NOAA Technical Report NOS CS 28

THREE-DIMENSIONAL HYDRODYNAMIC MODEL 

DEVELOPMENTS FOR A DELAWARE RIVER AND BAY 

NOWCAST/FORECAST SYSTEM 

Silver Spring, Maryland 

January 2011 

noaa National Oceanic and Atmospheric Administration 

U.S. DEPARTMENT OF COMMERCE 

National Ocean Service 

Coast Survey Development Laboratory 
Office of Coast Survey 

National Ocean Service 

National Oceanic and Atmospheric Administration 

U.S. Department of Commerce

The Office of Coast Survey (OCS) is the Nation’s only official chartmaker. As the oldest 

United States scientific organization, dating from 1807, this office has a long history. 

Today it promotes safe navigation by managing the National Oceanic and Atmospheric 

Administration’s (NOAA) nautical chart and oceanographic data collection and 

information programs. 

There are four components of OCS: 

The Coast Survey Development Laboratory develops new and efficient techniques 

to accomplish Coast Survey missions and to produce new and improved products 

and services for the maritime community and other coastal users. 

The Marine Chart Division acquires marine navigational data to construct and 

maintain nautical charts, Coast Pilots, and related marine products for the United 

States. 

The Hydrographic Surveys Division directs programs for ship and shore-based 

hydrographic survey units and conducts general hydrographic survey operations. 

The Navigational Services Division is the focal point for Coast Survey customer 

service activities, concentrating predominately on charting issues, fast-response 

hydrographic surveys, and Coast Pilot updates. 
NOAA Technical Report NOS CS 28 

THREE-DIMENSIONAL HYDRODYNAMIC MODEL 

DEVELOPMENTS FOR A DELAWARE RIVER AND BAY 

NOWCAST/FORECAST SYSTEM 

Richard A. Schmalz, Jr. 

Office of Coast Survey, Coast Survey Development Laboratory, 

Silver Spring, MD 

January 2011

noaa National Oceanic and Atmospheric Administration 

U. S. DEPARTMENT National Oceanic and National Ocean Service 

OF COMMERCE Atmospheric Administration David Kennedy 

Gary Locke, Dr. Jane Lubchenco Acting Assistant 

Secretary Under Secretary Administrator 

 

Office of Coast Survey Coast Survey Development Laboratory 

Captain John Lowell, NOAA Mary Erickson 
ii 

NOTICE 

Mention of a commercial company or product does not constitute an 

endorsement by NOAA. Use for publicity or advertising purposes of 

information from this publication concerning proprietary products or the 

tests of such products is not authorized. 
iii 

TABLE OF CONTENTS 

LIST OF FIGURES .........................................................................................................................v 

LIST OF TABLES ..........................................................................................................................x 

ABSTRACT ..................................................................................................................................xv 

Base Map 1: Upper Delaware River Principal City Locations ................................................... xvi 

Base Map 2: Lower Delaware River and Bay Principal City Locations ................................... xvii 

1. INTRODUCTION ......................................................................................................................1 

2. MODEL EVALUATION ENVIRONMENT EXPERIMENT ...................................................5 

2.1. Data Restoration and Analysis Efforts ...........................................................................5 

2.2. Grid Development ..........................................................................................................8 

2.3. Model Input Requirements ...........................................................................................13 

2.4. Model Evaluation Results ............................................................................................13 

3. POM MEDIUM RESOLUTION GRID HINDCASTS ............................................................19 

3.1. Hindcast Setup Procedures ...........................................................................................19 

3.2. Baseline Simulation ......................................................................................................19 

3.3. Revised Geometry High Flow Simulation ...................................................................26 

3.4. Revised Geometry Low Flow Simulation ....................................................................30 

3.5. Summary and Additional Considerations .....................................................................33 

 

4. ROMS MEDIUM RESOLUTION GRID HINDCASTS .........................................................35 

4.1. Model Revisions ...........................................................................................................35 

4.2. High Flow Simulation ..................................................................................................36 

4.3. Low Flow Simulation ...................................................................................................40 

4.4. Summary and Additional Considerations .....................................................................43 

5. ROMS HIGH RESOLUTION GRID HINDCASTS ................................................................45 

5.1. Medium and High Resolution Grids ............................................................................45 

5.2. Simulation Setup, Initial, Boundary, and Forcing Conditions .....................................47 
iv 

TABLE OF CONTENTS (Cont.) 

5.3. High Flow Simulation ................................................................................................. 49 

5.4. Low Flow Simulation .................................................................................................. 52 

5.5. Extended Hindcast March – September 1984 ............................................................. 57 

5.6. Tidal Analysis and Simulations ................................................................................... 58 

5.7. Summary and Additional Considerations .................................................................... 58 

6. ROMS HIGH RESOLUTION GRID EXTENDED HINDCASTS ......................................... 63 

6.1. 29-day Harmonic Analysis Considerations ................................................................. 63 

6.2. April 1984 Tidal Simulation Validation ...................................................................... 66 

6.3. March 1984 – March 1985 Tidal Simulation Validation ............................................ 83 

6.4. March 1984 – March 1985 Hindcast Simulation Validation ...................................... 85 

6.5. Summary and Additional Considerations ...................................................................166 

7. SEMI-OPERATIONAL NOWCAST/FORECAST SYSTEM CONSTRUCTION ...............167 

7.1. River Template ...........................................................................................................167 

7.2. Open Boundary Condition Template .........................................................................169 

7.3. Vertical Datum Considerations ..................................................................................170 

7.4. Operational Summary .................................................................................................172 

 

8. CONCLUSIONS AND RECOMMENDATIONS .................................................................173 

ACKNOWLEDGMENTS ..........................................................................................................174 

REFERENCES ...........................................................................................................................175 

 
v 

LIST OF FIGURES 

Figure 1.1. Delaware River and Bay PORTS ................................................................................2 

Figure 1.2. Text-based Delaware River and Bay PORTS screen capture, 

 March 3, 2010 9:34 EST .............................................................................................3 

Figure 2.1. Upper Delaware River NOS Water Level Station Locations ......................................6 

Figure 2.2. Lower Delaware River and Bay NOS Water Level Station Locations .......................7 

Figure 2.3. Upper Delaware River NOS Current, CT, and CTD Station Locations ....................10 

Figure 2.4. Lower Delaware River and Bay NOS Current, CT, and CTD Station Locations .....11 

Figure 2.5. Grid Section 5 with the 90 degree channel bend and the Grid Section 6 

 lower portion .............................................................................................................12 

Figure 2.6. Upper Delaware River ROMS grid ...........................................................................14 

Figure 2.7. Lower River and Bay ROMS grid .............................................................................15 

Figure 3.1. Upper River POM and ROMS grid ...........................................................................20 

Figure 3.2. Lower River and Bay POM and ROMS grid ............................................................21 

Figure 3.3. Baseline High Flow Hindcast (27 March – 5 April, 1984) 

 Water Surface Elevation at Trenton, NJ ....................................................................24 

Figure 3.4. Baseline High Flow Hindcast (27 March – 5 April, 1984) 

 Salinity at Station 33 .................................................................................................25 

Figure 3.5. Revised Geometry High Flow Hindcast (27 March – 10 April, 1984) 

 Water Surface Elevation at Trenton, NJ ....................................................................28 

Figure 3.6. Revised Geometry High Flow Hindcast (27 March – 10 April, 1984) 

 Salinity at Station 33 .................................................................................................29 

Figure 3.7. Revised Geometry Low Flow Hindcast (10 – 24 September, 1984) 

 Water Surface Elevation at Trenton, NJ ....................................................................31 

Figure 4.1. High Flow Hindcast (27 March – 10 April 1984) 

 Water Surface Elevation at Trenton, NJ ....................................................................37 

Figure 4.2. Simulated versus Observed (10 minute) Salinity 

 at Station 33 Level 4 at 11m above the bottom .........................................................39 

Figure 4.3. Low Flow Hindcast (10 – 24 September, 1984) 

 Water Surface Elevation at Trenton, NJ ....................................................................41 

Figure 5.1. Map depicting Delaware River and Bay DELFT-3D 

 High Resolution Grid in the C&D Canal Region ......................................................46 
vi 

LIST OF FIGURES (Cont.)

Figure 5.2. Map depicting bathymetry with respect to Model Datum 

 in the C&D Canal Region ........................................................................................46 

Figure 5.3. High Flow Hindcast (27 March – 10 April 1984) 

 Water Surface Elevation (m-MLLW) at Trenton, NJ .............................................50 

Figure 5.4. Simulated versus Observed (10 minute) Salinity 

 at Station 33 at 11 m above the bottom ..................................................................53 

Figure 5.5. Low Flow Hindcast (10 – 24 September, 1984) 

 Water Surface Elevation at Trenton, NJ ..................................................................54 

Figure 5.6. Tidal Water Level (m-demeaned) at Trenton, NJ 

 for Julian Days 90-100, 1984 ...................................................................................61 

Figure 6.1. Simulated Astronomical Tide JD 100-110, 1984 at Lewes, DE ..............................73 

Figure 6.2. Simulated Astronomical Tide JD 100-110, 1984 at Philadelphia, PA ....................74 

Figure 6.3. Simulated Astronomical Tide JD 100-110, 1984 at Trenton, NJ ............................75 

Figure 6.4. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 17 ......................76 

Figure 6.5. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 2 ........................77 

Figure 6.6. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 19 ......................78 

Figure 6.7. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 23 ......................79 

Figure 6.8. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 33 ......................80 

Figure 6.9. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 154 ....................81 

Figure 6.10. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 51 ......................82 

Figure 6.11. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 

 at Lewes, DE ..........................................................................................................105 

Figure 6.12. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 

 at Philadelphia, PA ................................................................................................106 

Figure 6.13. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 

 at Trenton, NJ ........................................................................................................107 

Figure 6.14. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 

 at Lewes, DE ..........................................................................................................108 

Figure 6.15. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 

 at Philadelphia, PA ................................................................................................109 
vii 

LIST OF FIGURES (Cont.) 

Figure 6.16. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 

at Trenton, NJ ........................................................................................................110 

Figure 6.17. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 

at Lewes, DE ..........................................................................................................111 

Figure 6.18. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 

at Philadelphia, PA ................................................................................................112 

Figure 6.19. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 

at Trenton, NJ ........................................................................................................113 

Figure 6.20. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 

at Lewes, DE ..........................................................................................................114 

Figure 6.21. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 

at Philadelphia, PA ................................................................................................115 

Figure 6.22. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 

at Trenton, NJ ........................................................................................................116 

Figure 6.23. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 

at Lewes, DE ..........................................................................................................117 

Figure 6.24. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 

at Philadelphia, PA ................................................................................................118 

Figure 6.25. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 

at Trenton, NJ ........................................................................................................119 

Figure 6.26. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 

at Lewes, DE ..........................................................................................................120 

Figure 6.27. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 

at Philadelphia, PA ................................................................................................121 

Figure 6.28. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 

at Trenton, NJ ........................................................................................................122 

Figure 6.29. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 

at Lewes, DE ..........................................................................................................123 

Figure 6.30. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 

at Philadelphia, PA ................................................................................................124 

Figure 6.31. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 

at Trenton, NJ ........................................................................................................125 
viii 

LIST OF FIGURES (Cont.) 

Figure 6.32. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 

at Lewes, DE ...........................................................................................................126 

Figure 6.33. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 

at Philadelphia, PA ................................................................................................127 

Figure 6.34. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 

at Trenton, NJ ........................................................................................................128 

Figure 6.35. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 

at Lewes, DE ..........................................................................................................129 

Figure 6.36. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 

at Philadelphia, PA ................................................................................................130 

Figure 6.37. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 

at Trenton, NJ ........................................................................................................131 

Figure 6.38. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 

at Lewes, DE ..........................................................................................................132 

Figure 6.39. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 

at Philadelphia, PA ................................................................................................133 

Figure 6.40. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 

at Trenton, NJ ........................................................................................................134 

Figure 6.41. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 23 ...................................135 

Figure 6.42. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 33 ...................................136 

Figure 6.43. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 51 ...................................137 

Figure 6.44. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 23 ...............................138 

Figure 6.45. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 33 ...............................139 

Figure 6.46. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 51 ...............................140 

Figure 6.47. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 23 ...............................141 

Figure 6.48. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 33 ...............................142 

Figure 6.49. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 51 ...............................143 

Figure 6.50. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 23 ...............................144 

Figure 6.51. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 33 ...............................145 
ix 

LIST OF FIGURES (Cont.) 

Figure 6.52. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 51 ...............................146 

Figure 6.53. DBOFS Version 1.1 Current JD 75-90, 1985 at Station 23 ...................................147 

Figure 6.54. DBOFS Version 1.1 Current JD 75-90, 1985 at Station 51 ...................................148 

Figure 6.55. DBOFS Version 1.1 Salinity JD 76-91, 1984 at Station 23 ...................................149 

Figure 6.56. DBOFS Version 1.1 Salinity JD 76-91, 1984 at Station 33 ...................................150 

Figure 6.57. DBOFS Version 1.1 Salinity JD 153-168, 1984 at Station 23 ...............................151 

Figure 6.58. DBOFS Version 1.1 Salinity JD 153-168, 1984 at Station 33 ...............................152 

Figure 6.59. DBOFS Version 1.1 Salinity JD 229-244, 1984 at Station 23 ...............................153 

Figure 6.60. DBOFS Version 1.1 Salinity JD 229-244, 1984 at Station 33 ...............................154 

Figure 6.61. DBOFS Version 1.1 Salinity JD 351-366, 1984 at Station 23 ...............................155 

Figure 6.62. DBOFS Version 1.1 Salinity JD 351-366, 1984 at Station 33 ...............................156 

Figure 6.63. DBOFS Version 1.1 Salinity JD 75-90, 1985 at Station 23 ...................................157 

Figure 6.64. DBOFS Version 1.1 Temperature JD 76-91, 1984 at Station 23 ...........................158 

Figure 6.65. DBOFS Version 1.1 Temperature JD 76-91, 1984 at Station 33 ...........................159 

Figure 6.66. DBOFS Version 1.1 Temperature JD 153-168, 1984 at Station 23 .......................160 

Figure 6.67. DBOFS Version 1.1 Temperature JD 153-168, 1984 at Station 33 .......................161 

Figure 6.68. DBOFS Version 1.1 Temperature JD 229-244, 1984 at Station 23 .......................162 

Figure 6.69. DBOFS Version 1.1 Temperature JD 229-244, 1984 at Station 33 .......................163 

Figure 6.70. DBOFS Version 1.1 Temperature JD 351-366, 1984 at Station 33 .......................164 

Figure 6.71. DBOFS Version 1.1 Temperature JD 75-90, 1985 at Station 23 ...........................165 

Figure 7.1. DBOFS MLLW to MSL Datum Conversion .........................................................171 
x 

LIST OF TABLES

Table 2.1. Tidal Elevation Station Harmonic Analysis Inventory ...............................................5 

Table 2.2. Tidal Current 29-day Harmonic Analysis Inventory ...................................................9 

Table 2.3. MEE Water Level Skill Assessment Results ............................................................16 

Table 2.4. MEE Current Skill Assessment Results ....................................................................17 

Table 2.5. MEE Salinity Skill Assessment Results ....................................................................17 

Table 2.6. MEE Water Temperature Skill Assessment Results .................................................17 

Table 3.1. Water Surface Elevation-MLLW (m) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984 ..........................................................................................22 

Table 3.2. Current Speed (cm/s) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984 ..........................................................................................23 

Table 3.3. Current Direction (o

T) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984 ..........................................................................................23 

Table 3.4. Salinity (PSU) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984 ..........................................................................................23 

Table 3.5. Temperature (oC) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984 ..........................................................................................23 

Table 3.6. Water Surface Elevation-MLLW (m) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984 ........................................................................................26 

Table 3.7. Current Speed (cm/s) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984 ........................................................................................26 

Table 3.8. Current Direction (o

T) Revised High Flow Hindcast: 

 March 27 - April 10, 1984 ........................................................................................27 

Table 3.9. Salinity (PSU) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984 ........................................................................................27 

Table 3.10. Temperature (o

C ) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984 ........................................................................................27 
xi 

LIST OF TABLES (Cont.)

Table 3.11. Water Surface Elevation-MLLW (m) Revised Geometry Low Flow Hindcast: 

September 10-24, 1984 ..............................................................................................30 

Table 3.12. Current Speed (cm/s) Revised Geometry Low Flow Hindcast: 

September 10-24, 1984 ..............................................................................................32 

Table 3.13. Current Direction (o

T) Revised Geometry Low Flow Hindcast: 

September 10-24, 1984 ..............................................................................................32 

Table 3.14. Salinity (PSU) Revised Geometry Low Flow Hindcast: 

September 10-24, 1984 ..............................................................................................33 

Table 3.15. Temperature (oC) Revised Geometry Low Flow Hindcast: 

September 10-24, 1984 ..............................................................................................33 

Table 4.1. Water Surface Elevation-MLLW (m) High Flow Hindcast: 

27 March – April 10, 1984: ROMS Results / POM Results .....................................36 

Table 4.2. Current Speed (cm/s) High Flow Hindcast: 

27 March – April 10, 1984: ROMS Results / POM Results .....................................36 

Table 4.3. Current Direction (o

T) High Flow Hindcast: 

27 March – April 10, 1984: ROMS Results / POM Results .....................................38 

Table 4.4. Salinity (PSU) High Flow Hindcast: 

27 March – April 10, 1984: ROMS Results / POM Results .....................................38 

Table 4.5. Temperature (o

C) High Flow Hindcast: 

27 March – April 10, 1984: ROMS Results / POM Results .....................................38 

Table 4.6. Water Surface Elevation-MLLW (m) Low Flow Hindcast: 

September 10-24, 1984: ROMS Results/ POM Results ............................................40 

Table 4.7. Current Speed (cm/s) Revised Low Flow Hindcast: 

September 10-24, 1984: ROMS Results/ POM Results ............................................42 

Table 4.8. Current Direction (o

T) Revised Low Flow Hindcast: 

September 10-24, 1984: ROMS Results/ POM Results ............................................42 

Table 4.9. Salinity (PSU) Revised Low Flow Hindcast: 

 September 10-24, 1984: ROMS Results/ POM Results ............................................43 
xii 

LIST OF TABLES (Cont.)

Table 4.10. Temperature (o

C) Revised Low Flow Hindcast: 

September 10-24, 1984: ROMS Results/ POM Results ............................................43 

Table 5.1. Simulation Description, Boundary and Forcing Conditions .....................................47 

Table 5.2. Water Surface Elevation-MLLW (m) High Flow Hindcast: 

27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results ...............49 

Table 5.3. Current Speed (cm/s) High Flow Hindcast: 

27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results ...............51 

Table 5.4. Current Direction (o

T) High Flow Hindcast: 

27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results ...............51 

Table 5.5. Salinity (PSU) High Flow Hindcast: 

27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results ...............51 

Table 5.6. Temperature (oC) High Flow Hindcast 

27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results ...............52 

Table 5.7. Water Surface Elevation-MLLW (m) Low Flow Hindcast 

September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results ......................55 

Table 5.8. Current Speed (cm/s) Revised Low Flow Hindcast 

September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results ......................55 

Table 5.9. Current Direction (o

T) Revised Low Flow Hindcast 

September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results ......................56 

Table 5.10. Salinity (PSU) Revised Low Flow Hindcast September 10-24, 1984: 

ROMS MRG Results/ ROMS HRG Results .............................................................56 

Table 5.11. Temperature (o

C) Revised Low Flow Hindcast September 10-24, 1984: 

ROMS MRG Results/ ROMS HRG Results .............................................................57 

Table 5.12. Seven Month ROMS HRG Hindcast March-September 1984 

Water Level RMSE (cm) Summary ..........................................................................57 

Table 5.13. Water Surface Elevation-MSL (m) Tidal Extraction from Hindcast 

and Tidal Simulations 1-3: April 1984 ......................................................................59 
xiii 

LIST OF TABLES (Cont.)

Table 5.14. Current Speed (cm/s) Tidal Extraction from Hindcast 

and Tidal Simulations 1-3: April 1984 ......................................................................60 

Table 6.1. Water Level Harmonic Constant Comparison at Ocean City Pier, MD ...................64 

Table 6.2. Water Level Harmonic Constant Comparison at Chesapeake City, MD ..................64 

Table 6.3. Water Level Harmonic Constant Comparison at Cape May, NJ ..............................65 

Table 6.4. Water Level Harmonic Constant Comparison at Lewes, DE ....................................65 

Table 6.5. Open Boundary Condition Error Summary ...............................................................66 

Table 6.6. Tidal Validation Simulation Summary ......................................................................67 

Table 6.7. Water Level Open Boundary Major Harmonic Constituent Sets ..............................67 

Table 6.8. Bottom Friction Coefficient Sets ...............................................................................68

Table 6.9. Bathymetric Sets ........................................................................................................69 

Table 6.10. M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors .....................................69 

Table 6.11. DBOFS Version 1.0 April 1984 Tide Simulation Water Level and 

PCD Current Results .................................................................................................71 

Table 6.12. DBOFS Version 1.1 April 1984 Tide Simulation 

 Water Level and PCD Current Results ......................................................................72 

Table 6.13. DBOFS Version 1.1 March 1984-March 1985 Tide Simulation 

 Water Level Results ..................................................................................................83 

Table 6.14. DBOFS Version 1.1 March 1984-March 1985 Tide Simulation 

 PCD Current Results .................................................................................................84 

Table 6.15. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Atmospheric Pressure: RMSE (mb)/RE(%) ...............................................................87 

Table 6.16. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Wind Speed: RMSE (m/s)/RE(%) ..............................................................................87 

Table 6.17. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Wind Direction: RMSE (oT)/RE(%) ..........................................................................87 
xiv 

LIST OF TABLES (Cont.)

Table 6.18. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Water Surface Elevations: RMSE (cm)/RE(%) .........................................................88 

Table 6.19. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Mean Water Surface Elevations: Model/Observed ...................................................88 

Table 6.20. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Current Speed: RMSE (cm/s)/RE(%) .........................................................................89 

Table 6.21. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Mean Current Speed (cm/s): Model/Observed ..........................................................91 

Table 6.22. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Current Direction: RMSE (oT)/RE(%) ......................................................................92 

Table 6.23. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Mean Current Direction (oT): Model/Observed .......................................................94 

Table 6.24. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Salinity: RMSE (PSU)/RE(%) ...................................................................................97 

Table 6.25. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Mean Salinity (PSU): Model/Observed ....................................................................98 

Table 6.26. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Temperature: RMSE (oC)/RE(%) ............................................................................101 

Table 6.27. DBOFS Version 1.1 March 1984-March 1985 Hindcast 

 Mean Temperature (oC): Model/Observed .............................................................103 

Table 7.1. Template of River Control File for DBOFS ............................................................167 

Table 7.2. Template of Open Boundary Condition Control File for DBOFS ..........................168 

Table 7.3. Seven Month March-September 1984 Water Level RMSE (cm) Summary ...........172 
xv 

ABSTRACT

The National Ocean Service (NOS) installed a Physical Oceanographic Real Time System (PORTS) 

during 2003 to provide water surface elevation, currents at prediction depth (4.7m below MLLW) as 

well as near-surface and near-bottom temperature and salinity, and meteorological information. To 

complement the PORTS, a new next generation nowcast/forecast system has been developed. This 

next generation nowcast/forecast system domain extends from the head of tide at Trenton, NJ out to 

the continental shelf break and is run on the National Center for Environmental Prediction (NCEP) 

supercomputers based on a recently developed High Performance Computing Coastal Ocean 

Modeling Framework (HPC-COMF; Zhang et al., 2010) to allow four times daily six-hour nowcasts 

and 48 hour forecasts. In conjunction with this effort, a Model Evaluation Environment (MEE) as 

described by Patchen (2008) was constructed for the Delaware River and Bay based on the NOS 

1984-1985 Circulation Data Survey (Klavans et al., 1986). As a first step the MEE results are used 

to guide the development of the Delaware River and Bay Nowcast/Forecast System. First, we 

describe and present the results from the MEE. Based on the MEE results, the Princeton Ocean 

Model (POM) and the Regional Ocean Modeling System (ROMS) were selected for further 

application in the Delaware River and Bay and both used the same medium resolution grid. Next, 

POM and ROMS common medium resolution grid revised simulation results are presented, 

respectively, in an effort to improve upon the MEE results. To further improve results in the river 

sections, a new higher resolution grid using the DELFT3D-RFGRID software was constructed. To 

take advantage of the parallel computing opportunities at National Centers for Environmental 

Prediction (NCEP), ROMS was selected as the hydrodynamic model in Delaware Bay Operational 

Forecast System (DBOFS). ROMS high resolution grid results are presented for the two 15-day 

simulations as well as for an extended seven month hindcast and contrasted with the medium 

resolution results. The ROMS high resolution grid was used to investigate the sensitivity of the tidal 

response to bottom roughness coefficients and offshore tidal constituents in eighteen tidal 

simulations during April 1984. Upon further improvement of the model tidal dynamics as a result of 

the sensitivity analysis, a 13-month tidal simulation as well as a 13-month hindcast were performed 

and are discussed. Next, the construction of the semi-operational nowcast/forecast system at NCEP 

is presented. Finally, conclusions are drawn and recommendations for formal skill assessment and 

transition to operations are advanced. 
xvi 

Base Map 1. Upper Delaware River Principal City Locations. 
xvii 

Base Map 2. Lower Delaware River and Bay Principal City Locations. 
xviii 
1 

1. INTRODUCTION 

The National Ocean Service (NOS), Center for Operational Products and Services (CO-OPS), 

installed a Physical Oceanographic Real Time System (PORTS) during 2003 to provide water 

surface elevation, currents at PORTS prediction depth (4.7m below MLLW) as well as near-surface 

and near-bottom temperature and salinity, and meteorological information at the locations shown in 

Figure 1.1 and the PORTS screen capture in Figure 1.2. To complement the PORTS, a new next 

generation nowcast/forecast system has been developed. This next generation nowcast/forecast 

system domain extends from the head of tide at Trenton, NJ out to the continental shelf break and is 

run on the National Center for Environmental Prediction (NCEP) supercomputers based on a 

recently developed High Performance Computing Coastal Ocean Modeling Framework (HPCCOMF; Zhang et al., 2010) to allow four times daily six-hour nowcasts and 48 hour forecasts. The 

approach used in the previous generation forecast systems, based on the original Coastal Ocean 

Modeling Framework (COMF; Gross et al., 2006) as discussed by Aikman et al. (2008), was to 

contain as little of the shelf as possible to still allow an appropriate response at the estuarine entrance 

to afford computation of hourly nowcasts and 30 hour forecasts (four times per day) on CO-OPS 

workstations. 

 While the majority of the previous generation forecast systems used the Princeton Ocean Model 

(POM), in conjunction with this effort, a Model Evaluation Environment (MEE) as described by 

Patchen (2008) was constructed for the Delaware River and Bay based on the NOS 1984-1985 

Circulation Data Survey (Klavans et al., 1986) to compare both structured and unstructured grid 

models. The purpose of the MEE was to provide for a consistent comparison of hydrodynamic 

models using the same geometrical, forcing, and validation data, which would assist the model 

selection for the next generation Delaware River and Bay Operational Forecast System (DBOFS). 

The MEE also provides additional validation data particularly for currents and density that is not 

available within the PORTS. Therefore as a first step, the MEE results were used to further guide the 

DBOFS development. 

 In Chapter 2, we describe and present the results from the MEE. Based on the MEE results, the 

Princeton Ocean Model (POM) and the Regional Ocean Modeling System (ROMS) were selected 

for further application in Delaware River and Bay and both used the same medium resolution grid. 

In Chapters 3 and 4, POM and ROMS medium resolution grid simulation results are presented, 

respectively, in an effort to improve upon the MEE results. To further improve results in the river 

sections, a new higher resolution grid using the DELFT3D-RFGRID software was constructed. To 

take advantage of the parallel computing opportunities at NCEP, ROMS was finally selected as the 

hydrodynamic model in DBOFS. In Chapter 5, ROMS high resolution grid results are presented for 

the two 15-day simulations as well as for an extended seven month hindcast and contrasted with the 

medium resolution results in Chapter 4. In Chapter 6, the ROMS high resolution grid was used to 

investigate the sensitivity of the tidal response to bottom roughness coefficients and offshore tidal 

constituents in eighteen tidal simulations during April 1984. Upon further improvement of the model 

tidal dynamics as a result of the sensitivity analysis, a 13-month tidal simulation as well as a 13-

month hindcast were performed and are discussed. In Chapter 7, the construction of the semioperational nowcast/forecast system at NCEP is presented. In Chapter 8, conclusions are drawn and 

recommendations for formal skill assessment and transition to operations are advanced. 
2 

Figure 1.1. Delaware River and Bay PORTS. Note cu=current meter, wl=water level, 

 wind=wind, at=air temperature, wt=water temperature, baro=barometric 

 pressure, and ag=air gap. 
3 

Figure 1.2. Text-based Delaware River and Bay PORTS screen capture, 

 March 3, 2010 9:34 EST. 
4 
5 

2. MODEL EVALUATION ENVIRONMENT EXPERIMENT 

The purpose of the Model Evaluation Environment (MEE) is to provide for a consistent comparison 

of hydrodynamic models using the same geometrical, forcing, and validation data (Patchen, 2008). 

In the context of the DBOFS, the MEE provides additional validation data particularly for currents 

and density that is not available within the PORTS and therefore further supports its development. 

Here, we first describe and present the results from the MEE. For additional information refer to 

Feyen and Yang (2008), Myers (2008), Zhang and Wei (2008), and Lanerolle (2008). 

2.1. Data Restoration and Analysis Efforts 

The initial effort was to organize, recover, and process the historical water level, CT and current, and 

CTD data that were collected during the NOS circulation survey of 1984-1985 (Klavens et al., 

1986). For further details on this effort refer to Loeper (2006) and Richardson and Schmalz (2006). 

Harmonic analysis results for water levels at the stations shown in Table 2.1 were obtained from 

CO-OPS. Station locations are shown in Figure 2.1 for the upper Delaware River and in Figure 2.2 

for the lower Delaware River and Bay, respectively. 

 Table 2.1. Tidal Elevation Harmonic Analysis Inventory 

 Station No. Lat Lon Description

 8539993 40.188 -74.755 Trenton, NJ 

8540433 39.812 -75.041 Marcus Hook, PA 

8534883 39.295 -74.748 Tuckahoe River, NJ 

8536110 38.968 -74.960 Cape May Canal, NJ 

8537121 39.305 -75.375 Ship John Shoal, NJ 

8538886 40.012 -75.043 Tacony Bridge, NJ 

8534720 39.355 -74.418 Atlantic City, NJ 

8539094 40.080 -74.873 Burlington, NJ 

8545240 39.933 -75.142 Phila USCG, PA 

8548989 40.137 -74.752 Newbold, PA 

8545530 39.953 -75.138 Phila Pier 11, PA 

8551762 39.582 -75.588 Delaware City, DE 

8551910 39.558 -75.573 Reedy Pt, DE 

8555889 38.987 -75.113 Brandywine Shoal, DE 

8557380 38.782 -75.120 Lewes, DE 

8558690 38.610 -75.070 Indian River, DE 

8570283 38.328 -75.092 Ocean City Inlet, MD 

8570280 38.327 -75.083 Ocean City Pier, MD 

8573927 39.527 -75.810 Chesapeake City, MD 
6 

 Figure 2.1. Upper Delaware River NOS Water Level Stations Locations. 
7 

 Figure 2.2. Lower Delaware River and Bay NOS Water Level Station Locations. 
8 

In addition to the CTD work, the following two programs and script were developed and tested: 1) 

del_ctd.filt.f (filtering program to remove S and T spikes and limit current directions), 2) harm29.f 

(program to develop control and data files for the NOS 29 day harmonic analysis program), and 3) 

harm29.sh (29 day harmonic analysis script, which performs the 29 harmonic analysis of all current 

stations with at least 29 days of data). All 29 day harmonic analyses of the current data at the 

locations shown in Table 2.2 and shown in Figures 2.3 and 2.4 were performed using the techniques 

described in Richardson and Schmalz (2006). 

2.2 Grid Development 

Here we focus on the development of the structured grids for POM and ROMS. To plan the grid 

development process, the following nautical charts were reviewed: 

12274 Head of Chesapeake Bay 

12277 Chesapeake and Delaware Canal 

12304 Delaware Bay 

12311 Delaware River: Smyrna River to Wilmington 

12312 Delaware River: Wilmington to Philadelphia 

12313 Delaware River: Philadelphia and Camden Water Fronts 

12314 Delaware River: Philadelphia to Trenton 

Of interest was to note the location of significant freshwater inflows and the configuration of the 

river above Philadelphia. Attention was also paid to the Schuylkill River inflow and the Chesapeake 

and Delaware (C&D) canal. After a review of the charts, 10 separate grid sections were identified as 

listed in Table 2.3. MATLAB was used with the SEAGRID grid generation (USGS Woods Hole 

Science Center, 2007) package to develop grids separately for each of the 10 sections. Two sections 

proved to be particularly difficult to generate grids for, due to 90 degree channel bends. A separate 

program was developed to link the grids by just using the downstream most grid coordinates at the 

junction of each of the two grids. The resulting grid was not orthogonal and proved not to be 

satisfactory due to the severity of the non-orthogonality. 

Next the grid generation software employed in the generation of the Houston Ship Channel grid was 

reviewed (Schmalz, 2000a). Under this approach the downstream most grid is developed and then 

the coordinates at the top of the grid are specified as the bottom coordinates of the next upstream 

grid. This method proved to be successful in linking all 10 grids, but several grid spacings were very 

small, particularly along the lateral boundaries for the grid sections containing the 90 degree channel 

bend. As a result, the first 5 downstream grids were linked using the above approach and then a 6th 

grid was constructed to replace the next 5 upstream grid sections. The resulting grid is shown in the 

vicinity of the Philadelphia waterfront in Figure 2.5. Lanerolle (2008) has developed a grid fill 

procedure to create dummy grid cells within a complete rectangular shape to allow the present 

versions of POM and ROMS to run over these grid sections. This procedure was used to fill in the 

high resolution ROMS grid discussed in Chapter 5. 
9 

 Table 2.2. Tidal Current 29-day Harmonic Analysis Inventory 

 Station Above Bottom (ft) Number of Sets MLLW Depth(ft)

1 5, 63 1 75 

2 5, 22, 47 2, 4, 2 60 

3 5, 15 2, 3 33 

4 6 2 21 

5 5, 15 2, 3 30 

11 10 1 60 

12 50, 90 1, 1 116 

16 10, 25, 35 2, 2, 3 59 

17 10, 50, 75 2, 3, 1 100 

18 6 1 20 

19 5, 26 1, 1 43 

21 5 1 20 

22 5, 20 2, 3 34 

23 8, 26 2, 2 38 

23X 5, 26 1, 1 35 

24 7 3 20 

25 5 1 18 

30 27 1 43 

32 5 1 20 

33 5, 36 1, 3 48 

33X 15 1 30 

41 14 1 28 

42 17 1 33 

43 19 1 34 

47 28 2 43 

49 18 1 30 

51 5, 8, 28 1, 2, 3 45 

52 14 1 34 

57 10 1 59 

58 16, 21 1, 1 36 

59 35 1 50 

60 30 1 45 

61 13 1 28 

134 10 1 25 

151 25 1 40 

152 25 1 40 

154 5, 25 1, 3 40 

155 7 1 22
10 

 Figure 2.3. Upper Delaware River NOS Current, CT, and CTD Stations Locations. 
11 

 Figure 2.4. Lower Delaware River and Bay NOS Current, CT, and CTD Station Locations. 
12 

Figure 2.5. Grid Section 5 with the 90 degree channel bend and the Grid Section 

 6 lower portion.
13 

As an alternative, a one piece grid was constructed for POM and ROMS using the SEAGRID 

package (USGS Woods Hole Science Center, 2007). Since the highest grid resolutions are on the 

order of 50 m, a fine resolution bathymetry and shoreline were obtained from the Cartographic and 

Geospatial Technical Program within the Coast Survey Development Laboratory. The computational 

grid for POM and ROMS is shown for the upper Delaware River in Figure 2.10 and for the 

Delaware Bay in Figure 2.11. The POM application employed 15 sigma coordinate levels in the 

vertical with uniform spacings below the surface level while ROMS used 10 generalized s 

coordinate levels. 

2.3 Model Input Requirements 

In addition to the computational grid, the models require accurate initial conditions of salinity and 

temperature; specification of conditions at the open-ocean lateral boundaries; river discharges; 

conditions at the Chesapeake side of the C&D Canal; and surface forcing, i.e., winds and heat fluxes. 

 Initial salinity and temperature conditions were developed from the NOS circulation survey. 

Salinity and temperature at the lateral boundaries were determined from NOAA’s World Ocean 

Atlas 2001 (NODC, www.nodc.noaa.gov), which provides monthly varying climatological values. 

Synoptic meteorological conditions were derived by blending NOAA’s reanalysis wind product 

(NCEP, www.ncep.noaa.gov/mmb/rrean/index.html) on a 32 km grid with meteorological 

observations at NOAA buoys, C-Man stations and airports. River discharge data, including water 

temperature were obtained from the USGS. To determine water levels and currents at the openocean lateral boundaries the ADCIRC model for the Western Atlantic Ocean on the East Coast 1995 

grid (Mukai et al., 2001) was used imposing the blended NCEP reanalysis wind product with 

available meteorological observations, and specifying the verified tidal constituents as developed by 

Myers (2007; personal communication) along the open-ocean boundary at 60o

 W. 

2.4. Model Evaluation Results 

The following models were evaluated based on the four experiments as described in Patchen (2008): 

1. Regional Ocean Modeling System (ROMS) as described in Shchepetkin and McWilliams 

(2005) and Haidvogel et al. (2008). On the Internet at: http://www.myroms.org 

2. Princeton Ocean Model (POM) as described in Blumberg and Mellor (1987) and Blumberg 

and Herring (1987). 

On the Internet at: http://www.aos.princeton.edu/WWWPUBLIC/htdocs.pom 

3. Finite Volume Coastal Ocean Model (FVCOM) as described in Chen et al. (2003, 2006). On 

the Internet at: http://fvcom.smast.umassd.edu/FVCOM/index.html 

4. Semi-Implicit Eulerian-Lagrangian Finite Element Model (SELFE) as described in Zhang 

and Baptista (2008). On the Internet at: http://www.ccalmr.ogi.edu/corie/modeling 
14 

Figure 2.6. Upper Delaware River ROMS grid. 
15 

Figure 2.7. Lower Delaware River and Bay ROMS grid. 
16 

The reader is referred to Patchen (2008) for discussion of the Experiment 1 Tidal Simulation, 

Experiment 2 Density Front Locations, and Experiment 3 High River Runoff. Here we focus on the 

final experiment, which is a synoptic hindcast during the 1984-1985 NOS circulation survey from 

March 21 – September 7, 1984 During this period, three strong spring freshets occur, which are 

followed by decreased river discharges into the Fall; a late Spring meteorological event occurs on 

March 31, 1984. Using the NOS standardized skill assessment software (Zhang et al., 2006), the 

two structured grid models ROMS and POM are contrasted with the two unstructured grid models 

FVCOM and SELFE. Water level skill assessment results are given in Table 2.3 and indicate that 

none of the models performed well in the river section above Philadelphia, PA. It should be noted 

for each model, model datum was considered equal to MSL. All the models used a spatially uniform 

bottom roughness. In terms of a reference level of 15 cm the Central Frequency criteria of 90 percent 

(refer to NOS, 1999 and Hess et al., 2003) is not met at any of the water level stations by any of the 

models, with the results above Philadelphia, PA being particularly problematical. Skill assessment 

results for currents are given in Table 2.4 and are nearly the same for ROMS and POM with 

FVCOM showing better results than SELFE. FVCOM results overall appear to be the best for 

currents. Salinity skill assessment results are shown in Table 2.5. POM results appear to be better 

than ROMS in the frontal zone, however as with currents FVCOM appears to represent the salinity 

structure the best in this area. In the river sections, FVCOM salinity is near 2 PSU due to a boundary 

condition specification issue. Temperature skill assessment results are given in Table 2.6. Although 

POM and ROMS used different heat flux specifications, they were similar in skill. Results for 

FVCOM and SELFE were similar but were in general not as good as those obtained by POM and 

ROMS. 

Table 2.3. MEE Water Level Skill Assessment Results. 

Station RMSE (cm) 

ROMS POM FVCOM SELFE

CF(15 cm) 

ROMS POM FVCOM SELFE 

Atlantic City, NJ 11.5 11.5 10.8 10.8 80.7 80.9 83.5 83.6 

Ocean City Pier, 

MD 

13.1 13.6 13.4 13.4 72.9 71.7 72.2 72.2 

Lewes, DE 11.9 13.3 10.7 12.3 80.7 75.8 85.0 84.5 

Reedy Pt, DE 29.1 24.4 13.5 20.8 35.6 48.5 77.7 67.7 

Philadelphia, PA 36.9 36.3 21.3 36.9 39.7 39.1 50.5 43.2 

Cape May, NJ 12.1 13.0 11.3 13.5 82.5 79.6 81.7 73.4 

Brandywine Shl, DB 11.7 12.7 10.3 13.8 85.4 81.8 85.4 73.4 

Chesapeake City, 

MD 

18.2 13.5 13.2 19.2 60.2 75.1 75.7 51.8 

Trenton, NJ 58.9 50.2 47.4 57.6 21.3 28.7 17.9 24.5 
17 

Table 2.4. MEE Current Skill Assessment Results. 

Station 

 No. 

Depth (m) 

Total Obs 

RMSE (cm/s) 

ROMS POM FVCOM SELFE 

CF(26cm/s) 

ROMS POM FVCOM SELFE 

1 22.9 3.7 25.4 24.5 19.4 24.4 66.6 67.9 81.9 71.0 

17 30.5 7.6 11.9 8.8 12.2 9.8 97.5 99.2 96.1 99.4 

23 11.6 3.7 15.1 15.7 23.7 21.4 91.3 89.9 73.7 78.9 

33 14.6 3.7 29.0 26.1 15.4 31.8 57.7 64.3 90.8 46.9 

39 12.8 4.3 23.0 40.8 17.7 34.4 72.8 36.4 82.4 49.8 

42 10.1 4.9 36.8 28.6 18.9 27.3 51.4 61.5 84.0 61.7 

47 13.1 4.6 37.7 36.9 19.2 29.8 36.9 32.6 82.1 49.6 

50 15.2 7.3 33.5 29.7 28.2 32.5 47.7 50.2 63.4 47.6 

51 13.7 5.2 33.6 33.7 21.9 34.1 44.2 40.1 76.6 45.2 

52 10.4 6.1 22.5 21.6 19.8 23.2 74.5 77.4 80.5 74.9 

54 11.0 4.6 11.3 9.4 8.3 9.1 98.0 99.4 100.0 99.6 

Table 2.5. MEE Salinity Skill Assessment Results 

Station 

 No. 

Depth (m) 

Total Obs 

RMSE (PSU) 

ROMS POM FVCOM SELFE 

CF(3.5 PSU) 

ROMS POM FVCOM SELFE 

1 22.9 3.7 4.1 4.0 1.5 11.4 48.0 54.3 97.3 0.0 

17 30.5 7.6 1.5 1.5 1.5 2.0 100.0 100.0 100.0 94.2 

23 11.6 3.7 6.3 5.5 3.2 10.8 4.3 40.7 73.8 0.9 

33 14.6 3.7 11.5 9.2 4.8 11.3 1.7 22.5 48.4 2.5 

39 12.8 4.3 6.1 3.2 1.8 3.5 43.2 67.5 96.6 61.6 

42 10.1 4.9 4.2 0.3 2.5 0.4 60.3 100.0 100.0 100.0 

47 13.1 4.6 0.0 0.0 1.7 0.0 100.0 100.0 100.0 100.0 

50 15.2 7.3 0.0 0.0 2.2 0.0 100.0 100.0 100.0 100.0 

51 13.7 5.2 0.0 0.0 1.6 0.0 100.0 100.0 100.0 100.0 

52 10.4 6.1 0.0 0.0 2.3 0.0 100.0 100.0 100.0 100.0 

54 11.0 4.6 0.0 0.1 1.2 0.1 100.0 100.0 100.0 100.0 

Table 2.6. MEE Water Temperature Skill Assessment Results 

Station 

 No. 

Depth (m) 

Total Obs 

RMSE (PSU) 

ROMS POM FVCOM SELFE 

CF(3.5 PSU) 

ROMS POM FVCOM SELFE 

1 22.9 3.7 2.5 2.3 1.7 3.5 78.0 83.9 94.5 53.4 

17 30.5 7.6 2.0 2.6 1.6 4.4 89.8 76.4 92.3 47.2 

23 11.6 3.7 3.3 3.4 2.2 6.0 67.7 54.1 84.2 16.7 

33 14.6 3.7 1.5 2.2 1.6 5.3 97.8 84.6 92.0 20.8 

39 12.8 4.3 0.4 0.9 6.8 6.6 100.0 100.0 0.0 0.0 

42 10.1 4.9 0.7 2.2 5.7 4.7 100.0 91.3 6.8 21.3 

50 15.2 7.3 1.1 0.8 2.0 1.5 100.0 100.0 84.6 100.0 

51 13.7 5.2 3.0 4.7 3.0 2.8 64.3 61.5 63.6 58.9 

52 10.4 6.1 1.1 0.9 2.0 1.5 100.0 100.0 84.9 100.0 

54 11.0 4.6 1.7 1.7 1.8 1.7 100.0 99.2 97.8 98.3 
18 

2.5 Summary and Additional Considerations 

To further study these results, values of bottom friction used in previous studies were reviewed. In 

the Long Island Sound Study, which employed 7 vertical levels to represent maximum depths order 

70m, z0=2 cm with CDmin=0.0025 was used (Schmalz, 1994. In Galveston Bay, the maximum 

water depths were only 20m and with 5 vertical levels, and z0=1.5 mm with CDmin=0.0025 was 

used (Schmalz, 2000a; 2000b). Whitney and Garvine (2006) in simulating the interaction of the 

Delaware Estuary plume with the Delaware Coastal Current used POM with z0=3 mm and 

CBCMIN=0.0050 (double the usual value). The high CBCMIN value would serve to increase the 

friction in the offshore regions to insure stability, while the lower z0 value order 3 mm would 

improve the tidal response up river. 

In reviewing the nautical charts, the depths within the present grid represent the channel up to 

Burlington, PA. From Burlington, PA to Newbold, PA the depths should be modified to insure the 

correct channel depth. However from Newbold, PA to Trenton, NJ, the navigation channel depths 

are only order 24 ft and they appear to be somewhat erratically represented in the present depth field. 

In addition, above Burlington, PA the grid cell widths may need some modification to insure that 

they represent the channel widths. It appears that some fine tuning in grid cell width and depths may 

need to be made above Burlington, PA to improve the tidal response at Trenton, NJ. 

Based on the assessment of the MEE results, additional improvement in the water level and current 

response in the river section above Philadelphia, PA is needed by all of the models to meet the NOS 

skill requirements (NOS, 1999; Hess et al., 2003). The three-dimensional unstructured model results 

from FVCOM and SELFE were not clearly superior to the structured three-dimensional models 

POM and ROMS predictions, despite the extremely complex sinuous nature of the river shoreline, 

and therefore additional work with POM and ROMS was conducted. The approach was to work with 

the POM and seek improvements, due to the fact that it had been used in the original 

nowcast/forecast systems in New York Harbor, Galveston Bay, and in the Great Lakes. 
19 

3. POM MEDIUM GRID RESOLUTION HINDCASTS 

Two fifteen day periods were selected for further consideration. The first period, 27 March – 10 

April, 2004 contained a coastal surge event as well as a high flow event of 121,000 cfs. The second 

period, 10-24 September, 1984 was dominated by extremely low flow of order 3000 cfs at Trenton, 

NJ and represented a period of potential salinity intrusion. There also was very little storm activity 

along the coast and hence the period was dominated by astronomic tides and allowed for an 

assessment of the tidal response. 

3.1 Hindcast Setup Procedures 

To move toward a more standard nowcast/forecast system setup, the NOS operational Galveston Bay 

Nowcast/Forecast System was emulated but slightly modified using the approach developed during 

the Long Island Sound Study (LISS). In LISS, a second section of the grid generation program was 

used to provide the initial density structure, the SST field at 15 to 30 day intervals, and the salinity 

and temperature boundary conditions for rivers and the ocean boundary (Schmalz, 1994). In the 

present NOS Galveston Bay operational nowcast/forecast, a ten-step set-up program is used to 

provide the forcing for each 24 hour nowcast, and for the 30 hour forecast (Schmalz and Richardson, 

2002). Within this program, the density structure is updated at the beginning of each nowcast based 

on the observed PORTS readings with the sea-surface temperature, salinity and temperature 

boundary conditions persisted over the nowcast/forecast period. Rather than employ this approach, 

the LISS approach for handling the initial and boundary conditions was used and then steps 6, 7, and 

8 in the ten-step nowcast/forecast procedure were eliminated. The remaining steps are used to 

specify the simulation period (Step 1), generate harmonically reconstructed water surface elevation 

(Step 2) and currents (Step 3), place the observed data in the appropriate format for the graphics 

programs (Step 4), produce the subtidal water level signals at Chesapeake City, MD and Cape May, 

NJ (Step 5), generate the average daily inflows for the 12 rivers (Step 9), and use Barnes (1973) 

interpolation from meteorological data at 10 stations (including 2 offshore NBDC buoys) to provide 

the wind and sea-level atmospheric pressure fields. The subtidal water level signal at Cape May, NJ 

was applied to the entire ocean open boundary. Within the present operational NOS nowcast/forecast 

systems, the approach of applying a coastal water level measured or forecast subtidal water level to 

the entire open boundary has been used. In the present case with the open boundary extending to the 

shelf break this may not be valid. An alternative approach would be to reduce the extent of the grid 

on the shelf to perhaps the 20 to 50 m contour as used by Celebioglu and Piasecki (2006). 

3.2 Baseline Simulation

Using the above methods, POM was used to simulate the period 27 March – 5 April, 1984 as an 

initial 10-day reference period. The medium resolution grid (also used in the ROMS medium grid 

simulations in Chapter 4) is shown in Figures 3.1 and 3.2 along with the locations of the NOS 

CTD/Current stations used in the model-data comparisons and the major surface meteorological 

stations used to develop the interpolated meteorological fields. Wind speed and direction and 

atmospheric pressure were produced using Barnes (1973) interpolation at three hour intervals with 
20 

PHL

TTN

54

52

Figure 3.1. Upper River POM and ROMS grid. Note CTD/Current stations are 

numbered with Met Stations in text. 
21 

Figure 3.2. Lower River and Bay POM and ROMS grid. Note Current/CTD stations are 

numbered, while major cities and Met Stations are in text. Note NBDC buoy 

44009 is located near the bottom left corner of the map, while NDBC buoy 

44012 is further to the northeast. 

16

17 18 19

23 22 21

33

24 25

154

50

51

ATL

Lewes

Cape May

Ches. Cty

WIL

PHL

2

49 47

39

42
22 

wind speed and direction RMS errors order 2 m/s and 25 oT, respectively, and sea level atmosphere 

pressure RMS errors order 1.5 mb. In the MEE the subtidal water level at the head of the C&D canal 

was considered zero. Here, the subtidal water level signal at the Chesapeake Bay end of the C&D 

canal was based on Chesapeake City, MD as determined via a linear regression (bias=0.003, 

gain=0.784) from the Baltimore, MD subtidal water level over the four month period July-October, 

1984. Monthly RMSEs were order 5 cm and storm periods were well produced. 

Within the NOS operational nowcast/forecast systems water levels are specified with respect to the 

MLLW datum at each PORTS station. Within the Galveston Bay Nowcast/Forecast System the 

model datum is taken as MTL and at each station the tidal epoch adjustment from MTL to MLLW is 

added to the model prediction. Within the Delaware River and Bay system, two datums are used. 

Along the coast and within the Bay proper MSL is taken as the model datum, while above 

Philadelphia, PA mean river level (MRL) is assumed equal to NAVD-1988 and is taken as the model 

datum. Simulated water levels are compared with observations in Table 3.1 with RMSEs increasing 

from 14 cm at the Capes to 23 cm at Philadelphia, PA with a maximum near the head of tide at 

Trenton, NJ of 47 cm as shown in Figure 3.3. It should be noted that if one uses MSL as the datum 

throughout, the RMSE at Trenton, NJ increases to 53 cm. In this and all subsequent tables, the 

relative error corresponds to the Wilmott et al. (1985) dimensionless (0-1) relative error, with zero 

representing perfect agreement. Note for the time series plots (Figures 3.3-3.7) the indicator of 

agreement (IND AGMT) equal to one minus the relative error is given. 

 

Table 3.1. Water Surface Elevation-MLLW (m) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984. 

Station RMS Error (cm) Relative Error (-) Model Mean (cm) Observed Mean 

(cm) 

Lewes, DE 14 0.02 91 86 

Cape May, NJ 14 0.01 98 93 

Indian River, DE 23 0.07 68 63 

Phila. Pier 11, PA 23 0.04 135 133 

Trenton, NJ 47 0.09 180 191 

Current speed and direction are compared against observations in Tables 3.2 and 3.3, 

respectively. The current strength is under-predicted at Station 33 and within the river sections. 

Current directions are reasonably represented within the Bay and river sections, where the 

currents are rectilinear. At continental shelf stations16 and 17 the currents are rotary in nature and the model 

directions exhibit larger discrepancies from the observations. The simulated salinity at the corresponding model 

sigma level (K=1, 15 with 1 representing the near surface) are compared with observations in Table 3.4. One notes 

as shown in Figure 3.4 at Station 33 in the region of large horizontal gradients, the RMSE of order 6.5 PSU with a 

large discrepancy in model and observed means. The model temperature response is contrasted with observations in 

Table 3.5. With the SST specification, the RMSEs are within order 2 o

C. 
23 

Table 3.2. Current Speed (cm/s) Baseline High Flow Hindcast: 

March 27 - April 5, 1984. DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

16 at 11 13.65 0.46 9.98 15.33 

17 at 3 13.45 0.55 13.56 13.34 

23 at 8 14.57 0.11 42.71 40.54 

33 at 11 25.74 0.22 43.58 58.17 

50 at 8 29.87 0.36 39.73 61.78 

52 at 4 21.54 0.34 30.97 47.17 

Table 3.3. Current Direction (oT) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984. DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

 (o

T) 

Relative Error 

 (-) 

Model Mean 

(

o

T) 

Observed Mean 

 (oT) 

16 at 11 89.75 0.85 186.29 228.85 

17 at 3 136.62 0.83 174.72 215.01 

23 at 8 26.40 0.02 243.53 254.61 

33 at 11 35.83 0.04 226.99 226.66 

50 at 8 30.15 0.03 167.41 176.83 

52 at 4 26.56 0.02 148.05 148.01 

 

Table 3.4. Salinity (PSU) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

16 at 3 0.95 0.73 31.66 32.58 

16 at 8 0.67 0.71 31.66 32.19 

16 at 11 0.83 0.70 31.63 32.28 

17 at 3 1.12 0.92 32.71 33.78 

23 at 8 1.23 0.57 25.81 25.58 

33 at 11 6.48 0.67 20.01 13.14 

 

Table 3.5. Temperature (oC) Baseline High Flow Hindcast: 

 March 27 - April 5, 1984. DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

16 at 3 2.07 0.84 6.78 5.01 

16 at 8 2.05 0.82 6.80 5.06 

16 at 11 1.99 0.79 6.83 5.17 

17 at 3 1.98 0.87 7.40 5.51 

23 at 8 0.65 0.55 6.43 6.43 

33 at 11 0.73 0.57 5.69 6.71 

 
24 

Figure 3.3. Baseline High Flow Hindcast (27 March – 5 April, 1984) Water Surface 

Elevation at Trenton, NJ. Note observations are at one hour intervals over the 

entire 15 day period, 27 March – 10 April, 1984. 
25 

Figure 3.4. Baseline High Flow Hindcast (27 March – 5 April, 1984) Salinity at Station 

33. Note observations are at 10 minute intervals over the entire 15 day period 

27 March – 10 April, 1984. 
26 

3.3 Revised Geometry High Flow Simulation 

To seek further improvement a revised geometry was employed. The C&D canal width was adjusted 

to its actual channel width of 121.9 m. It was straightened and made one grid cell wide. USACOE 

project channel depths were specified for the navigation channels from the Bay to Philadelphia, PA 

from Philadelphia, PA to Newbold, PA and from Newbold, PA to Trenton, NJ. In addition, several 

upriver marsh areas were specified at depths of order 1 m. A spatially varying bottom roughness was 

incorporated, such that over the continental shelf z0 = 1 cm, from the Capes to the river mouth z0

linearly decreases to 0.3 cm, from the river mouth to below the Tacony Bridge, NJ it remains at 0.3 

cm, and from there to the head of tide it linearly increases to 1.3 cm. 

Simulated water levels over the 27 March – 10 April, 1984 are contrasted with observations in Table 

3.6. RMSEs are slightly reduced by 1 cm at Cape May, NJ and at Philadelphia, PA and are 

substantially reduced by 10 cm at Trenton, NJ as shown in Figure 3.5. In Tables 3.7 and 3.8, the 

current speed and direction comparisons are given. One notes the improved current speed response 

at Station 33 with current directions remaining nearly the same. In Table 3.9, the salinity response at 

Station 33 in the region of large horizontal salinity gradients is substantially improved with the 

RMSE reduced by order 4 PSU and with a much closer agreement to the observed mean (see Figure 

3.6). In Table 3.10, the temperature response is very similar to that of the baseline hindcast. 

Table 3.6. Water Surface Elevation-MLLW (m) Revised Geometry High Flow Hindcast: 

March 27 - April 10, 1984.

Station RMS Error (cm) Relative Error (-) Model Mean (cm) Observed Mean 

(cm) 

Lewes, DE 13 0.02 86 86 

Cape May, NJ 13 0.01 93 93 

Indian River, DE 22 0.08 62 63 

Ocean City Pier, 

MD 

13 0.04 73 70 

Phila Pier 11, PA 22 0.03 145 133 

Trenton, NJ 37 0.04 204 191 

Table 3.7. Current Speed (cm/s) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

16 at 11 12.76 0.48 9.82 15.33 

17 at 3 12.73 0.59 14.06 13.34 

23 at 8 15.28 0.14 42.40 40.54 

33 at 11 19.46 0.12 52.19 58.17 

50 at 8 27.83 0.38 46.72 61.78 

52 at 4 17.99 0.26 38.65 47.17 
27 

Table 3.8. Current Direction (o

T) Revised High Flow Hindcast: 

 March 27 - April 10, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(

o

T) 

Relative Error 

(-) 

Model Mean 

(

o

T) 

Observed Mean 

(

o

T) 

16 at 11 86.25 0.78 194.21 228.85 

17 at 3 137.58 0.83 178.02 215.01 

23 at 8 31.54 0.03 239.16 254.61 

33 at 11 29.10 0.02 219.72 226.66 

50 at 8 36.06 0.04 170.13 176.83 

52 at 4 30.48 0.03 153.85 148.01 

Table 3.9. Salinity (PSU) Revised Geometry High Flow Hindcast: 

 March 27 - April 10, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

16 at 3 1.05 0.65 31.62 32.58 

16 at 8 0.69 0.60 31.60 32.19 

16 at 11 0.78 0.59 31.58 32.28 

17 at 3 1.01 0.89 32.79 33.78 

23 at 8 1.49 0.45 25.33 25.58 

33 at 11 2.72 0.17 12.61 13.14 

 

Table 3.10. Temperature (oC ) Revised Geometry High Flow Hindcast: 

March 27 - April 10, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

16 at 3 1.86 0.69 6.81 5.01 

16 at 8 1.82 0.67 6.82 5.06 

16 at 11 1.74 0.65 6.83 5.17 

17 at 3 2.02 0.85 7.51 5.51 

23 at 8 0.73 0.99 6.43 6.43 

33 at 11 1.40 0.51 5.71 6.71 
28 

Figure 3.5. Revised Geometry High Flow Hindcast (27 March – 10 April, 1984) 

Water Surface Elevation at Trenton, NJ. Note observations are at one hour 

intervals.
29 

Figure 3.6. Revised Geometry High Flow Hindcast (27 March – 10 April, 1984) 

Salinity at Station 33. Note observations are at 10 minute intervals. 
30 

3.4 Revised Geometry Low Flow Simulation 

To examine the effect of the revised geometry under low flow conditions, the 10-24 September, 

1984 period was simulated. Wind speed and direction and atmospheric pressure as produced by the 

Barnes (1973) interpolation at three hour intervals are compared with hourly observations and are of 

the same order RMSE as for the high flow period. Note mean wind speeds are lower than during the 

high flow period and are quite gentle. Simulated water levels are contrasted with observations in 

Table 3.11. RMSEs are generally of the same order as obtained under high flow conditions 

particularly at Trenton, NJ as shown in Figure 3.7. However, one notes at the Capes and at 

Philadelphia, PA an increase of order 6 cm in RMSE. These results may be improved by reducing 

the grid extent onto the shelf, thereby specifying the subtidal water level signal nearer the 

measurement location. However, in so doing one loses the ability to predict the Delaware coastal 

current. 

In Tables 3.12 and 3.13, the current speed and direction comparisons are given. One notes at Station 

33 the current speed responses are very similar to those obtained for the high flow hindcast. Note the 

current speeds are slightly under-predicted at the upriver stations (33, 51 and 154). Current direction 

errors are comparable under both high and low flow conditions. In Table 3.14, the salinity response 

is compared with observations. One notes a very favorable comparison, particularly at Station 33 in 

the region of large horizontal salinity gradients and the model successfully represents the salinity 

intrusion under low flow conditions. As shown in Table 3.15, the temperature response also 

compares very well to the observations. 

Table 3.11. Water Surface Elevation-MLLW (m) Revised Geometry Low Flow Hindcast: 

 September 10-24, 1984. 

 Station RMS Error (cm) Relative Error (-) Model Mean (cm) Observed Mean 

(cm) 

Lewes, DE 17 0.04 62 70 

Cape May, NJ 21 0.04 73 79 

Indian River, DE 17 0.07 39 47 

Ocean City Pier, 

MD 

17 0.06 51 61 

Phila. Pier 11, PA 27 0.05 104 107 

Chesapeake City, 

MD 

12 0.03 111 111 

Trenton, NJ 37 0.05 122 133 
31 

Figure 3.7. Revised Geometry Low Flow Hindcast (10 – 24 September, 1984) Water 

 Surface Elevation at Trenton, NJ. Note observations are at one hour intervals.
32 

 

Table 3.12. Current Speed (cm/s) Revised Geometry Low Flow Hindcast: 

 September 10-24, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

2 at 7 22.64 0.29 42.16 39.01 

16 at 11 7.55 0.53 7.44 9.89 

17 at 15 12.59 0.54 9.66 17.71 

18 at 2 11.47 0.24 25.97 25.18 

19 at 2 15.92 0.31 31.55 28.27 

19 at 8 22.65 0.27 44.74 45.45 

22 at 6 16.52 0.20 32.52 41.69 

23 at 2 20.50 0.47 32.84 17.34 

24 at 2 14.23 0.31 30.66 27.69 

25 at 2 10.90 0.22 23.04 29.22 

33 at 2 16.06 0.33 22.06 29.28 

15 at 9 27.15 0.36 43.12 61.46 

154 at 2 27.18 0.57 10.26 31.47 

Table 3.13. Current Direction (oT) Revised Geometry Low Flow Hindcast: 

 September 10-24, 1984. DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

(

o

T) 

Relative Error 

(-) 

Model Mean 

(

o

T) 

Observed Mean 

(

o

T) 

2 at 7 46.54 0.08 231.70 212.66 

16 at 11 59.06 0.30 159.53 217.85 

17 at 15 69.50 0.31 196.75 230.55 

18 at 2 17.12 0.01 220.75 238.79 

19 at 2 29.24 0.02 232.75 257.01 

19 at 8 39.79 0.05 234.96 247.18 

22 at 6 17.88 0.01 231.26 231.98 

23 at 2 6.56 0.00 240.77 269.80 

24 at 2 39.07 0.05 234.91 245.13 

25 at 2 120.56 0.86 117.22 184.53 

33 at 2 48.11 0.07 225.88 226.26 

15 at 9 39.65 0.04 186.91 194.25 

154 at 2 99.01 0.33 209.43 187.41 
33 

Table 3.14. Salinity (PSU) Revised Geometry Low Flow Hindcast: 

 September 10-24, 1984. DAB denotes distance above the bottom.

Station No 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

2 at 7 0.40 0.58 29.99 30.08 

16 at 3 1.38 0.93 31.08 29.68 

16 at 11 0.29 0.78 31.01 31.15 

19 at 2 0.41 0.14 28.58 28.67 

22 at 6 1.33 0.28 26.28 27.34 

23 at 2 0.64 0.45 27.22 27.44 

24 at 2 1.11 0.39 26.05 26.21 

33 at 2 2.06 0.51 18.01 18.81 

154 at 2 0.83 0.71 6.83 6.59 

Table 3.15. Temperature (oC) Revised Geometry Low Flow Hindcast: 

 September 10-24, 1984. DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

2 at 7 0.60 0.81 20.60 21.04 

16 at 3 1.19 0.57 19.36 20.87 

16 at 11 0.75 0.49 20.48 20.93 

19 at 2 0.29 0.60 20.93 20.67 

19 at 8 0.34 0.62 20.93 20.62 

22 at 6 0.52 0.67 21.22 20.75 

23 at 2 0.56 0.80 21.12 21.20 

24 at 2 0.61 0.57 21.10 20.63 

33 at 2 0.48 0.70 22.85 22.40 

3.5 Summary and Additional Considerations 

The revised geometry of the C&D canal, channel depth modifications, and the incorporation of a 

spatially varying bottom roughness, led to improved water level, current, salinity, and temperature 

response for both the high flow and low flow fifteen day periods. Further modification of the bottom 

roughness zones both in value and extent is warranted. The investigation of the bottom friction zones 

used by Walters (1992a; 1992b) and later employed by DiLorenzo et al. (1994) and Kim and 

Johnson (1998) would be worth consideration. In fact, Walters notes that it was only through the use 

of spatially varying bottom friction zones, that the correct astronomical tidal response could be 

achieved. Note in considering the Delaware Coastal Current, Whitney and Garvine (2006) employed 

a constant bottom roughness, z0 = 0.3 cm. Ramsey et al. (1996) used six different bottom roughness 

Manning’s n coefficients for the main channel and side embayments. 

As noted by Johnson et al. (1988) and Galperin and Mellor (1990a; 1990b) a major issue is the 

representation of the river sections above Philadelphia, PA. Parker (1984; 1991) has studied the 

frictional effects in the river sections with a one-dimensional model. Within the present grid 
34 

structure, order 4 grid cells are employed within the upper river sections with only 2 grid cells 

representing the river at Trenton, NJ. To specify the river inflow of the Delaware River at Trenton, 

NJ, the USGS station above the tide is used to specify the average daily discharge, which is split 

equally over two grid cells in POM and ROMS medium resolution grid. For the ROMS high 

resolution grid in Chapter 5 the flows are distributed as 0.3, 0.4, and 0.3 over the three grid cells. 

The USGS gage and forecast point is located on the left hand side bank looking downstream 

immediately above the Calhoun Bridge. The rapids seen on the navigation chart are called the 

"Trenton Falls" and the tide begins below them. Most of the diurnal fluctuations are from directed 

releases from the New York City reservoirs in the headwater areas in the Catskill Mountains of New 

York. In the USGS gage remarks section, it is noted that water is diverted just above the gage for 

Morrisville, PA and Trenton, NJ for water supply. They note that diurnal fluctuations at medium and 

low flow are caused by power plants on tributary streams. There are several large hydro-power 

stations on the Lackawaxen and Mongaup Rivers that release as needed. 99.99+% of the time the 

gage is not influenced by the tides. At two high tides during the April 2005 floods there may have 

been some influence (Nickelsburg, 2006). As a result, during high flow conditions, the average daily 

flow specification may need to be revised to hourly flow values. 

A transition from POM to ROMS, as discussed in subsequent chapters, was made to see if 

comparable improvement in results with respect to the MEE could be achieved. It is desirable to 

implement ROMS to enable more efficient parallel computation using MPI within the National 

Centers for Environmental Prediction (NCEP) environment, since POM was not implemented within 

the MPI framework. 
35 

4. ROMS MEDIUM GRID RESOLUTION HINDCASTS 

ROMS was employed to simulate the same high and low flow simulations of POM in Chapter 3. The 

same treatment of the subtidal water level boundary conditions and model datum were invoked. 

Within the Delaware River and Bay system, two datums are used. Along the coast and within the 

Bay proper MSL is taken as the model datum, while above Philadelphia, PA mean river level (MRL) 

is assumed equal to NAVD-1988 and is taken as the model datum. The medium resolution grid 

sections used in both POM and ROMS simulations are shown as previously in Figures 3.1 and 

Figure 3.2. 

4.1. Model Revisions 

To set the stage for the ROMS revised simulations, we first recap the POM revisions in Chapter 3. 

Within POM the following conditions were employed: 

1) The C&D canal width was adjusted to its actual channel width of 121.9 m. It was straightened and 

made one grid cell wide. 

2) The United States Army Corps of Engineers (USACOE) project channel depths were specified 

for the navigation channels from the Bay to Philadelphia, PA from Philadelphia, PA to Newbold, PA 

and from Newbold, PA to Trenton, NJ. 

3) Several upriver marsh areas were specified at depths of order 1 m. 

4) SST was specified by using the nearest surface value of the CT moorings and CTD profiles. 

5) A spatially varying bottom roughness was incorporated in the hydrodynamic model, such that 

over the continental shelf z0 = 1 cm, from the Bay entrance to the river mouth z0 linearly decreases to 

0.3 cm, from the river mouth to below the Tacony Bridge, NJ it remains at 0.3 cm, and from there to 

the head of tide it linearly increases to 1.3 cm. 

For the ROMS simulations, the following conditions were employed: 

1) The C&D canal width was adjusted to its actual channel width of 121.9 m. It was straightened and 

made two grid cells wide to accommodate the higher order numerical scheme. 

2) The USACOE project channel depths were specified using NOS bathymetric surveys. 

3) Upriver marsh areas were not explicitly considered. 

4) A full bulk flux formulation was used to provide the surface heat fluxes using the MEE forcing 

files (Patchen, 2008). 

5) A spatially varying quadratic friction coefficient set was incorporated in the hydrodynamic model, 

such that over the continental shelf rdr = 0.007, from the Bay entrance to the river mouth rdr 

linearly decreases to 0.005, from the river mouth to the head of tide it linearly increases to 0.009. 

The revision was incorporated as the CPPDEF option RDR_VAR. 

6) To output the wind and sea level atmospheric time series at stations in the stations file and to 

output these fields, the CPPDEF option MET_OUT was added. 
36 

4.2. High Flow Simulation 

Wind speed and direction and atmospheric pressure were produced using Barnes (1973) 

interpolation at three hour intervals with wind speed and direction RMS errors order 2 m/s and 25 o

T, respectively, and sea level atmosphere pressure RMS errors order 1.5 mb. Simulated water levels 

are compared with observations in Table 4.1 with RMSEs increasing from order 15 cm at the Bay 

entrance to 25 cm at Philadelphia, PA with a maximum near the head of tide at Trenton, NJ of 37 cm 

as shown in Figure 4.1 for both models. In this and all subsequent tables, the relative error 

corresponds to the Willmott et al. (1985) dimensionless (0-1) relative error, with zero representing 

perfect agreement. Note for the time series plots, the indicator of agreement (IND AGMT) equal to 

one minus the relative error is given. 

 

Table 4.1. Water Surface Elevation-MLLW (m) High Flow Hindcast: 

 27 March – April 10, 1984: ROMS Results / POM Results 

Station RMS Error 

(cm) 

Relative Error 

(-) 

Model Mean 

(cm) 

Observed Mean 

(cm) 

Lewes, DE 15/13 0.02/0.02 81/86 86 

Cape May, NJ 19/13 0.03/0.01 88/93 93 

Indian River, DE 20/22 0.07/0.08 58/62 63 

Phila. Pier 11, PA 27/22 0.05/0.03 143/145 133 

Trenton, NJ 37/37 0.04/0.04 200/204 191 

Current speed and direction model predictions are compared against observations in Tables 4.2 and 

4.3, respectively. The current strengths at Station 33 and within the river sections are in reasonable 

agreement with observations. Current directions are reasonably represented within the Bay and river 

sections, where the currents are rectilinear. At continental shelf stations 16 and 17 the currents are 

rotary in nature and both model directions exhibit larger discrepancies from the observations. 

Table 4.2. Current Speed (cm/s) High Flow Hindcast: 

 27 March – April 10, 1984: ROMS Results / POM Results 

 DAB denotes distance above the bottom. 

 Station No 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

16 at 11 13.28/12.76 0.49/0.48 7.96/9.82 15.33 

17 at 3 12.27/12.73 0.60/0.59 7.32/14.06 13.34 

23 at 8 16.76/15.28 0.16/0.14 43.12/42.40 40.54 

33 at 11 25.20/19.46 0.22/0.12 58.17/52.19 58.17 

50 at 8 22.65/27.83 0.22/0.38 59.52/46.72 61.78 

52 at 4 16.76/17.99 0.20/0.26 41.37/38.65 47.17 

 

 
37 

Figure 4.1. High Flow Hindcast (27 March – 10 April 1984) Water Surface Elevation 

 at Trenton, NJ. Top panel: ROMS Hindcast Bottom panel: POM Hindcast 

 Note observations are at one hour intervals. 
38 

Table 4.3. Current Direction (oT) High Flow Hindcast 

 27 March – April 10, 1984: ROMS Results / POM Results 

 DAB denotes distance above the bottom. 

 Station No 

at DAB (m) 

RMS Error 

 (o

T) 

Relative Error 

 (-) 

Model Mean 

(

o

T) 

Observed Mean 

 (oT) 

16 at 11 57.77/86.25 0.64/0.78 179.40/194.21 228.85 

17 at 3 113.22/137.58 0.84/0.83 188.76/178.02 215.01 

23 at 8 40.63/31.54 0.05/0.03 234.56/239.16 254.61 

33 at 11 41.86/29.10 0.05/0.02 210.39/219.72 226.66 

50 at 8 48.80/36.06 0.08/0.04 173.56/170.13 176.83 

52 at 4 41.50/30.48 0.06/0.03 154.80/153.85 148.01 

 

The simulated salinities at the corresponding POM model sigma levels (k=1, 15 with 1 representing 

the near surface) are compared with observations in Table 4.4. One notes as shown in Figure 4.2 at 

Station 33 in the region of large horizontal gradients, that a reasonable RMSE of order 3.0 PSU is 

achieved. The simulated temperature response is contrasted with observations in Table 4.5 for both 

models. With either the SST specification in POM or the bulk heat flux formulation in ROMS, the 

RMSEs are within order 2 o

C. 

Table 4.4. Salinity (PSU) High Flow Hindcast 

 27 March – April 10, 1984: ROMS Results / POM Results 

 DAB denotes distance above the bottom. 

 Station No 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

16 at 3 0.80/1.05 0.58/0.65 31.87/31.62 32.58 

16 at 8 0.51/0.69 0.56/0.60 31.80/31.60 32.19 

16 at 11 0.64/0.78 0.60/0.59 31.76/31.58 32.28 

17 at 3 0.93/1.01 0.93/0.89 32.97/32.79 33.78 

23 at 8 1.54/1.49 0.45/0.45 25.71/25.33 25.58 

33 at 11 2.97/2.72 0.20/0.17 12.63/12.61 13.14 

 

Table 4.5. Temperature (oC) High Flow Hindcast 

 27 March – April 10, 1984: ROMS Results / POM Results 

 DAB denotes distance above the bottom. 

 Station No 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

16 at 3 2.16/1.86 0.68/0.69 7.16/6.81 5.01 

16 at 8 2.24/1.82 0.66/0.67 7.29/6.82 5.06 

16 at 11 2.22/1.74 0.65/0.65 7.38/6.83 5.17 

17 at 3 2.19/2.02 0.85/0.85 7.66/7.51 5.51 

23 at 8 0.81/0.73 0.24/0.99 7.19/6.43 6.43 

33 at 11 0.38/1.40 0.04/0.51 6.74/5.71 6.71 

 
39 

Figure 4.2. Simulated versus Observed (10 minute) Salinity at Station 33 Level 4 at 11m 

 above the bottom. Top panel: ROMS Hindcast Bottom panel: POM Hindcast 

 Note observations are at 10-minute intervals. 
40 

4.3 Low Flow Simulation 

To examine the effect of the above revisions under low flow conditions, the 10-24 September, 1984 

period was simulated. Wind speed and direction and atmospheric pressure as produced by the Barnes 

(1973) interpolation at three hour intervals are compared with hourly observations and are of the 

same order RMSE as for the high flow period. Note that mean wind speeds are lower than during the 

high flow period and are quite gentle. Simulated water levels are contrasted with observations in 

Table 4.6. RMSEs are generally of the same order as obtained under high flow conditions as shown 

at Trenton, NJ in Figure 4.3. However, one notes in comparing Tables 4.1 and 4.6, at the Bay 

entrance and at Philadelphia, PA a decrease in mean water levels of order 15 cm. These results 

indicate the impact of the long period Sa and Ssa constituents. 

Table 4.6. Water Surface Elevation-MLLW (m) Low Flow Hindcast 

September 10-24, 1984: ROMS Results/ POM Results 

 Station RMS Error 

(cm) 

Relative Error 

 (-) 

Model Mean 

(cm) 

Observed Mean 

(cm) 

Lewes, DE 18/17 0.04/0.04 71/62 70 

Cape May, NJ 21/21 0.04/0.04 80/73 79 

Indian River, DE 17/17 0.07/0.07 48/39 47 

Ocean City Pier, 

MD 

14/17 0.04/0.06 58/51 61 

Phila. Pier 11, PA 27/27 0.05/0.05 113/104 107 

Trenton, NJ 35/37 0.04/0.05 132/122 131 

In Tables 4.7 and 4.8, the current speed and direction comparisons are given. One notes at Station 33 

the current speed responses are very similar to those obtained for the high flow hindcast. Note that 

the current speeds are slightly under-predicted at upriver station 51. Current direction errors are 

comparable under both high and low flow conditions. In Table 4.9, the salinity response is compared 

with observations. One notes a very favorable comparison, particularly at Station 33 in the region of 

large horizontal salinity gradients. As shown in Table 4.10, the temperature responses in both 

models also compare very well to the observations. 
41 

Figure 4.3. Low Flow Hindcast (10 – 24 September, 1984) Water Surface Elevation 

 at Trenton, NJ. Top panel: ROMS Hindcast Bottom panel: POM Hindcast 

 Note observations are at one hour intervals. 
42 

 

Table 4.7. Current Speed (cm/s) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS Results/ POM Results

Station 

Model Level 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

2 Level 8 35.00/22.64 0.57/0.29 40.48/42.16 39.01 

16 Level 12 10.35/9.18 0.72/0.65 6.96/6.59 14.38 

16 Level 6 7.91/7.55 0.59/0.53 7.39/7.44 9.89 

17 Level 6 14.59/12.59 0.58/0.54 7.03/9.66 17.71 

18 Level 9 8.25/11.47 0.10/0.24 26.95/25.97 25.18 

19 Level 13 14.66/15.92 0.21/0.31 34.81/31.55 28.27 

19 Level 5 14.02/22.65 0.09/0.27 46.99/44.74 45.45 

22 Level 7 11.15/16.52 0.08/0.20 37.37/32.52 41.69 

23 Level 11 18.31/20.50 0.40/0.47 31.24/32.84 17.34 

24 Level 8 7.99/14.23 0.10/0.31 28.62/30.66 27.69 

25 Level 11 7.04/10.90 0.07/0.22 27.94/23.04 29.22 

33 Level 15 19.22/16.06 0.40/0.33 33.72/22.06 29.28 

51 Level 5 23.62/27.15 0.28/0.36 48.96/43.12 61.46 

154 Level 15 33.53/27.18 0.63/0.57 29.16/10.26 31.47 

Table 4.8. Current Direction (oT) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS Results/ POM Results 

Station 

Model Level 

RMS Error 

(

o

T) 

Relative Error 

(-) 

Model Mean 

(

o

T) 

Observed Mean 

(

o

T) 

2 Level 8 71.90/46.54 0.14/0.08 223.04/231.70 212.66 

16 Level 6 113.91/59.06 

 

0.43/0.30 142.42/159.53 217.85 

17 Level 6 89.17/69.50 0.36/0.31 192.56/196.75 230.55 

18 Level 9 7.12/17.12 

 

0.00/0.01 223.29/220.75 238.79 

19 Level 13 18.40/29.24 

 

0.01/0.02 220.71/232.75 257.01 

19 Level 5 22.42/39.79 

 

0.01/0.05 229.33/234.96 247.18 

22 Level 7 9.92/17.88 0.00/0.01 227.50/231.26 231.98 

23 Level 11 6.07/6.56 0.00/0.00 238.76/240.77 269.80 

24 Level 8 45.35/39.07 0.06/0.05 242.35/234.91 245.13 

25 Level 11 119.80/120.56 0.87/0.86 107.83/117.22 184.53 

33 Level 15 99.29/48.11 0.30/0.07 231.22/225.88 226.26 

51 Level 5 30.09/39.65 0.03/0.04 189.95/186.91 194.25 

154 Level 15 91.09/99.01 0.31/0.33 165.19/209.43 187.41 
43 

Table 4.9. Salinity (PSU) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS Results/ POM Results

Station 

Model Level 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

2 Level 8 0.48/0.40 0.68/0.58 30.04/29.99 30.08 

16 Level 12 1.38/1.38 0.93/0.93 31.12/31.08 29.68 

16 Level 6 0.27/0.29 0.71/0.78 31.01/31.01 31.15 

19 Level 13 0.89/0.41 0.37/0.14 29.20/28.58 28.67 

22 Level 7 0.66/1.33 0.12/0.28 26.74/26.28 27.34 

23 Level 11 0.76/0.64 0.41/0.45 27.68/27.22 27.44 

24 Level 8 0.46/1.11 0.12/0.39 26.41/26.05 26.21 

33 Level 15 3.07/2.06 0.56/0.51 19.46/18.01 18.81 

154 Level 15 0.65/0.83 0.50/0.71 7.27/6.83 6.59 

Table 4.10. Temperature (oC) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS Results/ POM Results 

Station 

Model Level 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

2 Level 8 0.63/0.60 0.83/0.81 21.40/20.60 21.04 

16 Level 12 1.32/1.19 0.59/0.57 19.15/19.36 20.87 

16 Level 6 0.99/0.75 0.78/0.49 21.31/20.48 20.93 

19 Level 13 1.56/0.29 0.87/0.60 21.77/20.93 20.67 

19 Level 5 1.60/0.34 0.87/0.62 21.79/20.93 20.62 

22 Level 7 1.92/0.52 0.87/0.67 22.38/21.22 20.75 

23 Level 11 1.24/0.56 0.66/0.80 22.08/21.12 21.20 

24 Level 8 2.03/0.61 0.76/0.57 22.46/21.10 20.63 

33 Level 15 0.42/0.48 0.72/0.70 23.27/22.85 22.40 

4.4 Summary and Additional Considerations 

For both 15-day periods, the ROMS simulation results for water levels, currents, salinity, and 

temperature were very similar to those obtained with POM. Note ,while the same horizontal grid 

was used, in the vertical POM uses15 sigma levels while ROMS has 10 generalized s coordinate 

levels. The third order upstream horizontal advection schemes in ROMS as opposed to the second 

order central differencing schemes in POM necessitated an extra day of model spin-up from rest. 

Both models used the Mellor-Yamada 2.5 level turbulence scheme and employed similar offshore 

boundary conditions. Both models were run with a 1 second barotropic time step with POM using a 

10 second and ROMS a 20 second baroclinic time step. As previously noted, a major issue is the 

representation of the C&D Canal and the river sections above Philadelphia, PA. Within the present 

grid structure, the C&D Canal is one grid cell wide in POM and two grid cells wide in ROMS. Also 

order 4 grid cells are employed within the upper river sections with only 2 grid cells representing the 

river at Trenton, NJ. As a result, a higher resolution grid based on the Delft Hydraulics Laboratory 

grid generation software (Delft Hydraulics, 2004) was developed and additional ROMS simulations 

performed as presented in the following chapter. 
44 
45 

5. ROMS HIGH RESOLUTION GRID HINDCASTS 

Previous hydrodynamic simulations in Chapters 2 - 4 indicated the need for a higher resolution grid 

within the river sections to improve water level and current response from Philadelphia, PA to 

Trenton, NJ. First, we discuss the construction of a new high resolution river grid and contrast the 

grid features with those of the previous medium resolution grid. Next, simulation setup, boundary, 

and forcing conditions are discussed. To compare the model performance on the new high resolution 

grid (HRG) versus the previous medium resolution grid (MRG) 15 day simulations are performed 

under both high and low Delaware River flow conditions. To further assess model performance on 

the new grid, an extended seven month hindcast was performed and the water level response was 

evaluated over 15 day periods, as in the high and low flow simulation set. Next, a tidal analysis is 

performed by using a 30 hour low pass filter to extract the tidal signal from the hindcast results 

during April 1984. The resulting tide signal is compared to predicted water levels based on NOS 

accepted harmonic constants to determine the tidal error. Three astronomical tide simulations over 

the HRG are performed for April 1984 using different open boundary conditions to study the 

influence of the open boundary specification on the water level response. Finally, results are 

summarized and further considerations are then discussed. 

5.1 Medium and High Resolution Grids 

The initial medium resolution grid (MRG) shown in Figure 3.1 for the upper Delaware River and in 

Figure 3.2 for the lower Delaware River and Bay was developed using the SEAGRID software 

package (USGS Woods Hole Science Center, 2007). The horizontal grid is 150 x 550 and the grid 

cell length ranges are [110 m, 1665 m] in the x-direction and [140 m, 2645 m] in the y-direction. At 

head of tide at Trenton, NJ the Delaware River is represented by 2 grid cells across. Bathymetry 

adjusted to MLLW was placed on the grid via interpolation of NOS sounding data as detailed by 

Lanerolle (2007). 

A 120 x 733 horizontal high resolution grid (HRG) was developed using the DELFT3D RGFGRID 

software package (Delft Hydraulics, 2004) with resolution order 3 km at the shelf break and order 

100 m at the head of tide at Trenton, NJ. Resolution in the C&D Canal is 200 m with grid cell length 

ranges of [49 m, 6092 m] in the x-direction and [51 m, 3053 m] in the y-direction. At head of tide at 

Trenton, NJ the Delaware River is represented by 3 grid cells across. In the grid construction 

process, three separate splines and grid segments were developed for the upper River, the C&D 

canal, and for the lower Bay-Shelf region, respectively. To generate the final grid, the grid segments 

were combined using the active-passive option and then the grid was orthogonalized. Grid point 

locations were reviewed and edited as necessary to improve orthogonality. The SMS software 

package (Brigham Young University Environmental Modeling Research Laboratory, 2006) was used 

to place and edit the bathymetry on the grid. In Figure 5.1, the new HRG in the C&D canal region is 

shown. Note the ability of the grid to exactly follow the canal and to represent the main navigation 

channel bathymetric features as shown in Figure 5.2. 
46 

Figure 5.1. Map depicting Delaware River and Bay DELFT-3D High Resolution Grid in the C&D 

Canal Region. Splines are constructed through the appropriate points along each 

coordinate direction. Within each rectangle formed by the intersection of the splines, the 

number of grid cells in each coordinate direction is specified. 

Figure 5.2. Map depicting bathymetry with respect to Model Datum in the C&D Canal Region. 

Each dot corresponds to a grid cell center with the darker shadings indicating the 

navigation channel. 
47 

MLLW to model datum corrections at NOS water level gauges were used in a 1/r2 interpolation 

procedure to adjust the MLLW bathymetry to model datum over both grids. For the HRG the 

maximum depth was set to 300m as it extended over a large area at or beyond the shelf break. Both 

horizontal grids are of high quality with orthogonality errors less than 7 degrees. Ten generalized s 

coordinate levels are with surface, bottom, and control parameters of 4.5, 0.95 and 6 m, respectively. 

5.2 Simulation Setup, Initial, Boundary and Forcing Conditions 

All ROMS (Shchepetkin and McWilliams, 2005; Haidvogel et al., 2008) simulations are threedimensional including baroclinics with: a nonlinear equation of state, the Mellor-Yamada 2.5 

turbulence closure, non-normal radiation of the velocity at the boundary, quadratic bottom friction 

via a spatially varying bottom friction coefficient, spline vertical advection of tracer and momentum, 

and third order upstream-biased horizontal advection of tracer and momentum. Table 5.1 outlines the 

simulation setup and additional characteristics of the boundary and forcing conditions particular to 

Table 5.1. Simulation Description, Boundary and Forcing Conditions. 

Simulation Period 

In 1984 

 CPP 

DEF 

Set 

Bottom 

Friction 

Set 

OBC 

HA 

Set 

OBC 

TS 

Set 

UBAR 

VBAR 

Set 

Heat 

Flux 

Set 

Met 

Flux 

Set 

River 

Inflow 

Set 

MRG 15-day 

high and low 

flow 

3/27-

4/10; 

9/10-

9/25 

CPD1 BF1 HA1 ST1 UV1 HF1 MF1 RI1 

HRG 15-day 

high and low 

flow 

3/27-

4/10; 

9/10-

9/25 

CPD1 BF2 HA2 ST2 UV1 HF2 MF1 RI1 

HRG 7-mo 

simulation 

Mar-Sep CPD1 BF2 HA2 ST1 UV1 HF2 MF1 RI1 

HRG Tide 

Simulation 1 

Apr CPD1 BF3 HA1 ST2 UV1 HF2 MF2 RI2 

HRG Tide 

Simulation 2 

Apr CPD2 BF3 HA1 ST2 UV1 HF2 MF2 RI2 

HRG Tide 

Simulation 3 

Apr CPD3 BF3 HA1 ST2 UV2 HF2 MF2 RI2 

Notes: 

CPP DEF Set denotes the boundary ROMS CPPDEF options. 

Bottom Friction Set denotes the spatially varying bottom friction coefficient set. 

OBC HA Set denotes the open boundary harmonic constituent set. 

OBC TS Set denotes the open boundary condition salinity and temperature boundary condition set. 

UBAR VBAR Set denotes the u and v vertically integrated velocity set. 

Heat flux Set denotes the shortwave and downward longwave radiation set. 

Met Flux Set denotes the surface wind and sea-level atmospheric pressure set. 

River Inflow Set denotes the river inflow discharge set. 
48 

Supplemental Note Set: 

CPD1=FSOBC_REDUCED, FSCLAMPED and M2REDUCED at C&D canal and western 

boundary; FSCHAPMAN and M2FLATHER on southern and eastern boundaries 

CPD2=FSCLAMPED and M2REDUCED on all boundaries 

CPD3=FSCLAMPED and M2REDUCED at C&D canal, FSCHAPMAN with SSH_TIDES and 

M2FLATHER with UV_TIDES on southern and eastern boundaries 

Refer to Flather (1976) and Chapman (1985) for computational details. 

BF1= { .007 J=[1,90] , .007 J=[91,124], .005 J=[125,132], .006 J=[133-158], 

 .007 J=[159,232], .008 J=[233,299], .009 J=[300,550] } where J corresponds to the MRG 

 y-direction grid index 

BF2= { .007 J=[1,68] , .007 J=[69,117], .005 J=[118,125], .006 J=[126-209], 

 .007 J=[210,425], .008 J=[426-544], .009 J=[545,732] } where J corresponds to the HRG 

 y-direction grid index 

BF3= { .005 J=[1,68] , .007 J=[69,117], .005 J=[118,125], .007 J=[126-209], 

 .008 J=[210,425], .009 J=[426-544], .010 J=[545,732] } where J corresponds to the HRG 

 y-direction grid index 

HA1= Ssa and Sa included in the tide signal and not in the residual. 

HA2= Ssa and Sa not included in the tide signal but included in the residual. 

ST1=Open boundary salinity and temperature from NOAA’s World Ocean Atlas 2001 (NODC, 

www.nodc.noaa.gov) 

ST2=Adjustments to ST1 based on NOS 1984 Circulation Survey Data (Klavens et al., 1986) 

UV1=Vertically integrated u and v velocities set to zero 

UV2=Vertically integrated u and v velocities from tidal inversion using the ADCIRC model for the 

Western North Atlantic Ocean on the East Coast 1995 grid as developed by Myers (2007; personal 

communication) 

HF1==Radiation fluxes derived from a grid to grid interpolation of NOAA’s reanalysis product 

(NCEP, www.ncep.noaa.gov/mmb/rrean/index.html) on a 32 km grid to the ROMS grid 

HF2==Radiation fluxes derived from a Barnes (1973) interpolation of NOAA’s reanalysis product at 

10 meteorological station locations to the ROMS grid 

MF1==Wind and atmospheric pressure derived from a Barnes (1973) interpolation at 10 

meteorological stations. 

MF2==Winds set to zero and atmospheric pressure set to 1013 mb 

RI1==River inflows set to USGS daily mean discharge 

RI2==River inflows set to USGS mean annual discharge_________________________________

each simulation subsequently described. Initial salinity and temperature conditions and lateral river 

inflow boundary conditions were developed from the NOS circulation survey (Klavens et al., 

1984; Richardson and Schmalz, 2006). Salinity and temperature at the open boundaries were 

determined from NOAA’s World Ocean Atlas 2001 (NODC, www.nodc.noaa.gov). Wind speed and 

direction and atmospheric pressure were produced at three hour intervals using Barnes (1973) 

interpolation at 10 stations consisting of 2 NOAA buoys and 8 C-Man stations and airports. Using 

this procedure, wind speed and direction RMS errors are order 2 m/s and 25 o

T, respectively, and sea 

level atmosphere pressure RMS errors are order 1.5 mb. 

The water level subtidal signal at the Chesapeake Bay end of the C&D canal was based on 
49 

Chesapeake City, MD as determined via a linear regression (bias=0.003, gain=0.784) from the 

Baltimore, MD subtidal water level as discussed previously. The subtidal water level signal at Cape 

May, NJ is empirically reduced by 30% to prescribe the subtidal water level along the outer 

boundary of both grids at the shelf break. An alternative approach would be to reduce the extent of 

the grid on the shelf to perhaps the 20 to 50 m contour as used by Celebioglu and Piasecki (2006) 

and apply the subtidal water level signal at Cape May, NJ without empirical reduction. 

Within the Delaware River and Bay system, two datums are used. Along the coast and within the 

Bay proper MSL is taken as the model datum, while above Philadelphia, PA mean river level (MRL) 

is assumed equal to NAVD-1988 and is taken as the model datum. 

5.3 High Flow Simulation 

Simulated water levels are compared with observations in Table 5.2 with RMSEs increasing from 

order 15 cm at the Bay entrance to 25 cm at Philadelphia, PA with a maximum near the head of tide 

at Trenton, NJ of 37 cm (see Figure 5.3) on both grids. The difference in mean water levels is order 

3 cm at the entrance to the Bay indicating the influence of Sa and Ssa is small during this period (see 

Table 1). In this and all subsequent tables, the relative error corresponds to the Willmott et al. (1985) 

dimensionless (0-1) relative error, with zero representing perfect agreement. For the time series 

plots, the indicator of agreement (IND AGMT) equal to one minus the relative error is given. 

 

Table 5.2. Water Surface Elevation-MLLW (m) High Flow Hindcast 

 27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results 

Station RMS Error 

(cm) 

Relative Error 

(-) 

Model Mean 

(cm) 

Observed Mean 

(cm) 

Lewes, DE 15/17 0.02/0.03 81/85 86 

Cape May, NJ 19/20 0.03/0.04 88/91 93 

Indian River, DE 20/19 0.07/0.04 58/60 63 

Phila. Pier 11, PA 27/31 0.05/0.05 143/136 133 

Trenton, NJ 37/37 0.04/0.04 200/186 191 
50 

Figure 5.3. High Flow Hindcast (27 March – 10 April 1984) Water Surface Elevation (m-MLLW) 

at Trenton, NJ. Top panel: ROMS MRG Hindcast. Bottom panel: ROMS HRG 

Hindcast. Observations are at one hour intervals. 
51 

Current speed and direction model predictions are compared against observations in Tables 5.3 and 

5.4, respectively. The current strengths at Station 33 and within the river sections are in reasonable 

agreement with observations, while predicted current strengths on the shelf do not include the mean 

alongshore flow and are thus weaker than the observations. Current directions are reasonably 

represented within the Bay and river sections, where the currents are rectilinear. At continental shelf 

Stations16 and 17 the currents are rotary in nature and current directions on both grids exhibit larger 

discrepancies from the observations. 

Table 5.3. Current Speed (cm/s) High Flow Hindcast 

 27 March – April 10, 1984: ROMS MRG Results / ROMS HGR Results 

 DAB denotes distance above the bottom. 

Station No 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

16 at 11 13.28/13.45 0.49/0.50 7.96/8.81 15.33 

17 at 3 12.27/11.58 0.60/0.51 7.32/7.15 13.34 

23 at 8 16.76/16.82 0.16/0.18 43.12/39.88 40.54 

33 at 11 25.20/28.96 0.22/0.21 58.17/58.24 58.17 

50 at 8 22.65/25.74 0.22/0.27 59.52/55.11 61.78 

52 at 4 16.76/16.49 0.20/0.18 41.37/49.18 47.17 

 

Table 5.4. Current Direction (oT) High Flow Hindcast 

 27 March – April 10, 1984: ROMS MRG Results / ROMS HRG Results 

 DAB denotes distance above the bottom. Current direction comparisons are 

 only made for currents greater than 0.26 cm/s. 

Station 

at DAB (m) 

RMS Error 

 (o

T) 

Relative Error 

 (-) 

Model Mean 

(

o

T) 

Observed Mean 

 (oT) 

16 at 11 57.77/77.25 0.64/0.68 179.40/173.62 228.85 

17 at 3 113.22/86.04 0.84/0.82 188.76/210.14 215.01 

23 at 8 40.63/39.32 0.05/0.05 234.56/233.53 254.61 

33 at 11 41.86/49.09 0.05/0.08 210.39/209.19 226.66 

50 at 8 48.80/47.88 0.08/0.07 173.56/176.63 176.83 

52 at 4 41.50/45.33 0.06/0.07 154.80/153.11 148.01 

The simulated salinities on both grids are compared with observations in Table 5.5. 

Table 5.5. Salinity (PSU) High Flow Hindcast 

27 March – April 10, 1984: ROMS MRG Results / ROMS HRG Results 

DAB denotes distance above the bottom.

Station 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

16 at 3 0.80/0.56 0.58/0.76 31.87/32.80 32.58 

16 at 8 0.51/0.64 0.56/0.59 31.80/32.72 32.19 

16 at 11 0.64/0.50 0.60/0.51 31.76/32.61 32.28 

17 at 3 0.93/0.98 0.93/0.86 32.97/32.90 33.78 

23 at 8 1.54/2.56 0.45/0.55 25.71/27.37 25.58 

33 at 11 2.97/3.61 0.20/0.32 12.63/15.39 13.14 
52 

In Figure 5.4 at Station 33 in the region of large horizontal gradients, while a reasonable RMSE of 

order 3.0 PSU is achieved, both the ROMS MRG and HRG simulations do not follow the sag in the 

observed salinity signal. While the simulated temperature response RMSEs in Table 5.6 are within 

order 2 oC, the MRG and HRG mean temperatures on the shelf are 2-3 degrees larger than the 

observations. 

Table 5.6. Temperature (o

C) High Flow Hindcast 

27 March – April 10, 1984: ROMS MRG Results / ROMS HRG Results 

DAB denotes distance above the bottom. 

Station 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

16 at 3 2.16/3.16 0.68/0.77 7.16/8.16 5.01 

16 at 8 2.24/3.12 0.66/0.75 7.29/8.17 5.06 

16 at 11 2.22/2.98 0.65/0.72 7.38/8.13 5.17 

17 at 3 2.19/2.99 0.85/0.89 7.66/8.48 5.51 

23 at 8 0.81/0.81 0.24/0.16 7.19/6.59 6.43 

33 at 11 0.38/1.16 0.04/0.16 6.74/6.91 6.71 

5.4 Low Flow Simulation 

To examine model performance under low flow conditions, the 10-24 September, 1984 period was 

simulated. Wind speed and direction and atmospheric pressure as produced by the Barnes (1973) 

interpolation at three hour intervals are compared with hourly observations and are of the same order 

RMSE as for the high flow period. The mean wind speeds , river flows, and boundary subtidal water 

levels are lower than during the high flow period and the offshore tidal boundary conditions become 

more dominant even for the upriver stations. Simulated water levels are contrasted with observations 

in Table 5.7. While the ROMS MRG RMSEs are reduced from those for the HRG due to an 

improvement in phase, at the times of peak amplitudes the HRG results correspond more closely to 

the observations at Trenton, NJ as shown in Figure 5.5. The difference in the mean water levels at 

the entrance to the Bay is order 10 cm and may be due to the effects of Sa and Ssa (see Table 5.1) 

with the MRG RMSEs lower than on the HRG. 
53 

 Figure 5.4. Simulated versus Observed (10 minute) Salinity at Station 33 at 11 m above the 

bottom. Top panel: ROMS MRG Hindcast. Bottom panel: ROMS HRG Hindcast 

 Note observations are at 10-minute intervals. 
54 

Figure 5.5. Low Flow Hindcast (10 – 24 September, 1984) Water Surface Elevation at Trenton, 

NJ. Top panel: ROMS MRG Hindcast. Bottom panel: ROMS HRG Hindcast. 

Observations are at one hour intervals. 
55 

Table 5.7. Water Surface Elevation-MLLW (m) Low Flow Hindcast 

 September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results 

 Station RMS Error 

(cm) 

Relative Error 

 (-) 

Model Mean 

(cm) 

Observed Mean 

(cm) 

Lewes, DE 11/17 0.01/0.04 73/63 70 

Cape May, NJ 14/19 0.02/0.04 82/71 79 

Indian River, 

DE 

14/16 0.04/0.06 50/39 47 

Ocean City Pier, 

MD 

6/19 0.01/0.07 58/52 61 

Phila. Pier 11, 

PA 

18/25 0.02/0.04 117/105 107 

Trenton, NJ 22/37 0.02/0.05 136/124 131 

In Tables 5.8 and 5.9, the current speed and direction comparisons are given. At Station 33 the 

current speed responses are reduced from those obtained for the high flow hindcast. The current 

speeds are slightly under-predicted at upriver Station 51. Current direction errors are comparable 

under both high and low flow conditions. In Table 5.10, the salinity response is compared with 

observations. A very favorable comparison for the ROMS HRG, particularly at Station 33 in the 

region of large horizontal salinity gradients is obtained with the ROMS HRG RMSEs lower at the 

river Stations 33 and 154 than those on the MRG. As shown in Table 5.11, the temperature 

responses for both grids are comparable, but with the mean temperatures over the shelf order 1-3 oC 

larger than the observations.

Table 5.8. Current Speed (cm/s) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results 

 Note DAB denotes distance above the bottom. 

Station 

at DAB (m) 

RMS Error 

(cm/s) 

Relative Error 

(-) 

Model Mean 

(cm/s) 

Observed Mean 

(cm/s) 

2 at 7 13.30/11.95 0.12/0.11 43.89/39.00 39.01 

16 at 11 8.09/9.10 0.59/0.63 9.90/10.52 9.89 

17 at 15 14.30/12.78 0.61/0.59 17.72/12.43 17.71 

18 at 2 7.84/11.38 0.10/0.20 28.97/29.35 25.18 

19 at 2 14.34/18.13 0.20/0.18 37.28/35.64 28.27 

19 at 8 14.08/22.65 0.09/0.27 50.58/47.44 45.45 

22 at 6 11.06/13.13 0.08/0.10 40.49/42.97 41.69 

23 at 2 18.64/18.48 0.41/0.44 33.82/32.53 17.34 

24 at 2 8.05/10.95 0.10/0.19 30.65/31.49 27.69 

25 at 2 6.95/7.75 0.07/0.09 29.98/29.87 29.22 

33 at 2 11.02/13.10 0.13/0.20 35.53/33.20 29.28 

51 at 9 17.48/14.96 0.18/0.13 52.60/57.32 61.46 

154 at 2 22.48/12.73 0.48/0.23 26.07/29.71 31.47 
56 

Table 5.9. Current Direction (o

T) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results 

Note DAB denotes distance above the bottom. Current direction comparisons 

are only made for currents greater than 0.26 cm/s. 

Station 

at DAB (m) 

RMS Error 

(

o

T) 

Relative Error 

(-) 

Model Mean 

(

o

T) 

Observed Mean 

(

o

T) 

2 at 7 8.36/8.31 0.00/0.00 223.77/232.74 212.66 

16 at 11 104.56/121.72 

 

0.39/0.51 142.69/139.75 217.85 

17 at 15 108.20/90.96 0.44/0.53 165.46/190.02 230.55 

18 at 2 7.98/12.40 

 

0.00/0.01 225.93/226.27 238.79 

19 at 2 18.88/16.10 

 

0.01/0.01 229.55/234.91 257.01 

19 at 8 22.63/23.59 

 

0.02/0.02 231.13/238.18 247.18 

22 at 6 10.01/27.70 0.00/0.03 231.15/222.89 231.98 

23 at 2 5.87/19.88 0.00/0.01 238.76/226.89 269.80 

24 at 2 45.53/45.84 0.06/0.06 240.97/225.74 245.13 

25 at 2 119.44/117.30 0.87/0.87 107.40/107.5 184.53 

33 at 2 6.37/17.12 0.00/0.01 227.65/224.94 226.26 

51 at 9 18.16/30.13 0.01/0.03 191.47/194.09 194.25 

154 at 2 53.68/14.87 0.12/0.01 161.13/173.16 187.41 

Table 5.10. Salinity (PSU) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results 

 DAB denotes distance above the bottom.

Station 

at DAB (m) 

RMS Error 

(PSU) 

Relative Error 

(-) 

Model Mean 

(PSU) 

Observed Mean 

(PSU) 

2 at 7 0.14/0.73 0.28/0.71 30.40/30.77 30.08 

16 at 3 1.52/2.94 0.93/0.96 31.27/32.82 29.68 

16 at 11 0.26/1.01 0.65/0.81 31.03/32.14 31.15 

19 at 2 1.37/1.40 0.50/0.50 29.86/29.96 28.67 

22 at 6 0.81/0.82 0.15/0.12 27.64/27.02 27.34 

23 at 2 1.39/1.20 0.56/0.50 28.64/28.45 27.44 

24 at 2 0.79/1.14 0.29/0.40 25.48/25.15 26.21 

33 at 2 0.90/1.08 0.10/0.13 20.21/18.14 18.81 

154 at 2 0.76/1.68 0.57/0.50 7.00/5.05 6.59 
57 

Table 5.11. Temperature (oC) Revised Low Flow Hindcast 

 September 10-24, 1984: ROMS MRG Results/ ROMS HRG Results 

 DAB denotes distance above the bottom.

Station 

at DAB (m) 

RMS Error 

(

o

C) 

Relative Error 

(-) 

Model Mean 

(

o

C) 

Observed Mean 

(

o

C) 

2 at 7 1.57/2.82 0.92/0.95 21.99/24.11 21.04 

16 at 3 2.67/0.81 0.74/0.55 17.82/21.21 20.87 

16 at 11 1.22/2.97 0.56/0.67 21.93/23.89 20.93 

19 at 2 2.38/3.56 0.92/0.95 23.41/24.40 20.67 

19 at 8 2.43/3.60 0.91/0.95 23.42/24.40 20.62 

22 at 6 3.13/3.33 0.92/0.92 24.13/24.41 20.75 

23 at 2 2.88/3.25 0.72/0.74 24.04/24.42 21.20 

24 at 2 2.93/3.28 0.83/0.85 24.16/24.54 20.63 

33 at 2 2.07/2.01 0.91/0.91 24.38/24.23 22.40 

5.5 Extended Hindcast March – September 1984 

To further assess the ability of the ROMS HRG to replicate conditions in Delaware Bay a seven 

month hindcast was performed. Water level results were examined in 15 day increments to assess the 

variability of the skill as shown in Table 5.12. The range of RMSE over the fourteen 15 day periods 

decreases from 17 cm at Trenton, NJ to 7 cm at the Capes, indicating the influence of the flow 

variations in the Delaware River. Similar water level RMSEs were obtained for two 30-day 

simulations using the MRG. The percent of the RMSE to the mean tidal range at each station is 

given to assess the deviation from 10%, which is being considered as a supplemental water level 

skill assessment target to the formal targets outlined in NOS (1999) and in Hess et al. (2003). To 

meet this 

Table 5.12. Seven Month ROMS HRG Hindcast March-September 1984 Water Level RMSE 

(cm) Summary. The analyses are for 15 days, thus there are two entries for each 

month. PMTR denotes the RMSE expressed as a percentage of the mean tide range. 

ROMS MRG 30-day simulation water level RMSE (cm) are denoted by * over 27 

Mar – 25 Apr 1984 and + over 26 Aug – 24 Sep 1984. 

Station Mar Apr May Jun Jul Aug Sep Seven 

Month 

RMSE 

RMSE 

Range 

PMRT

Trenton

, NJ 

33/26 

29* 

33/25 39/34 42/35 33/39 35/34 

31+ 

28/39 34 17 13.7 

Phila., 

PA 

27/21 

22* 

27/21 30/24 32/28 31/32 25/26 

24+ 

20/25 27 12 14.8 

Lewes, 

DE 

17/13 

12* 

15/11 18/13 17/15 15/17 18/16 

17+ 

14/18 16 7 12.9 

Cape 

May, 

NJ 

21/14 

16* 

20/15 21/15 18/16 16/18 14/19 

20+ 

15/20 17 7 11.4 
58 

supplemental skill assessment target, the RMSEs would need to be reduced at Trenton, NJ by 9 cm, 

at Phila, PA by 9 cm, at Lewes, DE by 4 cm, and at Cape May, NJ by 2 cm, respectively. 

5.6 Tidal Analysis and Simulations 

To further analyze the water level response, an estimate of the tidal error (TE) given in Table 5.13 

was made by subtracting the 30 hour low pass filtered water level hindcast results from the hindcast 

total water levels. The tidal errors range from order 15 cm at the Capes to order 25 cm at the head of 

tide at Trenton, NJ. Based on these results, it is of benefit to further seek improvements in tide only 

simulations directly. Towards this end, three tidal simulations were performed using yearly average 

river flows. Wind, atmospheric pressure anomalies, and subtidal water levels were set to zero. 

However, salinity and temperature were initialized to observed non-uniform conditions and time and 

depth varying boundary conditions applied. Surface heat flux computations were made using the 

bulk flux formulation. For all three simulations at the C&D canal boundary the CLAMPED and 

M2REDUCED options were used for the water level and two-dimensional vertically integrated 

boundary velocities, respectively. Conditions varied along the southern and eastern open ocean 

boundaries for the water level and two-dimensional vertically integrated boundary velocities in each 

of the three simulations as shown in Table 5.1. RMSEs and relative errors are given in Table 5.13 for 

each of these three simulations. Simulation 2 exhibited the lowest errors at the entrance to Delaware 

Bay, but at the head of tide at Trenton, NJ, all the simulation results were similar as shown in Figure 

5.6. Of interest is the behavior of the simulations at several grid cells one grid cell in along the open 

boundaries as indicated by the last seven OBC entries in Table 5.13. Simulation 2 exhibited water 

levels with the closest agreement to the boundary water level specification. 

In Table 5.14, tidal current speed RMSEs and relative errors are considered. Tidally extracted 

current components are determined by subtracting the low pass filtered current component from the 

total current hindcast component. In general, RMSE and relative errors for all three tidal simulations 

are near the tidally extracted currents. 

5.7 Summary and Additional Considerations 

On the high resolution grid the C&D Canal and main navigation channel are well represented with 

the currents at Station 154 and in the upper river sections improved. For the high flow 15-day 

period, the ROMS MRG and HRG simulation results for water levels were very similar, while for 

the 15-day low flow period the ROMS MRG results were superior. For both 15-day periods, the 

ROMS MRG and HRG simulation results for Bay currents, salinity, and temperature were 

comparable. This version of the model, DBOFS Version 1.0, was ported to NCEP and run in semioperational mode in early June 2009. Significant variations in water level RMSEs at Trenton, NJ 

were exhibited during the seven month ROMS HRG hindcast using DBOFS Version 1.0 from March 

through September 1984 and indicated additional modification of the seven bottom roughness zones 

used by Walters (1992a; 1992b) should be pursued. In Chapter 6, efforts are first described to adjust 

the seven bottom roughness zone values under astronomical tide conditions. 
59 

Table 5.13. Water Surface Elevation-MSL (m) 

Tidal Extraction from Hindcast and Tidal Simulations 1-3: April 1984 

Station RMS Error (cm) 

TE S1 S2 S3 

Relative Error (-) 

TE S1 S2 S3 

Marcus Hook, 

PA 

24 21 10 16 0.04 0.04 0.01 0.02 

Cape May, NJ 15 13 7 12 0.02 0.01 0.00 0.01 

Ship John Shoal, 

NJ 

20 17 8 15 0.03 0.02 0.00 0.01 

Tacony Bridge, 

NJ 

21 17 12 16 0.02 0.02 0.01 0.01 

Burlington, NJ 21 18 18 19 0.02 0.01 0.01 0.02 

Phila. USCG, 

PA 

20 17 8 14 0.03 0.02 0.00 0.01 

Phila. Pier 11, 

PA 

18 13 16 16 0.02 0.01 0.02 0.02 

Delaware City, 

DE 

18 14 8 13 0.03 0.02 0.01 0.01 

Reedy Point, DE 17 13 8 12 0.02 0.01 0.01 0.01 

Brandywine 

Shoal, DE 

17 15 7 13 0.03 0.02 0.00 0.01 

Lewes, DE 13 11 6 11 0.02 0.01 0.00 0.01 

Indian River, 

DE 

15 12 15 18 0.05 0.03 0.05 0.06 

Ocean City Pier, 

MD 

14 14 5 10 0.04 0.04 0.00 0.02 

Chesapeake 

City, MD 

14 13 10 12 0.04 0.04 0.02 0.03 

Trenton, NJ 24 19 21 22 0.02 0.01 0.02 0.02 

W-OBC n/a 3 2 2 n/a 0.00 0.00 0.00 

S-OBC 1 n/a 18 2 10 n/a 0.08 0.00 0.02 

S-OBC2 n/a 12 2 8 n/a 0.04 0.00 0.01 

S-OBC3 n/a 9 1 8 n/a 0.02 0.00 0.01 

S-OBC4/EOBC1 n/a 8 2 7 n/a 0.02 0.00 0.01 

E-OBC2 n/a 8 2 7 n/a 0.01 0.00 0.01 

E-OBC3 n/a 9 3 9 n/a 0.01 0.00 0.01 
60 

Table 5.14. Current Speed (cm/s) 

 Tidal Extraction from Hindcast and Tidal Simulations 1-3: April 1984 

 DAB denotes distance above the bottom. 

Station 

DAB (m) 

RMS Error 

(cm/s) 

TE S1 S2 S3 

Relative Error 

 (-) 

TE S1 S2 S3 

2 at 7 11.51 11.60 9.38 13.39 0.01 0.02 0.01 0.02 

3 at 5 16.62 15.58 9.92 16.08 0.02 0.02 0.01 0.02 

5 at 5 20.03 17.99 7.19 15.05 0.03 0.02 0.00 0.01 

11 at 3 4.49 3.64 5.87 5.31 0.03 0.02 0.04 0.04 

16 at 8 6.01 6.37 3.69 6.15 0.52 0.57 0.21 0.38 

17 at 15 5.87 9.60 8.01 8.77 0.12 0.25 0.20 0.17 

18 at 2 9.45 8.15 13.33 11.59 0.03 0.02 0.05 0.04 

19 at 8 15.40 13.10 9.04 15.71 0.02 0.02 0.01 0.02 

21 at 2 11.08 9.88 15.56 14.94 0.03 0.03 0.06 0.06 

22 at 6 14.67 11.86 18.21 14.57 0.02 0.02 0.05 0.02 

23 at 8 11.78 9.89 8.41 12.13 0.02 0.01 0.01 0.02 

24 at 2 11.93 10.68 16.37 14.29 0.04 0.03 0.07 0.05 

25 at 2 35.27 34.91 37.40 37.21 0.82 0.82 0.83 0.82 

33 at 11m 18.25 14.01 21.13 18.47 0.02 0.01 0.04 0.02 

51 at 9 30.81 26.89 26.80 29.51 0.11 0.09 0.10 0.10 

154 at 8 50.05 47.67 34.87 39.77 0.26 0.25 0.14 0.17 
61 

Figure 5.6. Tidal Water Level (m-demeaned) at Trenton, NJ for Julian Days 90-100, 1984. Top, 

Middle, and Bottom Panel: Simulation 1, Simulation 2 and Simulation 3. Simulations 1 

and 2 employ external and Simulation 3 internal to ROMS tidal water level 

specification. Note predictions are at 6-minute intervals. 
62 
63 

6. ROMS HIGH RESOLUTION GRID EXTENDED HINDCASTS 

Prior to performing the 13 month extended hindcast, as suggested in Chapter 5, improvements were 

sought in the tidal response. The following approach was used. The simulation 2 CPPDEF options in 

Table 5.1 of Chapter 5 (FSCLAMPED and M2REDUCED) were used on the open ocean 

boundaries. To further adjust the offshore tidal harmonic constants, harmonic analyses of simulated 

water levels were performed at all water level stations and compared to NOS accepted harmonic 

constants. Before performing the comparison, coastal water level time series were reconstructed 

from the 37 accepted NOS tidal harmonics. Next, the reconstructed time series were harmonically 

analyzed to see how closely the tidal constituents could be recovered. Once it was determined, that 

the tidal constituents could be recovered, eighteen one-month tidal simulation were performed in 

which the off shore boundary tidal water level constituents were varied along with the bottom 

roughness zone values to seek to optimize the tidal response. Upon completion of the tidal response 

optimization, an extended 13-month tidal simulation was performed and evaluated, followed by a 

13-month hindcast simulation both over the period from March 1984 through March 1985. 

6.1 29-day Harmonic Analysis Considerations 

One notes the following issues associated with this process. 

1. When one predicts a water level series from the harmonic constants, the constituent equilibrium 

arguments, [(Vo+u)i]

p

 , i=1,37, are based on 1 January hour zero of the year of the prediction, while 

the constituent node factors, [fi ]p, i=1,37, are based on the middle of the year of prediction.

2. When one performs a harmonic analysis from the predicted water level series, the constituent 

equilibrium arguments, [(Vo+u)i]

a

 , i=1,37, are based on the start month, day, and hour of the series, 

while the constituent reduction factors, [Fi ]a, i=1,37, are based on the middle of the prediction 

period. 

3. Note Fi=1/fi and thus the reduction factors are the reciprocals of the node factors, which vary 

slowly over the year and are taken equal to the mid-year value. 

4. Therefore the two sets of node factors are nearly equal. That is [fi ]p, i=1,37 ~ [fi ]a, i=1,37. 

However, the two set of equilibrium arguments are significantly different, unless the prediction 

period starts at the beginning of the year. That is [(Vo+u)i]

p

 , i=1,37 ≠ [(Vo+u)i]

a

 , i=1,37. 

The above points are illustrated by: 

First, a prediction of water level series from the 37 NOS accepted harmonic constituents at Ocean 

City Pier, MD, Chesapeake City, MD, Cape May, NJ, and Lewes, DE starting on 27 March 1984 

over a period of 33 days. 

Second, the performance of a 29-day harmonic analysis of the water level series is conducted with a 

comparison of the 24 tidal constituents derived from the analysis shown in the corresponding Tables 

6.1-6.4. In Table 6.5, a NOS accepted constituent amplitude weighted ratio of the 29-day harmonic 

analysis amplitude to the NOS accepted amplitude is given as the weighted gain. The weighted 
64 

phase in Table 6.5 is the difference in phase in hours weighted analogously, while the estimated 

RMS error is based on the method described by Hess (1994). 

Table 6.1. Water Level Harmonic Constant Comparison at Ocean City Pier, MD. 

Constituent Model Amplitude (m) 

Amp (m) Phase (o) 

NOS Accepted 

Amp (m) Phase (o) 

Difference 

Amp (m) Phase (o) 

M(2) 0.4990 215.70 0.5010 215.90 -.0020 -0.20 

S(2) 0.0940 233.20 0.0970 234.60 -.0030 -1.40 

N(2) 0.1220 199.70 0.1170 199.90 0.0050 -0.20 

K(1) 0.0760 113.60 0.0880 119.10 -.0120 -5.50 

M(4) 0.0070 293.10 0.0070 291.60 0.0000 1.50 

O(1) 0.0870 115.60 0.0850 115.50 0.0020 0.10 

M(6) 0.0140 236.40 0.0140 236.50 0.0000 -0.10 

S(4) 0.0040 269.20 0.0030 271.30 0.0010 -2.10 

NU(2) 0.0240 201.90 0.0230 199.00 0.0010 2.90 

Q(1) 0.0170 116.50 0.0160 105.00 0.0010 11.50 

P(1) 0.0250 113.80 0.0310 117.90 -.0060 -4.10 

L(2) 0.0170 194.30 0.0140 231.80 0.0030 -37.50 

K(2) 0.0260 234.60 0.0250 232.90 0.0010 1.70 

Table 6.2. Water Level Harmonic Constant Comparison at Chesapeake City, MD. 

Constituent Model Amplitude (m) 

Amp (m) Phase (o) 

NOS Accepted 

Amp (m) Phase (o) 

Difference 

Amp (m) Phase (o) 

M(2) 0.4320 308.60 0.4340 309.00 0.4340 309.00 

S(2) 0.0650 344.40 0.0590 341.50 0.0060 2.90 

N(2) .0810 290.30 0.0750 294.00 0.0060 -3.70 

K(1) 0.0180 271.60 0.0320 268.90 -.0140 2.70 

M(4) 0.0260 208.70 0.0260 208.80 0.0000 -0.10 

O(1) 0.0150 286.20 0.0140 292.70 0.0010 -6.50 

M(6) 0.0090 25.60 0.0090 26.50 0.0000 -0.90 

S(4) 0.0020 261.80 0.0020 261.60 0.0000 0.20 

NU(2) 0.0160 292.80 0.0210 285.50 -.0050 7.30 

Q(1) 0.0030 293.50 0.0090 274.10 -.0060 19.40 

P(1) 0.0060 272.70 0.0100 256.20 -.0040 16.50 

L(2) 0.0120 284.90 0.0300 303.00 -.0180 -18.10 

K(2) 0.0180 347.30 0.0180 340.50 0.0000 6.80 
65 

Table 6.3. Water Level Harmonic Constant Comparison at Cape May, NJ. 

Constituent Model Amplitude (m) 

Amp (m) Phase (o) 

NOS Accepted 

Amp (m) Phase (o) 

Difference 

Amp (m) Phase (o) 

M(2) 0.7120 243.40 0.7140 243.60 -.0020 -0.20 

S(2) 0.1260 265.40 0.1250 265.30 0.0010 0.10 

N(2) 0.1650 227.10 0.1590 227.50 0.0060 -0.40 

K(1) 0.1650 227.10 0.1590 227.50 0.0060 -0.40 

M(4) 0.0100 168.40 0.0100 171.10 0.0000 -2.70 

O(1) 0.0860 116.50 0.0840 115.80 0.0020 0.70 

M(6) 0.0080 302.50 0.0080 306.00 0.0000 -3.50 

S(4) 0.0010 280.80 0.0000 0.00 0.0010 -79.20 

NU(2) 0.0320 229.30 0.0320 224.80 0.0000 4.50 

Q(1) 0.0170 115.30 0.0130 117.10 0.0040 -1.80 

P(1) 0.0320 118.90 0.0360 124.40 -.0040 -5.50 

L(2) 0.0240 221.70 0.0370 256.20 -.0130 -34.50 

K(2) 0.0340 267.20 0.0330 264.00 0.0010 3.20 

Table 6.4. Water Level Harmonic Constant Comparison at Lewes, DE. 

Constituent Model Amplitude (m) 

Amp (m) Phase (o) 

NOS Accepted 

Amp (m) Phase (o) 

Difference 

Amp (m) Phase (o) 

M(2) 0.6140 245.90 0.6160 246.10 -.0020 -0.20 

S(2) 0.1110 264.40 0.1080 266.80 0.0030 -2.40 

N(2) 0.1410 228.00 0.1340 228.40 0.0070 -0.40 

K(1) 0.0950 122.30 0.1030 126.40 -.0080 -4.10 

M(4) 0.0120 255.80 0.0130 256.40 -.0010 -0.60 

O(1) 0.0840 119.50 0.0830 118.80 0.0010 0.70 

M(6) 0.0060 271.40 0.0060 274.70 0.0000 -3.30 

S(4) 0.0010 267.80 0.0000 0.00 0.0010 -92.20 

NU(2) 0.0270 230.40 0.0280 228.80 -.0010 1.60 

Q(1) 0.0160 118.10 0.0130 115.90 0.0030 2.20 

P(1) 0.0310 122.10 0.0340 124.30 -.0030 -2.20 

L(2) 0.0200 222.50 0.0200 260.30 0.0000 -37.80 

K(2) 0.0300 265.90 0.0300 261.40 0.0000 4.50 
66 

 

 

Table 6.5. Open Boundary Condition Tidal Error Summary 

Station Weighted Gain 

(-) 

Weighted Phase 

(hrs) 

Estimated RMSE 

(cm) 

Ocean City Pier, MD 0.99 -0.05 1 

Chesapeake City, MD 0.91 0.07 2 

Cape May, NJ 0.99 -0.07 2 

Lewes, DE 1.00 -0.06 2 

One important detail about the 29-day harmonic analysis program is that it only calculates 10 

constituents directly by Fourier series from the input 29-day time series. These constituents are M2, 

S2, N2, K1, O1, and the overtides M4, M6, S4, S6, and M8. The program next infers the 14 additional 

constituents which cannot be resolved with only 29 days of data by redistributing the energy in the 

10 calculated constituents according to the standard ratios in the astronomical tide potential driving 

force as discussed by Shureman (1958) on page 79. The input prediction has 37 accepted 

constituents which were obtained by least squares analysis of several full years of data, so the ratios 

of the small constituents to the large ones are determined by the actual data. 

6.2 April 1984 Tidal Simulation Validation 

To obtain accurate water levels from the coast to the head of tide, it was necessary to adjust: 1) the 

amplitude and phase of the M2, N2, and S2 constituents , 2) the bottom friction coefficients in the 

seven zones used by Walters (1992a; 1992b), and 3) the bathymetric cutoff depths. The simulations 

performed were for the 30 days of April 1984 and are summarized in Table 6.6. The boundary 

harmonic constants sets are given in Table 6.7, the bottom friction sets in Table 6.8, and the 

bathymetric sets are given in Table 6.9. The associated water level station M2 amplitude and phase 

rms errors for the 18 simulations given in Table 6.6 are shown in Table 6.10. Note simulations 1-4 

used free slip lateral boundary conditions, while the remaining simulations used a lateral boundary 

condition half-way between free slip and no slip as used in POM. No difference in results was 

obtained using the different lateral boundary conditions as noted in the comparison between 

simulations 4 and 5. Simulation 1 corresponds to DBOFS Version 1.0 while simulation 18 

corresponds to DBOFS Version 1.1 as implemented at NCEP. DBOFS Version 1.0 and Version 1.1 

results are given in Tables 6.11 and 6.12, respectively. One notes the significant improvement in 

water surface elevation RMSE at the Entrance to the Bay of order 10 cm (also see Figure 6.1), at 

Philadelphia, PA of order 12 cm (also see Figure 6.2), and at the head of tide at Trenton, NJ of order 

11 cm (also see Figure 6.3). Principal component direction current strength RMSEs are generally 

less than 26 cm/s (0.5 kt) at all stations and where they exceed this value, this may be due to the 

discrepancy in the principal component directions exhibited in the model versus the data. In these 

comparisons, the model currents are resolved along the measured principal component direction. 

DBOFS Version 1.1 simulated currents are shown for JD 100-110, 1984 as one proceeds from the 

shelf at Stations 17 and 2 in Figures 6.4 and 6.5 through the Bay from Stations 19, 23, and 33 in 

Figures 6.6 – 6.8 and into the river at Station 154 and 51 in Figures 6.9 and 6.10, respectively. 
67 

Table 6.6. Tidal Validation Simulation Summary 

Note Expmm.comf and Expmm.1.o use the Flather (1976) and Chapman (1985) 

boundary conditions, while the remaining simulations use the clamped and reduced 

boundary conditions. 

Simulation 

 No. and Name 

 Date 

 Performed 

Bathymetric 

 Set 

Bottom Friction 

Set 

 HA 

 Set 

1 Expmm.comf 11/16/2009 1 1 0 

2 Expmm.1.o 10/23/2009 1 1 0 

3 Expmm.1 10/29/2009 2 1 0 

4 Expmm.11 10/30/2009 2 1 1 

5 Expmm.111 11/6/2009 2 1 1 

6 Expmm.1111 11/9/2009 2 2 2 

7 Expmm.11111 11/10/2009 2 3 2 

8 Expmm.1.6 11/10/2009 2 4 2 

9 Expmm.1.7 11/10/2009 2 5 2 

10 Expmm.1.8 11/19/2009 2 6 2 

11 Expmm.1.9 11/19/2009 2 7 2 

12 Expmm.1.10 11/20/2009 2 8 3 

13 Expmm.1.11 11/23/2009 2 9 3 

14 Expmm.1.12 11/23/2009 2 10 3 

15 Expmm.1.13 11/23/2009 2 11 3 

16 Expmm.1.14 11/24/2009 2 12 4 

17 Expmm.1.15 11/25/2009 2 12 4 

18 Expmm.1.16 11/30/2009 3 12 4 

 

Table 6.7. Water Level Open Boundary Major Harmonic Constituent Sets 

 853-4720 at Atlantic City, NJ 

Set No. M2 

Amp (m) Phase (o) 

S2 

Amp (m) Phase (o) 

N2 

Amp (m) Phase (o) 

0 0.594 210.4 0.116 227.8 0.141 193.7 

1 0.494 210.4 0.136 218.8 0.210 152.7 

2 0.524 210.4 0.116 227.8 0.201 200.0 

3 0.524 210.4 0.116 227.8 0.201 200.0 

4 0.524 215.4 0.116 227.8 0.171 200.0 

Table 6.7. (Cont.) Water Level Open Boundary Major Harmonic Constituent Sets 

 857-0280 at Ocean City Pier, MD 

Set No. M2 

Amp (m) Phase (o) 

S2 

Amp (m) Phase (o) 

N2 

Amp (m) Phase (o) 

0 0.501 215.9 0.097 234.6 0.117 199.9 

1 0.495 210.6 0.117 213.5 0.177 143.8 

2 0.470 215.9 0.097 234.6 0.170 179.0 

3 0.470 215.9 0.097 234.6 0.170 179.0 

4 0.470 220.9 0.097 234.6 0.140 179.0 
68 

Table 6.7. (Cont.) Water Level Open Boundary Major Harmonic Constituent Sets 

 857-3927 at Chesapeake City, MD 

Set No. M2 

Amp (m) Phase (o) 

S2 

Amp (m) Phase (o) 

N2 

Amp (m) Phase (o) 

0 0.434 309.0 0.059 341.5 0.075 294.0 

1 0.314 296.0 0.049 328.5 0.065 275.0 

2 0.332 303.0 0.049 335.5 0.075 294.0 

3 0.332 303.0 0.049 335.5 0.055 284.0 

4 0.332 303.0 0.049 335.5 0.055 284.0 

Table 6.8. Bottom Friction Coefficient Sets.

Zone No. Description Set 1 Set 2 Set 3 Set 4 Set 5 Set 6 

1 OB to Bay 

Entrance 

0.005 0.005 0.005 0.005 0.005 0.005 

2 Bay Entrance to 

Ship John Shoal 

0.007 0.007 0.007 0.007 0.007 0.010 

3 Ship John Shoal 

to Station 33 

0.005 0.005 0.005 0.005 0.005 0.014 

4 Station 33 to 

Station 154 

0.009 0.009 0.009 0.009 0.009 0.018 

5 Station 154 to 

Station 51 

0.010 0.010 0.010 0.010 0.010 0.020 

6 Station 51 to 

Station 52 

0.011 0.012 0.015 0.025 0.045 0.036 

7 Station 52 to 

TTN 

0.012 0.013 0.016 0.066 0.066 0.039 

Table 6.8. (Cont.) Bottom Friction Coefficient Sets. 

Zone No. Description Set 7 Set 8 Set 9 Set 10 Set 11 Set 12 

1 OB to Bay 

Entrance 

0.005 0.005 0.005 0.005 0.005 0.005 

2 Bay Entrance to 

Ship John Shoal 

0.010-

0.014 

0.010 0.010 0.010 0.010 0.010 

3 Ship John Shoal 

to Station 33 

0.014-

0.018 

0.012 0.012 0.012 0.010 0.012 

4 Station 33 to 

Station 154 

0.018-

0.020 

0.014 0.014 0.014 0.010-

0.014 

0.012 

5 Station 154 to 

Station 51 

0.020-

0.022 

0.016 0.016 0.016 0.014-

0.016 

0.012 

6 Station 51 to 

Station 52 

0.022-

0.028 

0.025 0.020 0.018 0.016-

0.019 

0.014 

7 Station 52 to 

TTN 

0.028-

0.036 

0.028 0.025 0.020 0.019-

0.022 

0.016 
69 

Table 6.9. Bathymetric Sets 

Set 

No. 

Free Surface Open 

Ocean Boundary 

Condition 

C&D Canal River 

Entrance Adjustment

Shelf 

Cutoff 

Depth 

(m) 

Bay Cutoff 

Depth (m) 

River 

Cutoff 

Depth 

(m) 

1 Chapman No 300 5 5 

2 Clamped Yes 130 5 5 

3 Clamped Yes 130 5 2 

Table 6.10. M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 1 

Amp Phase 

 (cm) (o) 

Sim. 2 

Amp Phase 

(cm) (o) 

Sim. 3 

Amp Phase 

 (cm) (o) 

Sim. 4 

Amp Phase 

 (cm) (o) 

Ocean City Pier, MD 4.0 6.7 2.9 0.3 2.9 0.3 -2.4 -2.8 

Chesapeake City, MD 9.8 8.0 10.2 5.9 10.2 5.8 0.8 2.3 

Lewes, DE 8.9 3.1 6.7 -2.8 6.7 -2.8 0.6 -4.1 

Cape May, NJ 9.2 3.4 6.7 -2.6 6.7 -2.6 0.1 -4.1 

Brandywine Shoal, 

DE 

10.9 4.7 8.5 -1.4 8.5 -1.4 1.8 -2.9 

Ship John Shoal, DE 14.0 0.7 11.4 -5.9 11.4 -5.9 4.4 -7.8 

Reedy Point, DE 10.0 -2.2 7.8 -8.7 7.7 -8.6 1.9 -10.6 

Delaware City, DE 9.5 -1.5 7.7 -7.9 7.6 -7.9 1.8 -9.9 

Marcus Hook, PA 2.7 3.2 1.3 -3.4 1.3 -3.4 -3.8 -5.3 

Phila. USCG, PA 10.4 -3.8 9.0 -10.6 9.0 -10.6 3.5 -12.6 

Phila. Pier 11, PA 13.7 -10.8 12.4 -17.7 12.4 -17.7 6.8 -19.7 

Tacony Bridge, NJ 15.6 -6.7 14.2 -13.7 14.2 -13.7 8.2 -15.7 

Burlington, PA 17.7 -11.1 16.1 -18.1 16.1 -18.1 9.3 -20.3 

Trenton, NJ 17.2 -12.7 15.2 -19.8 15.2 -19.8 8.0 -22.0 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 5 

Amp Phase 

 (cm) (o) 

Sim. 6 

Amp Phase 

(cm) (o) 

Sim. 7 

Amp Phase 

 (cm) (o) 

Sim. 8 

Amp Phase 

 (cm) (o) 

Ocean City Pier, MD -2.4 -2.8 -2.4 -2.8 -2.4 -2.8 -2.4 -2.8 

Chesapeake City, MD 0.8 2.3 1.2 2.2 1.3 2.2 1.6 2.6 

Lewes, DE 0.6 -4.1 0.3 -4.2 0.3 -4.2 0.6 -4.1 

Cape May, NJ 0.1 -4.1 0.8 -4.2 0.7 -4.1 0.2 -4.1 

Brandywine Shoal, 

DE 

 1.8 -2.9 2.1 -2.9 2.0 -2.9 1.9 -2.8 

Ship John Shoal, DE 4.4 -7.8 5.0 -8.0 5.0 -7.8 4.9 -7.3 

Reedy Point, DE 1.9 -10.6 2.9 -10.9 3.5 -10.7 5.0 -10.0 

Delaware City, DE 1.8 -9.9 2.9 -10.2 3.7 -10.1 5.6 -9.6 

Marcus Hook, PA -3.8 -5.3 -2.8 -6.4 -1.9 -7.4 1.1 -9.6 
70 

Phila. USCG, PA 3.5 -12.6 3.3 -12.6 1.9 -12.3 -0.9 -13.6 

Phila. Pier 11, PA 6.8 -19.7 6.5 -19.7 4.9 -19.3 1.7 -20.5 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 5 

Amp Phase 

 (cm) (o) 

Sim. 6 

Amp Phase 

(cm) (o) 

Sim. 7 

Amp Phase 

 (cm) (o) 

Sim. 8 

Amp Phase 

 (cm) (o) 

Tacony Bridge, NJ 8.2 -15.7 7.8 -15.6 5.8 -14.7 -0.2 -13.6 

Burlington, PA 9.3 -20.3 8.9 -19.9 6.4 -18.5 -2.1 -13.1 

Trenton, NJ 8.0 -22.0 7.6 -21.5 4.9 -19.9 -4.9 -12.4 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors.

Station Sim. 9 

Amp Phase 

 (cm) (o) 

Sim. 10 

Amp Phase 

(cm) (o) 

Sim. 11 

Amp Phase 

 (cm) (o) 

Sim. 12 

Amp Phase 

 (cm) (o) 

Ocean City Pier, MD -2.4 -2.8 -2.3 -2.9 -2.3 -2.9 -2.4 2.1 

Chesapeake City, MD 1.8 2.8 -0.2 3.9 -0.8 3.9 -0.3 5.7 

Lewes, DE 0.5 -4.0 0.4 -5.4 -0.6 -5.9 0.3 -0.5 

Cape May, NJ 0.1 -4.0 -0.7 -4.7 0.4 -6.3 -0.8 0.3 

Brandywine Shoal, 

DE 

 1.8 -2.7 0.7 -3.2 0.4 -4.6 0.5 1.7 

Ship John Shoal, DE 4.9 -7.0 0.8 -5.8 -1.9 -4.9 0.3 -0.7 

Reedy Point, DE 6.0 -9.8 -3.3 -7.6 -5.5 -7.3 -2.2 -3.3 

Delaware City, DE 6.9 -9.4 -3.4 -6.9 -5.7 -6.6 -2.3 -2.6 

Marcus Hook, PA 2.7 -11.2 -12.3 -3.8 -15.2 -1.4 -10.1 0.7 

Phila. USCG, PA -4.3 -12.1 -13.6 -6.6 -13.2 -6.5 -9.2 -3.2 

Phila. Pier 11, PA -1.9 -18.7 -10.9 -13.5 -10.4 -13.5 -6.4 -10.2 

Tacony Bridge, NJ -4.1 -11.3 -11.9 -7.8 -10.9 -8.5 -6.8 -4.9 

Burlington, PA -6.2 -11.5 -13.6 -10.5 -12.3 -11.8 -7.9 -8.1 

Trenton, NJ -9.3 -11.1 -17.0 -11.3 -15.5 -12.8 -10.7 -9.1 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 13 

Amp Phase 

 (cm) (o) 

Sim. 14 

Amp Phase 

(cm) (o) 

Sim. 15 

Amp Phase 

 (cm) (o) 

Sim. 16 

Amp Phase 

 (cm) (o) 

Ocean City Pier, MD -2.4 2.1 -2.4 2.1 -2.4 2.1 -2.3 2.0 

Chesapeake City, MD -0.4 5.5 -0.4 5.4 -0.3 5.5 -0.6 5.1 

Lewes, DE 0.3 -0.4 0.3 -0.5 0.5 -0.5 0.3 -0.6 

Cape May, NJ -0.8 0.3 -0.7 0.2 -0.4 -0.2 -0.8 0.1 

Brandywine Shoal, DE 0.5 1.8 0.5 1.7 0.8 1.4 0.4 1.5 

Ship John Shoal, DE 0.3 -0.7 0.4 -0.9 0.9 -1.3 -0.2 -0.9 

Reedy Point, DE -2.6 -3.4 -2.8 -3.6 -2.6 -4.0 -3.0 -3.5 

Delaware City, DE -2.8 -2.6 -3.1 -2.8 -2.9 -3.1 -2.9 -2.8 
71 

Marcus Hook, PA -10.8 1.6 -11.3 2.0 -11.1 1.9 -8.7 1.5 

Phila. USCG, PA -8.1 -3.5 -7.6 -3.5 -7.1 -4.0 -3.3 -4.9 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 13 

Amp Phase 

 (cm) (o) 

Sim. 14 

Amp Phase 

(cm) (o) 

Sim. 15 

Amp Phase 

 (cm) (o) 

Sim. 16 

Amp Phase 

 (cm) (o) 

Phila. Pier 11, PA -5.3 -10.5 -4.6 -10.5 -4.1 11.1 -0.2 -12.0 

Tacony Bridge, NJ -5.4 -5.7 -4.3 -6.1 -3.9 -6.6 0.6 -7.9 

Burlington, PA -6.1 -9.0 -4.8 -10.1 -4.3 -10.5 0.8 -12.1 

Trenton, NJ -8.8 -10.1 -7.3 -11.5 -6.8 -11.8 -1.3 -13.7 

Table 6.10. (Cont.) M2 Tidal Constituent Amplitude (cm) and Phase (o) Errors. 

Station Sim. 17 

Amp Phase 

 (cm) (o) 

Sim. 18 

Amp Phase 

(cm) (o) 

Ocean City Pier, MD -2.3 1.8 -2.3 2.0 

Chesapeake City, 

MD 

 1.0 11.1 -0.5 5.1 

Lewes, DE -0.1 -1.9 0.3 -0.6 

Cape May, NJ -1.2 -0.8 -0.8 0.1 

Brandywine Shoal, 

DE 

 -0.2 0.7 0.4 1.6 

Ship John Shoal, DE -2.8 2.3 -0.2 -0.8 

Reedy Point, DE -6.0 0.9 -2.5 -3.4 

Delaware City, DE -6.8 2.3 -2.3 -2.7 

Marcus Hook, PA -15.0 9.0 -8.1 0.6 

Phila. USCG, PA -10.8 5.1 -4.0 -5.4 

Phila. Pier 11, PA -7.9 - 2.1 -1.0 -12.5 

Tacony Bridge, NJ -7.5 2.3 -0.5 -7.4 

Burlington, PA -7.9 -0.9 -0.3 -9.9 

Trenton, NJ -10.5 -1.3 -2.2 -10.0 

Table 6.11. DBOFS Version 1.0 and Version 1.1 April 1984 Tidal Simulation Results: 

Water Surface Elevation. 

Station RMSE (m) 

Version 1.0 Version 

1.1 

 Relative Error (-) 

 Version 1.0 Version 1.1 

Marcus Hook, PA 13 10 0.01 0.01 

Cape May, NJ 13 4 0.01 0.00 

Ship John Shoal, 

NJ 

15 7 0.01 0.00 

Tacony Bridge, NJ 19 12 0.02 0.01 

Burlington, NJ 25 16 0.03 0.01 

Phila. USCG, PA 16 10 0.01 0.01 
72 

Table 6.11. (Cont.) DBOFS Version 1.0 and Version 1.1 April 1984 Tidal Simulation Results: 

 Water Surface Elevation. 

Station RMSE (m) 

Version 1.0 Version 1.1 

 Relative Error (-) 

 Version 1.0 Version 1.1 

Phila. Pier 11, PA 21 17 0.03 0.02 

Delaware City, 

DE 

14 7 0.01 0.00 

Reedy Point, DE 13 7 0.01 0.00 

Brandywine 

Shoal, DE 

14 6 0.02 0.00 

Lewes, DE 11 3 0.01 0.00 

Indian River, DE 18 14 0.06 0.04 

Ocean City Pier, 

MD 

10 5 0.02 0.00 

Chesapeake City, 

MD 

9 4 0.02 0.00 

Trenton, NJ 30 19 0.03 0.01 

W-OBC 1 6 0.00 0.01 

S-OBC 1 10 5 0.02 0.00 

S-OBC2 8 5 0.02 0.01 

S-OBC3 8 5 0.01 0.01 

S-OBC4/E-OBC1 8 5 0.01 0.01 

E-OBC2 7 6 0.01 0.01 

E-OBC3 9 7 0.01 0.01 

Table 6.12. DBOFS Version 1.0 and Version 1.1 April 1984 Tidal Simulation Results: 

 Principal Component Direction Current. 

Station 

DAB (m) 

 RMSE (cm/s) 

Version 1.0 Version 1.1 

 Relative Error (-) 

 Version 1.0 Version 1.1 

2 at 7 12.7 15.3 0.02 0.03 

3 at 5 17.6 7.8 0.02 0.01 

5 at 5 16.8 8.0 0.02 0.00 

11 at 3 5.6 3.8 0.04 0.02 

16 at 8 6.5 4.0 0.42 0.24 

17 at 15 8.4 7.0 0.15 0.11 

18 at 2 12.2 7.2 0.04 0.02 

19 at 8 16.3 8.4 0.02 0.01 

21 at 2 16.1 11.5 0.06 0.04 

22 at 6 14.8 14.1 0.02 0.02 

23 at 8 11.7 6.9 0.01 0.01 

24 at 2 12.7 9.8 0.05 0.03 

25 at 2 33.9 30.3 0.81 0.81 

33 at 11 16.7 17.5 0.02 0.02 

51 at 9 33.7 29.6 0.13 0.11 

154 at 8 35.6 33.2 0.12 0.11 
73 

Figure 6.1. Simulated Astronomical Tide JD 100-110, 1984 at Lewes, DE. Top panel

shows DBOFS Version 1.0 results. Bottom panel shows DBOFS Version 1.1 

 results. Predictions are at 6-minute intervals.
74 

Figure 6.2. Simulated Astronomical Tide JD 100-110, 1984 at Philadelphia, PA. Top panel

shows DBOFS Version 1.0 results. Bottom panel shows DBOFS Version 1.1 results. 

 Predictions are at 6-minute intervals.
75 

Figure 6.3. Simulated Astronomical Tide JD 100-110, 1984 at Trenton, NJ. Top panel

 shows DBOFS Version 1.0 results. Bottom panel shows DBOFS Version 1.1 results.

Predictions are at 6-minute intervals. 
76 

Figure 6.4. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 17. Predictions are 

at 6-minute intervals. 
77 

Figure 6.5. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 2. Predictions are 

 at 6-minute intervals. 
78 

Figure 6.6. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 19. Predictions 

 are at 6-minute intervals. 
79 

Figure 6.7. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 23. Predictions are 

 at 6-minute intervals. 
80 

Figure 6.8. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 33. Predictions 

 are at 6-minute intervals. 
81 

Figure 6.9. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 154. Predictions are 

 at 6-minute intervals. 
82 

Figure 6.10. DBOFS Version 1.1 Tidal Current JD 100-110, 1984 at Station 51. 

 Predictions are at 6-minute intervals.
83 

6.3 March1984 – March 1985 Tidal Simulation Validation

An extended 13-month tidal simulation was performed over the period March 1984-March 1985. 

The objective was to assess the tidal dynamics over an extended time frame and compare with the 

results for April 1984. Since the Sa and Ssa long period constituents are included, the seasonal 

heating and cooling effects are also included in the tidal dynamics. USGS daily mean flow values 

were used as inflows, with salinity set to zero and temperature specified from the NOS historical 

Delaware River and Bay circulation survey dataset (Klavans et al., 1986). Water surface elevation 

results are shown in Table 6.13 compared to NOS tidal predictions in terms of RMSE and Willmott 

(1985) relative error. The results at the entrance to Delaware Bay, at Philadelphia, PA and at 

Trenton, NJ are consistent with the results for April 1984 and vary gradually from month to month. 

Note all model and predicted time series are at 6 minute intervals and were demeaned. 

Model principal component direction currents are compared to NOS predictions in Table 6.14 in 

terms of RMSE and Willmott (1985) relative error and are generally consistent with the results for 

April 1984 and vary slightly from month to month. Model currents are resolved along the observed 

flood direction. All model and current time series are at 6 minute intervals and were not demeaned. 

Table 6.13. DBOFS Version 1.1 March 1984-March 1985 Tide Simulation Results. 

Station March April May June July August Sept 

Marcus Hook, PA 12/1 10/1 11/1 11/1 12/1 12/1 11/1 

Cape May, NJ 7/0 4/0 5/0 8/1 9/1 8/1 6/0 

Ship John Shoal, DB 9/1 8/0 9/1 12/1 12/1 11/1 8/0 

Tacony Bridge, NJ 15/1 13/1 13/1 14/1 16/2 17/2 16/2 

Burlington, NJ 18/2 17/1 17/1 19/2 21/2 21/2 21/2 

Phila. USCG, PA 12/1 10/1 11/1 12/1 14/1 14/1 14/2 

Phila. Pier 11, PA 19/2 18/2 17/2 18/2 20/3 21/3 22/3 

Delaware City, DE 9/1 7/0 8/1 9/1 11/1 10/1 9/1 

Reedy Point, DE 8/1 7/0 8/0 9/1 11/1 11/1 9/1 

Brandywine Shoal, DB 8/1 6/0 7/0 9/1 10/1 8/1 6/0 

Lewes, DE 7/1 3/0 5/0 8/1 9/1 8/1 5/0 

Ocean City Pier, MD 7/1 5/0 5/1 7/1 8/1 7/1 6/1 

Chesapeake City, MD 4/1 4/0 4/0 4/0 4/0 4/0 4/0 

Trenton, NJ 22/2 20/2 20/2 21/2 24/2 25/2 25/2 

Table 6.13. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Tide Simulation Results. 

Station Oct Nov Dec Jan Feb Mar 

Marcus Hook, PA 10/1 11/1 11/1 10/1 10/1 10/1 

Cape May, NJ 5/0 6/0 7/1 8/1 7/1 7/1 

Ship John Shoal, DB 8/0 9/1 10/1 10/1 8/1 8/1 

Tacony Bridge, NJ 14/1 13/1 12/1 12/1 14/1 13/1 

Burlington, NJ 18/2 17/1 16/1 16/1 16/1 17/1 

Phila. USCG, PA 12/1 11/1 10/1 10/1 11/1 11/1 

Phila. Pier 11, PA 19/2 18/2 16/1 17/2 19/3 20/3 
84 

Table 6.13. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Tide Simulation Results. 

Station Oct Nov Dec Jan Feb Mar 

Delaware City, DE 7/0 7/0 8/1 9/1 9/1 8/1 

Reedy Point, DE 8/0 8/1 8/0 8/1 8/1 8/1 

Brandywine Shoal, DB 7/0 7/1 8/1 9/1 7/1 6/1 

Lewes, DE 4/0 5/0 6/1 8/1 7/1 6/1 

Ocean City Pier, MD 5/1 5/1 7/1 8/1 7/1 6/1 

Chesapeake City, MD 4/0 5/1 5/1 5/1 5/0 5/1 

Trenton, NJ 22/2 20/2 19/2 19/1 20/2 20/2 

Table 6.14. DBOFS Version 1.1 March 1984-March 1985 Tide Simulation PCD Current Results. 

Station 

DAB (m) 

March April May June July August Sept 

2 at 7 24/8 25/9 22/7 27/11 28/11 27/10 21/5 

3 at 5 8/1 6/0 6/0 7/0 8/1 8/1 7/1 

5 at 5 11/1 9/1 9/1 9/1 10/1 10/1 10/1 

11 at 3 4/2 4/2 4/2 4/2 4/2 3/2 3/2 

16 at 8 3/21 3/22 2/15 4/30 4/29 3/18 3/22 

17 at 15 5/8 6/11 6/11 7/13 6/9 5/8 6/12 

18 at 2 8/2 7/2 8/2 8/2 8/2 8/2 8/2 

19 at 8 13/3 12/2 12/2 13/3 14/3 14/3 12/2 

21 at 2 12/4 12/4 12/4 12/4 13/4 13/4 12/4 

22 at 6 23/9 23/9 22/8 22/8 23/9 24/9 23/8 

23 at 8 15/4 15/4 13/3 15/4 16/4 16/4 14/3 

24 at 2 11/4 10/3 9/3 10/3 11/4 12/4 11/4 

33 at 11 34/13 35/15 33/13 34/14 35/14 36/14 34/13 

51 at 9 20/8 20/8 19/7 20/7 21/8 22/9 20/8 

154 at 8 38/17 36/15 36/15 33/13 35/13 37/15 39/18 

Table 6.14. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Tide Simulation PCD 

 Current Results. 

Station DAB (m) Oct Nov Dec Jan Feb Mar 

2 at 7 20/6 20/5 19/5 19/6 20/5 21/7 

3 at 5 7/1 7/1 7/1 7/0 7/0 7/0 

5 at 5 10/1 9/1 10/1 9/1 9/1 9/0 

11 at 3 4/2 4/2 4/2 4/1 3/1 3/2 

16 at 8 3/19 3/20 3/20 3/19 3/16 3/16 

17 at 15 11/30 9/20 9/17 6/12 5/7 5/8 

18 at 2 8/2 8/2 8/2 8/2 8/2 8/2 

19 at 8 11/2 11/2 12/2 11/2 11/2 11/2 

21 at 2 12/4 12/4 12/5 12/4 12/4 12/4 

22 at 6 22/9 20/7 20/7 21/7 22/8 23/9 

23 at 8 13/3 12/3 13/3 13/3 13/3 14/3 

24 at 2 10/4 10/3 9/3 10/3 11/4 11/4 

33 at 11 34/14 33/14 33/14 33/12 33/13 34/14 

51 at 9 21/8 20/8 19/7 19/7 20/8 21/8 

154 at 8 36/16 36/15 36/15 35/15 35/15 36/15 
85 

6.4 March1984 – March 1985 Hindcast Simulation Validation

The specification of the meteorological forcings was accomplished via Barnes (1973) interpolation 

of surface meteorological observations as previously described. Of interest is to note that the 

forcings were computed at 3 hour intervals and compared with observations at one hour intervals as 

shown in Tables 6.15 – 6.17 at 15-day intervals for atmospheric pressure, wind speed, and wind 

direction, respectively. In most 15-day segments, the wind speed errors are less than 4 m/s (< 10 

kts) and the wind direction errors are less than 22.5 degrees (within an octant), indicating that the 3 

hour interpolation interval is sufficient. The extended hindcast was analyzed in 15-day segments for 

water levels, currents, salinity, and temperature in terms of RMSE and Willmott (1985) relative error 

as discussed in turn. 

Water Levels 

In Table 6.18, the water level comparisons are given in 15-day segments. One notes that the RMSEs 

are generally very consistent over the initial 7-8 month period, while over the winter period there are 

data issues within the upper estuary caused by icings as indicated by the missing values in Table 

6.18.. One also notes that there are datum problems for the observed water levels at Burlington, PA, 

Newbold, PA, and at Chesapeake City, MD. In general RMSEs increase from order 8 cm at the 

Entrance to order 10 cm at Marcus Hook, PA and are order 15 cm at Philadelphia, PA before 

increasing to order 20 cm at Trenton, NJ. Simulated water surface elevation time series plots from 

the Bay entrance at Lewes, DE, up river to Philadelphia Pier 11, PA, and finally to the head of tide 

at Trenton, NJ are shown in Figures 6.11 – 6.13 for JD 70-91, 1984, respectively, in Figures 6.14 -

6.16 for JD 92 – 107, respectively, in Figures 6.17 – 6.19 for JD 137-152, respectively, in Figures 

6.20 – 6.22 for JD 153-168, respectively, in Figures 6.23 – 6.25 for JD 229-244, respectively, in 

Figures 6.26-6.28, respectively for JD 306-321, respectively, in Figures 6.29-6.31, respectively for 

JD 351-366, in Figures 6.32-6.34, respectively for JD 47-60, and in Figures 6.35-6.37 in Figures 

6.38-6.40, respectively for JD 75-90. Several interesting aspects of the water level response occur. 

Flow events at the Trenton, NJ location are noted in the JD 92-107 and JD 137-152 time series plots, 

with the influences extending to Philadelphia, PA. Average daily inflow values are used for the 

present forcings, but it may be necessary during high flow events to use 3-6 hour interval flows. 

During the JD 306-321, 1984 and JD 33-47, 1985 period, the water level gage at Philadelphia, PA 

goes flat to zero indicating potential ice problems. During 1985, there may also be an issue with the 

recorded water level gage datum at Trenton, NJ. 

Currents 

In Tables 6.20 and 6.21, the simulated currents are compared to observed currents in 15-day 

segments for speed and direction, respectively. In general, the RMSEs are very consistent from one 

15-day period to another with the RMSEs at most stations under 26 cm/s (<0.5kt). The direction 

comparisons are more problematical at Stations 154 and 51 in the river and at Station 16 on the 

shelf. In Tables 6.22 and 6.23, the mean of the simulated currents speeds and directions are 

compared to the mean observed current speed and directions, respectively. At most stations there is 

good agreement and consistent results from one 15-day period to the next. Current speed and 

direction time series plots are shown for Stations 23, 33, and 51 progressing from the lower Bay into 

the river below Philadelphia, PA in Figures 6.41-6.43, respectively for JD 76-91, 1984, in Figures 
86 

6.44-6.46, respectively for JD 153-168, in Figures 6.47-6.49, respectively for JD 229-254, in Figures 

6.50-6.52, for JD 351-366, and in Figure 6.53 at Station 23 and in Figure 6.54 at Station 51 for JD 

75-90, 1985. There are limited observation data, but favorable comparisons are achieved at Stations 

33 and 51 during JD 229-254, 1984 and at Stations 23 and 51 during JD 75-90, 1985. 

Salinity 

In Table 6.24, the simulated salinities are compared to observed salinities in 15-day segments. In 

general, the RMSEs are very consistent from one 15-day period to another with the RMSEs at most 

stations under 3 PSU. The comparisons are more problematical at Stations 23 and 33 in the upper 

Bay in the region of the large salinity gradient. In Table 6.25, the mean of the simulated salinities are 

compared to the mean observed salinities. At most stations there is good agreement and consistent 

results from one 15-day period to the next. The simulated salinities appear to be too low at Stations 

23 and 33 during the first 7 months, but then come in closer agreement to the observations over the 

last 5 months indicating that there may be some issues with the initial condition specification. 

Salinity time series plots at Stations 23 and 33 are shown in Figures 6.55 and 6.56, respectively, for 

JD 76-91, 1984, in Figures 6.57 and 6.58, respectively, for JD 153-168, in Figures 6.59 and 6.60, 

respectively, for JD 229-244, in Figures 6.61 and 6.62, respectively, for JD 351-366, and in Figure 

6.63 at Station 23 for JD 75-90, 1985. One notes the large amplitude order 5 to 6 PSU in the 

simulated salinity at Station 33, indicating that it is located in the region of strong salinity gradient. 

During the JD 153-168, 1984 period there is evidence that the simulated salinity is too low at Station 

33. The amplitude of the simulated salinity at Station 23, further down estuary, mid-Bay, is 

generally less than 4 PSU and is reduced from that at Station 33, indicating that the gradients in 

salinity are not as strong at this station. 

Temperature 

In Table 6.26, the simulated temperatures are compared to observed temperatures in 15-day 

segments. In general, the RMSEs are very consistent from one 15-day period to another with the 

RMSEs at most stations under 3 o

C . There is consistent over-heating by order 5 oC during the first 8 

months of the simulation and ice forms during the winter. However, during the spring of 1985 the 

temperatures recover in close agreement to observations. This behavior is further confirmed by 

examining the temperature time series plots at Station 23 and 33, for JD 76-91, 1984, in Figures 6.64 

and 6.65, in Figures 6.66 and 6.67 for JD 153-168, and in Figures 6.68 and 6.69 for JD 229-244, 

respectively, in Figure 6.70 at Station 33 for JD 351-366, and in Figure 6.71 at Station 23 for JD 75-

90, 1985. In general, the heating and cooling cycle is well represented, as shown in Table 6.27, but 

there may be some issues with the radiation balance. 
87 

Table 6.15. DBOFS Version 1.1 March 1984-March 1985 Atmospheric Pressure: 

 RMSE (mb)/RE(%). 

Station No. March April May June July August Sept 

61N Indian River, 

DE 

2/1 - - - - - - 

N91 Cape May, NJ 4/6 - - - - - - 

44009 1/0 0/0 0/0 0/0 0/0 0/0 0/0 

44012 - - - 0/0 0/0 0/0 0/0 

Table 6.15. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Atmospheric Pressure: 

 RMSE (mb)/RE(%). 

Station No. Oct Nov Dec Jan Feb Mar 

61N Indian River, 

DE 

- - - - - - 

N91 Cape May, NJ - - - - - - 

44009 0/0 0/0 0/0 - - - 

44012 0/0 0/0 0/0 - - - 

Table 6.16. DBOFS Version 1.1 March 1984-March 1985 Wind Speed: RMSE(m/s)/ RE(%). 

Station No. March April May June July August Sept 

61N Indian River, 

DE 

3/30 - - - - - - 

N91 Cape May, NJ 3/24 - - - - - - 

44009 1/4 1/7 1/4 1/3 1/4 0/4 1/4 

44012 - - - 1/3 1/4 0/4 1/4 

Table 6.16. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Wind Speed: 

 RMSE (m/s)/RE(%). 

Station No. Oct Nov Dec Jan Feb Mar 

61N Indian River, 

DE 

- - - - - - 

N91 Cape May, NJ - - - - - - 

44009 1/3 0/1 1/3 - - - 

44012 0/2 0/1 0/2 - - - 

Table 6.17. DBOFS Version 1.1 March 1984-March 1985 Wind Direction: RMSE (oT)/RE(%). 

Station No. March April May June July August Sept 

61N Indian River, 

DE 

39/6 - - - - - - 

N91 Cape May, NJ 40/7 - - - - - - 

44009 22/2 22/2 17/1 16/1 16/1 15/1 15/0 

44012 - - - 15/1 16/1 15/1 12/0 
88 

Table 6.17. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Wind Direction: 

 RMSE (oT)/RE(%). 

Station No. Oct Nov Dec Jan Feb Mar 

61N Indian River, 

DE 

- - - - - - 

N91 Cape May, NJ - - - - - - 

44009 14/1 13/0 15/1 - - - 

44012 12/0 13/0 15/1 - - - 

Table 6.18. DBOFS Version 1.1 March 1984-March 1985Water Surface Elevations: 

 RMSE (cm)/RE(%) 

Station No. March April May June July August Sept 

Trenton, NJ 25/23 

2/2 

23/16 

2/1 

17/26 

1/2 

22/20 

1/1 

25/20 

2/1 

20/23 

1/2 

18/18 

1/1 

Phila. Pier 11, PA 17/15 

2/1 

12/11 

1/1 

11/11 

1/1 

13/12 

1/1 

17/16 

2/2 

11/11 

1/1 

10/15 

1/1 

Lewes, DE 14/12 

2/1 

9/9 

1/1 

10/9 

1/1 

11/10 

1/2 

12/11 

1/2 

11/10 

1/1 

8/8 

1/1 

Cape May, NJ 15/11 

2/1 

9/10 

1/1 

9/9 

1/1 

10/11 

1/1 

10/11 

1/1 

10/8 

1/1 

7/8 

1/1 

Table 6.18. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Mean Water Surface Elevations: 

 RMSE (cm)/RE(%) 

Station No. Oct Nov Dec Jan Feb Mar 

Trenton, NJ 23/20 

2/1 

23/25 

2/2 

19/16 

1/1 

33/33 

4/4 

-/- 

-/- 

21/22 

2/2 

Phila. Pier 11, PA 16/11 

2/1 

-/- 

-/- 

13/13 

1/1 

-/- 

-/- 

-/23 

-/4 

13/16 

1/2 

Lewes, DE 8/8 

1/1 

9/9 

1/1 

10/10 

1/1 

11/13 

1/2 

12/9 

1/1 

10/9 

1/1 

Cape May, NJ 8/7 

1/0 

8/8 

1/1 

9/9 

1/1 

11/12 

1/1 

12/9 

1/1 

9/9 

1/1 

Table 6.19. DBOFS Version 1.1 March 1984-March 1985 Mean Water Surface Elevations (cm): 

 Model/Observed. 

Station No. March April May June July August Sept 

Trenton, NJ 124/125 

146/153 

200/197 

169/172 

153/158 

158/156 

157/165 

135/144 

147/151 

132/139 

133/143 

136/140 

133/134 

131/130 

Phila. Pier 11, PA 95/91 

117/117 

137/136 

128/126 

112/114 

111/110 

114/115 

111/112 

109/117 

105/110 

112/115 

115/112 

112/107 

116/110 

Lewes, DE 55/57 

78/82 

81/81 

76/78 

61/62 

60/60 

62/65 

67/68 

56/61 

61/65 

70/75 

76/75 

75/75 

81/81 

Cape May, NJ 62/65 

83/87 

87/91 

83/88 

68/71 

67/69 

68/72 

74/76 

63/65 

68/69 

76/77 

82/83 

81/82 

81/83 
89 

Table 6.19. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Mean Water Surface Elevations 

 (cm): Model/Observed. 

Station No. Oct Nov Dec Jan Feb Mar 

Trenton, NJ 135/133 

140/142 

134/130 

121/118 

120/118 

124/121 

125/117 

108/99 

120/115 

113/113 

120/119 

122/120 

Phila. Pier 11, PA 116/110 

119/118 

- 96/94 

99/96 

- 

- 

- 

87/83 

91/89 

97/90 

Lewes, DE 81/81 

78/78 

78/76 

63/61 

58/57 

59/56 

64/62 

47/43 

62/64 

43/43 

50/50 

59/59 

Cape May, NJ 87/89 

84/86 

85/86 

70/71 

65/67 

66/68 

72/75 

55/58 

69/74 

51/54 

57/61 

66/69 

Table 6.20. DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Speed Skill Results: 

RMSE (cm/s) / RE (%). 

Station 

DAB (m)

March April May June July August Sept 

2 at 14 x-24/ 

x-15 

5 at 2 

5 at 5 

11 at 3 

16 at 3 x-6/ 

x-54 

5-4/ 

41-46 

7-9/ 

53-54 

7-x/ 

63-x 

16 at 8 

16 at 11 

17 at 3 x-5/ 

x-42 

5-5/ 

48-38 

7-4/ 

58-32 

17 at 15 14-15/ 

75-63 

17 at 23 x-22/ 

x-76 

27-31/ 

75-73 

30-16/ 

79-71 

17-9/ 

68-48 

 

18 at 2 x-8/ 

x-8 

19 at 2 x-10/ 

x-10 

19 at 8 

22 at 2 x-11/ 

x-18 

 

22 at 6 x-17/ 

x-16 

23 at 2 11-14/ 

21-32 

23 at 8 

24 at 2 x-6/ 

x-6 

25 at 2 x-9/ 

x-13 
90 

Table 6.20. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Speed Skill 

 Results: RMSE (cm/s) / RE (%). 

Station 

DAB (m)

March April May June July August Sept 

33 at 2 23-20/ 

46-33 

19-17/ 

31-22 

13-x/ 

19-x 

33 at 11 20-29/ 

12-20 

23-33/ 

11-26 

27-29/ 

17-21 

23-x/ 

14-x 

51 at 2 15-18/ 

20-37 

51 at 9 18-18/ 

16-17 

16-19/ 

14-19 

154 at 2 17-24/ 

25-26 

15-32/ 

17-27 

154 at 8 

Table 6.20. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current 

 Speed Skill Results: RMSE (cm/s) / RE (%). 

Station 

 DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 17-13/ 

15-16 

2 at 14 20-21/ 

17-12 

18-17/ 

14-9 

16-x/ 

20-x 

 

5 at 2 x-10/ 

x-4 

11-11/ 

8-6 

 

5 at 5 x-10/ 

x-3 

12-14/ 

7-7 

 

11 at 3 x-7/ 

x-25 

6-5/ 

28-18 

 

16 at 8 14-8/ 

46-47 

8-7/ 

63-53 

 

16 at 11 15-9/ 

43-50 

9-7/ 

62-53 

 

17 at 15 17-11/ 

51-51 

14-13/ 

68-64 

 

17 at 23 

18 at 2 8-12/ 

15-38 

 

19 at 2 9-12/ 

12-24 

19 at 8 10-10/ 

7-9 

22 at 6 16-17/ 

20-23 

23 at 2 6-13/ 

7-21 

9-10/ 

16-13 

 
91 

Table 6.20. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current 

 Speed Skill Results: RMSE (cm/s) / RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

23 at 8 10-21/10-24 10-12/ 

8-8 

 17-14/ 

18-15 

24 at 2 7-13/13-53 

25 at 2 9-17/22-68 

33 at 2 

33 at 11 

51 at 2 26-24/ 

77-73 

22-x/ 

68-x 

25-25/ 

67-59 

 x-18/ 

x-27 

17-16/ 

22-20 

51 at 9 18-17/ 

20-17 

17-16/ 

17-16 

11-x/ 

8-x 

 x-14/ 

x-13 

16-14/ 

14-10 

154 at 8 21-22/ 

17-23 

 x-28/ 

x-39 

31-25/ 

30-26 

Table 6.21. DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current Speed (cm/s) 

Skill Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

2 at 14 x-49/x-64 

5 at 2 

5 at 5 

11 at 3 

16 at 3 x-8/x-8 9-8/7-7 8-7/11-12 8-x/11-x 

16 at 8 

16 at 11 

17 at 3 x-10/x-10 11-9/11-8 12-10/8-9 

17 at 15 17-20/15-22 

17 at 23 x-27/x-14 33-38/13-14 38-22/11-14 23-23/18-11 

18 at 2 x-29/x-28 

19 at 2 x-49/x-49 

19 at 8 

22 at 2 x-11/x-18 31-x/26-x 

22 at 6 x-44/x-45 

23 at 2 30-32/19-17 

23 at 8 

24 at 2 x-29/x-29 

25 at 2 x-27/x-32 

33 at 2 33-29/51-39 30-30/40-40 28-x/31-x 

33 at 11 69-56/70-60 64-58/65-62 64-58/62-61 60-x/57-x 

51 at 2 37-38/48-45 

51 at 9 54-53/64-64 53-53/62-63 

154 at 2 32-31/39-47 30-x/32-x 

154 at 8 x-41/x-59 
92 

Table 6.21. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current Speed 

 (cm/s) Skill Results: Model/Observed. 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 43-37/48-39 

2 at 14 42-51/49-56 41-48/46-51 43-x/35-x 

5 at 2 x-50/x-48 42-48/38-41 

5 at 5 x-59/x-61 50-57/52-58 

11 at 3 x-16/x-17 14-16/13-13 

16 at 8 12-11/19-13 9-12/12-13 

16 at 11 13-11/20-13 10-12/12-12 

17 at 15 16-17/22-15 19-20/14-14 

17 at 23 

18 at 2 26-31/22-14 

19 at 2 31-37/25-20 

19 at 8 42-51/40-32 

22 at 6 40-46/36-32 

23 at 2 27-33/25-28 27-32/23-27 

23 at 8 37-45/31-26 36-43/31-37 44-40/41-36 

24 at 2 25-30/23-14 

25 at 2 23-28/20-9 

33 at 2 

33 at 11 

51 at 2 36-40/42-47 36-x/43-x 37-37/48-38 x-37/x-48 38-37/51-50 

51 at 9 51-55/59-62 51-54/56-59 52-x/51-x x-52/x-57 54-52/62-60 

154 at 8 42-41/47-42 x-41/x-34 43-39/53-45 

Table 6.22. DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Direction Skill Results: 

RMSE (oT) / RE (%). 

Station 

DAB (m)

March April May June July August Sept 

2 at 14 

5 at 2 

5 at 5 

11 at 3 

16 at 3 70-56/ 

62-22 

16 at 8 

16 at 11 

17 at 3 

17 at 15 104-79/ 

57-34 

17 at 23 x-95/ 

x-40 

72-114/ 

8-22 

64-103/ 

58-42 

66-x/ 

12-x 

 
93 

Table 6.22.(Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Direction Skill 

 Results: RMSE (oT) / RE (%). 

Station 

DAB (m)

March April May June July August Sept 

18 at 2 x-8/ 

x-0 

19 at 2 x-9/ 

x-0 

19 at 8 

22 at 2 x-18/ 

x-1 

12-x/ 

1-x 

22 at 6 x-17/ 

x-1 

23 at 2 6-5/ 

0-0 

23 at 8 

24 at 2 x-46/ 

x-6 

25 at 2 x-122/ 

x-60 

33 at 2 47-39/ 

9-5 

31-23/ 

3-2 

15-x/ 

1-x 

33 at 11 11-42/ 

0-5 

18-37/ 

1-4 

26-30/ 

2-3 

23-x/ 

2-x 

51 at 2 9-25/ 

0-2 

51 at 9 21-23/ 

1-2 

19-28/ 

1-2 

154 at 2 12-35/ 

0-4 

35-x/ 

4-x 

154 at 8 x-57/ 

x-13 

Table 6.22. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Direction Skill 

 Results: RMSE (oT) / RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 22-12/ 

2-1 

2 at 14 18-20/ 

1-1 

13-13/ 

1-1 

7-x/ 

0-x 

 

5 at 2 x-7/ 

x-0 

13-20/ 

1-1 

 

5 at 5 x-9/ 

x-0 

16-24/ 

1-2 

 

11 at 3 x-34/ 

x-3 

21-x/ 

69-x 

 
94 

Table 6.22. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Current Direction Skill 

 Results: RMSE (oT) / RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

16 at 8 30-46/ 

46-4 

42-x/ 

15-x 

 

16 at 11 25-48/ 

38-7 

36-x/ 

39-x 

 

17 at 15 58-66/ 

29-12 

72-36/ 

55-4 

 

17 at 23 

18 at 2 10-4/ 

0-49 

 

19 at 2 8-6/ 

0-0 

19 at 8 15-6/ 

1-0 

22 at 6 17-18/ 

1-1 

23 at 2 7-7/ 

0-0 

11-11/ 

0-0 

 

23 at 8 5-4/ 

0-0 

11-11/ 

0-0 

 18-17/ 

1-1 

24 at 2 39-x/ 

4-x 

 

25 at 2 124-8/ 

91-79 

33 at 2 

33 at 11 

51 at 2 68-67/ 

15-15 

64-x/ 

13-x 

132-125/ 

57-52 

 x-8/ 

x-0 

9-8/ 

0-0 

51 at 9 28-25/ 

2-2 

24-26/ 

2-2 

4-x/ 

0-x 

 x-4/ 

x-0 

21-12/ 

1-0 

154 at 8 41-44/ 

5-6 

 x-116/ 

x-47 

52-42/ 

9-6 

Table 6.23. DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current Direction (oT) 

Skill Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

2 at 14 

5 at 2 

5 at 5 

11 at 3 

16 at 3 176-185/212-260 

16 at 8 

16 at 11 
95 

Table 6.23. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current 

Direction (oT) Skill Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

17 at 3 

17 at 15 167-168/ 

217-242 

17 at 23 x-255/ 

x-213 

245-266/ 

187-138 

295-263/ 

262-92 

207-x/ 

118-x 

 

18 at 2 x-226/ 

x-233 

19 at 2 x-229/ 

x-255 

19 at 8 

22 at 2 x-232/ 

x-237 

235-x/ 

243-x 

22 at 6 x-223/ 

x-235 

23 at 2 227-233/ 

271-269 

23 at 8 

24 at 2 x-182/ 

x-248 

25 at 2 x-107/ 

x-184 

33 at 2 227-223/ 

289-266 

227-224/ 

258-258 

228-x/ 

259-x 

33 at 11 212-201/ 

229-229 

210-206/ 

225-229 

207-210/ 

232-220 

210-x/ 

228-x 

51 at 2 193-192/ 

197-190 

51 at 9 195-193/ 

201-195 

193-193/ 

195-194 

154 at 2 165-175/ 

150-164 

175-x/ 

174-x 

154 at 8 x-184/ 

x-208 

Table 6.23. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current 

Direction (oT) Skill Results: Model/Observed. 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 237-238/ 

224-226 

2 at 14 230-231/ 

216-216 

232-232/ 

221-222 

229-x/ 

212-x 

 

5 at 2 x-218/ 

x-220 

219-215/ 

220-218 

 

5 at 5 x-216/ 

x-222 

217-214/ 

219-219 

 
96 

Table 6.23. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Current Direction 

 (oT) Skill Results: Model/Observed. 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

11 at 3 x-210/ 

x-237 

208-x/ 

288-x 

 

16 at 8 153-172/ 

229-185 

132-x/ 

66-x 

 

16 at 11 157-174/ 

219-184 

131-x/ 

55-x 

 

17 at 15 164-180/ 

223-195 

166-160/ 

218-164 

 

17 at 23 

18 at 2 226-225/ 

244-315 

 

19 at 2 227-231/ 

261-220 

19 at 8 236-237/ 

247-231 

22 at 6 224-222/ 

243-219 

23 at 2 227-235/ 

257-252 

238-236/ 

267-256 

 

23 at 8 242-245/ 

257-246 

245-243/ 

255-253 

 245-246/ 

241-245 

24 at 2 170-x/ 

252-x 

 

25 at 2 105-109/ 

183-181 

33 at 2 

33 at 11 

51 at 2 192-193/ 

200-199 

193-x/ 

199-x 

194-194/ 

200-204 

 x-196/ 

x-223 

196-193/ 

205-204 

51 at 9 192-193/ 

196-203 

192-194/ 

201-198 

195-x/ 

176-x 

 x-196/ 

x-213 

196-194/ 

198-197 

154 at 8 182-178/ 

180-154 

 x-152/ 

x-164 

151-158/ 

153-164 

Table 6.24. DBOFS Version 1.1 March 1984-March 1985 Hindcast Salinity Skill Results: RMSE 

(PSU)/ RE (%). 

Station 

DAB (m) 

March April May June July August Sept 

2 at 2 x-0.8/ 

x-41 

0.5-1.4/ 

54-71 

4.2-x/ 

66-x 

2 at 7 x-0.4/ 

x-42 

2 at 14 

5 at 2 

5 at 5 

11 at 3 
97 

Table 6.24. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Salinity Skill Results: 

 RMSE (PSU)/ RE (%). 

Station 

DAB (m) 

March April May June July August Sept 

16 at 3 x-0.7/ 

x-62 

0.7-0.5/ 

62-82 

1.2-1.6/ 

52-64 

1.4/ 

59- 

16 at 8 

16 at 11 

17 at 3 x-0.8/ 

x-85 

1.1-1.1/ 

84-91 

 

17 at 15 0.3-0.5/66-56 

17 at 23 x-1.5/ 

x-66 

1.4-1.3/ 

81-79 

1.2-0.5/ 

67-62 

 

18 at 2 x-2.2/ 

x-51 

19 at 2 x-1.8/ 

x-47 

19 at 8 

22 at 2 x-3.4/ 

x-49 

1.8-x/ 

35-x 

22 at 6 x-1.1/ 

x-16 

23 at 2 0.8-1.4/ 

46-48 

23 at 8 

24 at 2 x-1.8/ 

x-60 

25 at 2 

33 at 2 9.0-9.1/ 

78-67 

8.1-6.4/ 

70-53 

4.6-x/ 

55-x 

33 at 11 6.6-6.8/ 

60-67 

2.9-7.2/ 

28-67 

6.5-7.9/ 

62-70 

3.2-x/ 

46-x 

51 at 2 0.0-0.0/0-0 

51 at 9 0.0-0.0/ 

0-0 

0.0-0.0/0-100 

154 at 2 3.9-5.4/ 

91-70 

4.7-x/84-x 

154 at 8 x-4.4/ x-70 

Table 6.24. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Salinity Skill Results: 

 RMSE (PSU)/ RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 0.4-0.3/ 

19-44 

0.4-0.3/ 

37-22 

0.4-x/ 

43-x 

 1.5-1.3/ 

77-49 

2 at 14 0.7-0.2/ 

55-71 

0.3-0.2/ 

45-12 

0.1-x/ 

24-x 

 

5 at 2 x-0.5/ 

x-8 

0.2-x/ 

3-x 

 
98 

Table 6.24. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Salinity Skill Results: 

 RMSE (PSU)/ RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

5 at 5 x-0.5/ 

x-8 

1.4-1.3/ 

21-22 

 

11 at 3 x-0.5/ 

x-57 

0.4-0.2/ 

51-28 

 

16 at 8 0.6-0.5/ 

92-60 

0.5-0.2/ 

53-60 

 

16 at 11 0.8-0.5/ 

97-76 

1.2-1.0/ 

72-76 

 

17 at 15 1.0-0.9/ 

69-73 

0.4-0.2/ 

79-53 

 

17 at 23 

18 at 2 2.1-0.7/ 

52-24 

 

19 at 2 1.6-0.2/ 

57-5 

19 at 8 0.2-0.3/ 

5-13 

22 at 6 1.7-1.6/ 

36-41 

23 at 2 1.2-0.4/ 

50-61 

0.4-1.0/ 

23-74 

 

23 at 8 0.2-0.4/ 

8-25 

0.4-0.9/ 

20-75 

 3.2-2.5/ 

60-59 

24 at 2 2.0-1.8/ 

68-78 

 

25 at 2 

33 at 2 

33 at 11 

51 at 2 0.0-0.2/ 

74-83 

0.3-x/ 

100-x 

0.5-0.5/ 

100-100 

 x-0.0/ 

x-100 

0.0-0.0/ 

100-0 

51 at 9 0-0.2/ 

100-100 

0.3-0.4/ 

100-100 

0.5-x/ 

100-x 

 x-0.0/ 

x-100 

0.0-0.0/ 

99-58 

154 at 8 3.6-2.6/ 

67-62 

 x-1.9/ 

x-59 

2.0-2.3/ 

59-89 

Table 6.25. DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Salinity (PSU) Skill 

Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

2 at 2 x-31.0/ 

x-31.7 

31.0-31.1/ 

30.4-29.9 

30.8-x/ 

26.8-x 

2 at 7 x-30.7/ 

x-30.8 

2 at 14 x-30.6/ 

x-30.3 

5 at 2 
99 

Table 6.25. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Salinity (PSU) 

 Skill Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

5 at 5 

11 at 3 

16 at 3 x-31.5/ 

x-32.0 

31.9-32.0/ 

32.5-31.7 

31.8-31.7/ 

30.8-30.2 

31.8-x/ 

30.5-x 

16 at 8 

16 at 11 

17 at 3 x-32/2/ 

x-33.0 

32.2-32.1/ 

33.2-33.2 

31.9-31.8/ 

33.1-32.8 

17 at 15 32.0-32.1/ 

31.9-32.3 

17 at 23 x-32.5/ 

x-33.0 

32.6-32.4/ 

31.7-30.9 

32.0-31.8/ 

30.7-30.5 

31.8-31.8/ 

30.7-31.5 

 

18 at 2 x-27.0/ 

x-26.2 

19 at 2 x-29.5 

x-28.1 

19 at 8 

22 at 2 x-25.3/ 

x-28.4 

25.9-x/ 

27.5-x 

22 at 6 x-26.9/ 

x-26.9 

23 at 2 28.0-28.4 

27.3-27.1 

23 at 8 

24 at 2 x-24.4/ 

x-26.1 

25 at 2 

33 at 2 9.7-11.2/ 

17.1-20.0 

11.8-15.5/ 

19.6-21.3 

16.3-x/ 

20.6-x 

33 at 11 4.8-8.1/ 

11.9-13.8 

8.8-7.8/ 

11.2-14.6 

10.2-12.9/ 

16.5-19.4 

15.1-x/ 

18.2-x 

51 at 2 0.0-0.0/ 

0-1 

51 at 9 0.0-0.0/ 

0-0 

0.0-0.0/ 

0-0 

154 at 2 1.1-1.2/ 

4.5-6.4 

2.2-x/ 

6.7-x 

154 at 8 x-3.5/ 

x-8.2 
100 

Table 6.25. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Salinity (PSU) 

 Skill Results: Model/Observed. 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 30.9-30.8/ 

30.7-31.0 

31.1-30.7/ 

31.4-31.0 

31.3-x/ 

31.6-x 

 31.3-31.6/ 

32.7-32.9 

2 at 14 30.7-30.8/ 

30.1-30.8 

31.0-30.7/ 

31.1-30.7 

31.1-x/ 

31.0-x 

 

5 at 2 x-31.0/ 

x-30.7 

30.7-x/ 

31.0-x 

 

5 at 5 x-31.0/ 

x-30.7 

30.6-30.4/ 

30.0-28.3 

 

11 at 3 x-32.6/ 

x-32.2 

32.8-32.8/ 

32.4-32.6 

 

16 at 8 32.0-32.0/ 

32.0-32.2 

32.6-32.8/ 

32.2-32.8 

 

16 at 11 32.0-32.0/ 

31.6-31.7 

32.6-32.8/ 

31.4-31.7 

 

17 at 15 32.1-32.3/ 

33.0-33.2 

32.6-32.9/ 

32.9-33.0 

 

17 at 23 

18 at 2 27.2-27.5/ 

27.4-27.5 

 

19 at 2 29.8-30.0/ 

29.3-30.2 

19 at 8 29.8-29.9/ 

29.7-30.0 

22 at 6 27.3-27.4/ 

27.6-28.8 

23 at 2 28.7-28.8/ 

27.7-28.9 

29.1-29.2/ 

29.2-30.1 

 

23 at 8 28.7-28.8/ 

28.6-28.7 

29.1-29.2/ 

29.1-30.1 

 28.4-29.9/ 

26.9-27.7 

24 at 2 24.9-25.5 

26.6-27.1 

 

25 at 2 

33 at 2 

33 at 11 

51 at 2 0.0-0.2/ 

7-4 

0.3-x/ 

0.0-x 

0.5-0.5/ 

0.0-0.0 

 x-0.0/ 

x-0.0 

0.0-0.0/ 

0.0-0.0 

51 at 9 0.0-0.2/ 

0-0 

0.3-0.4/ 

0.0-0.0 

0.5-x/ 

0.0-x 

 x-0.0/ 

x-0.0 

0.0-0.0/ 

0.0-0.0 

154 at 8 5.5-7.2/ 

8.9-9.8 

 x-6.5/ 

x-3.1 

2.1-2.9/ 

4.0-3.9 
101 

Table 6.26. DBOFS Version 1.1 March 1984-March 1985 Hindcast Temperature Skill Results: 

 RMSE (oC)/ RE (%). 

Station 

DAB (m) 

March April May June July August Sept 

2 at 2 5.7-x/ 

67-x 

2 at 7 x-3.8/ 

x-72 

2 at 14 x-3.7/ 

x-71 

5 at 2 

5 at 5 

11 at 3 

16 at 3 6.1-x/ 

54-x 

16 at 8 

16 at 11 

17 at 3 

17 at 15 4.7-4.5/ 

62-65 

17 at 23 x-4.1/ 

x-81 

2.9-2.7/ 

57-47 

3.8-2.7/ 

74-52 

2.7-x/ 

52-x 

 

18 at 2 x-3.3/ 

x-60 

19 at 2 x-3.1/ 

x-74 

19 at 8 

22 at 2 5.9-x/ 

68-x 

22 at 6 x-2.9/ 

x-67 

23 at 2 3.3-3.1/ 

93-70 

23 at 8 

24 at 2 x-2.5/ 

x-54 

33 at 2 4.4-5.4/ 

89-80 

4.0-5.4/ 

62-80 

2.3-x/ 

50-x 

33 at 11 3.0-3.5/ 

87-81 

2.6-3.8/ 

70-76 

3.4-3.8/ 

67-76 

2.7-x/ 

55-x 

51 at 2 0.2-0.4/ 

10-6 

51 at 9 

154 at 2 

154 at 8 x-0.7/ 

x-21 
102 

Table 6.26. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Temperature Skill 

 Results: RMSE (oC)/ RE (%). 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 4.3-3.1/ 

88-83 

3.5-5.3/ 

53-64 

4.8-/ 

89-x 

 1.6-1.68/ 

66-82 

2 at 14 4.3-3.1/ 

88-82 

3.5-5.3/ 

51-65 

5.1-x/ 

96-x 

 

5 at 2 x-2.7/ 

x-83 

3.8-5.0/ 

46-76 

 

5 at 5 x-2.7/ 

x-82 

3.8-5.1/ 

46-76 

 

11 at 3 x-3.9/ 

x-93 

3.7-4.8/ 

62-89 

 

16 at 8 3.9-2.2/ 

85-80 

3.8-5.2/ 

63-65 

 

16 at 11 3.8-2.3/ 

84-76 

3.1-4.2/ 

67-60 

 

17 at 15 1.5-1.0/ 

75-71 

1.9-1.5/ 

52-43 

 

17 at 23 

18 at 2 3.2-2.7/ 

82-95 

 

19 at 2 3.9-3.6/ 

79-97 

19 at 8 3.8-3.4/ 

81-97 

22 at 6 2.9-2.6/ 

74-96 

23 at 2 3.1-2.2/ 

77-73 

2.3-3.3/ 

31-48 

 

23 at 8 3.2-2.4/ 

90-74 

2.3-3.3/ 

31-48 

 1.2-0.9/ 

49-42 

24 at 2 2.4-1.9/ 

76-91 

 

33 at 2 

33 at 11 

51 at 2 0.4-0.5/ 

11-69 

 1.1-5.4/ 

40-74 

 x-0.9/ 

x-94 

51 at 9 x-1.0/ 

x-76 

1.1-0.6/ 

44-35 

154 at 8 0.9-0.4/ 

39-31 

 x-0.8/ 

x-59 

0.7-0.6/ 

15-22 
103 

Table 6.27. DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Temperature (oC) Skill 

 Results: Model/Observed. 

Station 

DAB (m) 

March April May June July August Sept 

2 at 2 x-25.2/ 

x-22.7 

24.6-x/ 

19.3-x 

2 at 7 x-23.8/ 

x-19.5 

2 at 14 x-23.8/ 

x-19.6 

5 at 2 

5 at 5 

11 at 3 

16 at 3 22.5-22.5/ 

13.2-18.8 

22.4-x/ 

17.0-x 

16 at 8 

16 at 11 

17 at 3 

17 at 15 21.0-20.2/ 

16.6-17.1 

17 at 23 x-11.1/ 

x-7.1 

13.0-15.9/ 

10.1-13.3 

18.9-21.2/ 

15.1-18.9 

23.3-23.5/ 

19.1-15.8 

 

18 at 2 x-23.4/ 

x-20.0 

19 at 2 x-23.6/ 

x-20.4 

19 at 8 

22 at 2 x-25.7/ 

x-16.6 

26.8-x/ 

20.8-x 

22 at 6 x-23.5/ 

x-20.5 

23 at 2 25.7-23.6/ 

21.9-20.5 

23 at 8 

24 at 2 x-22.9/ 

x-20.3 

25 at 2 

33 at 2 26.4-27.4/ 

23.1-22.1 

27.9-27.4/ 

24.0-24.9 

25.6-x/ 

23.5-x 

33 at 11 22.1-25.4/ 

22.6-22.1 

26.6-27.5/ 

24.1-23.8 

28.2-27.5/ 

24.8-24.8 

25.6-x/ 

23.2-x 

51 at 2 24.4-21.6/ 

23.8-21.9 

51 at 9 

154 at 2 

154 at 8 x-21.7/ 

x-19.5 
104 

Table 6.27. (Cont.) DBOFS Version 1.1 March 1984-March 1985 Hindcast Mean Temperature (oC) 

 Skill Results: Model/Observed. 

Station 

DAB (m)

Oct Nov Dec Jan Feb Mar 

2 at 7 21.6-20.3/ 

17.2-17.3 

18.9-15.5/ 

15.5-10.2 

13.5-x/ 

9.9-x 

 7.2-7.7/ 

5.6-6.2 

2 at 14 21.5-20.3/ 

17.2-17.3 

18.8-15.4/ 

15.4-10.1 

13.4-x/ 

9.4-x 

 

5 at 2 x-20.2/ 

x-17.6 

18.2-14.7/ 

14.6-9.9 

 

5 at 5 x-20.2/ 

x-17.6 

18.2-14.7/ 

14.5-9.9 

 

11 at 3 x-21.0/ 

x-17.0 

19.4-x/ 

15.8-x 

 

16 at 8 19.9-17.5/ 

17.0-16.8 

19.0-x/ 

15.4-x 

 

16 at 11 20.0-17.9/ 

17.1-17.1 

19.1-x/ 

16.1-x 

 

17 at 15 17.8-16.1/ 

16.8-16.4 

13.9-13.3/ 

15.2-12.9 

 

17 at 23 

18 at 2 20.1-19.8/ 

16.9-16.8 

 

19 at 2 21.0-19.9/ 

17.0-16.6 

19 at 8 20.9-19.9/ 

17.1-16.7 

22 at 6 20.1-19.9/ 

17.2-16.9 

23 at 2 20.4-19.8/ 

17.3-17.6 

17.6-12.6/ 

15.3-9.6 

 

23 at 8 20.4-19.8/ 

16.9-17.5 

17.6-12.6/ 

15.3-9.6 

 6.5-7.3/ 

5.6-6.4 

24 at 2 19.0-19.2/ 

16.6-16.6 

 

25 at 2 

33 at 2 

33 at 11 

51 at 2 17.7-17.6/ 

18.0-17.5 

 6.3-6.6/ 

6.0-1.4 

 x-7.1/ 

x-9.0 

51 at 9 x-1.8/ 

x-5.3 

6.0-7.1/ 

7.0-7.7 

154 at 8 17.8-18.2/ 

17.0-17.1 

 x-2.9/ 

x-5.5 

5.7-6.9/ 

6.2-7.4 

 

 
105 

Figure 6.11. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
106 

Figure 6.12. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 at Philadelphia, PA. 

Observations are at one hour intervals. 
107 

Figure 6.13. DBOFS Version 1.1 Water Surface Elevation JD 70-91, 1984 at Trenton, NJ. 

 Observations are at one hour intervals. 
108 

Figure 6.14. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
109 

Figure 6.15. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 at Philadelphia, PA. 

 Observations are at one hour intervals. 
110 

Figure 6.16. DBOFS Version 1.1 Water Surface Elevation JD 92-107, 1984 at Trenton, NJ. 

 Observations are at one hour intervals. 
111 

 Figure 6.17. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
112 

 Figure 6.18. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 at Philadelphia, 

PA. Observations are at one hour intervals. 
113 

Figure 6.19. DBOFS Version 1.1 Water Surface Elevation JD 137-152, 1984 at Trenton, NJ. 

Observations are at one hour intervals. 
114 

Figure 6.20. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
115 

 Figure 6.21. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 at Philadelphia, 

PA. Observations are at one hour intervals. 
116 

Figure 6.22. DBOFS Version 1.1 Water Surface Elevation JD 153-168, 1984 at Trenton, NJ. 

Observations are at one hour intervals. 
117 

 Figure 6.23. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
118 

 Figure 6.24. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 at Philadelphia, 

PA. Observations are at one hour intervals. 
119 

Figure 6.25. DBOFS Version 1.1 Water Surface Elevation JD 229-244, 1984 at Trenton, NJ. 

Observations are at one hour intervals. 
120 

 Figure 6.26. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
121 

Figure 6.27. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 at Philadelphia, 

PA. Observations are at one hour intervals. 
122 

Figure 6.28. DBOFS Version 1.1 Water Surface Elevation JD 306-321, 1984 at Trenton, NJ. 

Observations are at one hour intervals. 
123 

Figure 6.29. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 at Lewes, DE. 

Observations are at one hour intervals. 
124 

 Figure 6.30. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 at Philadelphia, 

PA. Observations are at one hour intervals. 
125 

 Figure 6.31. DBOFS Version 1.1 Water Surface Elevation JD 351-366, 1984 at Trenton, NJ. 

Observations are at one hour intervals. 
126 

Figure 6.32. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 at Lewes, DE. 

Observations are at one hour intervals. 
127 

 Figure 6.33. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 at Philadelphia, PA. 

Observations are at one hour intervals.
128 

Figure 6.34. DBOFS Version 1.1 Water Surface Elevation JD 32-47, 1985 at Trenton, NJ. 

Observations are at one hour intervals. 
129 

Figure 6.35. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 at Lewes, DE. 

Observations are at one hour intervals.
130 

Figure 6.36. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 at Philadelphia, PA. 

Observations are at one hour intervals.
131 

Figure 6.37. DBOFS Version 1.1 Water Surface Elevation JD 47-60, 1985 at Trenton, NJ. 

 Observations are at one hour intervals.
132 

Figure 6.38. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 at Lewes, DE. 

Observations are at one hour intervals.
133 

Figure 6.39. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 at Philadelphia, PA. 

Observations are at one hour intervals.
134 

Figure 6.40. DBOFS Version 1.1 Water Surface Elevation JD 75-90, 1985 at Trenton, NJ. 

 Observations are at one hour intervals.
135 

Figure 6.41. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 23. 
136 

Figure 6.42. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 33. 
137 

Figure 6.43. DBOFS Version 1.1 Current JD 76-91, 1984 at Station 51. 
138 

Figure 6.44. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 23. 
139 

Figure 6.45. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 33. Observations are at 

10-minute intervals.
140 

Figure 6.46. DBOFS Version 1.1 Current JD 153-168, 1984 at Station 51.
141 

Figure 6.47. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 23.
142 

Figure 6.48. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 33. Observations are at 

10-minute intervals.
143 

Figure 6.49. DBOFS Version 1.1 Current JD 229-254, 1984 at Station 51. Observations are at 

10-minute intervals.
144 

Figure 6.50. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 23. 
145 

Figure 6.51. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 33.
146 

Figure 6.52. DBOFS Version 1.1 Current JD 351-366, 1984 at Station 51.
147 

Figure 6.53. DBOFS Version 1.1 Current JD 75-90, 1985 at Station 23. Observations are at 10-

minute intervals.
148 

Figure 6.54. DBOFS Version 1.1 Current JD 75-90, 1985 at Station 51. Observations are at 10-

minute intervals.
149 

Figure 6.55. DBOFS Version 1.1 Salinity JD 76-91, 1984 at Station 23.
150 

Figure 6.56. DBOFS Version 1.1 Salinity JD 76-91, 1984 at Station 33.
151 

Figure 6.57. DBOFS Version 1.1 Salinity JD 153-168, 1984 at Station 23.
152 

Figure 6.58. DBOFS Version 1.1 Salinity JD 153-168, 1984 at Station 33. Observations are at 

10-minute intervals.
153 

Figure 6.59. DBOFS Version 1.1 Salinity JD 229-244, 1984 at Station 23.
154 

Figure 6.60. DBOFS Version 1.1 Salinity JD 229-244, 1984 at Station 33. Observations are at 

10-minute intervals.
155 

Figure 6.61. DBOFS Version 1.1 Salinity JD 351-366, 1984 at Station 23.
156 

Figure 6.62. DBOFS Version 1.1 Salinity JD 351-366, 1984 at Station 33.
157 

Figure 6.63. DBOFS Version 1.1 Salinity JD 75-90, 1985 at Station 23. Observations are at 10-

minute intervals.
158 

Figure 6.64. DBOFS Version 1.1 Temperature JD 76-91, 1984 at Station 23.
159 

Figure 6.65. DBOFS Version 1.1 Temperature JD 76-91, 1984 at Station 33.
160 

Figure 6.66. DBOFS Version 1.1 Temperature JD 153-168, 1984 at Station 23.
161 

Figure 6.67. DBOFS Version 1.1 Temperature JD 153-168, 1984 at Station 33. Observations are 

at 10-minute intervals.
162 

Figure 6.68. DBOFS Version 1.1 Temperature JD 229-244, 1984 at Station 23.
163 

Figure 6.69. DBOFS Version 1.1 Temperature JD 229-244, 1984 at Station 33. Observations are 

at 10-minute intervals.
164 

Figure 6.70. DBOFS Version 1.1 Temperature JD 351-366, 1984 at Station 33.
165 

Figure 6.71. DBOFS Version 1.1 Temperature JD 75-90, 1985 at Station 23. Observations are at 

10-minute intervals. 
166 

6.5. Summary and Additional Considerations 

The optimized offshore tidal water level constituents and bottom roughness coefficient sets obtained 

for the April 1984 tidal simulation, lead to much improved model responses in both the 13-month 

tidal and hindcast simulations. Due to the fact that the offshore boundary extends to the continental 

shelf break, it is necessary during the optimization process to perform harmonic analysis of the tidal 

simulations to further refine the tidal water level harmonic constants obtained from the ADCIRC 

Western North Atlantic tidal inversion. This approach was not necessary for the previous generation 

forecast systems, whose offshore boundaries did not extend substantially on to the shelf and 

therefore their tidal water level harmonic constants could be obtained by an adjustment of nearby 

coastal water level station values. Sufficient accuracies in these revised model predictions were 

obtained to justify the development of the semi-operational nowcast/forecast system at NCEP. 
167 

7. SEMI-OPERATIONAL NOWCAST/FORECAST SYSTEM CONSTRUCTION 

To develop a semi-operational nowcast/forecast system, it was necessary to revise the COMF used at 

CO-OPS for implementation at NCEP. In this effort, it was necessary to standardize the initial 

condition, boundary condition, and forcing files for the operational nowcast forecast systems to be 

run at NCEP. To support this effort several templates were developed to aid in the development of 

the appropriate fixed files. 

7.1 River Template 

To specify the lateral (river) boundary conditions the template given in Table 7.1 was developed for 

DBOFS. 

Table 7.1. Template of River Control File for DBOFS. 

Section 1: USGS real-time streamflow gages 

NO USGS_ID NWS_ID min(cfs) max(cfs) mean(cfs) Name 

1 01411500 20. 5260. 253. Maurice River, Norma, NJ 

2 01412800 5. 2150. 56. Cohansey River, Seeley, NJ 

3 01463500 1240. 279000. 11850. Delaware River, Trenton, NJ 

4 01465500 3. 27300. 302. Neshaminy Creek, Langhorne, PA 

5 01467087 1. 3140. 41. Frankford Creek, Philadelphia, 

PA 

6 01474500 1. 93400. 2773. Schuylkill River, Philadelphia, 

PA 

7 01477120 3. 1260. 40. Racoon Creek, Swedesboro, NJ 

8 01478650 35. 14200. 45. Brandywine Creek, Wilmington, DE 

9 01482500 0. 4460. 20. Salem River, Woodstown, NJ 

10 01484525 0. 1260. 95. Millsboro Pond, Millsboro, DE 

11 01477000 6. 6510. 92. Chester Creek, PA 

Section 2: ROMS river discharge inputs 

GRID_ID I/Xpos J/Ypos DIR FLAG DQ_USGS_ID DQ_Scale TS_USGS_ID TS_SCALE River_Basin_Name 

 1 94 92 0 3 01411500 1.0 01474500 1.0 MAURICE RIVER 

 2 88 128 0 3 01412800 1.0 01474500 1.0 COHANSEY RIVER 

 3 77 730 1 3 01463500 0.33 01463500 1.0 DELAWARE RIVER 

 4 78 730 1 3 01463500 0.34 01463500 1.0 DELAWARE RIVER 

 5 79 730 1 3 01463500 0.33 01463500 1.0 DELAWARE RIVER 

 6 73 608 0 3 01465500 1.0 01467087 1.0 NESHAMINY CREEK 

 7 76 542 0 3 01467087 1.0 01467087 1.0 FRANKFORD CREEK 

 8 73 426 0 3 01474500 1.0 01474500 1.0 SCHUYLKILL RIVER 

 9 86 341 0 3 01477120 -1.0 01474500 1.0 RACCOON CREEK 

 10 73 283 0 3 01478650 1.2 01474500 1.0 BRANDYWINE CREEK 

 11 87 206 0 3 01482500 -1.0 01474500 1.0 SALEM RIVER 

 12 65 52 0 3 01484525 1.0 01474500 1.0 MILLSBORO POND 

 13 73 349 0 3 01477000 1.0 01474500 1.0 CHESTER CREEK 

 14 67 96 0 3 01484525 0.25 01474500 1.0 ROACH MARSH 

Note min, max, and mean flows are in cfs. Note DQ_SCALE is negative for Raccoon Creek 

and Salem River to note the flow is in the direction of decreasing coordinate values. 
168 

7.2 Open Boundary Condition Template 

For the open boundary condition, the template given in Table 7.2 was constructed, which seeks to 

use secondary and backup water level gages for subtidal water level. In general the A and B 

coefficients would need to be determined via linear regression of at least one month of subtidal 

water levels. 

Table 7.2. Template of Open Boundary Condition Control File for DBOFS. 

Section 1: OBC Boundary Signal Information 

NO NOS_ID SEC_WL_ID As Bs BKP_WL_ID Ab Bb PORTS_SIG_ID Clim_SIG_ID Name 

1 853-4720 2 1. 0. 4 1.0 0. 0 0 Atlantic City, NJ 

2 857-0283 1 1. 0. 4 1.0 0. 0 0 Ocean City Inlet, MD 

3 857-3927 5 1. 0. 99 1.0 0. 1 1 Chesapeake City, MD 

4 853-6110 99 1. 0. 99 1.0 0. 99 99 Cape May, NJ 

5 857-9999 99 1. 0. 99 1.0 0. 99 99 Baltimore, MD 

Note for subtidal water level: SEC_WL_ID is the secondary water level station 

id and BKP_WL is the backup water level station id. 

A(s,b) and B(s,b) are used to estimate the water level at the NOS_ID as 

follows: 

WL(NOS_ID)= As*WL(SEC_WL_ID) + Bs, and WL(NOS_ID)= Ab*WL(BKP_WL_ID) + Bb. 

Note ids equal to 99 indicate no stations for secondary or backup water level. 

Note for T and S: PORTS_SIG_ID and CLIM_SIG_ID equal zero corresponds to 

Levitus. If PORTS_SIG_ID is not 

zero, specify PORTS signal information in Section 2. If CLIM_SIG_ID is not 

zero then you must provide 

T and S information in Section 3 as follows. Note ids equal to 99 indicate no 

stations for PORTS or climatology, these are water level backup stations only. 

Section 2: PORTS Signal Information 

NO PORTS Station BKP_PORTS_ID Tadj Sadj 

1 DBOFS-Chesapeake 2 0. -5. 

2 CBOFS-Baltimore 99 0. 0. 

Note Tajd and Sadj are temperature and salinity adjustments in deg C and PSU, 

respectively, 

which are added to the CBOFS-Baltimore station values used to backup 

Chesapeake City, MD. 

If CBOFS-Baltimore is not available than one uses the climatological values in 

Section 3. 

Section 3: Interior Boundary Signal T/S Climatology 

NO T/S Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

1 3 3 8 12 15 18 19 22 24 18 12 7 --Temperature (Deg C) 

 8 6 4 4 3 7 10 10 9 5 7 8 --Salinity (PSU) 

Section 4: ROMS grid control information

Section # IROMS_L IROMS_U JROMS_L JROMS_U Bdy_ID_1 Bdy_ID_2 Scale_1 Scale_2 P_ID C_ID 

 1 60 69 1 1 2 1 1. 0. 0 0 

 2 70 119 1 1 2 2 0. 0. 0 0 

 3 1 1 210 211 3 3 1. 0. 1 1 

 4 119 119 2 59 1 1 0. 0. 0 0 

 5 119 119 60 69 1 2 1. 0. 0 0 

Note L_U denotes lower and upper bounds of grid cell indicies. Note Bdy_IDs and 

Scales used for subtidal water level signal determination. PORTS and Clim_Sig_IDs 
169 

used for T and S. If PORTS (P_ID) and Climatology(C_ID)Signal IDS are 0 use 

Levitus. If P_ID is not zero attempt to use PORTS data in Section 2, if not 

available use climatological information in section 3. 

In addition, the specification of the subtidal water level was generalized based the previous 

operational forecast systems in New York (NYOFS), Chesapeake Bay (CBOFS), and Galveston Bay 

(GBOFS) using the following approach. During the nowcast, consider water level observations, 

wlobs(T-nΔt), where T is the forecast start time and n=0,....,24 with Δt=1 hr. Note one could also 

use 6 minute data. The coastal water level station is near the offshore model boundary intersection 

with the coast. During the nowcast, consider Extratropical Storm Surge (ETSS) model predictions 

wlmod(T-nΔt), at this same coastal water level station with the T and nΔt as defined above. One then 

forms corrections, δ(T-nΔt)=wlobs(T-nΔt) – wlmod(T-nΔt). 

Consider 

( , 24 ) ( )/ 25

0

24



     ndf T T t  T n t (7.1) 

and 

 (T  nt)  (T  nt)  df (T,T  24t) (7.2) 

During the Nowcast: 

OBCN(T-nΔt)= wlmod(T-nΔt) + df(T,T-24Δt) + ε(T-nΔt), n=0,...,24 (7.3) 

At each Δt during the nowcast period, one may scale the correction, δ(T - nΔt), which is equal to 

df(T,T - 24Δt) + δ(T - nΔt), on a e-folding scale based on increasing distance from the shore 

point. 

During the forecast: 

OBCF(T + nΔt)= wlmod(T + nΔt) + F1df(T,T - 24Δt) + F2ε(T) , n=0,...,24 (7.4) 

where F1=max(0.,1-nΔt/TR1) and F2=max(0.,1-nΔt/TR2). 

At each Δt during the forecast period, one may scale the correction, F1df(T,T - 24Δt) + F2ε(T), on a 

e-folding scale based on increasing distance from the shore point. One notes the specification of TR1 

and TR2 are as follows for the previous operational forecast systems. 

Chesapeake Bay Operational Forecast System (CBOFS): TR1= ∞, TR2 = 6 

New York Harbor Operational Forecast System (NYOFS): TR1= 6, TR2=6 

Galveston Bay Operational Forecast System (GBOFS): TR1=∞, TR2=∞

To standardize the specification of the tidal boundary conditions at each open boundary cell, a 

harmonic constituent netCDF file for water level amplitude and phase and East and North vertically 

integrated horizontal current amplitudes and phases was constructed, such that all phases are in 

GMT. The HPC-COMF software at NCEP access this netCDF harmonic constituent file and for tidal 
170 

currents computes the current ellipse parameters required by ROMS. The software also computes the 

node factors and equilibrium arguments and adjusts the harmonic constants. 

7.3 Vertical Datum Considerations 

Model datum specification is made to be consistent with the VDATUM Project utilizing the 

following approach. In GBOFS, the model datum was taken as equivalent to MTL and the MTL to 

MLLW field over the Galveston Bay grid was provided via VDATUM to enable specification of the 

water level forecast fields with respect to MLLW. In NYOFS and CBOFS, model datum is assumed 

equal to MSL and the VDATUM MSL to MLLW field is used to enable specification of the water 

level forecast fields with respect to MLLW. An alternative approach used here is to assume model 

datum equal to the North American Vertical Datum of 1988 (NAVD88) in the upper reaches of the 

Delaware Estuary in the river sections above Philadelphia, PA, but near the coast assume model 

datum equal to MSL. Therefore, an additional field, model datum minus mean sea level, was 

developed. For the majority of the coastal estuaries, the values in this file will be zero. For the 

Delaware Estuary, nonzero values were added as one proceeded up the Delaware River above 

Marcus Hook, PA to the head of tide at Trenton, NJ. As more gravity data become available the 

coastal geoid will be better determined; then these values can be further refined up the estuary. On 

the shelf, with advanced satellite altimeter observations, the tie to the mean sea level at the coast can 

be better determined as well. 

A program was developed to access the VDATUM database for three separate VDATUM Projects 

with datum information to interpolate onto the high resolution DBOFS grid the following four datum 

fields: MLLW to MSL, MLW to MSL, MHHW to MSL, and MHW to MSL. The MLLW to MSL 

field is shown in Figure 7.1 and exhibits a smooth transition of contours out on to the continental 

shelf from the lower Bay region. 
171 

Figure 7.1 DBOFS MLLW to MSL Datum Conversion. 
172 

7.4 Operational Summary 

In early June 2009, DBOFS Version 1.0 was provided to CO-OPS for implementation in the 

development mode at NCEP. The bathymetry was revised to increase the cutoff depth from 2 m to 5 

m to overcome a stability problem. Since the revised bathymetry was used in late June 2009, the 

hydrodynamics have been very stable. 

During the period June – December 2009, the work reported in Chapter 6 was conducted to further 

seek improvements and to develop DBOFS Version 1.1. In December 2009, DBOFS Version 1.1 

was provided to CO-OPS and they implemented this version in January 2010 in parallel with version 

1.0. The two versions are compared in Table 7.3 over the seven month period March-September 

1984. One notes the substantial improvement gained by refining the open boundary tidal constituents 

and further adjusting the bottom roughness coefficients. The ten percent of water level range RMSE 

criteria is now satisfied at all stations up the estuary. 

Table 7.3. Seven Month March-September 1984 Water Level RMSE (cm) Summary. The 

analyses are for 15 days, thus there are two entries for each month. PMTR denotes the 

RMSE expressed as a percentage of the mean tide range. First line denotes DBOFS 

Version 1.0 results, while DBOFS Version 1.1 results are given in line 2 and in line 3 

for tide only. 

Station Mar Apr May Jun Jul Aug Sep Seven 

Month 

RMSE 

RMSE 

Range 

PMRT

Trenton

, NJ 

33/26 

25/25 

22 

33/25 

23/16 

20 

39/34 

17/26 

20 

42/35 

22/20 

21 

33/39 

25/20 

24 

35/34 

20/23 

25 

28/39 

18/18 

25 

34 

23 

23 

17 

8 

5 

13.7 

9.3 

9.3 

Phila., 

PA 

27/21 

17/15 

19 

27/21 

12/11 

18 

30/24 

11/11 

17 

32/28 

13/12 

18 

31/32 

17/16 

20 

25/26 

11/11 

21 

20/25 

10/15 

22 

27 

14 

19 

12 

7 

5 

14.8 

7.7 

10.4 

Lewes, 

DE 

17/13 

14/12 

8 

15/11 

9/9 

3 

18/13 

10/9 

5 

17/15 

11/10 

8 

15/17 

12/11 

9 

18/16 

11/10 

8 

14/18 

8/8 

5 

16 

11 

7 

7 

6 

6 

12.9 

8.9 

5.6 

Cape 

May, 

NJ 

21/14 

15/11 

7 

20/15 

9/10 

4 

21/15 

9/9 

5 

18/16 

10/11 

8 

16/18 

10/11 

9 

14/19 

10/8 

8 

15/20 

7/8 

6 

17 

10 

7 

7 

8 

5 

11.4 

6.7 

4.7 
173 

8. CONCLUSIONS AND RECOMMENDATIONS 

Following the Model Evaluation Experiment Project, two 15-day simulation periods one for high 

flow (April 1984) and one for low flow (September 1984) were used to compare POM with ROMS 

on the MEE Project medium resolution grid and to investigate the sensitivity of the water level 

response to the Walters (1992a; 1992b) bottom friction zones using different bottom friction 

coefficient sets. A high resolution grid using the DELFT3D RGFGRID package (Delft Hydraulics, 

2004) was developed and the previous 15-day periods were used to further refine the bottom 

roughness and the open boundary condition conditions with the result being the construction of 

DBOFS version 1.0. An initial seven month hindcast was performed and evaluated for total water 

levels and tides for DBOFS Version 1.0, which was provided to CO-OPS in June 2009. To seek 

further improvements, an extensive set of 18 tidal simulations were used to further adjust the bottom 

roughness and open boundary water level specification via modification of the open water level 

boundary tidal constituents to develop DBOFS Version 1.1. Both 13-month simulations were 

performed using DBOFS Version 1.1 and informally skill assessed for water levels, currents, 

salinity, and temperature in terms of RMSE and Willmott et al. (1985) relative error. Improvements 

in water level RMSEs were significant over those in DBOFS Version 1.0 and met the informal ten 

percent range criteria at all stations. As a result, it is recommended that a formal skill assessment be 

performed over the 13-month period March 1984- March 1985 for both the hindcast and tidal 

simulations described in Chapter 6 for DBOFS Version. In addition, DBOFSVersion 1.1 

implemented in the development mode at NCEP should be formally skill assessed and compared 

with the results for the 13-month hindcast and tidal simulations to insure proper implementation at 

NCEP. 

In conjunction with the model development effort, the results of the 13-month hindcast suggest that 

further improvements can be made in the following areas: 

The temperature response exhibited overheating during the summer and fall of 1984, thereby 

suggesting that the downward short wave radiation be attenuated. However, during the winter, the 

water temperatures in the upper Bay and lower river sections remained extremely cold with freezing 

indicated. This indicated that the attenuation in downward short wave radiation may need to be 

seasonally specified. Heat flux algorithm adjustments may need to be further considered in the 

coastal zone in conjunction with ice dynamics. The development of the cold water pool along the 

outer shelf also was a feature that needs a more refined open boundary condition than Levitus 

climatology. 

The salinity response in the lower Bay was considerably fresher than the observations at Station 33, 

and suggests that the location of the salt wedge needs further study.The δxH/H criteria of under 0.25 

is violated throughout the grid and may result in horizontal pressure gradient errors which tend to 

effect the salt wedge representation. It is recommended that additional levels in the vertical be 

considered as well as the δxΔH/H criteria. Additional data from the DRBC salt line dataset may be 

useful in further studying the salt wedge dynamics. 

Bottom currents tend to be overestimated and there becomes a trade-off between water level 
174 

representation, salt wedge location, and current dynamics. Additional ADCP data over vertical 

sections in the upper Bay would be useful to further adjust the hydrodynamics. Inclusion of the 

alongshore transport over the shelf should also be further investigated. 

To extend the model prediction skill to major storm surge events (enumerated by Mark and 

Scheffner, 1994), accounting for the low lying marsh areas through the use of using wetting and 

drying techniques (see Schmalz, 2007) should be considered. In addition, the treatment of the 

change in cross-sectional area with discharge due to the low lying marsh areas is extremely difficult 

to accomplish. We note at the flood stage of 20 ft the corresponding flow is 137,000 cfs. At 330,000 

cfs based on an average daily flow, which is the flood of record the stage would be 29 ft. One might 

estimate channel width changes as the flows increase by using a very simple method as follows. If 

the cross-section were approximately 300m wide by 5m in depth for 3900 m3/s (137,000 cfs), then 

the expected flow velocity would be order 2.6 m/s. Assuming the same flow speed of 2.6 m/s and an 

increase of 3 m in elevation the channel width (w) would can be approximated as 9430 m3/s 

(330,000 cfs) = 2.6m/s * w*(5+3m), which would imply w = 453m. This would be an increase of 

153m assuming a constant depth of 8 m, which is somewhat under the 29 ft (8.84m) level. Another 

approach might be to assume a maximum flow speed of 3 m/s at 29 ft (8.84m) and then based on this 

uniform depth compute w= 355.6 m. Additional efforts may have to be made to adjust the bottom 

roughness as a function of Delaware River flow at Trenton, NJ to simulate frictional effects at higher 

flows. 

ACKNOWLEDGMENTS 

This work has been carried out in the Coast Survey Development Laboratory (CSDL) of NOS’s 

Office of Coast Survey under the direction of Dr. Frank Aikman, Chief of the Marine Modeling and 

Analysis Programs. Mr. Richard C. Patchen, Chief Science Officer, directed the MEE Project and 

provided format information for the archived CTD/CT data. Mr. Philip H. Richardson and Mr. 

Thomas Loeper assisted in the CTD and CT/Current data recovery and analysis efforts. Dr. Lyon 

Lanerolle provided the POM and ROMS medium resolution grid with initial bathymetry as well as 

many useful discussions ROMS numerics throughout the project. Dr. Aijun Zhang performed the 

POM skill assessment with the MEE. 
175 

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