Rus and others Prepared in cooperation with the City of Lincoln, Nebraska, and the Lower Platte South Natural Resources District —An Assessment of Cardwell Branch Watershed, Nebraska, 2003−04— An Assessment of Hydrology, Fluvial Geomorphology, and Stream Ecology in the Cardwell Branch Watershed, Nebraska, 2003−04 Scientific Investigations Report 2007–5177 Scientific Investigations Report 2007–5177 U.S. Department of the Interior Printed on recycled paper U.S. Geological Survey (B) (A) (C) Front cover: (A) U.S. Geological Survey personnel collecting biota from overhanging vegetation habitat. (B) The diatom Nitzschia was collected in Cardwell Branch (photograph by Loren Bahls, Hannae, Helena, Montana). (C) A representative stream channel in the Cardwell Branch watershed. An Assessment of Hydrology, Fluvial Geomorphology, and Stream Ecology in the Cardwell Branch Watershed, Nebraska, 2003–04 By David L. Rus, Benjamin J. Dietsch, Brenda K. Woodward, Beth E. Fry, and Richard C. Wilson Prepared in cooperation with the City of Lincoln, Nebraska, and the Lower Platte South Natural Resources District Scientific Investigations Report 2007–5177 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2007 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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Suggested citation: Rus, D.L., Dietsch, B.J., Woodward, B.K., Fry, B.E., and Wilson, R.C., 2007, An assessment of hydrology, fluvial geo- morphology, and stream ecology in the Cardwell Branch watershed, Nebraska, 2003–04: U.S. Geological Survey Scientific Investigations Report 2007–5177, 70 p. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Study Area..............................................................................................................................................2 Purpose and Scope ..............................................................................................................................2 Methods...........................................................................................................................................................2 Data Compilation ...................................................................................................................................2 Topographic Surveying and Stream-Channel Characterization ..........................................2 Water-Quality and Ecological Sampling ..................................................................................4 Existing Spatial Data Sets ..........................................................................................................4 Assessment of Hydrology ....................................................................................................................4 Hydrologic Simulation .................................................................................................................5 Initial Watershed Parameter Estimation .........................................................................5 Adjustment of Watershed Parameters ............................................................................5 Regional Regression Equations ...............................................................................5 Model Adjustment .....................................................................................................6 Hydraulic Simulation ...................................................................................................................6 Cross-Sectional Information .............................................................................................6 Manning’s Roughness Coefficients .................................................................................8 Bridges and Culverts ..........................................................................................................8 Estimating Peak Streamflow from High-Water Marks .................................................8 Assessment of Fluvial Geomorphology .............................................................................................8 Stream-Channel Cross-Sectional Characterization ...............................................................9 Channel Geometry ..............................................................................................................9 Energy Associated with Bankful Conditions ..................................................................9 Channel Classification .......................................................................................................9 Streambank-Stability Analysis .........................................................................................9 Reach Characterization ............................................................................................................10 Thalweg Profile and Streambed Gradation ...........................................................................10 Assessment of Stream Ecology ........................................................................................................10 Fish Community Assessment ...................................................................................................10 Aquatic Invertebrate Metrics ..................................................................................................10 Algal Community Metrics .........................................................................................................10 Results of Hydrologic Assessment ...........................................................................................................12 Hydrologic Simulations ......................................................................................................................12 Regional Regression Equation Results ..................................................................................12 Initial Model Results ..................................................................................................................12 Adjusted Model Results ............................................................................................................13 Comparison to Local High-Water Marks ...............................................................................13 Hydraulic Simulations ........................................................................................................................14 Results of Fluvial-Geomorphic Assessment ............................................................................................14 Cross-Sectional Characterization ....................................................................................................15 Channel Geometry .....................................................................................................................15 Streambank-Stability Assessments ........................................................................................15 iv Reach Characterization .....................................................................................................................17 Summary of Cross-Sectional Characterizations ..................................................................17 Meander Geometry ...................................................................................................................18 Thalweg Profiles ........................................................................................................................18 Results of Ecological Assessment ............................................................................................................18 Water Quality .......................................................................................................................................19 Aquatic Biota .......................................................................................................................................24 Fish .........................................................................................................................................24 Aquatic Invertebrates ...............................................................................................................25 Algal Community ........................................................................................................................25 Aquatic Habitat....................................................................................................................................27 Summary and Conclusions 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