1. Chesapeake Bay Program Phase 6 Watershed Model Development Update, Key Issues & Recommendations Water Resources Technical Committee Oct. 29, 2015 Presented by Karl Berger, COG; Norm Goulet, NVRC

2. Updates & Key Issues – Model Background – Schedule – Loading Calculations – BMP Changes – Land Use Changes – Other Changes & Additional Data Technical & Policy Issues (key items & implications for COG Region) Recommendations 10/29/2015WRTC Meeting2 Note on slides: all graphics derived from slides originally presented by CBP or USGS Presentation Outline

3. Do not currently use Occoquan watershed monitoring data Modeling Background 10/29/2015WRTC Meeting3 BACKGROUND: Input Monitoring (RIM)Stations

4. 10/29/2015WRTC Meeting4 BACKGROUND: Modeling Framework

5. Key points Running out of time to meet Mid-Point Assessment schedule Some planned features may not make it into this version of the model Ex. Tree canopy land use 10/29/2015WRTC Meeting5 Schedule

6. CREATE THE MODEL REVIEW THE MODEL Expect Changes Nothing Guaranteed USE THE MODEL 10/29/20156 WE ARE HERE SCHEDULE: Phase 6 Progress and Assessment

7. October 2014 – Rough Draft of major changes to nutrient processing in Scenario Builder will need to be complete. Continued sensitivity refinement February 2015 - draft targets for draft land Uses March 2015 – All major partnership decisions are made on changes to scenario builder processing and data. Scenario builder final modifications begin. April 2015 – Final targets approved by Modeling Workgroup for draft land uses Early October 2015 – All inputs are final and delivered to the WSM by the scenario builder team for the final calibration run. Final targets are based on this information. December 2015 -Phase 6 draft model is complete. December 2015 –December 2016 - Evaluation Period, followed by fine tuning during the next year. Key scenarios available September 2016 –Final comments and inputs on the draft Phase 6 model due December 2016 -All models are final. The partnership decision-making process begins to discuss how these new models will be used in the WIP3 process 10/29/2015WRTC Meeting7 SCHEDULE: Model Development Timeline

8. Jan 2016 Climate Change Approach workshop Jan 2016 Conowingo Modeling Approach workshop Feb 2016 Phase 6 watershed model peer review Spring 2016 Uncertainty Approach workshop June 2016 Water Quality Sediment Transport model peer review Summer 2016: Climate Change approach reviewed by STAC 10/29/2015WRTC Meeting8 2016 Work Plan SCHEDULE: STAC Workshops & Third-Party Review

9. Key points Major determinant of sector loads Will include expanded loading sources (e.g., biosolids & septic/onsite systems) Used multiple model approach – as recommended by STAC Importance of SPARROW (SPAtially-Referenced Regression On Watershed attributes), 10/29/2015WRTC Meeting9 Loading Calculations

10. LOADING: Load for a land use in a segment = Estimated Average Load + Sensitivity * ∆ Inputs * BMPs * Watershed Delivery Variance Stream Delivery * * River Delivery Phase 6 Inputs from SPARROW Simulated in HSPF SPARROW for nutrients; USGS for sediments Derived from multiple models, including SPARROW 10/29/2015WRTC Meeting10

11. LOADING: Calibration to Global Targets Global Targets set for land use loading rates of four groups (Crop, Pasture/Hay, Developed, Natural) – Calculated as load/acre at edge-of-small-stream scale Σ loads from four groups set to match average of 1993-2014 monitored loads at RIM stations minus point source loads and six other factors Relative ratios between four groups calculated from average differences of multiple models –SPARROW, WSM Phase 5, CEAP (CEAP not used for developed group) Phase 6 target loads will change as inputs (land use, updated SPARROW) change TN≈ 400 MM Lb/Year, Avg. TP≈ 30 MM Lb/Year, Avg. 10/29/2015WRTC Meeting11

12. LOADING: Global Target Relative Ratios* ** * Numbers to change as land use, SPARROW and other inputs are updated ** Ratios are calculated as an average of values from CEAP, SPARROW and WSM 5.3.2, except only the latter two are used for the Developed target 10/29/2015WRTC Meeting12

13. Land Use TN Loads – Overall Sector Scale* * Numbers to change as land use, SPARROW and other inputs are updated 10/29/2015WRTC Meeting13 LOADING: Overall Sector TN Loads *

14. LOADING: Developed Sector Relative Ratios* * Numbers to change as land use, SPARROW and other inputs are updated 10/29/2015WRTC Meeting14

15. Urban Inputs = atmospheric deposition, fertilizer 10/29/2015WRTC Meeting15 LOADING: From Targets to LRS Loads

16. LOADING: Delivery Factors Watershed Delivery Variance -- simulates how much of nutrients and sediment at the edge of field are delivered to small streams (< 100 cfs) – To be calculated by SPARROW Stream-to-River Delivery Factors -- simulates how much of nutrients and sediment are attenuated in their passage from small order streams to simulated river reaches (> 100 cfs) – To be calculated by SPARROW River Delivery Factors -- simulates how much of the nutrient and sediment loads are attenuated in their passage from modeled river reaches to tidal waters – same as Version 5, done in HSPF Replaces “Regional Factors” 10/29/2015WRTC Meeting16

17. Key points Main factor in determining reduction progress More focus on verification, clean up of BMP history o Credit for BMPs implemented before 2009? BMPs 10/29/2015WRTC Meeting17 BMPs

18. For more details: http://chesapeakestormwater.net/bay-stormwater/urban-stormwater-workgroup/ PanelStatus New State Stormwater Performance StandardsApproved Urban Stormwater Retrofit ProjectsApproved Urban Stream RestorationApproved Urban Nutrient ManagementApproved Illicit Discharge DetectionApproved Enhanced Erosion and Sediment ControlApproved Street SweepingFinal Recommendations Floating Treatment WetlandsOngoing Urban Filter Strips (facilitated by CWP)Approved Shoreline Management (facilitated by CWP)Final Recommendations 10/29/2015WRTC Meeting18 BMPs: New or Revised Urban BMPs

19. Urban Street Sweeping – Final Draft Report released 9/24 – 60 day comment period with initial webinar 9/29 – Presented to USWG - 10/20 – WTWG and WQGIT - TBA Impervious Surface Disconnection – Crediting the disconnection of existing acres of impervious cover through certain engineering and/or field assessment methods evaluated and defined by the expert panel. Initial public meeting – 9/15 10/29/2015WRTC Meeting19 BMPs: Urban Expert Panels

20. Street Cleaning Credit for lane miles swept – Rates for eleven different street cleaning practices, primarily involving the use of different street cleaning technology at different frequencies – No credit for Mechanical broom technology Previous credit for hopper mass being phased out with Phase 6 model. Storm Drain Cleaning Credit, mass collected. http://www.chesapeakebay.net/calendar/event/22425/ 10/29/2015WRTC Meeting20 BMPs: Street Sweeping Credit Changes

21. State drafts submitted to Verification Review Panel mid-July – VA code yellow -- Lacks detail on some of the reporting requirements and how will be verified – MD code yellow – missing documentation on who, when, where and how BMPs will be verified; submitted revised draft – DC code red – no supporting documentation beyond urban BMP database Revised Draft due November 16 th 2016 – 2017 Ramp Up http://www.chesapeakebay.net/about/programs/bmp/additional_resources 10/29/2015WRTC Meeting21 BMPs: Urban Stormwater Verification

22. Key points Significantly more land uses in Phase 6 than Phase 5 Focus on using local and high resolution data to improve accuracy and buy-in by local governments 10/29/2015WRTC Meeting22 Land Use

23. May 2015Complete regional land use dataset using nationally available data: Phase 6 Land Use Database Version 1 Sep 1, 2015Deadline to incorporate local land use/cover data. Submit Version 2 land use to CBP Modeling Team Oct 15 – May 16 Incorporate additional local data and high-res land cover into P6 Land Use Version 3 Jan – Jul 2016Rolling jurisdictional review of P6 Land Use Version 3 and CBPO response to comments Aug 2016Finalization of P6 Land Use Version 3 (1985 – 2014 extent will require backcasting) Sep 1, 2016Submit P6 Land Use Version 3 database to CBP Modeling Team Modeling Team 10/29/2015WRTC Meeting23 WE ARE HERE LAND USE: Development Schedule

24. Version 1 (July 2015) Based on national/regional data Version 2 (October 2015) Incorporates some local land use/cover data Version 3 (August 2016) Incorporates local land use/cover data (Have impervious cover data from 114 counties; tree cover/forest data from 130 counties; developed land/parcel data from 146 counties) Incorporates high-resolution land cover, everywhere 10/29/2015WRTC Meeting24 LAND USE: Development Schedule

25. LAND USE: Phase 6 Overall Types Primary Sectors: Agriculture Developed Natural Overlays: Developed Areas Federal Agency Lands Combined Sewer Overflows (CSS) Municipal Separate Storm Sewer System (MS4) Wastewater Sewer Service Areas 10/29/2015WRTC Meeting25

26. LAND USE: Phase 6 Developed Impervious Surfaces Roads Non-Roads (e.g. buildings) Tree Canopy over Impervious Turf Grass Tree canopy over Herbaceous Construction Excavation* Abandoned Mines Active Mines * no current loading rates for this land use in the model; not clear that it should be part of Developed Land sector 10/29/2015WRTC Meeting26

27. LAND USE: Roads Load Differently 27

28. LAND USE: Tree Canopy Proposed as separate land use by Forestry Workgroup Three Classes Tree canopy over impervious surfaces Tree canopy over urban pervious (turfgrass) -- Proposed relative loading rate reductions of 18.5% for TN, 17% for TP/TSS -- Tree canopy over open space – Still many unresolved issues related to loading and BMP impact – General agreement that canopy in model would be a good thing, but final decision postponed pending more info 10/29/2015WRTC Meeting28

29. Key point New features will drive major changes in loads in some areas How will these load changes be addressed in Phase III WIPs? - TBD 10/29/2015WRTC Meeting29 Other Changes

30. Incorporate new Conowingo dynamics Uncertainty analysis (due in 2016 - ?) Climate Change – will run scenarios incorporating predicted changes in precipitation, temperature and CO2 concentrations Lag time – Groundwater storage for N – Still working on P New approach to P dynamics for ag land uses 10/29/2015WRTC Meeting30 CHANGES: Major New Features

31. Revised architecture – Many new land uses – Some things that were land uses are now BMPs Updated BMP efficiencies New P load methodology (APLE) Use of RUSLE2 for sediment transport 10/29/2015WRTC Meeting31 CHANGES: Agricultural Sector

32. Observation datasets – Model will be calibrated to the most recent water quality data available: 1985 to 2013. Flow Data: 1985 to 2014 WRTDS loads: 1985 to 2012 (no longer using concentration data) – New precipitation dataset Updated air deposition model (CMAQ) Added more reservoirs 10/29/2015WRTC Meeting32 CHANGES: Additional or Updated Data

33. CHANGES: WRTDS TP Yields Out of 30 non-tidal network stations with enough data for trend analysis: 12 are improving 13 are degrading 5 have no discernible change Detailed trends report – Due out December 2015 10/29/2015WRTC Meeting33

34. Discrepancy thought to be due to P storage 10/29/2015WRTC Meeting34 ISSUES: Modeling vs. Monitoring

35. ISSUES: What will be the impact of increased P from Eastern Shore on water quality attainment? Derived from (need USGS report reference here) 10/29/2015WRTC Meeting35

36. Technical Issues Validity of global target approach? Accuracy of model results at different scales? Accuracy of “other” data – point sources, septic systems, land applied biosolids? Continued discrepancies between monitoring and modeling results (although a lot better)? How well will the model backcast BMPs, land use, etc.? Will post-2010 progress numbers make sense? Will updated progress information change Bay-wide and/or Potomac allocation assumptions? 10/29/2015WRTC Meeting36 Technical Issues

37. Policy Issues How much weight will be given to monitoring and modeling information in water quality attainment decisions? How will major changes in Version 6 loads compared to 5.3.2 play out in terms of attainment and allocation decisions? – Conowingo for TN, TP and TSS – Lower Eastern Shore for TP – Will there be shifting baselines for attainment locally? How will the Bay Partnership address major adjustments since 2010 TMDL - Whether due to changes in modeling or actual progress? Does EPA re-open the TMDL? – How would that affect load allocations (by state/by sector/by permit)? Should lagged outputs be weighted differently than non-lagged outputs (e.g. wastewater loads)? Should the Phase III WIPs be based on 2025 forecasted land use? What happens if 2017 targets not met (overall/by sector/by state/basin)? – How/Does that affect the 2025 schedule commitment? – Who has to make up the difference/who’s loads might be affected? 10/29/2015WRTC Meeting37 Policy Issues

38. Active participation & monitoring of critical CBP activities & work group efforts – Continue use of OWML Chain Bridge data set to compare to CBP results – Plan technical workshops to update/inform & seek input from WRTC – Continue to identify key policy issues for CBPC – Continue to provide technical & policy input and reflect the interests of COG’s members – Continue to coordinate with other local govt./utility organizations on common technical & policy issues Propose use of specialized consultant support to review modeling work, as well as use of monitoring & modeling data in attainment decisions [Similar to pre-Bay TMDL work conducted in 2009-2010] – Focus on Watershed Model, Water Quality & Sediment Transport Model, Water Quality Criteria & Attainment framework, and Climate Change assumptions – Organize WRTC focus group to help frame issues for modeling consultant 10/29/2015WRTC Meeting38 Recommendations

39. Extra Slides 10/29/2015WRTC Meeting39

40. Federal segments will be eliminated and replaced with tabular federal land use data County boundaries will be updated with new GIS data New county subdivision will be based on actual precipitation data 100 mm greater or lesser than county mean threshold and minimum 72 sq. km. patch size 10/29/2015 New Segmentation Rules

41. Partnership’s Independent Review Panel Feedback on States’ Draft BMP Verification Plans – August 2015 10/29/2015WRTC Meeting41 BMP Verification Overall

42. Increased time frame expands data from which to calibrate Usable records at more monitoring stations increase scope of calibration Increasing model complexity 10/29/2015WRTC Meeting42 WSM Increases in Data, Complexity

43. http://water.usgs.gov/nawqa/sparrow SPARROW is a USGS modeling tool for the regional interpretation of water-quality monitoring data. The model relates in-stream water- quality measurements to spatially referenced characteristics of watersheds, including contaminant sources and factors influencing terrestrial and aquatic transport. USGS is redoing its Chesapeake Bay- specific version of SPARROW for input into Version 6 of the watershed model. 10/29/2015WRTC Meeting43 What is Sparrow