Water Quality Dynamics of Lake James in the Catawba River Basin of North Carolina Susan Stokes Clemson University, [email protected]
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Clemson University TigerPrints All Dissertations Dissertations 12-2007 Water quality dynamics of Lake James in the Catawba River Basin of North Carolina Susan Stokes Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Part of the Fresh Water Studies Commons Recommended Citation Stokes, Susan, "Water quality dynamics of Lake James in the Catawba River Basin of North Carolina" (2007). All Dissertations. 165. https://tigerprints.clemson.edu/all_dissertations/165 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. WATER QUALITY DYNAMICS OF LAKE JAMES IN THE CATAWBA RIVER BASIN OF NORTH CAROLINA A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Biological Sciences by Susan Marie Lloyd Stokes December 2007 Accepted by: Dr. James Schindler, Committee Chair Dr. James Colacino Dr. Gene Eidson Dr. John Hains ABSTRACT Lake James is the uppermost hydropower reservoir in the Catawba River drainage in North Carolina. The Lake James Assessment (LJA) was a descriptive study initiated between Clemson University and Duke Energy Corporation to explore the physical, chemical and biological dynamics of this oligotrophic reservoir from spring 1997 through fall 1999 (Schindler 1997). The goals of this study were to ascertain the primary drivers for the chemical dynamics of Lake James, to assess the quantities of constituents entering and leaving the reservoir, where these chemicals were incorporated within the reservoir basins, and to evaluate the efficacy of the LJA chemical budget model (LJA-CB) against traditional calculations for measures of reservoir loading and yield. I hypothesized that meteorology and lithology would be the dominant factors regulating the chemical dynamics of Lake James (Gibbs 1979, 1992). I also hypothesized that assimilation of chemical constituents within Lake James would adhere to the heuristic model of longitudinal segmentation of reservoirs of Thornton et al. (1981). I further hypothesized that the LJA-CB model based on average daily flows and monthly chemical concentrations would be more reflective of the variability in constituent loading and yield for Lake James than the traditional methods generated using average annual flows and average annual chemical concentrations (Olem and Flock 1990). The LJA water balance (LJA-WB) and LJA-CB models were developed in the STELLA modeling environment to quantify the hydrological and chemical dynamics of Lake James. Results of the energy budget (LJA-EB) and LJA-WB generated during the period of study indicated significant water losses (approaching 20% of the total volume) ii from the reservoir each year with 7% attributed to evaporation and 13% to unmonitored losses. Post facto analysis of turbine losses conducted by Knight (2003) indicated losses of 1.56 m3/s (55 ft3/s) through the turbines in the Bridgewater Hydroelectric Facility (BHF), a value twice what was estimated at the time of our study (Knight 2003). The LJA-CB was developed around the LJA-WB in STELLA as a Graphical User Interface (GUI) based modified Vollenweider (1969)/Chapra (1975 and 1979) style empirical mass balance model for an incompletely-mixed laterally-segmented reservoir with an embayment. Thornton et al. (1981) developed a heuristic model of longitudinal segmentation of reservoirs which stresses the importance of linear distance in the processing of watershed inputs into the reservoir (Thornton et al. 1981, Thornton 1990, Kennedy and Walker 1990). The LJA-CB allows for determination of lateral zones of constituent assimilation and assumes hydrology is the driving variable for the system. By summing the daily loading over a year, an annual loading estimate for each segment of the lake was calculated that was volume weighted and was used to make inferences about the spatial distribution of chemicals within the lake. I ascertained that most of the constituent loading into the Lake James basin is derived from the Catawba River watershed (most notably the North Fork Catawba sub- watershed) and that most of the inflowing material is retained by the reservoir. I further discerned that relatively limited numbers of high flow events are responsible for providing the bulk of materials assimilated within the lake basins. I confirmed that the headwaters and upper transition zones of the Lake James reservoir have greater rates of sedimentation of most constituents relative to the lower transition and lacustrine zones iii and validates the model proposed by Thornton et al. (1981) and later work on spatial sedimentation of constituents and subsequent ecosystem production by Kennedy et al. (1982). However, the lacustrine station for the Linville basin is the receiving embayment for both basins and reflects the greater loading being brought in from the Catawba Basin. I employed traditional loading calculations (Olem and Flock 1990) using monthly chemical concentrations and average daily discharge which were averaged for each year to provide a conservative estimate of loading and yield from the Lake James watershed. By comparing the LJA-CB with traditional loading and yield calculations I found that the traditional methods, in general, tended to be adequate for hydrologically driven constituents; however, biologically and redox regulated constituents do not appear to be sufficiently represented using traditional calculations of loading and yield. iv DEDICATION I dedicate this volume to my family and friends who have lovingly supported my efforts throughout my education. I thank my parents, Thames and Tootsie Lloyd, for their ongoing support and I credit them with my endless love of reading and passion for knowledge. To my in-laws, Al and Elouisa Stokes, I offer my deepest gratitude for their generous care of my family in the midst of this commitment. To my siblings and friends I offer my appreciation for the many phone calls and notes of support when the pressures of work kept me from returning the sentiment – they have always filled my cup. To my husband, Mark Stokes, I offer my love and thanks for his care and technical skills that have made the impossible become possible. And above all, I dedicate this work to my sons, Riley and Thames Stokes, in hopes that perhaps some day they will understand my passion for learning and the time it has required. v ACKNOWLEDGMENTS I wish to acknowledge Duke Energy Corporation for their funding and for engaging Clemson University in this characterization of Lake James and the opportunity it provided me to learn about reservoir limnology. I would like to thank Bill Foris of Duke Energy and Dr. Jon Knight of Devine, Tarbell and Associates for their education, friendship and support during this study. I thank Dr. Hap Wheeler, Department Chair of Biological Sciences, for believing in me even when the chips were down. I wish to recognize my officemate and colleague, Master Kate Elrod, for her insightful perceptions, her editorial assistance and helping to care for my children. I thank Dr. Howard Loring for many years of coffee and good counsel. I wish also to thank Chris Benson for his instruction in guitar and Mary Ellen LeFort for instruction in yoga - whose care and teaching have brought balance to my universe. I thank my graduate committee, Dr. Jim Colacino, Dr. John Hains and Dr. Gene Eidson, for their collegiality, for supporting my first grant attempt, and for challenging me to grow. And I offer my deepest appreciation to my major professor, Dr. Jim Schindler, who has been patient and forgiving, but above all, for sharing his passion for the breadth of knowledge and being a mentor worthy of emulation. Arigato gozaimashita vi TABLE OF CONTENTS Page TITLE PAGE....................................................................................................................... i ABSTRACT........................................................................................................................ ii DEDICATION.....................................................................................................................v ACKNOWLEDGMENTS ................................................................................................. vi LIST OF TABLES............................................................................................................. ix CHAPTER 1 INTRODUCTION ............................................................................................. 1 Characterization of the geology and hydrology of the Lake James watershed ........................................................................................ 1 Lake James Assessment............................................................................ 15 2 WATER BALANCE: LAKE JAMES, NC...................................................... 23 Lake James Assessment............................................................................ 23 Methods..................................................................................................... 25 Results and Discussion ............................................................................. 32 Conclusions............................................................................................... 39 3 CHEMICAL DYNAMICS OF LAKE JAMES, NORTH CAROLINA.........