Assessing the Impact of Land Use Changes on Hydropower Production and Erosion in the Coca River Basin
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ASSESSING THE IMPACT OF LAND USE CHANGES ON HYDROPOWER PRODUCTION AND EROSION IN THE COCA RIVER BASIN. A CONTRIBUTION TOWARDS INTEGRATED WATER RESOURCES MANAGEMENT IN ECUADOR. Zur Erlangung des akademischen Grades eines DOKTOR-INGENIEURS (Dr.-Ing.) von der KIT - Fakultät für Bauingenieur-, Geo- und Umweltwissenschaften des Karlsruher Instituts für Technologie (KIT) genehmigte DISSERTATION von Carlos Alberto Zuleta Salmon aus Ecuador Tag der mündlichen Prüfung: 18. Mai 2021 Referent: Dr.-Ing. Uwe Ehret Korreferent: Jun.-Prof. Dr.rer.nat. Andreas Braun Karlsruhe 2021 Contents List of Figures ....................................................................................................................................................... iii List of Tables ........................................................................................................................................................ iv Abstract .................................................................................................................................................................. v German Abstract ................................................................................................................................................. vii CHAPTER 1: Introduction .................................................................................................................................. 1 1.1- General overview ................................................................................................................................. 1 1.2.- Objectives ................................................................................................................................................ 10 1.3.- Thesis outline .......................................................................................................................................... 11 1.4.- Study area ............................................................................................................................................... 12 1.5.- Integrated Water Resources Management – IWRM ........................................................................... 18 1.5.1.- IWRM Process................................................................................................................................. 19 CHAPTER 2. Data and Methods ....................................................................................................................... 21 2.1.- Available data ......................................................................................................................................... 21 2.1.1.- Digital Elevation Model (DEM) ..................................................................................................... 22 2.1.2.- Soil map and soil data ..................................................................................................................... 22 2.1.3.- Land-Use data ................................................................................................................................. 23 2.1.4.- Meteorological and Hydrological Data.......................................................................................... 23 2.1.5.- Data for LU/LUC analysis .............................................................................................................. 26 2.2.- Uncertainty in IWRM ............................................................................................................................ 27 2.2.1.- Uncertainties and the Modeling role inside the IWRM Process. ................................................ 27 2.2.2.- Modeling uncertainty sources ........................................................................................................ 28 2.2.3.- Methodologies for uncertainty analysis in model-based IWRM process ................................... 29 2.2.4.- Methodology selection for uncertainty analysis............................................................................ 29 2.2.5.- Input and output uncertainties throughout the study area modeling process ........................... 30 2.3.- Methods for analyzing socioeconomic aspects and creating scenarios .............................................. 31 2.3.1.- Historical Land-use Change analysis ............................................................................................ 32 2.3.2.- Markov Chain Model ...................................................................................................................... 32 2.3.3.- Cellular Automata Model (CA) ..................................................................................................... 33 2.3.4.- The CA_Markov Chain Model ...................................................................................................... 33 2.3.5.- CA_Markov parameter selection and modeling procedure ........................................................ 34 2.3.6.- Land-use modeling evaluation ....................................................................................................... 38 i 2.4.- Methods for analyzing and modeling hydrological processes and creating scenarios ...................... 38 2.4.1.- Time series trend analysis methods ............................................................................................... 40 2.4.2- The SWAT model ............................................................................................................................. 40 2.4.3.- SWAT model set-up for the study area ......................................................................................... 42 2.4.4.- Model Calibration, evaluation, and uncertainty procedures ...................................................... 45 2.4.5.- Calibration, Validation, Sensitivity, and Uncertainty analysis ................................................... 47 CHAPTER 3.- Results and Discussion .............................................................................................................. 50 3.1.- Land-use change (LUC) analysis and scenarios of socioeconomic aspects ........................................ 50 3.2.- Hydrological analysis and scenarios ..................................................................................................... 56 3.2.1.- Trend analysis ................................................................................................................................. 56 3.2.2.- Results of the SWAT modeling ...................................................................................................... 58 3.2.3.- Effect of the different LUC scenarios on streamflow and water balance components ............. 62 CHAPTER 4.- Summary, Conclusions, and Recommendations ..................................................................... 72 Bibliography ........................................................................................................................................................ 76 Acknowledgments ............................................................................................................................................... 88 Author´s declaration ........................................................................................................................................... 89 ii List of Figures Figure 1-1: Relevant chapters of the thesis structure. ..................................................................................... 12 Figure 1-2: Study Area – Upper Coca River basin. ......................................................................................... 13 Figure 1-3: Study Area main ecosystems. ......................................................................................................... 14 Figure 1-4: Land-use cover map of 2016. .......................................................................................................... 15 Figure 1-5: Land-use cover changes (%) in the catchment between 1990 and 2016. .................................... 16 Figure 1-6: Total population and proportion (%) in economic activities in the study area. ........................ 17 Figure 1-7: The seven different steps with their main processes in the IWRM cycle. .................................. 20 Figure 2–1: Digital Elevation Model (DEM) (A) and Soil map of the Study Area (B). ................................. 23 Figure 2-2: Land-use maps of the Study Area. ................................................................................................. 24 Figure 2-3: Meteorological and Hydrological stations in the Study Area ...................................................... 25 Figure 2-4: Average daily precipitation (mm) and temperatures (°C) by month (1980 -2016). ................... 26 Figure 2-5: Average monthly flow (m³/s) of the Study Area (1980 – 2016). ................................................... 26 Figure 2-6: The Modeling role inside the IWRM process. .............................................................................. 28 Figure 2-7: Standard 5 x 5-pixel contiguity filter. ............................................................................................ 34 Figure 2-8: CA-Markov Model Flowchart. ....................................................................................................... 35 Figure 2-9: SWAT Model set-up process and model inputs. ........................................................................... 43 Figure 3-1: Land-use map of 2016 vs. Predicted Land-use map