1. Chesapeake Bay TMDL Primer: Chesapeake Bay Watershed and Bay Water Quality Models The Economics of Water Quality Improvements in Chesapeake Bay Workshop October 31 and November 1, 2011 Rich Batiuk, Associate Director for Science Chesapeake Bay Program Office U.S. Environmental Protection Agency Region 3

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4. 4 Can you say m_o_d_e_l?

5. 5 VERY GOOD!

6. Chesapeake Bay Airshed ModelChesapeake Bay Land Change Model Chesapeake Bay Watershed Model Chesapeake Bay Water Quality and Sediment Transport Model Chesapeake Bay Filter Feeder Model Chesapeake Bay Scenario Builder

7. For Our Beloved Economists… Access to suite of state of science, fully independent scientifically peer reviewed, fully documented models and tools available NO WHERE else for a single great waterbody Access to two+ decades of input data and model scenario outputs Model outputs stated in management applicable terms—pounds of pollution delivered to impaired waters, percentage of water quality standards attainment, etc. 7

8. Role of the Bay Models In Decision-Making

9. For Our Beloved Economists… Access to decision making processes developed and blessed by the partnership 1 –Water criteria attainment assessment –Load allocations to major river basin by jurisdiction –3 year critical period, etc. Where applicable, computer programming available to apply the agreed to decision making process All decision making processes fully documented within the Bay TMDL document 9 1. Ok, so NY told us otherwise on the allocation methodology….

10. 10 Farmland and Forest Land Loss (2000 to 2030) Source: Chesapeake Bay Land Change Model Version 3

11. For Our Beloved Economists Extent of development by county and modeling segment Fraction of development impacting farmland and forest lands Fraction of future population on sewer and septic systems Changes in land uses for input into watershed model 11

12. 12 Scenario Builder

13. For Our Beloved Economists… Access to the full suite of data, inputs, conservation practices, BMPs,….ok go back to the previous slide and pick your favorite data, application rate, and its yours! 13

14. 14 Calibration sites = 296 Land Segments = 308 River Segments= 1,063 Land uses = 25 Simulation Years = 21 (’85-’05) Phase 5 Calibration Sites Phase 5 Chesapeake Bay Watershed Model Phase 5 Segmentation

15. 15 Annual, monthly, or daily values of anthropogenic factors: Land Use Acreage BMPs Fertilizer Manure Tillage Crop types Atmospheric deposition Waste water treatment Septic loads Hourly or daily values of Meteorological factors: Precipitation Temperature Evapotranspiration Wind Solar Radiation Dew point Cloud Cover Daily flow, nitrogen, phosphorus, and sediment compared to observations over 21 years How the Watershed Model Works HSPF

16. 16 Each segment consists of 25 separately-modeled land uses: Developed –High Density Pervious Urban –High Density Impervious Urban –Low Density Pervious Urban –Low Density Impervious Urban –Construction –Extractive –Combined Sewer System Natural –Wooded / Open –Disturbed Forest Agriculture –Corn/Soy/Wheat rotation –Other Row Crops –Hay –Alfalfa –Pasture –Livestock production –Nursery –Plus specialized versions of the above for a total of 15 agricultural land uses Plus: Point Source and Septic Loads, and Atmospheric Deposition Loads How the Watershed Model Works

17. 17 Precipitation Fertilizer Manure Atmospheric deposition Runoff How the Watershed Model Works Hydrology submodel Management filter River Sediment submodel Phosphorus submodel Nitrogen submodel } hourly

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19. For Our Beloved Economists… Access to the nitrogen, phosphorus, and sediment loads –End of stream –Delivered to the Bay –Yield (pounds/area) –Model segment, county, major river basin, jurisdiction and basinwide scales BMPs—acreages, linear feet, animal units Practice efficiency/effectiveness measures 19

20. 20 Bay Water Quality Model 57,000 cells Predicts changes in water quality due to changes in nitrogen, phosphorus, and sediment loads –Dissolved Oxygen –Water clarity –Chlorophyll a Also simulates algae, underwater Bay grasses, bottom dwelling worms and clams, Linked with filter feeders (oysters, menhaden) model Developed by scientists at the US Army Corps of Engineers, University of Maryland, Virginia Institute of Marine Science, HydroQual, Versar, and Rutgers University

21. Bay Dissolved Oxygen Criteria Minimum Amount of Oxygen (mg/L) Needed to Survive by Species Migratory Fish Spawning & Nursery Areas Hard Clams: 5 Striped Bass: 5-6 Worms: 1 Shallow and Open Water Areas Deep Water Deep Channel 6 5 3 2 1 4 0 Crabs: 3 Spot: 2 White Perch: 5 American Shad: 5 Yellow Perch: 5 Alewife: 3.6 Bay Anchovy: 3

22. 22 Scenario→ 2010 No Action N-Based Scenario 371 TN, 37.6 TP, 10630TSS '91 -'00 Base Scenario 318 TN, 20.3 TP, 9440 TSS 2007 Scenario 269 TN, 19.5 TP, 8770 TSS 2009 Scenario 262TN, 18.8 TP, 8510 TSS 200 Scoping Scenario 200 TN, 14.7 TP, 6810 TSS 196 Scoping Scenario 196TN, 14.9TP 6680 TSS 195 Scoping Scenario 195 TN, 14.8 TP, 6660 TSS 194 Scoping Scenario 194 TN, 14.7 TP, 6640 TSS 193 Scoping Scenario 193 TN, 14.6 TP, 6610 TSS 192 Scoping Scenario 192 TN, 14.6 TP, 6590 TSS 191 Scoping Scenario 191 TN, 14.5 TP, 6570 TSS Year →'93-'95 CbsegState DO Deep Water CB3MHMD4%2% 0% CB4MHMD27%20%17%16%6%5% CB5MHboth6%4%3% 1% 0% CB6PHVA1%0% CB7PHVA0% CHSMHMD34%26%21%19%0% EASMHMD34%6%4% 1% MAGMHMD51% 43%17% MD5MHMD12%9%7% 2% 1% PATMHMD26%13%11% 0% PAXMHMD23%7%4%3%0% POMMHMD8%4%2% 0% POTMHboth8%4%2% 0% RPPMHVA13%6%3%1%0% SBEMHVA5%0% SEVMHMD19%6% 0% SOUMHMD36%19% 0% VA5MHVA1%0% YRKPHVA0%

23. Bay Water Quality Model Results

24. For Our Beloved Economists… Model simulated water quality standards attainment values for each unique designated use segment –Dissolved oxygen –SAV acreage –Water clarity –Chlorophyll a (tidal James, DC waters only) Estimates of pollutant load reductions on ecosystem processes e.g., filter feeding Relationships between pounds reduced and water quality standards attainment 24

25. 25 Allocations Based on Relative Effect of a Pound of Pollution on Bay WQ

26. For Our Beloved Economists… Access to ‘water quality impact per pound of pollution’ information for any location within the watershed and any of the 92 tidal Bay segments Tool that illustrates ‘relative effect’ of each basin on each of the 92 segments Essentially provides a common currency— relative effect on dissolved oxygen per pound of pollutant reduced across the entire watershed 26

27. 27 Developing a Bay Pollution Diet in Six Easy Steps Step 1: Quantify per pound impact on Bay water quality. Step 2: Array major river basins by jurisdiction by their relative impact on Bay water quality. Step 3. Determine allocation for the major river basins and jurisdictions by applying the agreed to allocation methodology. Step 4: Jurisdictions further allocate to 92 segment watersheds. Step 5: Jurisdictions allocate to sources.

28. 28 Developing a Bay Pollution Diet in Six Easy Steps Step 1: Quantify per pound impact on Bay water quality. Step 2: Array major river basins by jurisdiction by their relative impact on Bay water quality. Step 3. Determine allocation for the major river basins and jurisdictions by applying the agreed to allocation methodology. Step 4: Jurisdictions further allocate to 92 segment watersheds. Step 5: Jurisdictions allocate to sources. Step 6. EPA based the TMDL allocations on jurisdictions’ WIPs, with adjustments as needed for reasonable assurance.

29. For Our Beloved Economists… Access to a comprehensive load allocation methodology that formed the basis for the December 2010 Bay TMDL Incorporation of ‘reasonable assurance’ into the final allocations, again, following a documented evaluation process Allocation process is completely scalable….can be applied at the basinwide down to the county or small watershed scales 29

30. Rich Batiuk Associate Director for Science U.S. Environmental Protection Agency Chesapeake Bay Program Office 410-267-5731 batiuk.richard@epa.gov www.chesapeakebay.net