Plumbing agricultural landscapes for water quality improvement: coexistence of intensive agriculture and good water quality

...................................................................................................................... iv CHAPTER 1. GENERAL INTRODUCTION .................................................................. 5 Introduction......................................................................................................................... 5 Thesis Organization ............................................................................................................ 7 Literature Review................................................................................................................ 7 Objectives ......................................................................................................................... 16 References......................................................................................................................... 16 CHAPTER 2. RELATIVE EFFECTS OF WATERSHED COMPOSITION AND CONFIGURATION: USING SPATIALLY EXPLICIT DATA TO MODEL LAKE WATER QUALITY IN AGRICULTURAL WATERSHEDS ........................................ 27 Abstract ............................................................................................................................. 27 Introduction....................................................................................................................... 28 Materials and Methods...................................................................................................... 31 Study Area ............................................................................................................... 31 Water quality data................................................................................................... 32 Geospatial data acquisition .................................................................................... 33 Verification and manipulation of geospatial data .................................................. 34 Whole landscape and class metrics ....................................................................... 34 Geospatial Analysis ................................................................................................ 35 Statistical Analyses ................................................................................................. 37 Results and Discussion ..................................................................................................... 38 Water Quality.......................................................................................................... 38 Land use patterns in the studied watersheds .......................................................... 38 Whole watershed composition and configuration................................................... 39 Conclusions............................................................................................................. 44 References......................................................................................................................... 45 CHAPTER 3. GENERAL CONCLUSIONS................................................................... 74 APPENDIX A. LIST OF LAKES ................................................................................... 76 APPENDIX B. STEP-BY-STEP GUIDE FOR DERIVING RUNOFF COEFFICIENTS FOR LAND COVER, SLOPE AND SOIL HYDROLOGIC GROUP EFFECT USING ARCGIS............................................................................................................................ 82 APPENDIX C. ILLUSTRATION ................................................................................... 92 APPENDIX D. WATERSHED DELINEATION EXAMPLE ....................................... 97 APPENDIX F. THE RATIONAL METHOD FORMULA........................................... 100 APPENDIX G. DISTRIBUTION OF STUDY LAKES ACCORDING TO IOWA LAND FORM REGIONS............................................................................................... 101 APPENDIX H. DEPENDENT VARIABLES............................................................... 102