RESILIENT NEW YORK FLOOD MITIGATION INITIATIVE Cayuga Creek, NY Prepared by: OBG, Part of Ramboll 101 First Street, 4th Floor Utica, NY 13501 (315) 956-6950 https://www.ramboll.com OBG, PART OF RAMBOLL | APRIL 2020 RESILIENT NEW YORK FLOOD MITIGATION INITIATIVE IN NOVEMBER 2018, NEW YORK STATE GOVERNOR ANDREW CUOMO COMMITTED FUNDING TO UNDERTAKE ADVANCED MODELING TECHNIQUES AND FIELD ASSESSMENTS OF 48 FLOOD-PRONE STREAMS TO IDENTIFY PRIORITY PROJECTS AND ACTIONS TO REDUCE COMMUNITY FLOOD AND ICE JAM RISKS, WHILE IMPROVING HABITAT. THE OVERALL GOAL OF THE PROGRAM IS TO MAKE NEW YORK STATE MORE RESILIENT TO FUTURE FLOODING. New York State Department of Environmental Conservation 625 Broadway Albany, New York 12233 NOTICE This copyrighted material represents the proprietary work product of OBG. This material was prepared for the specific purpose of securing a contract with the New York State Department of Environmental Conservation. 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OBG, PART OF RAMBOLL | APRIL 2020 FINAL | i Project #SC806 RESILIENT NEW YORK FLOOD MITIGATION INITIATIVE TABLE OF CONTENTS Table of Contents ................................................................................................................................................. ii List of Tables......................................................................................................................................................... iv List of Figures ....................................................................................................................................................... iv Appendices .............................................................................................................................................................. v Acronyms/Abbreviations .................................................................................................................................. v Introduction........................................................................................................................................................... 1 Historical Initiatives .......................................................................................................................................................... 1 Floodplain Development ................................................................................................................................................. 1 Resilient NY Initiative ....................................................................................................................................................... 2 Data Collection ...................................................................................................................................................... 3 Initial Data Collection ....................................................................................................................................................... 3 Public Outreach ................................................................................................................................................................... 3 Field Assessment ................................................................................................................................................................ 3 Watershed Characteristics ............................................................................................................................... 5 Study Area ............................................................................................................................................................................. 5 Watershed Land Use ......................................................................................................................................................... 5 Geomorphology .................................................................................................................................................................. 5 Hydrology ........................................................................................................................................................................... 10 Infrastructure ................................................................................................................................................................... 14 Climate Change Implications ......................................................................................................................... 20 Future Projected Discharge in Cayuga Creek ....................................................................................................... 20 Flooding Characteristics ................................................................................................................................. 23 Flooding History .............................................................................................................................................................. 23 Flood Risk Assessment .................................................................................................................................... 27 Flood Mitigation Analysis ............................................................................................................................................ 27 Cost Estimate Analysis .................................................................................................................................................. 28 Ice Jam Analysis .................................................................................................................................................. 29 Ice Jam Formation ........................................................................................................................................................... 29 Ice-jam Flooding Mitigation Alternatives .............................................................................................................. 29 Ice-jam Prone Areas ....................................................................................................................................................... 30 High Risk Area #1: Village of Depew Old Division of Public Works Landfill/Rowley Rd Bridge, Depew, NY ...................................................................................................................................................................... 30 High Risk Area #2: Broadway/US-20 Shopping Plaza and Residences, Lancaster, NY ................... 31 High Risk Area #3: Confluence with Little Buffalo Creek, Lancaster, NY.............................................. 31 Mitigation Recommendations ....................................................................................................................... 35 OBG, PART OF RAMBOLL | APRIL 2020 FINAL | ii Project #SC806 RESILIENT NEW YORK FLOOD MITIGATION INITIATIVE High Risk Area #1 ........................................................................................................................................................... 35 Alternative #1-1: Widen/Remove the Rowley Road Bridge ...................................................................... 35 Alternative #1-2: Remove Inactive Railroad Bridge ..................................................................................... 39 Alternative #1-3: Install Flood Bench in Vicinity of Inactive Railroad Bridge.................................... 43 Alternative #1-4: Ice Control Structure – Inactive Railroad Bridge ....................................................... 54 Alternative #1-5: Streambank Stabilization – Village of Depew Old DPW Landfill .......................... 56 High Risk area #2 ............................................................................................................................................................ 60 Alternative #2-1: Increase the Borden Road Bridge Opening ................................................................... 60 Alternative #2-2: Install Flood Bench Downstream of Penora Street Bridge ..................................... 64 Alternative #2-3: Ice Control Structure – Penora Street Bridge .............................................................. 68 High Risk area #3 ............................................................................................................................................................ 70 Alternative #3-1: Remove Sediment Under the Bowen Road Bridge Pier ........................................... 70 Alternative #3-2: Install Flood Bench Upstream of the Bowen Road Bridge ...................................... 75 Basin Wide Mitigation Alternatives ......................................................................................................................... 79 Early Warning Flood Detection System .............................................................................................................. 79 Ice Management ........................................................................................................................................................... 80