Coupled Hydrodynamic and Water Quality Modeling of Florida Bay

Coupled Hydrodynamic and Water Quality Modeling of Florida Bay John Hamrick Tetra Tech Jeff Ji AEE Florida Bay Science Conference December 10, 2008

Acknowledgement This work was funded by the South Florida Water Management District and benefited from the collaboration with numerous members of the Florida Bay scientific community

Outline Background Review of the Hydrodynamic Model Water Quality Modeling Approach Water Quality Data Set and Model Configuration Significant WQ Modeling Issues Water Quality Model Results Summary Future Directions

Background Proof of Concept Study Using EFDC Model: 2002 Focused on Freshwater Inflow Presented at Tampa FBS 2003? Grid Resolution Analysis: 2003 Technical Review Jan 2004 Hydrodynamic Model Calibration: 2004 Technical Review October 2005 Presented at 2005 FBS Water Quality Model Development: 2006 Workshop Jan 2007

A Model Includes The Code Representing a Space-Time Approximation of Physics and Biogeochemical Processes The Input Domain Representation including Bathymetry and Topography Boundary Conditions and Forcing Functions Process Parameters The Modeler Ability to Manipulate the Input and Use the Code to Achieve an Acceptable Approximation of Reality and Identify What is Missing and/or Uncertain

Hydrodynamic and Salinity Model EFDC Based Multiple Levels of Grid Resolution 1996-2002 Historical Simulation Period Iterative Two-Way Coupling to TIME Model Demonstrated One-Way Coupling to HYCOM Model Calibrated to Water Surface Elevation, Currents, Temperature and Salinity Used to Evaluate Salinity Response to CERP Inflow Distribution Alternatives Used to Provide Physical Transport for WQ Model

Medium Resolution Grid with Wetlands

Medium Resolution Grid Nominal Coastline Version

Hydrodynamic Model: Water Surface Elevation Calibration Model and Predicted Harmonic Amplitudes Agree Well At Stations Which Are Not Strongly Influenced by Local Effects (Banks, etc) The Model Reproduces Observed Low Frequency Sea Level Variability In Central and Eastern Florida Bay Low Frequency Sea Level Forcing on Boundary Propagates with Little Attenuation to Eastern Bay Eastern Bay Response Indicates Local Wind Forcing Also Contributes to Variability Configuration with NE Wetlands Captures Some Observed Events Better Than Nominal Coastline Configuration

Zoom In of Observed and Predicted Low- Frequency Sea Level at Trout Cove

Hydrodynamic Model: Current Meter Calibration Model Reproduces Tidal Frequency Current Magnitudes, Phases and Angles Reasonably Well Model Reproduces NW-SE Low Frequency Current on SW Shelf Well Low Frequency Current Prediction Along 81d05m Needs Improvement and Could Benefit from Additional Bathymetric Data Over Eastern Banks Additional Low Frequency Current Meter Comparisons Were Made

1997-1998 North LF Current NOAA A 1999-2000

Hydrodynamic Model: Temperature Calibration Model Temperature Prediction Is Very Good at 12 of 14 Stations with Normalized RMS Error Less Than 5 % for Nominal and Wetland Configurations The 2 Stations with Over Prediction Have Normalized Errors of Less Than 13 % Over Prediction at These Station Is Due to Shallow Depth A Bed Thermal Layer Will Be Used to Improve These and Over Shallow Water Cells Evaporation Is Dynamically Predicted

Hydrodynamic Model: Salinity Calibration Two-Way Iterative Coupling with TIME Model Is Critical Nominal Coastline Currently Performs Better Than Wetlands Configuration Wetlands Configuration Does Not Include Surface- Ground Water Volume and Salinity Exchange Representation of Button Wood Embankment Can Be Refined Model Predicts Hyper-Salinity Hyper-Salinity Predicted Very Well at Garfield, Terrapin and Whipray Over Prediction at Johnson, Little Rabbit and Murray Refinement Could Address Basin Residence Time and Evaporation Prediction

Whipray Basin Salinity

Calibration and Performance Measures What Measures Good Performance? Comparison of Observed and Predicted Means and Standard Deviations Mean Absolute Error and Normalized MAE Most Widely Used Error for WQ Models Root Mean Square Errors Index of Agreement, A Normalized RMS Error with 0<COI<1 Compare with Results for Other Water Bodies

Index of Agreement Skill Parameter IA = 1 M m= 1 n= 1 M N ( O P ) mn, mn, m= 1 n= 1 N ( ) P O + O O mn, mn, 0 IA 1 2 2

Florida Bay Salinity Calibration Compared with Chesapeake Bay Index of Agreement, A Normalized RMS Error with 0<COI<1 Li, Zhong, & Boicourt Chesapeake Bay Reported Range of 0.46 to 0.96 with a Mean of 0.76 (Monitoring Observations) Florida Bay Range 0.57 to 0.88 with a Mean of 0.79 for Continuous ENP Observations Florida Bay Range 0.58 to 0.85 with a Mean of 0.71 for FIU Monitoring (Shelf and Straits Excluded)

Water Quality Modeling Approach Builds on the Previous WQ Modeling Study COE CE-QUAL-ICM WQ Model 30 Day RMA10 Hydrodynamics Recycled 2 Year Model Simulations Current EFDC WQ Model Hydrodynamic and WQ Run Simultaneously for 8 Year Simulations Same Basic WQ Formulation Formulation Reviewed by Dr. Carl Cerco

EFDC Water Quality Overview Directly coupled to hydrodynamics. No external linking is required Based on CE-QUAL-IC (Chesapeake Bay WQ Model) kinetics previously used for Florida Bay 22 water column state variables including multiple classes of algae and organic carbon, nitrogen and phosphorous Sediment diagenesis/flux sub-model with 27 state variable Generic rooted aquatic plant sub-model with most of the features of the FB Sea Grass Model

EFDC Water Quality Schematic RPOC RPON RPOP SU LPOC LPON LPOP DOC DON DOP NH4 PO4t SA PO4d SAd NO23 PO4p SAp DO photosynthesis light TSS* or reaeration respiration TAM COD Bc Bg Bd FCB * TSS from hydrodynamic model

Observational Data for Water Quality Model Configuration and Calibration ENP Interior - Load estimation Florida Bay - Load estimation and calibration Ten Thousand Islands Load estimation Southwest Florida Shelf Open boundary conditions and calibration Florida Keys Open boundary conditions and calibration Various Process Orient Studies

Southwest Shelf and Keys Stations

Configuration and Calibration Approach Boundary Conditions Well defined for calibration period Estimation and Adjustment of Loads Correlation of inflow with concentrations Splitting of organic matter loads into labile and refractory reaction classes Sensitivity with respect to loads demonstrated Adjustment of Reaction Rates and Parameters Constrained to be within scientifically acceptable range Enhancement of Water Quality Processes Representations

Example of Loading Functions 7-9 STA# FB 10 R^2 = 0.952958 Y=A+B*X+C*X^2+D*X^3 A = -4.66E+002 B = 1.11E+003 50000 C = -1.08E+001 D = 7.76E-002 7-5 3000 2500 R^2 = 0.694433 Y = A + B*X + C*X^2 + D*X^3 A = -2.73E+001 B = 6.37E+001 C = -8.53E-001 D = 6.54E-003 STA# FB 10 7-2 800 R^2 = 0.74165 Y=A+B*X+C*X^2+D*X^3 A = -2.39E+001 B = 1.11E+001 C = -3.19E-001 D = 4.83E-003 STA# FB 10 40000 2000 600 TOC(kg/d) 30000 20000 TON(kg/d) 1500 1000 NH4(kg/d) 400 10000 500 200 0 10 20 30 40 50 60 Q(m3/s) 7-6 40 R^2 = 0.79967 Y=A+B*X+C*X^2+D*X^3 A=-1.20E+000 B = 1.28E+000 C = -2.03E-002 D = 1.67E-004 STA# FB 10 0 10 20 30 40 50 60 Q(m3/s) 7-7 25 20 R^2 = 0.603554 Y=A+B*X+C*X^2+D*X^3 A = -9.32E-001 B = 5.58E-001 C = -1.61E-002 D = 1.84E-004 STA# FB 10 0 10 20 30 40 50 60 Q(m3/s) Total P(kg/d) 30 20 Po4(kg/d) 15 10 10 5 0 10 20 30 40 50 60 Q(m3/s) 0 10 20 30 40 50 60 Q(m3/s)

Flow and Loads at Trout Net Freshwater Inflow Location

Water Quality Modeling Issues Algae Dynamics Phosphorous Dynamics Nutrient and Organic Matter Loading Organic Matter Reaction Rates Benthic Algae Sediment Flux Sea Grass

WQ Modeling Issues Algae Dynamics Problem: Model Predicted Algae Levels Too Low in Some Areas Investigated Phosphorous Limitations Including DOP Utilization Nutrient Loads Nonlinear vs Linear Predation Nonlinear Predation Provided Most Significant Improvement DOP Utilization and Load Changes Were Not Required Higher Algae Level Improved Prediction of Organic Matter without Significant Changes in Reaction Rates

WQ Modeling Issues Loadings and Organic Material Reaction Rates Problems/Questions: Do Potential Loading Uncertainties Contribute to Algae Prediction Problems Influence of Loading and Organic Reaction Rates on Organic Levels Investigate Loading Estimation and Organic Reaction Rates Algae Prediction Improved without Significant Changes in Loading Estimation Higher Algae Level Improved Prediction of Organic Matter without Significant Changes in Reaction Rates

WQ Modeling Issues Phosphorous Dynamics Problem/Question: How Does Highly Variable Phosphorous Prediction Relate to Algae Prediction Investigate Best Formulation for Ortho-Phosphorous Sorption and Settling Phosphorous Loads Used Best Estimate of PO4 Partitioning and Suspended Sediment Concentration and Settling to Define Phase Distribution Higher Algae Levels Also Tended to Improve PO4 Prediction Significant Load Changes Were Not Required

WQ Modeling Issues Benthic Micro Algae and Sediment Flux Problems/Questions: How Important Are Benthic Micro Algae and Sediment Flux How Does Predicted Flux Compare with Observations Investigate Micro Algae Calibration Benthic Micro Algae Levels Low and Little Data to Evaluate Calibration Sediment Flux Data at Light/Dark Time Scale while Model at Net Time Scale Makes Comparison Difficult

Water Quality Model Results and Comparison with Previous WQM Comparison of Model Predicted and Observed Time Series of State Variables at Monitoring Locations Quantify Prediction Performance Using Various Time Series Error Measures Such as Mean, Mean Absolute, RMS, and Fractional MAE Compare Quantitative Measures with Previous Model and WQM s for Other Water Bodies Previous Model Lumped in Space and Time For the Current Model Presented Errors Measures Include Combinations of Point to Point Lumped in Space and Time Range of Point to Point Average of Point of Point

Comparison of Mean Absolute Errors Variable COE WQ Model Lumped over all Stations Current WQ Model Averaged over 35 Stations Temperature 1.378 1.427 Salinity 1.605 6.066 Algae Chlorophyll (ug/l) 0.558 0.979 Total Organic Carbon (mg/l) 1.611 2.96 Total Nitrogen (mg/l) 0.123 0.224 Ammonium (mg/l) 0.014 0.057 Nitrate (mg/l) 0.005 0.020 Total Phosphorous (mg/l) 0.003 0.013 Phosphate (mg/l) 0.002 0.0011 Dissolved Oxygen (mg/l) 0.495 0.720

Visual Comparison By Region of Bay Using Specific Monitoring Locations Results For Northern Transition Joe Bay FB10 Eastern Duck Key FB9 Central Whipray FB13 Western Johnson FB17 Atlantic Transition Porpoise Lake - FB21 Gulf Transition East Cape FB25 Post Processor Provides Results for 35 Location

Calibration Zones for COE WQ Model

North Transition Zone Chlorophyll a (10)

Eastern Zone Chlorophyll a (9)

Central Zone Chlorophyll a (13)

Western Zone Chlorophyll a (17)

Atlantic Transition Zone Chlorophyll a (21)

Gulf Transition Zone Chlorophyll a (25)

North Transition Zone TOC (10)

Eastern Zone TOC (9)

Central Zone TOC(13)

Western Zone TOC (17)

Atlantic Transition Zone TOC (21)

Gulf Transition Zone TOC (25)

North Transition Zone TN (10)

Eastern Zone TN (9)

Central Zone TN (13)

Western Zone TN (17)

Atlantic Transition Zone TN (21)

Gulf Transition Zone TN (25)

North Transition Zone NH4 (10)

Eastern Zone NH4 (9)

Central Zone NH4 (13)

Western Zone NH4 (17)

Atlantic Transition Zone NH4 (21)

Gulf Transition Zone NH4 (25)

North Transition Zone TP (10)

Eastern Zone TP (9)

Central Zone TP (13)

Western Zone TP (17)

Atlantic Transition Zone TP (21)

Gulf Transition Zone TP (25)

North Transition Zone PO4 (10)

Eastern Zone PO4 (9)

Central Zone PO4 (13)

Western Zone PO4 (17)

Atlantic Transition Zone PO4 (21)

Gulf Transition Zone PO4 (25)

Comparison of EFDC Lumped Species Sea Grass Model with the FBSG Model FBSG Model Results Shown Below

EFDC SG Model Rankin

EFDC SG Model Little Maderia

EFDC SG Model Duck

EFDC SG Model Rabbit

Whipray Basin Primary Production and Nutrients

Summary and Future Directions Directly Coupled Public Domain EFDC Based Water Quality Model Configured for 1996-2002 Calibration to Date Has Demonstrated WQ Model Performance At Level of Previous Model The Model Including Inputs, Post- Processor and Results Is Available Additional Processes Enhancements and Calibration Are Required

Summary and Future Directions Forcing Function and Processes Enhancements Phosphorous Dynamics Fully Equivalent Embedded Sea Grass Model Refined Load Estimation Additional Calibration Alternate Calibration Measures Research Level Model Development to Compliment Management Tool Driven Development

Final Salinity Calibration Station Med Resol RMSE Coarse Resol RMSE Med Resol RMSEs Coarse Resol RMSEs Med Resol RMSEu Coarse Resol RMSEu Med Resol IA Coarse Resol IA Bob Allen 7.11 3.65 4.49 2.38 5.51 2.76 0.52 0.84 Buoy Key 5.11 4.95 2.29 2.31 4.57 4.38 0.82 0.83 Butternut 7.59 4.46 6.69 3.10 3.58 3.21 0.60 0.80 Duck Key 7.90 3.78 6.62 1.84 4.31 3.30 0.63 0.87 Garfield 11.15 8.89 7.86 6.43 7.90 6.14 0.75 0.76 Johnson 4.20 4.66 1.83 2.32 3.78 4.04 0.79 0.76 Lt Maderia 9.39 5.85 7.80 4.77 5.22 3.38 0.70 0.83 Lt Rabbit 3.95 4.24 1.94 2.11 3.44 3.67 0.72 0.70 Murray 3.97 4.05 1.26 1.58 3.76 3.73 0.83 0.83 Peterson 2.83 2.95 2.16 2.52 1.83 1.53 0.65 0.57 Terrapin 18.36 7.27 17.39 4.17 5.88 5.95 0.54 0.88 Trout 16.11 10.84 14.63 7.80 6.73 7.53 0.44 0.75 Whipray 4.33 4.39 2.79 2.76 3.31 3.41 0.81 0.83

North Transition Zone Chlorophyll a (10)

Eastern Zone Chlorophyll a (9)

Central Zone Chlorophyll a (13)

Western Zone Chlorophyll a (17)

Atlantic Transition Zone Chlorophyll a (21)

Gulf Transition Zone Chlorophyll a (25)

Outer Keys Zone Chlorophyll a (294)

Southwest Shelf Chlorophyll a (369)

North Transition Zone TOC (10)

Eastern Zone TOC (9)

Central Zone TOC(13)

Western Zone TOC (17)

Atlantic Transition Zone TOC (21)

Gulf Transition Zone TOC (25)

Outer Keys Zone TOC (294)

Southwest Shelf TOC (369)

North Transition Zone TN (10)

Eastern Zone TN (9)

Central Zone TN (13)

Western Zone TN (17)

Atlantic Transition Zone TN (21)

Gulf Transition Zone TN (25)

Outer Keys Zone TN (294)

Southwest Shelf TN (369)

North Transition Zone NH4 (10)

Eastern Zone NH4 (9)

Central Zone NH4 (13)

Western Zone NH4 (17)

Atlantic Transition Zone NH4 (21)

Gulf Transition Zone NH4 (25)

Outer Keys Zone NH4 (294)

Southwest Shelf NH4 (369)

North Transition Zone NOx (10)

Eastern Zone NOx (9)

Central Zone NOx (13)

Western Zone NOx (17)

Atlantic Transition Zone NOx (21)

Gulf Transition Zone NOx (25)

Outer Keys Zone NOx (294)

Southwest Shelf NO3 (369)