Riverbend Levee Setback and Floodplain Restoration Cedar River Alternatives Analysis Report 10/5/2016 Prepared by: Jon Hansen, Project Manager Sarah McCarthy, Senior Ecologist Kate Akyuz, Senior Ecologist Todd Hurley, LEG, Senior Geologist Jay Smith, PE, Senior Engineer Alex Hallenius, PE, Senior Engineer Will Mansfield, PE, Supervising Engineer Water and Land Resources Division Department of Natural Resources and Parks RIVERBEND ALTERNATIVES ANALYSIS OCTOBER 5, 2016 Table of Contents Table of Figures .................................................................................................................................................................................. iv Executive Summary ..................................................................................................................................... 1 Introduction ................................................................................................................................................. 3 Project Goals and Objectives .................................................................................................................. 3 Goal 1 ......................................................................................................................................................................................................... 3 Goal 2 ......................................................................................................................................................................................................... 3 Goal 3 ......................................................................................................................................................................................................... 4 Goal 4 ......................................................................................................................................................................................................... 4 Location .................................................................................................................................................... 5 Existing Conditions ................................................................................................................................. 7 Hydrology and Hydraulics ............................................................................................................................................................. 7 Geology and Geomorphology....................................................................................................................................................... 7 Habitat and Fish Use ......................................................................................................................................................................... 8 Land Use ............................................................................................................................................................................................... 11 Recreational Use .............................................................................................................................................................................. 14 Relevance and Urgency ......................................................................................................................... 14 Consistency with regional planning efforts ...................................................................................................................... 14 Urgency ................................................................................................................................................................................................. 15 Project Alternatives ................................................................................................................................... 16 Project Elements .................................................................................................................................... 16 Riverbend Upper Options ........................................................................................................................................................... 16 Riverbend Lower ............................................................................................................................................................................. 16 Herzman Options ............................................................................................................................................................................. 16 Expected Effect of Project Options ......................................................................................................................................... 17 Alternative Descriptions ....................................................................................................................... 20 Alternative 0. No action ................................................................................................................................................................ 20 Alternative 1. Full Floodplain Reconnection and Herzman Removal ................................................................. 20 Alternative 2. Moderate Floodplain Reconnection, Herzman Removal, and High Pond Connection 20 Alternative 3. Moderate Floodplain Reconnection, Herzman Removal, and Low Pond Connection 20 Alternative 4. Moderate Floodplain Reconnection, No Herzman Removal, and High Pond Connection .......................................................................................................................................................................................... 21 Alternative 5. Low Floodplain Reconnection, No Herzman Removal, and Low Pond Connection .... 21 Alternative 6. Low Floodplain Reconnection, No Herzman Removal and No Pond Connection ......... 21 Alternatives Analysis Methods ................................................................................................................. 28 Site Investigations/Existing Data Collection ....................................................................................... 28 ii RIVERBEND ALTERNATIVES ANALYSIS OCTOBER 5, 2016 Hydraulic Modeling ............................................................................................................................... 30 Geomorphic Assessment ....................................................................................................................... 31 Permitting and Stakeholder Consultation ........................................................................................... 31 Alternative Scoring ................................................................................................................................ 31 Screening Criteria ............................................................................................................................................................................ 31 Readiness Criteria ........................................................................................................................................................................... 37 Findings ...................................................................................................................................................... 39 Habitat .................................................................................................................................................... 39 Flood ....................................................................................................................................................... 39 Recreation .............................................................................................................................................. 40 Cost Effectiveness .................................................................................................................................. 40 Conclusions ................................................................................................................................................ 41 Rating of Project Alternatives .............................................................................................................. 41 Recommendations ................................................................................................................................. 41 Future Considerations Related to the Recommended Alternative .................................................... 42 Project design development ...................................................................................................................................................... 42 Additional analyses required to advance project .......................................................................................................... 42 Risks and Constraints .................................................................................................................................................................... 42 Permitting ............................................................................................................................................................................................ 43 Project sequencing .......................................................................................................................................................................... 43 Funding and Acquisitions ..........................................................................................................................................................