1. Progress in Implementing the EPA WASP Model for Narragansett Bay 1 Lucner Charlestra 1, Edward Dettmann 2 1 Postdoc., USEPA, Atlantic Ecology Div., charlestra.lucner@epa.gov 2 USEPA, Atlantic Ecology Div., dettmann.edward@epa.gov CHRP-EPA Modeling Workshop July 7, 2015

2. Presentation Outline Introduction Linkage between hydrodynamic and water quality models WASP input data Simulation results Summary/Discussion 2

3. Introduction  Acknowledgments:  Bob Ambrose, Tim Wool, Chris Knights, Jim Hagy  Mohamed Abdelrhman, Jason Grear, Hal Walker, Brenda Rashleigh  EPA and CHRP models differ in approach  Model segmentation scheme  Time step  Equation formulation  Our model includes organic as well as inorganic N and P 3

4. Model Linkage 4

5. 5 Linkage between Hydrodynamic and Water Quality Models EFDC Hyd File WASP Environmental Fluid Dynamics Code (EFDC) provides hydrodynamics, temperature, salinity EFDC output is stored for use by WASP WASP calculates water quality using EFDC output and biochemical kinetics

6. Model Grid 6 WASP Model Domain: 661 segments per layer 8 Water column layers (sigma grid) 5288 segments total Segment size is variable Typical segment size: 640 m east-west 1220 m north-south EFDC only

7. Model State Variables 7 Ammonia Nitrogen (mg N L -1 )Detrital Phosphorus (mg-P L -1 ) Nitrate Nitrogen (mg N L -1 )Detrital Silica (mg Si L -1 ) Dissolved Organic Nitrogen (mg N L -1 )Total Detritus (mg DW L -1 ) Inorganic Phosphate (mg P L -1 )Salinity (ppt) Dissolved Organic Phosphorus (mg-P L -1 )Benthic Algae (g DW m -2 ) Inorganic Silica (mg Si L -1 )Periphyton Cell Quota Nitrogen (mg N gDW -1 ) Dissolved Organic Silica (mg Si L -1 )Periphyton Cell Quota Phosphorus (mg P gDW -1 ) CBOD1 (ultimate) (mg O 2 L -1 )Inorganic Solids 1 (mg DW L -1 ) CBOD2 (ultimate) (mg O 2 L -1 )Inorganic Solids 2 (mg DW L -1 ) CBOD3 (ultimate) (mg O 2 L -1 )Inorganic Solids 3 (mg DW L -1 ) Dissolved Oxygen (mg O 2 L -1 ) Phytoplankton 1 (  g Chl a L -1 ) Detrital Carbon (mg C L -1 ) Phytoplankton 2 (  g Chl a L -1 ) Detrital Nitrogen (mg N L -1 )Phytoplankton 3 (  g Chl a L -1 )

8. Data Sources Tributaries Wastewater Treatment Facilities Solar Radiation Atmospheric Deposition Kinetic Parameters Benthic Fluxes (SOD and Nutrients) 8

9. NBC Tributary Monitoring Stations Nutrient monitoring 1 or 2 x per month USGS flows adjusted to account for ungauged flows Adjusted flows used to calculate loads Interpolate loads between monitoring dates 9

10. Nutrient Loads from WWTFs 10 Nixon et al. (1995) Fields Point, Bucklin Point: Monitored 3 X per week Other 9 WWTFs: Monthly data only

11. Nutrient Loads from WWTFs (cont.) Except for Bucklin and Fields Point Plants, loads calculated as product of monthly “average” concentrations and flows. Mass. plants had only 12-month running mean flows NH 3 sometimes had to be estimated from TKN NO 2 added to NO 3 Total P only monitored. DIP was estimated as 0.8 TP Si not monitored 11

12. Seaward Boundary 12 J. Krumholz (pers. comm.) Data for Krumholz Station #3 used for nutrients at seaward boundary Data are nominally monthly, but some months are missing Data are available only for the surface layer

13. Solar Radiation 13 Solar Radiation at T.F. Green Airport No locally measured solar radiation for Narragansett Bay for 2009, so used modeled data (National Solar Radiation Data Base) that has same statistical distribution as the local site.

14. Atmospheric Deposition and Kinetic Constants Atmospheric deposition (NH 3, NO 3, ORGN, DIP, ORGP, CBOD) calculated using data from the literature (Nixon et al., 1995; Luo et al.,2002; Bowen and Valiela, 2001; Yang et al., 1996; Nixon et al., 1995; Chen et al., 1985; Jurado et al., 2008) Kinetic constants (typical values) from published studies and WASP documentation (Kremer and Nixon, 1978; Wang et al., 1999,(Ambrose and Wool, (undated) 14

15. Sediment Oxygen Demand 15 SOD based on Fulweiler and Nixon (2010)

16. Benthic Nutrient Fluxes Data on nutrient flux rates, including temperature dependence, from a variety of sources:  Lindsey Fields (pers. comm.)  Fulweiler and Nixon (2010)  Kremer and Nixon (1978) 16

17. Simulation Results 17

18. Dissolved oxygen 18 Conimicut Pt., near surface Conimicut Pt., bottom Tributaries & effluents  all 8 layers

19. Total Nitrogen 19 Conimicut Pt. Gould I. Tributaries & effluents  all 8 layers

20. Total Nitrogen (longitudinal gradient) 20 Fields Pt. Bullock R. Conimicut. Warwick Pt. Hope I. N. J’town Fields Pt.. Bullock R. Conimicut. Poppasquash Gould I. East Passage, Fields Pt.  Gould I. West Passage, Fields pt.  N. Jamestown Tribs. & effluents  all 8 layers

21. Chlorophyll a 21 Mount View, near surface Conimicut Pt., near surface Tributaries & effluents  top 2 layers

22. Summary/Discussion 1 Simulation Results:  At present, we’re simulating one phytoplankton group  Model does better at simulating seasonal patterns of DO and chl a than short-term dynamics o This is likely caused, at least in part, by low frequency of boundary data, and surrogate solar radiation data  Simulation of seasonal chl a trends is getting close, but needs more work  Simulation of seasonal DO trends (surface and bottom) is getting close, but needs more work  Simulated longitudinal TN gradients look promising 22

23. Summary/Discussion 2 Status of Database:  Database for some variables is pretty good: e.g. DO, Chl a, salinity, temperature  Database for in-estuary nutrients is sparse, especially below Providence River: surface only through 2010, less after that  Only TP measured in WWTFs, silica essentially not at all  Except for Narragansett Bay Commission Plants, data for nutrients are sketchy  No solar radiation measurements on the Bay after 2008 23

24. Where do we go from here?  Continue exploring effects of nonuniform vertical distribution of WWTF and tributary inputs  We’re improving treatment of benthic nutrient fluxes  Consider phytoplankton metabolism  Continue calibration of kinetic parameters 24

25. Slides for possible discussion follow 25

26. Periphyton Biomass D : C : N : P : Chl IP IN Phytoplankton Biomass Group 3 D : C : N : P : Si: Chl DO Group 2 D : C : N : P : Si: Chl Group 1 D : C : N : P : Si : Chl TIC H 2 CO 3 – HCO 3 - – CO 3 2 - Total Alkalinity Particulate Detrital OM Si PNC D Dissolved OM Si P N CBOD 1 CBOD 2 CBOD 3 Inorganic Nutrients NO 3 PO 4 SiO 2 NH 4 pH atmosphere uptake excretion uptake excretion Inorganic Solids S3S3 S1S1 S2S2 oxidation nitrification photosynthesis and respiration death dissolution mineralization sorption reaeration 26 State Variables and Processes

27. DON and DIN in Narragansett Bay Baywide and segment-specific mean DON and DIN concentrations and DON/DIN ratios in Narragansett Bay in SINBADD Cruises (1985-1986)*. *Pilson, M.E.Q. and C.D. Hunt. 1989. Water quality survey of Narragansett Bay: A summary of results from the SINBADD 1985-1986. Marine Ecosystems Research Laboratory. GSO, URI: 124 pp. Available as Report NBEP-89-22 at http://www.nbep.org/publications.html. http://www.nbep.org/publications.html 27

28. DON usage by Bacteria & Flagellates 28 Fraction of DON used by bacteria & heterotrophic flagellates over 8-15 days, by source and season (Seitzinger and Sanders 1997)*. *Seitzinger, S.P. and R.W. Sanders. Contribution of dissolved organic nitrogen from rivers to estuarine eutrophication. Marine Ecology Progress Series 159: 1-12.

29. Fraction of DON Used by Bacteria and Phytoplankton Fraction of DON used over 10 – 12 days, by source (Seitzinger et al. 2002)*. *Seitzinger, S.P., R.W. Sanders, and R. Styles, Bioavailability of DON from natural and anthropogenic sources to estuarine plankton. Limnology and Oceanography 47(2):353-366. 29