FINAL REPORT LITTLE SARASOTA BAY CIRCULATION STUDY Prepared for County of Sarasota Coastal Zone Management Division Environmental Services Department 9250-110-RT Contract No. C82-66 Prepared by Stergios A. Dendrou Charles I. Moore Raymond Walton CAMP DRESSER & MCKEE 7630 Little River Turnpike Annandale, Virginia 22003 August 1983 Suggested reference Camp Dresser & McKee and Mote Marine Laboratory. 1983. Little Sarasota Bay circulation study. Sarasota County. Contract no C82-66. Mote Marine Laboratory Technical Report no 57. 175 p. Available from: Mote Marine Laboratory Library. TABLE OF CONTENTS Section Page No. LIST OF FIGURES . iii LIST OF TABLES . ix I INTRODUCTION ........................................... I-1 DESCRIPTION OF THE STUDY AREA .......................... I-1 SCOPE OF WORK .......................................... I-3 REPORT OUTLINE ......................................... I-4 II RESULTS AND CONCLUSIONS . II-1 III LITTLE SARASOTA BAY MODEL .............................. III-1 DYNAMIC ESTUARY MODEL .................................. III-1 MODEL THEORY ........................................... III-1 Basic Hydrodynamic Equations ...................... III-4 Numerical Solution-Stability ...................... III-5 Boundary Conditions ............................... III-6 LITTLE SARASOTA BAY GRID NETWORK ....................... III-7 Geometric Input Data .............................. III-7 IV PRELIMINARY ANALYSIS ................................... IV-1 TIDES AND TIDAL PHASING ................................ IV-1 WIND EFFECTS ........................................... IV-16 FRESHWATER INFLOWS ..................................... IV-17 V FIELD PROGRAM .......................................... V-1 INTRODUCTION ........................................... V-1 BATHYMETRIC SURVEY ..................................... V-1 TIDE GAGES ............................................. V-2 CURRENT VELOCITY STUDIES ............................... V-5 DYE AND DROGUE STUDIES ................................. V-9 VI MODEL CALIBRATION ...................................... VI-1 CALIBRATION PROCEDURE .................................. VI-1 CALIBRATION RESULTS .................................... VI-2 July Simulation Period ............................ VI-3 April Simulation Period ........................... VI-9 DISCUSSION ............................................. VI-9 VII MODEL VERIFICATION ..................................... VII-1 VERIFICATION PROCEDURE ................................. VII-1 NOVEMBER SIMULATION RESULTS ............................ VII-1 DISCUSSION ............................................. VII-19 TABLE OF CONTENTS (Continued) Section Page No. VIII MODEL APPLICATIONS ..................................... VIII-1 ANALYSIS OF BAY CIRCULATION ............................ VIII-1 "NO-NAME" STORM ANALYSIS ............................... VIII-18 Introduction ...................................... VIII-18 Simulation of Storm ............................... VIII-23 Simulation Results ................................ VIII-25 IMPACTS OF INTRACOASTAL WATERWAY ON BAY CIRCULATION .... VIII-43 CONSEQUENCES OF MIDNIGHT PASS DREDGING ................. VIII-46 CONVECTION AND DISPERSION CHARACTERISTICS AROUND BIRD ISLAND - DYE STUDY ................................... VIII-62 IX CONCLUSIONS AND RECOMMENDATIONS . IX-1 REFERENCES APPENDICES (Separate Volume) A Preliminary Model Inputs B Bathymetric Survey Data C Reduced Tide Data for Four Study Periods D Field Data E Final Model Inputs F Velocity Vector Plots for April and July Periods G Program Listing ii LIST OF FIGURES Figure No. Page No. I-1 Little Sarasota Bay .................................... I-2 III-1 Definition Sketch - Node-Link Estuary Model ............ III-2 III-2 Little Sarasota Bay DEM Link Node Network .............. III-8 IV-1 Predicted High and Low Tides at St. Petersburg, April 1982 ................................................. IV-7 IV-2 Diurnal Tide at all Boundaries ......................... IV-8 IV-3 Semi-Diurnal Tide at all Boundaries .................... IV-10 IV-4 Semi-Diurnal Tide in Phase at Stickney and Blackburn Points ............................................... IV-12 IV-5 Semi-Diurnal Tide with Stickney Point Lagged One Half- Hour from Blackburn Point ............................ IV-13 IV-6 Semi-Diurnal Tide with Stickney Point Lagged Two Hours from Blackburn Point ................................. IV-14 IV-7 Effect of 50 mph Wind from Stickney Point .............. IV-18 IV-8 Little Sarasota Bay Drainage Subbasins ................. IV-19 V-1 Bathymetry Transects ................................... V-3 V-2 Location of Tidal Gages and Velocity Measurement Stations ............................................. V-4 VI-1 Observed vs. Simulated Elevations at Gage No. 2, July 13-14, 1982 .......................................... VI-5 VI-2 Observed vs. Simulated Elevations at Gage No. 3, July 13-14, 1982 .......................................... VI-6 VI-3 Observed vs. Simulated Elevations at Gage No. 4, July 13-14, 1982 .......................................... VI-7 VI-4 Observed vs. Simulated Elevations at Gage No. 5, July 13-14, 1982 .......................................... VI-8 VI-5 Observed vs. Simulated Velocity at Station No. 1, July 13-14, 1982 .......................................... VI-10 VI-6 Observed vs. Simulated Velocity at Station No. 2, July 13-14, 1982 .......................................... VI-11 iii LIST OF FIGURES (Continued) Figure No. Page No. VI-7 Observed vs. Simulated Velocity at Station No. 3, Magnitude and Direction, July 13-14, 1982 . VI-12 VI-8 Observed vs. Simulated Velocity at Station No. 4, Magnitude and Direction, July 13-14, 1982 . VI-13 VI-9 Observed vs. Simulated Velocity at Station No. 5, July 13-14, 1982 . VI-14 VI -10 Observed vs. Simulated Velocity at Station No. 6, July 13-14, 1982 . VI-15 VI -11 Observed vs. Simulated Velocity at Station No. 7, July 13-14, 1982 . VI-16 VI-12 Observed vs. Simulated Velocity at Station No. 8, July 13-14, 1982 . VI-17 VI-13 Observed vs. Simulated Velocity at Station No. 9, July 13-14, 1982 . VI-18 VI-14 Observed vs. Simulated Velocity at Station No. 10, Magnitude and Direction, July 13-14, 1982 . VI-19 VI-15 Observed vs. Simulated Velocity at Station No. 11, Magnitude and Direction, July 13-14, 1982 . VI-20 VI-16 Observed vs. Simulated Velocity at Station No. 12, July 13-14, 1982 . VI-21 VI-17 Observed vs. Simulated Elevation at Gage No. 2, April 28- 29, 1982 . VI-22 VI-18 Observed vs. Simulated Elevation at Gage No. 3, April 28- 29, 1982 . VI-23 VI-19 Observed vs. Simulated Elevation at Gage No. 4, April 28- 29, 1982 . VI-24 VI-20 Observed vs. Simulated Elevation at Gage No. 5, April 28- 29, 1982 . VI-25 VI-21 Observed vs. Simulated Velocity at Station No. 1, April 28-29, 1982 . VI-26 VI-22 Observed vs. Simulated Velocity at Station No. 2, April 28-29, 1982 . VI-27 iv LIST OF FIGURES (Continued) Figure No. Page No. VI-23 Observed vs. Simulated Velocity at Station No. 3, Magnitude and Direction, April 28-29, 1982 . VI-28 VI-24 Observed vs. Simulated Velocity at Station No. 4, Magnitude and Direction, April 28-29, 1982 . VI-29 VI-25 Observed vs. Simulated Velocity at Station No. 5, April 28-29, 1982 . .... VI-30 VI-26 Observed vs. Simulated Velocity at Station No. 6, April 28-29, 1982 . VI-31 VI-27 Observed vs. Simulated Velocity at Station No. 7, April 28-29, 1982 . VI-32 VI-28 Observed vs. Simulated Velocity at Station No. 8, April 28-29, 1982 . VI-33 VI-29 Observed vs. Simulated Velocity at Station No. 9, April 28-29, 1982 . VI-34 VI-30 Observed vs. Simulated Velocity at Station No. 10, Magnitude and Direction, April 28-29, 1982 . VI-35 VI -31 Observed vs. Simulated Velocity at Station No. 11, Magnitude and Direction, April 28-29, 1982 . VI-36 VI-32 Observed vs. Simulated Velocity at Station No. 12, April 28-29, 1982 . VI-37 VI-33 Velocity and Vorticity at the Centroid of a Grid Element VI-40 VI-34 Vorticity Calculations at Station 4 . VI-41 VI-35 Vorticity Field and Sub-Grid Scale Vorticity . VI-44 VII-1 Observed vs. Simulated Elevation at Gage No. 2, November 10-11, 1982 . VII-3 VII-2 Observed vs. Simulated Elevation at Gage No. 3, November 10-11, 1982 . VII-4 VII-3 Observed vs. Simulated Elevation at Gage No. 4, November 10-11, 1982 . VII-5 VII-4 Observed vs. Simulated Elevation at Gage No. 5, November 10-11, 1982 . VII-6 V LIST OF FIGURES (Continued) Figure No. Page No. VII-5 Observed vs. Simulated Velocity at Station No. 1, November 10-11, 1982 . VII-7 VII-6 Observed vs. Simulated Velocity at Station No. 2, November 10-11, 1982 . VII-8 VII-7 Observed vs. Simulated Velocity at Station No. 3, Magnitude and Direction, November 10-11, 1982 . VII-9 VII-8 Observed vs. Simulated Velocity at Station No. 4, Magnitude and Direction, November 10-11, 1982 . VII-10 VII-9 Observed vs. Simulated Velocity at Station No. 5, November 10-11, 1982 . VII-11 VII-10 Observed vs. Simulated Velocity at Station No. 6, November 10-11, 1982 . VII-12 VII-11 Observed vs. Simulated Velocity at Station No. 7, November 10-11, 1982 . VII-13 VII-12 Observed vs. Simulated Velocity at Station No. 8, November 10-11, 1982 . VII-14 VII-13 Observed vs. Simulated Velocity at Station No. 9, November 10-11, 1982 . VII-15 VII-14 Observed vs. Simulated Velocity at Station No. 10, Magnitude and Direction, November 10-11, 1982 . VII-16 VII-15 Observed vs. Simulated Velocity at Station No. 11, Magnitude and Direction, November 10-11, 1982 . VII-17 VII-16 Observed vs. Simulated Velocity at Station