Simulation of Hydrodynamics and Solute Transport in the Pamlico River Estuary, North Carolina
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SIMULATION OF HYDRODYNAMICS AND SOLUTE TRANSPORT IN THE PAMLICO RIVER ESTUARY, NORTH CAROLINA By Jerad D. Bales and Jeanne C. Robbins U.S. GEOLOGICAL SURVEY Open-File Report 94-454 Albemarle-Pamlico Estuarine Study Report No. 94-10 Prepared in cooperation with the ALBEMARLE-PAMLICO ESTUARINE STUDY of the NORTH CAROLINA DEPARTMENT OF ENVIRONMENT, HEALTH, AND NATURAL RESOURCES Raleigh, North Carolina 1995 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director Any use of trade, product, or firm names is for descriptive purposes only and does not impiy endorsement by the U.S. Geological Survey or the State of North Carolina. For additional information Copies of this report may be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Earth Science Information Center 3916 Sunset Ridge Road Open-File Reports Section Raleigh, North Carolina 27607 Denver Federal Center, Box 25286, MS 517 Denver, Colorado 80225 CONVERSION FACTORS, TEMPERATURE, VERTICAL DATUM, AND ABBREVIATIONS ________Multiply__________By To obtain Length centimeter (cm) 0.3937 inch meter (m) 3.281 foot kilometer (km) 0.6214 mile Area square meter (m2) 10.76 square foot square kilometer (km2) 0.3861 square mile Volume cubic meter (m3) 35.31 cubic foot Mass gram (g) 0.03527 ounce avoirdupois kilogram (kg) 2.205 pound avoirdupois Temperature: In this report, temperature is given in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by the following equation: °F=1.8(°C) + 32 Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929) a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929. Abbreviations and acronyms used in this report in addition to those shown above: cm/s centimeter per second m/d meter per day m/s meter per second m2 /s square meter per second m/s cubic meter per second ppt parts per thousand ppt/km parts per thousand per kilometer /I CONTENTS Page Abstract.............................................................................................................................................................................. 1 Introduction..................................................................................................................^^ 2 Purpose and scope.................................................................................................................................................... 3 Approach.................................................................................................................................................................. 3 Description of study area......................................................................................................................................... 3 Previous studies........................................................................................................................................................ 5 Acknowledgments.................................................................................................................................................... 5 Data collection and hydrologic conditions ........................................................................................................................ 5 Water level............................................................................................................................................................... 5 Salinity and water temperature................................................................................................................................ 11 Wind......................................................................................................................................................................... 15 Freshwater inflow.................................................................................................................................................... 15 Currents.................................................................................................................................................................... 18 Bathymetry............................................................................................................................................................... 20 Modeling approach............................................................................................................................................................ 22 Numerical model description............................................................................................................................................. 25 Governing equations................................................................................................................................................ 25 Numerical solution scheme...................................................................................................................................... 30 Model input requirements........................................................................................................................................ 31 Model implementation....................................................................................................................................................... 32 Computational grid and time step............................................................................................................................ 33 Boundary conditions................................................................................................................................................ 36 Bottom boundary............................................................................................................................................ 36 Shoreline and tributary streams...................................................................................................................... 38 Open-water boundaries.................................................................................................................................. 39 Water-surface boundary................................................................................................................................. 39 Initial conditions...................................................................................................................................................... 39 Model parameters..................................................................................................................................................... 40 Simulation of hydrodynamics and solute transport........................................................................................................... 41 Preliminary simulations........................................................................................................................................... 41 Rectangular channel....................................................................................................................................... 41 Pamlico River bathymetry.............................................................................................................................. 42 Pamlico River model calibration.............................................................................................................................. 43 Pamlico River model validation............................................................................................................................... 47 1989 validation period.................................................................................................................................... 47 1991 validation period.................................................................................................................................... 55 Sensitivity analysis................................................................................................................................................... 57 Model application.................................................................................................................................................... 61 Flow computation........................................................................................................................................... 61 Circulation patterns........................................................................................................................................ 65 Solute transport.............................................................................................................................................. 70 Conclusions.............................................................................................................................................................. 73 Summary............................................................................................................................................................................ 78 References.......................................................................................................................................................................... 81 Mi ILLUSTRATIONS Page Figures 1-3. Maps showing: 1. Location of the Tar-Pamlico River and data-collection sites outside of study reach................ 4 2. Pamlico River study reach showing bathymetry......................................................................