Chesapeake Bay Program Reevaluation Technical Workgroup Conference Call February 7, 2008 SUMMARY OF DECISIONS, ACTIONS AND ISSUES Review of Agenda Rich Batiuk, EPA CBPO, facilitated this conference call in place of Sue McDowell. The objectives of this call were to: 1) Reach agreement on next steps for developing procedures for assessing Bay criteria attainment using Bay WQ/sediment transport model outputs. 2) Reach agreement on the schedule/next steps for determining the Bay watershed model hydrologic period and supporting decision criteria. 3) Reach agreement on the schedule of topics for workgroup discussion and decision making leading up to the March 26-27 WQSC meeting. *All presentations and handouts for this conference call can be accessed at: http://www.chesapeakebav.net/calendar.cfm?EventDetails=9356&DefaultView=2 Assessing Bay Water Quality/Sediment Transport Model Output for Bay Water Quality Criteria Attainment Jeni Keisman presented an overview of the Chesapeake Bay criteria assessment procedures (PowerPoint presentation). ¦ The Chesapeake Bay Program Office data analyst has performed dissolved oxygen (DO) criteria assessment for all partners (DC, DE, MD, VA) recently in support of the jurisdictions' 2008 303(d) lists. ¦ Currently, EPA and states assess the 30-day mean DO criterion for open water and deep water designated uses, and the instantaneous criterion for the deep channel designated use. ¦ See Attachment B for the full set of published Chesapeake Bay dissolved oxygen criteria. ¦ The EPA published dissolved oxygen criteria attainment assessment methodology and results have been accepted by all Bay Program partners. See the PowerPoint presentation for an overview of the DO procedures. ¦ For the 2008 listing cycle, DO impaired water results were delivered to the partners at the end of November 2007. The excel spreadsheet on slide 10 of the presentation is an example of assessment results what the partners received. Gary Shenk presented a briefing on the 2001-2003 Bay criteria assessments using Bay model outputs. His presentation was entitled "Combining Monitoring and Modeling to Determine Criteria Achievement Under Management Scenarios" (PowerPoint presentation). ¦ In 2002, the Water Quality Steering Committee (WQSC) approved a methodology for assessing Bay water quality model output for Bay water quality ------- criteria attainment for application during the 2001-2003 development of the basinwide and jurisdictional tributary basin cap load allocations. ¦ The 2002 approved procedures involved using model simulated outputs to transform Bay monitoring program data. ¦ Since 2003, there have been a few changes to both the models and the details of criteria attainment assessment procedures. These changes include new modeling tools (54,000 cell Bay water quality/sediment transport model vs. 13,000 cell Bay water quality model), upgraded criteria assessment methods, and different criteria attainment assessment averaging periods. ¦ For the averaging period in 2003, a 1985-1994 10-year CFD was used. For application in the Bay TMDL, Gary recommended that a 3-year CFD be used to directly match with the criteria assessment procedures now adopted into all four jurisdictions' Chesapeake Bay water quality standards regulations. ¦ The 3-year assessment periods would apply to both the DO and water clarity criteria, but not in the same way to the assessment of the SAV restoration acreage criteria which are assessed based on the single best year of three years. ¦ The Technical Workgroup reviewed the list of issues that is found on page two of Attachment A. These issues need to be resolved in order to position the partners to be able to assess attainment of the full suite of Chesapeake Bay water quality criteria now adopted into the states' water quality standards regulations using outputs from the new Chesapeake Bay water quality/sediment transport model. ISSUE: If a 3-year CFD is used, a decision will have to be made on whether a single 3- year period is used (best, average, or worst) or whether all 3-year periods in the modeling hydrologic period are used (all meet standards, most meet standards, or at least one meets standards). ISSUE: Should the most current 3-year period be used, to the extent possible, so that it is closer to where we are now? ACTION: The Chesapeake Bay Program's Modeling Subcommittee and the Monitoring Subcommittee be brought in to review these issues when appropriate. DECISION: The Re-evaluation Technical Workgroup agreed that the full suite of issues to be addressed has been documented within Attachment A. DECISION: The Re-evaluation Technical Workgroup agreed to the proposed schedule and overall approach laid out in Attachment A for how the partners should proceed from here to resolve the full list of issues and reach partner consensus. Selection of the Hydrologic Period for Running Phase 5 Watershed Model Management Scenarios Gary Shenk gave a presentation entitled "Evaluation of Hydrologic Periods for the Reevaluation" (PowerPoint presentation). Attachment C provides additional information on this topic. 2 ------- ¦ The WQSC needs to decide on the ten-year period of annual hydrologies that will be used to run all future Phase 5 watershed model and Bay water quality/sediment transport model management scenarios. ¦ During today's call, the workgroup reviewed the initial evaluation of possible hydrologic periods, including initial findings and possible decision criteria. ¦ Possible criteria include: Continuity (1985-1994) Most recent (1996-2005) Overlap Bay Model calibration (1993-2000) - Encompass best and worst conditions ¦ Another option would be to use a separate representative time period that included high, low, and average years. ¦ Additional actions that were previously requested by the WQSC include an evaluation of the effects of removing extreme events, an examination of major tributaries rather than the Bay as a whole, and a check of the mean and variances for the 1984-2005 period vs the 1930s to the present. RECOMMENDATIONS: Technical Workgroup members contributed the following additional recommendations for consideration in selecting the hydrologic period: o Include a graph of average annual flows over the full record of flows, o Build in an assessment hydrologic variability. o Provide the River Input Monitoring stations' loads and flow estimates over the period of record, o Keep the focus on hydrologic variability, not changes in water quality conditions over time, o Include an assessment of average annual flows over the period of record, o Try and ensure the selected 10-year period is representative of a set of years that capture key seasonality events and critical periods—two key TMDL requirements. ACTION: The CBPO Modeling Team will work through these issues and requests during the next two months. Refined outputs will be presented to the Re-evaluation Technical Workgroup at their March 6th conference call. DECISION: The Re-evaluation Technical Workgroup agreed to proceed forward with the recommended schedule as laid out in Attachment C. Preparation for the March 26-27 Water Quality Steering Committee Meeting Rich Batiuk led a discussion on what issues need to be addressed by Re-evaluation Technical Workgroup in order to prepare for the March 26-27 WQSC Meeting. ¦ There are five specific sets of issues that the Technical Workgroup scheduled itself to discuss and work towards resolution during the winter-spring 2008 timeframe: Scope of the Bay TMDL 2008-2011 Bay TMDL timeline and schedule 3 ------- Addressing the margin of safety - Watershed model hydrologic period for running management scenarios Allocation to sources—wastewater component ¦ These issues, along with the options and the Technical Workgroup's recommendation(s), are scheduled to be presented at the March WQSC meeting. ¦ A schedule outlining the topics to be discussed at each of the upcoming workgroup conference calls is proposed in Attachment D. The objective is to have the workgroup discuss each of the aforementioned issues and reach consensus on recommendations prior to the WQSC's March meeting. REQUEST: Pennsylvania requested that the February 21st Technical Workgroup conference call be rescheduled since it conflicts with an Implementation Committee conference call. DECISION: The Re-evaluation Technical Workgroup agreed to address these different issues and topics following the recommended schedule as laid out in Attachment D. Participants Rich Batiuk EPA CBPO Sally Bradley CRC/CBPO Francoi se Brai ser EPA HQ Bill Brown PA DEP Pat Buckley PA DEP Arthur Butt VADEQ Monir Chowdhury DDOE Chris Day EPA Region 3 Dinorah Dalmasy MDE Ron Entringer NY DEC Mike Haire EPA HQ Jeni Kesiman UMCES Robert Koroncai EPA Lewis Linker EPA CBPO Felix Locicero EPA Region 2 Hassan Mirsajadi DEDNREC Dave Montali WV DEP Kenn Pattison PA DEP Russ Perkinson VADCR Ed Reilly NY DEC Gary Shenk EPA CBPO Tom Thornton MDE batiuk.richard@epa.gov sbradlev@chesapeakebav.net brai ser. francoi se@epa. gov willbrown@state.pa.us pbucklev@state.pa.us aibutt@deq.virginia.gov monir.chowdhury@dc.gov dav.christopher@epa.gov ddalmasv@mde. state, md. us raentrin@ gw. dec. state. ny. us haire.michael@epa.gov ikeisman@chesapeakebav.net koroncai. robert@epa. gov LLinker@chesapeakebav.net locicero.felix@epa.gov has san. mir sai adi @ state. de. us dmontali@wvdep. org kpattison@state.pa.us russ.perkinson@dcr.virginia.gov exreilly@gw.dec. state, ny. us GShenk@chesapeakebav.net tthornton@mde. state.md.us 4 ------- |