Minnesota River, Mankato Watershed Characterization Report MINNESOTA DEPARTMENT OF NATURAL RESOURCES: DIVISION OF ECOLOGICAL AND WATER RESOURCES September 20, 2016 Table of Contents Contents Table of Contents .......................................................................................................................................... 1 Table of Figures ............................................................................................................................................ 4 List of Acronyms and Abbreviations .......................................................................................................... 11 Introduction ................................................................................................................................................. 12 Study Background ................................................................................................................................... 12 Watershed Characteristics ........................................................................................................................... 12 Location .................................................................................................................................................. 12 Geology ................................................................................................................................................... 12 Bedrock Geology ................................................................................................................................. 12 Surficial Geology ................................................................................................................................ 15 Soils ........................................................................................................................................................ 18 Land Use ................................................................................................................................................. 21 Sediment Sources .................................................................................................................................... 23 Sub-watersheds ....................................................................................................................................... 25 High Value Resources ............................................................................................................................. 29 Rare Natural Features Mapped in the Middle Minnesota River Watershed ...................................... 29 Native Plant Communities .................................................................................................................. 31 Aquatic Invasive Species ........................................................................................................................ 33 Hydrology ................................................................................................................................................... 35 Introduction ............................................................................................................................................. 35 Methods .................................................................................................................................................. 36 Crop Changes ..................................................................................................................................... 36 Precipitation ....................................................................................................................................... 36 Discharge Analysis ............................................................................................................................. 37 Double Mass Curve ............................................................................................................................. 37 Web-based Hydrograph Analysis Tool ............................................................................................... 38 Ground Water Usage .......................................................................................................................... 38 Results ..................................................................................................................................................... 38 Crop Changes ..................................................................................................................................... 38 Precipitation ....................................................................................................................................... 41 1 Discharge Analysis ............................................................................................................................. 42 Double Mass Curve ............................................................................................................................. 45 Web-based Hydrograph Analysis Tool ............................................................................................... 47 Ground Water Usage .......................................................................................................................... 48 Hydrology Summary ............................................................................................................................... 52 Connectivity ................................................................................................................................................ 53 Introduction ............................................................................................................................................. 53 Methods .................................................................................................................................................. 55 Longitudinal Connectivity ................................................................................................................... 55 Lateral Connectivity ............................................................................................................................ 56 Vertical Connectivity .......................................................................................................................... 56 Results ..................................................................................................................................................... 56 Longitudinal Connectivity (Fish Barriers).......................................................................................... 56 Longitudinal Connectivity (Riparian) ................................................................................................. 88 Lateral Connectivity ............................................................................................................................ 91 Vertical Connectivity .......................................................................................................................... 92 Connectivity Summary ........................................................................................................................... 94 Fish Barriers ....................................................................................................................................... 94 Riparian Connectivity ......................................................................................................................... 95 Lateral Connectivity ............................................................................................................................ 95 Vertical Connectivity .......................................................................................................................... 95 Geomorphology .......................................................................................................................................... 96 Introduction ............................................................................................................................................. 96 Methods .................................................................................................................................................. 96 Field Methods ..................................................................................................................................... 96 Office Methods .................................................................................................................................. 101 Results ................................................................................................................................................... 102 Spring Creek ..................................................................................................................................... 103 Fort Ridgely Creek ............................................................................................................................ 113 Unnamed Creek ................................................................................................................................ 118 Little Cottonwood River .................................................................................................................... 121 Seven Mile Creek .............................................................................................................................. 143 Geomorphology Summary ...................................................................................................................