University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2005 Three Dimensional Modeling Of Wekiva Springshed With Wash123d Sandeep Paladagu University of Central Florida Part of the Civil Engineering Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Masters Thesis (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Paladagu, Sandeep, "Three Dimensional Modeling Of Wekiva Springshed With Wash123d" (2005). Electronic Theses and Dissertations, 2004-2019. 481. https://stars.library.ucf.edu/etd/481 THREE DIMENSIONAL MODELING OF WEKIVA SPRINGSHED WITH WASH123D by SANDEEP PALADAGU B.S, M.Sc., Birla Institute of Technology and Science, 2003 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the Department of Civil and Environmental Engineering in the College of Engineering at the University of Central Florida Orlando, Florida Summer Term 2005 © 2004 Sandeep Paladagu ii ABSTRACT This thesis presents a three-dimensional groundwater modeling of Wekia springshed in central Florida using a numerical model, WASH123D. Springs have historically played an important role in Florida’s history. The Wekiva River is a spring-fed system associated with about 19 springs connected to the Floridan aquifer. With increased urbanization and population growth in this region, there has been an increased strain on the water levels of Floridan aquifer which is a major source of potable water. Maintaining groundwater recharge to the aquifer is a key factor of the viability of the regional water supply as well as Wekiva ecosystem. Hence, the first-principle, physics-based watershed model WASH123D has been applied to conduct the study of Wekiva “springshed”, which is the recharge area and watershed contributing groundwater and surface water to the spring. In this work, the hydrogeologic conditions of the Wekiva springshed are discussed followed by the modeling details such as mathematical background, domain discretization and initial and boundary conditions considered. Finally, the results from the model are discussed. The Wekiva WASH123D model was run to evaluate the average, steady state 1995 hydrological conditions. The distribution of simulated Floridan aquifer system groundwater levels using WASH123D shows very good agreement with the field observations at corresponding locations. iii ACKNOWLEDGMENTS I am grateful to my advisor, Dr. G.T.Yeh for his excellent guidance that made it possible for me to successfully accomplishing this thesis. I want to thank him for giving generously his time in reading the early drafts of this thesis. I would also like to thank my thesis committee members Dr. Nnadi and Dr. Hagen for their expert review and guidance. In addition, I would like to thank Dr. Fan Zhang and Dr. Hua Shan for their valuable suggestions. Special thanks are extended to family and friends for their continuous support and encouragement. I would also like to thank U.S. EPA-Science to Achieve Results (STAR) Program and University of Central Florida to make this research possible under Grant# R-82795602. iv TABLE OF CONTENTS LIST OF FIGURES .....................................................................................................................viii LIST OF TABLES......................................................................................................................... ix 1. INTRODUCTION .................................................................................................................. 1 2. LITERATURE REVIEW ....................................................................................................... 5 2.1 Springs of Florida ................................................................................................................. 5 2.1.1 Springs Geology............................................................................................................. 5 2.1.2 Springs Connectivity...................................................................................................... 6 2.1.3 Negative Impact of Land Use on Springs...................................................................... 7 2.1.4 Springs Protection and Remediation.............................................................................. 8 2.2 Preserving the Wekiva River Basin Ecosystem.................................................................... 9 2.2.1 Background.................................................................................................................... 9 2.2.2 The Wekiva Springshed............................................................................................... 11 2.2.3 Task Force Recommendations..................................................................................... 13 2.3 A Numerical Model Simulating Water Flow and Contaminant and Sediment Transport in Watershed Systems of 1-D Stream-River Network, 2-D Overland Regime, and 3-D Subsurface Media ........................................................................................................................................ 24 2.4 Numerical Prediction Experiment of a Watershed Modeling System................................ 26 3. DESCRIPTION OF STUDY AREA .................................................................................... 29 3.1 Introduction......................................................................................................................... 29 3.2 Description of the Hydrogeologic System.......................................................................... 30 v 3.2.1 Climate......................................................................................................................... 30 3.2.2 Topography and Surface Water Features..................................................................... 31 3.3 Groundwater Flow .............................................................................................................. 32 3.3.1 Surficial Aquifer System.............................................................................................. 33 3.3.2 Intermediate Confining Unit........................................................................................ 34 3.3.3 Floridan Aquifer System.............................................................................................. 34 3.3.4 Recharge and Discharge .............................................................................................. 37 3.3.5 Hydraulic Characteristics............................................................................................. 41 3.3.6 Potentiometric Levels .................................................................................................. 42 3.3.7 Historic and Projected Water Use................................................................................ 44 4. SIMULATION OF GROUNDWATER FLOW................................................................... 46 4.1 Conceptual Model of Groundwater Flow ........................................................................... 46 4.2 Computer Code Selection ................................................................................................... 47 4.2.1 Mathematical Basis...................................................................................................... 48 4.2.2 Unique Features of WASH123D ................................................................................. 51 4.3 Finite Element Discretization ............................................................................................. 52 4.4 Hydrologic Data Input ........................................................................................................ 55 4.4.1 Boundary Conditions ................................................................................................... 55 4.4.2 Applied Stresses........................................................................................................... 57 4.4.3 Aquifer and Confining Unit Characteristics ................................................................ 57 5. RESULTS ............................................................................................................................. 59 5.1 Potentiometric Levels ......................................................................................................... 61 5.2 Groundwater Flow .............................................................................................................. 65 vi 6. Conclusions........................................................................................................................... 67 APPENDIX................................................................................................................................... 69 LIST OF REFERENCES.............................................................................................................. 78 vii LIST OF FIGURES Figure 1-1 Land Surface Elevations and Floridan Aquifer Springs in Modeling Area.................. 2 Figure 2-1 Population Growth in the Wekiva Basin Area............................................................ 10 Figure 2-2 Wekiva River Springshed/Recharge Area .................................................................