UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION III 1650 Arch Street Philadelphia, Pennsylvania 19103-2029
December 29, 2000 Kevin Donnelly, Director Delaware Department of Natural Resources and Environmental Control Division of Water Resources Silver Lake Office Plaza, Suite 220 820 Silver Lake Boulevard Dover, DE 19004-2464 Dear Mr. Donnelly: The Environmental Protection Agency (EPA) Region III has reviewed the report “Total Maximum Daily Load (TMDL) Analysis for Tributaries and Ponds of the Nanticoke River and Broad Creek, Delaware” (herein referred to as “the Tributary Report”), which was submitted by the Delaware Department of Natural Resources and Environmental Control (DNREC) on December 8, 2000. This Tributary Report provided an excellent and thorough analysis of recent monitoring data for those tributaries and concluded that no revision was necessary to the Nanticoke River and Broad Creek mainstems’ TMDLs established by Delaware on December 10, 1998, and approved by EPA on December 15, 1998. As you know, consistent with your Continuing Planning Process and Delaware law, that TMDL was adopted as a state regulation applicable to the entire Nanticoke River waterbasin and set forth certain reductions for nutrients for both point and nonpoint sources in order to attain and maintain applicable water quality standards for dissolved oxygen and nutrients. Since the establishment of the Nanticoke TMDL, DNREC has been collecting and analyzing additional and more specific data for the individual tributary segments of the Nanticoke basins that culminated in your recent Tributary Report. EPA concurs with your conclusion that no further revision of the Nanticoke TMDL is necessary to attain and maintain water quality standards for dissolved oxygen and nutrients in the Nanticoke tributaries. As you know, EPA has entered a Consent Decree in American Littoral Society et al. V. EPA, Civil No. 96-591 (D. De) that requires EPA to ensure that TMDLs are established for Delaware waters listed on the 1996 Section 303(d) list. Section 8(b) of the Consent Decree also authorizes EPA to determine whether such a TMDL is necessary: “...EPA is under no obligation to establish TMDLs for any pollutant(s) for which a WQLS is listed or for any WQLS(s) that EPA determines do not need TMDLs consistent with Section 303(d) of the Clean Water Act and its implementing regulations, including 40 C.F.R. § 130.7(b)...”. In addition to the Nanticoke and Broad Creek mainstem segments, DNREC’s 1996 303(d) list included a number of individual tributary segments. Based on EPA review of that Tributary Report, and the Nanticoke TMDL, EPA has determined that no additional TMDLs are necessary beyond those established in the Nanticoke TMDL for the listed tributaries and ponds of the Nanticoke River and Broad Creek. In general,
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EPA makes this determination based on the following: 1. The Tributary Report shows that reductions required in the DNREC regulation establishing the 1998 TMDLs for the mainstems of the Nanticoke River and Broad Creek are adequate to attain and maintain the water quality standards of the tributaries and ponds. The Nanticoke TMDL established a state regulation applicable to the entire Nanticoke River waterbasin with required reductions for nutrients for both point and nonpoint sources. The monitoring data collected from the tributaries and ponds in 1998-1999 show that the tributaries and ponds were meeting water quality standards for dissolved oxygen (DO). For nutrients, DNREC has no applicable numeric water quality criteria for these segments but rather uses “target levels” based on literature values. Although the concentrations of nutrients in some tributaries and ponds exceeded the target levels for nutrients, DNREC originally listed these segments in 1996 on the basis of downstream impacts of those nutrients on the mainstem segments rather than on the impact of nutrients on the tributaries and ponds themselves. The state’s rationale for considering downstream impacts rather than the tributaries themselves can be found in Attachment 2, “Listing Rationale and Priority Setting for Delaware’s 1996 Clean Water Act Section 303(d) list”, to Delaware’s 1996 303(d) list. In this attachment, Delaware states that for elevated nutrient levels in tributaries feeding waterbodies (which exhibited signs of eutrophication), adverse water quality conditions may not be apparent in the tributaries themselves. In other words, the tributaries and ponds themselves may not be impaired but are listed because they are feeding into a waterbody that is showing signs of impairment. Therefore, utilizing this rationale, in the Tributary Report Delaware modeled the tributaries and ponds for nutrients to consider downstream impacts, rather than for the tributaries and ponds themselves. As the numeric criteria for DO has shown to be met in the tributaries and ponds, EPA accepts DNREC’s approach concerning nutrients.
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EPA encloses a more comprehensive rationale setting forth the details of this determination including the list of individual segments covered by this determination. Please express my appreciation to your staff for their excellent work in compiling this analysis. If you have any questions or concerns, please contact me at (215) 814-1111 or Thomas Henry at (215) 814-5752. Sincerely, /s/ Rebecca W. Hanmer, Director Water Protection Division Enclosure