Commonwealth of Virginia Fecal Coliform Bacteria TMDLs Four Mile Run Public Meeting #1 June 14, 2001

What is A TMDL? Process or plan to attain and maintain water quality standards Consist of 3 basic actions: –identifies sources of pollution –quantifies pollutant loads from each source –quantifies allocations or reductions needed to attain and maintain water quality standards

TMDL Equation TMDL =  WLAs +  LAs + MOS Where: WLA is pollutant load allocated to all point sources. LA is pollutant load allocated to all nonpoint sources. MOS is the margin of safety to account for uncertainity in calculations.

TMDLs and Standards TMDLs have put spotlight on Virginia’s WQ standards. Bacteria issues –application to stream –wildlife –all waters designated and protected for primary contact swimming use.

Application of Virginia’s Fecal Coliform Standard geometric mean* or more samples every 30 days instantaneous* at any time 0 violation rate * colonies / 100 ml

Application of Virginia’s Bacteria Standard One criterion, never both, applies to a data set 303(d) assessment –Use instantaneous 1000 and EPA’s 10% violation rate TMDLs –TMDL based on geometric mean of 200 –impossible to meet instantaneous 1000

Public Response to Bacteria TMDLs Public wants good information on source identification –Performing bacteria source tracking (BST) studies on all fecal coliform TMDLs Public is concerned about primary contact (beach) protection for all waters –Limited access & minimal stream depth

Four Mile Run BST Study “Wildlife” - 56% Human, canines, other - 44% TMDL must address human and other anthropogenic sources Will water quality standards be attained if all anthropogenic contributions are removed?

Wildlife and Bacteria Standard In some other TMDLs, bacteria source tracking and wildlife densities show significant contributions by wildlife –critical conditions occur during base flow –water quality is not attained with 100% removal of human related pollutants Public has expressed concerns –staged targets in TMDL –standards change may impact TMDL?

TMDL Allocation Scenario Percent reductions Percent Violation of Standard Upland Areas Livestock in Stream Wildlife in Stream Scenario

Bacteria Indicator Change for Protection of Swimming Use All of Virginia’s waters designated and protected for primary contact swimming use –EPA proposing “ 4 levels” of use EPA believes there are better indicators than fecal coliform for human health protection Virginia is proposing changing to –E. coli for freshwater –Enterococci for marine water

EPA’s New Swimming Use and Bacteria Criteria*

Preliminary Evaluation of Impact 100 Stations N = 336

TMDL Impacts TMDLs to be adopted by SWCB as regulations VPDES must be consistent with TMDLs EPA HQ developing TMDL / MS4 guidance –case-by-case decision –TMDL to include numeric limits if practical, or BMPs if impractical –DEQ to include only BMPs in TMDLs