Texas Riparian Areas WHY SO DIFFERENT? This book describes the physical setting of the river’s edge environments in Texas. This corridor contains a diverse range of plant and animals, but we focused on the physical features of this environment. This book simplifies existing riparian jargon and provides definitions that will aid the Texas Instream Flow Program (TIFP) with setting high flow pulse and overbank flows that will maintain river edge health EDITED BY Dr. Thomas B. Hardy and Nicole Davis Meadows Center for Water and Environment Texas State University Page | i June 1, 2013 TWDB Contract #1004831142 Preface The physical environment of the river’s edge has many hidden features that one does not normally notice. In this book, experts point out gradients and boundaries found in most riparian areas. With an understanding of these features, one hopes that a set of definitions will emerge that will assist land managers and the Texas Instream Flow Program (TIFP). The book provides insights into riparian areas in the state of Texas as well as a hierarchical understanding of the physical setting of riparian corridors. It provides an overview of what government agencies are doing to protect or encourage people to protect this environment. The book also explains the physical landscape of the river’s edge and addresses why Texas riparian areas have many unique characteristics. It also gives Texas river managers a set of terms to describe their riparian projects across multiple disciplines and across different river system boundaries. Page | ii TABLE OF CONTENTS CHAPTER 1 - INTRODUCTION (MARK WENTZEL) ....................................................................................... 1-1 CHAPTER 2 – AN INTEGRATED OVERVIEW (NICOLE DAVIS AND THOMAS HARDY) .................................... 2-1 INTERACTION BETWEEN HYDROLOGY, GEOMORPHOLOGY AND RIPARIAN SYSTEMS ....................................................... 2-2 RELATIONSHIP BETWEEN FLOW REGIME AND RIPARIAN SYSTEMS ............................................................................. 2-6 RIPARIAN ECOTONES AND TEXAS ECOREGIONS ..................................................................................................... 2-8 BOTTOMLAND HARDWOODS ................................................................................................................................ 2-11 CHAPTER 3 - STREAM BUFFERS (JONATHAN PHILLIPS) .............................................................................. 3-1 WATER QUALITY BUFFER EFFECTIVENESS ............................................................................................................ 3-1 LOCAL RUNOFF PRODUCTION ................................................................................................................................. 3-1 DELAYING FLOW .................................................................................................................................................. 3-2 MINIMIZING STREAM POWER ................................................................................................................................. 3-2 FILTERING POLLUTANTS ......................................................................................................................................... 3-2 LOCAL AND UPSTREAM RUNOFF........................................................................................................................ 3-2 RELATIVE IMPORTANCE INDEX ................................................................................................................................. 3-3 EVALUATING BUFFER EFFECTIVENESS ................................................................................................................. 3-3 BUFFER EXAMPLE .......................................................................................................................................... 3-5 DISCUSSION ................................................................................................................................................. 3-6 CONCLUSIONS ............................................................................................................................................... 3-7 CHAPTER 4 - RIPARIAN GEOMORPHOLOGY (JONATHAN PHILLIPS) ........................................................... 4-1 GEOMORPHIC PERSPECTIVE ............................................................................................................................. 4-3 GEOMORPHOLOGY AND RIPARIAN ZONES ........................................................................................................... 4-3 GEOMORPHIC INDICATORS ..................................................................................................................................... 4-4 RIPARIAN ZONE PROCESSES .................................................................................................................................... 4-6 Page | iii DEPOSITION ........................................................................................................................................................ 4-7 WEATHERING AND REGOLITH FORMATION ................................................................................................................ 4-8 MASS WASTING ................................................................................................................................................... 4-8 BIOGEOMORPHOLOGY ........................................................................................................................................... 4-9 RIPARIAN LANDFORMS ................................................................................................................................... 4-9 ALLUVIAL VALLEY LANDFORMS ............................................................................................................................... 4-10 BANK LANDFORMS ............................................................................................................................................. 4-11 NON-ALLUVIAL RIPARIAN LANDFORMS ................................................................................................................... 4-11 A GEOMORPHIC FRAMEWORK FOR UNDERSTANDING RIPARIAN ZONES ................................................................... 4-13 CROSS-VALLEY AND DOWN-VALLEY FLUXES ............................................................................................................. 4-13 AGE AND ACTIVITY OF RIPARIAN LANDFORMS .......................................................................................................... 4-14 CONCLUDING REMARKS ................................................................................................................................ 4-16 CHAPTER 5 - RIPARIAN SOILS (JOHN JACOB) ............................................................................................. 5-1 SOIL DEVELOPMENT –THE VERY BASICS ............................................................................................................... 5-2 FEATURES OF SOIL DEVELOPMENT ........................................................................................................................... 5-3 FEATURES IN RIPARIAN SOILS .................................................................................................................................. 5-4 THE FACTORS OF SOIL FORMATION .................................................................................................................... 5-6 SOIL CLASSIFICATION/TAXONOMY ..................................................................................................................... 5-7 SOIL TAXONOMY IN THE FLOODPLAINS OF TEXAS ...................................................................................................... 5-10 THE SOIL SURVEY AND RIPARIAN SOILS ON THE TEXAS COASTAL PLAIN .................................................................... 5-12 SOIL SURVEY DATA ............................................................................................................................................. 5-13 GIS DATA ......................................................................................................................................................... 5-13 THE WEB SOIL SURVEY ........................................................................................................................................ 5-14 THE SOIL SURVEY ON GOOGLE EARTH (SOILWEB): ................................................................................................... 5-14 SOME CAVEATS ABOUT THE USE OF THE SOIL SURVEY ................................................................................................ 5-14 WETLANDS IN THE RIPARIAN ZONE OF THE TEXAS COASTAL PLAIN .......................................................................... 5-15 Page | iv WETLANDS DEFINED ........................................................................................................................................... 5-15 WETLANDS IN FLOODPLAINS ON THE TEXAS COASTAL PLAIN ....................................................................................... 5-17 APPENDIX A - REPRESENTATIVE SOIL AND WETLAND TRANSECTS FROM FLOODPLAINS ON THE TEXAS COASTAL PLAIN ........ 5-20 NECHES RIVER TRANSECT: ............................................................................................................................. 5-21 COLORADO RIVER TRANSECT: ........................................................................................................................