UUttaahh SSttaattee UUnniivveerrssiittyy DDiiggiittaallCCoommmmoonnss@@UUSSUU All Graduate Theses and Dissertations Graduate Studies 5-2014 CChhaannnneell AAddjjuussttmmeenntt aanndd CChhaannnneell--FFllooooddppllaaiinn SSeeddiimmeenntt EExxcchhaannggee iinn tthhee RRoooott RRiivveerr,, SSoouutthheeaasstteerrnn MMiinnnneessoottaa Michael A. Souffront Alcántara Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Life Sciences Commons RReeccoommmmeennddeedd CCiittaattiioonn Souffront Alcántara, Michael A., "Channel Adjustment and Channel-Floodplain Sediment Exchange in the Root River, Southeastern Minnesota" (2014). All Graduate Theses and Dissertations. 3334. https://digitalcommons.usu.edu/etd/3334 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. CHANNEL ADJUSTMENT AND CHANNEL-FLOODPLAIN SEDIMENT EXCHANGE IN THE ROOT RIVER, SOUTHEASTERN MINNESOTA by Michael A. Souffront Alcántara A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Watershed Science Approved: _______________________________ _______________________________ Patrick Belmont R. Douglas Ramsey Major Professor Committee Memeber _______________________________ _______________________________ Joseph M. Wheaton Mark R. McLellan Committee Member Vice President for Research and Dean of the School of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2014 ii Copyright © Michael A. Souffront Alcántara 2014 All Rights Reserved iii ABSTRACT Channel Adjustment and Channel-Floodplain Sediment Exchange in the Root River, Southeastern Minnesota by Michael A. Souffront Alcántara, Master of Science Utah State University, 2014 Major Professor: Dr. Patrick Belmont Department: Watershed Sciences A better understanding of transport and deposition of fine sediment in alluvial rivers, including their floodplains, is essential for improved understanding of sediment budgets and prediction of river morphological changes. Previous work in the Root River indicates that channel-floodplain sediment exchange exerts strong control on the sediment flux of this system. In addition, improvements in agricultural practices and increases in high and low flows during the past five decades have led us to believe that sediment sources in the Root River may be shifting from uplands to near-channel sources. This thesis estimated the total amount of fine sediment contributed to the channel from near-channel sources due to the processes of lateral channel adjustment (channel migration and channel widening) using a quantitative approach based on the use of multiple epochs of aerial photographs (1930s-2010s), lidar data available for the entire watershed from 2008, and other GIS analysis. The results obtained in this thesis serve as another line of evidence to constrain a sediment budget for the Root River watershed and iv to improve our understanding of the sediment dynamics within the watershed. In addition, we found that the Root River presents a marked division between its lateral channel adjustment trends before and after the 1970s. We also found that while increases in flows have affected lateral channel adjustment rates throughout the entire channel network, other factors like sediment supply and riparian vegetation may be playing an equally important role. (182 pages) v PUBLIC ABSTRACT Channel Adjustment and Channel-Floodplain Sediment Exchange in the Root River, Southeastern Minnesota by Michael A. Souffront Alcántara, Master of Science Utah State University, 2013 Major Professor: Dr. Patrick Belmont Department: Watershed Sciences The shape and location of a river can change through time, moving large amounts of sediment in the process. This is because the land that is immediately next to the active channel of a river, known as floodplain, is considered to be part of the river system. A better understanding of how the river channel and its floodplain interact is needed to improve our ability to predict how rivers change through time. A previous study in the Root River, southeastern Minnesota, USA indicates that the relation between the channel and the floodplain in this river is very important. In addition, improvements in agriculture and changes in water flow have led us to believe that sources of sediment in the Root River may be shifting from uplands to near-channel sources (floodplain). This thesis estimated the total amount of sediment contributed to the channel from the floodplain due to lateral changes in the shape (channel widening or narrowing) and location (channel migration) of the Root River. Multiple epochs of aerial photographs together with other database and GIS (Geographic Information Systems) analyses were vi used to accomplish this goal. The results of this thesis contribute to the understanding of how much sediment flows into the Root River and where it comes from. In addition, we found that the rates of channel adjustments in the Root River have changed since the 1970s. We also found that while changes in water flow are very important in the channel-floodplain relation, other factors like sediment supply and riparian vegetation may be playing an equally important role. vii ACKNOWLEDGMENTS This thesis is the result of the work and help of many people. I want to first thank God for his many blessings and for putting such great people around me, and then all the people that in one way or another contributed to the completion of this thesis. I am very grateful to my advisor, Patrick Belmont, for giving me the opportunity to be part of a wonderful group and for all his advice throughout this last two years. He introduced me to the field of geomorphology and without him I would literally not be here. Thanks to Justin Stout for providing the background necessary to make this project relevant. Thanks to my committee members, Joe Wheaton and Doug Ramsey, for their teachings, comments and advice throughout the entire process of developing this thesis. Thanks to Chris Garrard for her help with the python scripts developed for this thesis. I would also like to thank my lab mates for their ideas, time spent reviewing, and for their many contributions to the analyses presented here. In the same order, thanks to Toby Dogwiler and his group at Winona State University for all their help with fieldwork and with the aerial photograph analysis. Without all your help I would be far from done. I would also like to thank Brian Bailey and Enid Kelley from the Watershed Science Department office. They would always receive me with a smile on their faces and answer my many questions regarding the watershed science program. Thanks to Shelly Ortiz Hernández and the people at the Office of International Students and Scholars for their help regarding orientation and accommodations for international students. You have being excellent hosts. viii I would also like to express my appreciation to the Dominican community at Utah State University for making Logan feel more like home. Many of you have become like family. Thanks for making the stay here much more pleasurable. Lastly, I would like to say thanks to my family for their unconditional love and for all their support. To my parents, Rafael Souffront and Tamara Alcántara, for teaching me values and for their infinite love; to my wife and to my sister, Jolyn Souffront and Yosayris Souffront, for being part of my life. You two are my motivation to become better every day, I love you. ¡Gracias a todos! Michael Souffront ix CONTENTS Page ABSTRACT ....................................................................................................................... iii PUBLIC ABSTRACT .........................................................................................................v ACKNOWLEDGMENTS ................................................................................................ vii LIST OF TABLES ............................................................................................................ xii LIST OF FIGURES ......................................................................................................... xiii CHAPTER 1. UNDERSTANDING NEAR-CHANNEL SEDIMENT EXCHANGE PROCESSES.........................................................................................................1 1.1 Introduction ............................................................................................1 1.2 Sediment Budgets ..................................................................................2 1.3 Variables Influencing Channel Form .....................................................3 1.4 Channel Morphology .............................................................................4 1.5 Channel Planform ..................................................................................6 1.5.1 Channel Migration .....................................................................6 1.5.2 Channel Widening .....................................................................7 1.6 Floodplain Grain Size Composition.......................................................9 1.7 Research Context .................................................................................10 1.7.1 Research Questions ..................................................................11 1.7.2 Objectives ................................................................................11 1.8 Study Area ...........................................................................................12 1.9 Methods................................................................................................15