Prepared in cooperation with the U.S. Fish and Wildlife Service Geomorphic Classification of the Lower Platte River, Nebraska 97°30' 97°05' 96°40' 96°15' 95°50' Elkhorn IOWA M is so u ri 41°30' R # i R v Columbus ! i e v ! Fremont r Loup North e # River r Genoa Bend Platte River Omaha ! ! Council 41°15' NEBRASKA Bluffs EXPLANATION Bellevue ! Four-cluster classification Cluster 1 Cluster 2 Cluster 3 # Cluster 4 Louisville 41° Genoa# U.S. Geological Survey streamflow-gaging k ee station Cr lt Platte River Valley Sa 97°30' 97°05' 96°40' 96°15' 95°50' Elkhorn IOWA M is so u ri 41°30' R # R ! i Columbus v i ! Fremont e v Loup North r e # River r Genoa Bend Platte River Omaha Louisville Gage ! ! Council 41°15' NEBRASKA Bluffs EXPLANATION Bellevue ! Seven-cluster classification Cluster 1 Cluster 5 Cluster 2 Cluster 6 Cluster 3 Cluster 7 Cluster 4 # Louisville 41° Genoa# U.S. Geological Survey streamflow-gaging k station ee Cr lt Platte River Valley Sa Scientific Investigations Report 2009–5198 U.S. Department of the Interior U.S. Geological Survey Cover. Examples of four- and seven-cluster classifications on the Lower Platte River. Geomorphic Classification of the Lower Platte River, Nebraska By Caroline M. Elliott, Brittany L. Huhmann, and Robert B. Jacobson Prepared in cooperation with the U.S. Fish and Wildlife Service Scientific Investigations Report 2009–5198 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2009 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Elliott, C.M., Huhmann, B.L., Jacobson, R.B., 2009, Geomorphic Classification of the Lower Platte River, Nebraska: U.S. Geological Survey Scientific Investigations Report 2009–5198, 29 p. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................1 Purpose and Scope ..............................................................................................................................1 Least Tern and Piping Plover Habitat ................................................................................................1 Physical Setting and Study Section ...................................................................................................2 Hydrology ...............................................................................................................................................2 Geomorphology .....................................................................................................................................2 River Classification ...............................................................................................................................6 Approach and Methods ................................................................................................................................6 Aerial Orthophotography .....................................................................................................................6 Channel and Valley Boundary Determinations ................................................................................8 Address System ....................................................................................................................................8 Image Classification for In-Channel Characteristics ......................................................................9 Statistical Classification ....................................................................................................................10 Classification Assessment ................................................................................................................12 Results ...........................................................................................................................................................15 Valley and Channel Width .................................................................................................................22 Sinuosity ...............................................................................................................................................22 Braiding ................................................................................................................................................22 Statistical Classification ....................................................................................................................22 Classification Assessment Based on In-Channel Dependent Variables ..........................22 Classification Assessment Based on Nesting Locations ....................................................23 Discussion .....................................................................................................................................................26 Summary .......................................................................................................................................................27 Acknowledgments .......................................................................................................................................27 References Cited..........................................................................................................................................27 Figures 1. Map showing the Platte River Basin and the Lower Platte River study area ....................3 2–3. Graphs showing — 2. Discharge for the Lower Platte River and tributaries ......................................................4 3. Locations and discharges on the Lower Platte River for 2006 National Aerial Imagery Program photographs used in this study at the Grand Island, North Bend, and Louisville gages on the Platte River, Nebraska .....................7 4–6. Maps showing— 4. Address system created for data collection based on the channel centerline ..........8 5. Selection of training samples for the woody vegetation category of the computerized classification .................................................................................................9 6. Comparison of National Aerial Imagery Program (NAIP) photography, manual classification, and computerized classification for a 2-kilometer representative section of the Platte River .......................................................................11 iv 7–8. Graphs showing— 7. Platte River geomorphic characteristics including valley width, channel width, sinuosity, sandbar count, braiding index, and percent of channel composition ......................................................................................................13 8. Principal components analysis of selected variables ...................................................14 9–10. Scatterplots showing— 9. Selected, non-transformed classification variables .....................................................15 10. The reduced set of selected classification variables ...................................................16 11. Hierarchical cluster dendrogram of the reduced dataset. ..................................................16 12–16. Graphs showing— 12. Changes in sum of square differences within and among clusters as number of clusters changes ..............................................................................................17 13. Clustering results from the K-means procedure for four clusters ..............................17 14. Clustering results from the K-means procedure for seven clusters. ..........................18 15. Canonical scores for the four-cluster classification .....................................................18 16. Canonical scores for the seven-cluster classification .................................................19 17. Maps showing examples of four- and seven-cluster classifications on the Lower Platte River ......................................................................................................................21 18–19. Box plots showing— 18. Response variables by four- and seven-cluster classifications ..................................24 19. Percent channel type from supervised imagery classification by reach for the Lower Platte River ..................................................................................................25 Tables 1. Dates and river discharges for 2006 digital photography ......................................................5 2. Comparison of automated and manual classifications of a 2-kilometer reach of the Platte River .......................................................................................................................10