Streambed Adjustment and Channel Widening in Eastern Nebraska
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Streambed Adjustment and Channel Widening in Eastern Nebraska By David L. Rus, Benjamin J. Dietsch, U.S. Geological Survey, and Andrew Simon, National Sedimentation Laboratory U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 03-4003 Prepared in cooperation with the NEBRASKA DEPARTMENT OF ROADS, NEBRASKA DEPARTMENT OF NATURAL RESOURCES, LOWER PLATTE SOUTH NATURAL RESOURCES DISTRICT, PAPIO-MISSOURI RIVER NATURAL RESOURCES DISTRICT, U.S. ARMY CORPS OF ENGINEERS, and the NATIONAL SEDIMENTATION LABORATORY OF THE U.S. DEPARTMENT OF AGRICULTURE Lincoln, Nebraska 2003 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Information Services 406Box Federal25046, MailBuilding Stop 415 Box 25286 100Denver Centennial Federal MallCenter North Denver Federal Center Lincoln,Denver, CONE 6850880225–0046 Denver, CO 80225 http://www.usgs.gov/ CONTENTS Abstract.................................................................................................................................................................................. 1 Introduction............................................................................................................................................................................ 1 Purpose and Scope....................................................................................................................................................... 2 Description of Study Area ........................................................................................................................................... 2 Attributes Associated with Channel Adjustment in Eastern Nebraska ....................................................................... 5 Acknowledgments ....................................................................................................................................................... 6 Methods ................................................................................................................................................................................. 6 Site Selection ............................................................................................................................................................... 6 Data Collection ............................................................................................................................................................ 6 Topographic Data............................................................................................................................................... 13 First-Round Survey.................................................................................................................................. 13 Second-Round Survey ............................................................................................................................. 13 Reference to National Geodetic Vertical Datum of 1929 ........................................................................ 13 Streambed Particle-Size Analyses ............................................................................................................................... 14 Characterization of Streambed Adjustment................................................................................................................. 14 Streambed Elevation History............................................................................................................................. 14 Influences on the Streambed.............................................................................................................................. 17 Disturbances ............................................................................................................................................ 17 Knickpoints.............................................................................................................................................. 17 Grade-Control Structures......................................................................................................................... 18 Characterization of Recent Channel Widening............................................................................................................ 18 Contouring First-Round Survey Data................................................................................................................ 18 Overlay of Second-Round Survey Data ............................................................................................................ 18 Characterization of Individual Top-of-Bank Failures........................................................................................ 18 Computation of Widening Rates........................................................................................................................ 18 Streambed Adjustment........................................................................................................................................................... 19 Potential Study-Area-Wide Disturbances .................................................................................................................... 20 Changes to the Median Water-Surface Elevation of the Missouri River........................................................... 20 Agricultural Development in Nebraska ............................................................................................................. 20 Missouri River Tributary Basins.................................................................................................................................. 20 Documented Disturbances, Knickpoints, and Grade-Control Structures .......................................................... 20 Streambed Summaries ....................................................................................................................................... 22 Papillion Creek Basin .................................................................................................................................................. 23 Documented Disturbances, Knickpoints, and Grade-Control Structures .......................................................... 25 Original Straightening.............................................................................................................................. 25 Urbanization ............................................................................................................................................ 26 Flood-Control Channel Modifications Since the 1960s .......................................................................... 27 Degradation of the Missouri River .......................................................................................................... 27 Streambed Summaries ....................................................................................................................................... 27 Platte River Tributary Basins....................................................................................................................................... 29 Documented Disturbances, Knickpoints, and Grade-Control Structures .......................................................... 29 Straightening in the Platte River Flood Plain .......................................................................................... 29 Basinwide Straightening.......................................................................................................................... 29 Straightening at PRT-3............................................................................................................................. 29 Streambed Summaries ....................................................................................................................................... 31 Elkhorn River Basin .................................................................................................................................................... 32 Documented Disturbances, Knickpoints, and Grade-Control Structures .......................................................... 34 Straightening of the Elkhorn River.......................................................................................................... 34 Straightening of Logan Creek.................................................................................................................. 34 Straightening of Maple Creek.................................................................................................................. 35 Straightening of Other Elkhorn River Tributaries ................................................................................... 35 CONTENTS iii Streambed Summaries ....................................................................................................................................... 35 Salt Creek Basin .......................................................................................................................................................... 37 Documented Disturbances, Knickpoints, and Grade-Control Structures.......................................................... 37 Original Channelization