Integrated Water Operations in California: Hydropower, Overdraft, and Climate Change By MUSTAFA SAHIN DOGAN B.S. (Dokuz Eylul University, Izmir, Turkey) 2011 THESIS Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Civil and Environmental Engineering in the OFFICE OF GRADUATE STUDIES of the UNIVERSITY OF CALIFORNIA DAVIS Approved: _____________________________________ Jay R. Lund, Chair _____________________________________ Samuel Sandoval Solis _____________________________________ Jonathan Herman Committee in Charge 2015 i Abstract Several management and climate cases are evaluated with the updated CALVIN, a hydro-economic optimization model of California’s inter-tied water supply infrastructure. Updates to the CALVIN model include new projected 2050 agricultural target demands and scarcity penalties, improvements to network- flow representation, especially agricultural, urban, and wildlife refuge demands, and extended surface and ground water hydrology, now covering an 82-year historical inflow hydrology. A new energy price scheme is applied to CALVIN, which incorporates hourly energy price variations into monthly CALVIN operations. Using one constant average price for a month underestimates hydropower revenue and overestimates pumping costs. Hourly-varying moving average prices improved representation of hydropower revenue without creating significant scarcities to agricultural and urban water users. Effects of ending long-term groundwater overdraft in the Central Valley are evaluated with several management cases using CALVIN. The cases include effects of Delta outflow and Delta exports from a “no overdraft” policy. The least cost overdraft that minimizes groundwater pumping and scarcity costs is calculated for the 82- year period. Prohibiting Delta exports result in severe water scarcities south of the Delta. Water operations are more economical when overdraft is ended with adaptations, such as more Delta exports, increased groundwater banking, and water trades, than historical operations with overdraft. Finally, climate change effects under a warmer and drier climate scenario are studied and results are compared to historical hydrology. A drier and warmer climate shifts the timing and magnitude of stream flows. Spring snowmelt decreases and winter flows increase. Modelled reduction in rim inflows averages about 28%. This warmer- drier climate increases water scarcities, but adverse effects can be diminished with water sales, higher Delta exports, more conjunctive use, and wastewater recycling. ii Acknowledgements I would like to express my sincere appreciation to my adviser and committee chair, Professor Jay R. Lund, for his enthusiasm, guidance, constant support, and invaluable comments, without which this thesis would have never been completed. Thanks also to my committee members, Professor Samuel Sandoval- Solis and Professor Jonathan Herman, for their editorial reviews. Special thanks to Josué Medellín-Azuara, who was always available to answer my endless questions and provided assistance during my research. I would also like to thank to Karandev Singh, with whom I worked together while updating CALVIN model. Without his contribution, this work would have never been done. I am also thankful for his friendship, suggestions, and conversations on academic and daily life. I am grateful to members of CALVIN update project, Alessia Siclari, Lily Tomkovic, Chad Whittington, Andy Tweet, Eric Mork, Hillary Ships, and Stephanie Saiz. Also, special thanks to my officemates and the staff at the Center for Watershed Sciences. Thanks to Ministry of National Education of the Republic of Turkey for providing me with full scholarship to pursue my academic goals. Last but not least, I am so grateful to my family for their continuous encouragement, patience, and moral support during my stay in the U.S. Without their love, presence and support, I would never be successful. iii Table of Contents Abstract ........................................................................................................................................................ ii Acknowledgements .................................................................................................................................... iii Table of Figures.......................................................................................................................................... vi Table of Tables ......................................................................................................................................... viii Abbreviations ............................................................................................................................................. ix Chapter 1. Introduction .............................................................................................................................. 1 References ................................................................................................................................................ 4 Chapter 2. CALVIN Model and Updates ................................................................................................. 8 Introduction .............................................................................................................................................. 8 Data Flow ................................................................................................................................................. 9 Hydrology .............................................................................................................................................. 11 Limitations ............................................................................................................................................. 12 Recent Model Updates ........................................................................................................................... 12 Hydrology Updates ........................................................................................................................... 13 Network Representation .................................................................................................................... 14 Agricultural Demand and Shortage Penalties ................................................................................... 18 Hydropower Improvements .............................................................................................................. 19 Conclusions ............................................................................................................................................ 23 References .............................................................................................................................................. 23 Chapter 3. Reflecting Hourly Energy Price Variability in Long-Term Hydropower Operations .... 25 Introduction ............................................................................................................................................ 25 CALVIN Operations with Hourly-Varying Electricity Prices ............................................................... 25 Results .................................................................................................................................................... 27 Power Generation and Revenue ........................................................................................................ 27 Scarcity and Operating Costs ............................................................................................................ 33 Surface Water Storage ...................................................................................................................... 33 Conclusions ............................................................................................................................................ 35 References .............................................................................................................................................. 36 Chapter 4. Groundwater Overdraft Management in the Central Valley ............................................ 37 Introduction ............................................................................................................................................ 37 Management Scenarios .......................................................................................................................... 37 Method ................................................................................................................................................... 38 Study Area ............................................................................................................................................. 39 Results .................................................................................................................................................... 42 Water Delivery and Scarcity ............................................................................................................. 42 Groundwater Storage ........................................................................................................................ 46 Artificial Recharge ............................................................................................................................ 47 Delta Exports ...................................................................................................................................