1. Chesapeake Bay Program Decision Support System Management Actions Watershed Model Bay Model Criteria Assessment Procedures Effects Allocations Airshed Model Land Use Change Model COAST

2. Annual or Monthly: Land Use Acreage BMPs Fertilizer Manure Atmospheric Deposition Point Sources Septic Loads Hourly Values: Rainfall Snowfall Temperature Evapotranspiration Wind Solar Radiation Dewpoint Cloud Cover Daily output compared To observations Quick overview of watershed model Calibration HSPF

3. Each segment consists of separately-modeled land uses High Density Pervious Urban High Density Impervious Urban Low Density Pervious Urban Low Density Impervious Urban Construction Extractive Wooded Disturbed Forest Corn/Soy/Wheat rotation (high till) Corn/Soy/Wheat rotation (low till) Other Crops Alfalfa Nursery Pasture Degraded Riparian Pasture Animal Feeding Operations Fertilized Hay Unfertilized Hay –Nutrient management versions of the above Plus Point Source and Septic Each calibrated to nutrient and Sediment targets

4. Land Use Source Ultimate Source WSM Uses: Divide Load into contributing areas and sources

5. From the Chesapeake Bay Commission Report: Cost-Effective Strategies for the Bay December, 2004 WSM Uses: Determine Effective Practices

6. WSM Uses: Track Implementation Progress

8. Cap Load Allocation

9. WSM Uses: Estimate annual loads below monitoring stations Roughly 25% of the total load is unmonitored

10. 2003 Decision: Reduce annual loads to 175 million lbs TN and 12.8 million lbs TP

11. Phase 4 Phase 5 Development Phase 5

12. Large Community of Developers Maryland Department of the Environment Virginia Department of Conservation and Recreation Developers EPA U of Maryland USGS NRCS Chesapeake Research Consortium Virginia Tech Interstate Commission on the Potomac River Basin Chesapeake Bay Program Advisors and data suppliers State Governments of NY, PA, MD, DE, VA, WV, DC Scientific and Technical Advisory Committee USGS $ $ $

13. Phase 4.3 CalibrationPhase 5 Calibration Calibration sites = 20 Land Segments = 94 River Segments = 94 Land uses = 9 Simulation Years = 10 Calibration sites = 296 Land Segments = 308 River Segments= 1,063 Land uses = 25 Simulation Years = 20 Fine Segmentation

14. ETM Functionality Greater Accuracy: –Time Varying Land Use –Time Varying BMPs –BMP efficiency reacting to hydrologic condition –Design life of BMPs –Sub-grid effects (differential land-to-river transport) Easier Data Handling –Easily allows large-scale parameter adjustments during calibration –Parallel computing operations convenient –Easy to add new land use types –Easily integrated into outside databases for scenarios –Relatively easy to add new WQ constituents (bacteria) Additional CBPO-coded features allow: Flexible Functionality

15. Better, extended, and finer scale data sets High Resolution Input Data Land Use Acreage BMPs Fertilizer Manure Atmospheric Deposition Point Sources Septic Loads Rainfall Snowfall Temperature Evapotranspiration Wind Solar Radiation Dewpoint Cloud Cover Simulation period is 1984-2005: Two decades of meteorology and watershed management data

16. Open-Source Model Entire model available on web Already in Use –Climate Change Study –Community model at ICPRB –Potomac PCB TMDL –MDE TMDLs –USGS Factors Affecting Trends –USGS Shenandoah Models –Academic studies –UNC / Baltimore LTER study –60-year ‘Tipping point’ investigation Transferability

17. User-Friendliness

18. Ensures even treatment across jurisdictions Fully documented calibration strategy Repeatable Makes Calibration Feasible Enables uncertainty analysis Automated Calibration

19. Chesapeake Bay Program Decision Support System Management Actions Watershed Model Bay Model Criteria Assessment Procedures Effects Allocations Airshed Model Land Use Change Model COAST

20. Nitrogen Pollution and Cost

21. Non-attaining water vs annual cost Tier3 Tier2 Tier1

22. Difficult Consensus Tier3 Drastic Option

23. Estuarine model used to determine basins with highest effect on DO Increasing effect of each pound of reduction 

24. Effect of Geographic Targeting Tier3 Drastic Option Efficient Option

25. Watershed States Responsibility Nitrogen-Phosphorus-Sediment Load Allocation Process By 9 major river basins...then by 20 major tributary basins by jurisdiction …then by 44 state- defined tributary strategy subbasins Watershed Partners Responsibility Watershed States Responsibility