

The Department of Natural Resources and Environmental Control’s Tentative Determination concerning the 2020 Section 303(d) List is based upon information compiled in previous Watershed Assessment Reports; data analyses performed for the 2020 Combined Watershed Assessment Report and 303(d)List; and other sources judged to be reliable and relevant.  Prioritization of the identified segments considers, among other factors, the severity of the pollution involved and the beneficial water uses impacted.

The Department is also soliciting additional data or information from the public that may not have been considered for the Tentative Determination. Please contact David Wolanski using the contact information that follows before July 10, 2020 to submit pertinent data and information.

Copies of the Draft State of Delaware 2020 Combined Watershed Assessment Report (305(b)) and Determination for the Clean Water Act Section 303(d) List of Waters Needing TMDLs (The Integrated Report) are available on the Department’s Web Site, by writing to David Wolanski, DNREC/Division of Watershed Stewardship, Watershed Assessment and Management Section, 285 Beiser Blvd., Suite 102, Dover, DE 19904, by calling (302) 739-9939 or by e-mail (  All comments received on or prior to July 10, 2020 will be considered in developing the Final 2020 Section 303(d) List.  Comments may be sent to Mr. Wolanski by mail or E-mail. Electronic submissions are preferred. Please call David Wolanski at (302) 739-9939 with questions or requests for additional information.

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