BLOEDE DAM 60 PERCENT DESIGN REPORT Bloede Dam Removal 60% Design Report SUBMITTED TO American Rivers Maryland Department of Natural Resources JANUARY 2015 I.Bloede Dam Removal 60% Design Report PREPARED FOR Serena McClain American Rivers 1101 14th Street NW Suite 1400 Washington, DC 20005 [email protected] Maryland Department of Natural Resources Engineering and Construction 580 Taylor Avenue, D3 Annapolis, MD 21401 PREPARED BY Inter-Fluve, Inc. 501 Portway Ave., Suite 101 Hood River, OR 97031 541-386-9003 IN ASSOCIATION WITH Hazen and Sawyer McCormick Taylor PRINCIPAL AUTHORS Bill Norris, with Jonathon Kusa, Marty Melchior, Greg Orum, Jeremy Hise, Graham Boardman and Scott Lowe BLOEDE DAM 60 PERCENT DESIGN REPORT Table of Contents I. Executive Summary .............................................................................................. 1 Introduction ............................................................................................................................................... 3 Site description .......................................................................................................................................... 4 Field Data Collection .................................................................................................................................. 5 Existing Data Collection ................................................................................................................................................... 5 Survey ...................................................................................................................................................................................... 6 Geomorphology ................................................................................................................................................................... 6 Sediment Investigations .................................................................................................................................................. 7 II. Data Analysis .................................................................................................... 9 Impounded Sediment Volume ................................................................................................................... 9 Metals ...................................................................................................................................................... 10 Nutrient Loading ...................................................................................................................................... 11 Hydrology ................................................................................................................................................. 13 Hydrologic Analysis ......................................................................................................................................................... 13 Hydraulics ................................................................................................................................................. 14 Summary of Data Collected .......................................................................................................................................... 14 Existing Conditions Model ............................................................................................................................................ 15 Anticipated Conditions Model ..................................................................................................................................... 16 Fish Passage Hydraulic Analysis ................................................................................................................................ 19 Sediment transport .................................................................................................................................. 20 Sediment Transport Modeling ................................................................................................................. 21 Sediment Monitoring Results ................................................................................................................... 21 Biotic Impacts ........................................................................................................................................... 21 Biotic Impacts of the Patapsco River Dams........................................................................................................... 21 Short-Term Bloede Dam Removal Impacts ........................................................................................................... 23 Long-Term Removal Impacts ...................................................................................................................................... 25 RECREATIONAL AND Social Impacts ......................................................................................................... 26 Other Impacts .......................................................................................................................................... 26 Infrastructure Summary ................................................................................................................................................ 27 III. Design ............................................................................................................ 29 Recommended Design Approach ............................................................................................................. 29 Access ..................................................................................................................................................................................... 29 Staging ................................................................................................................................................................................... 30 Existing 42-Inch Diameter Sanitary Sewer Relocation .................................................................................... 31 Bonnie Branch Sanitary Sewer (12-inch Sewer) ................................................................................................ 34 Dam Breaching ................................................................................................................................................................... 34 Dam Demolition ................................................................................................................................................................ 36 Overlook ............................................................................................................................................................................... 36 Disturbed Area Restoration ......................................................................................................................................... 36 Long-Term Stabilization ................................................................................................................................................ 37 Schedule ................................................................................................................................................................................ 37 Estimated Opinion of Cost ............................................................................................................................................ 38 Citations ..................................................................................................................... 1 BLOEDE DAM 60 PERCENT DESIGN REPORT List of Figures Figure 1- USGS Topographic map of the Patapsco River at Ellicott City, MD showing the location of the Simkins, Bloede and Union dams. ......................................................................................................... 3 Figure 2- Dredging upstream of Bloede Dam (ca 1920) ................................................................................. 4 Figure 3 - Sediment Core Locations. .............................................................................................................. 8 Figure 4 - Left Bank Impoundment Deposit Location ..................................................................................... 9 Figure 5 - View of the Patapsco River prior to dam construction. ............................................................... 17 Figure 6 - Excerpt from HEC-RAS model output showing water surface elevations for existing (light blue) and anticipated conditions (dark blue) in the impoundment area. .................................................... 18 Figure 7 - Excerpt from HEC-RAS model output showing shear stress values (lb/ft2) associated with the 2-, 10-, and 100-yr recurrence flood for anticipated conditions. ............................................................. 18 Figure 8 - Pre-dam photo of railroad bridge that has been converted to the Grist Mill Trail Cable Stay pedestrian bridge ................................................................................................................................ 27 Figure 9- Proposed In-river Alignment Pre- and Post-Simkins Dam Removal. ............................................. 30 Figure 10- Existing 42-Inch Diameter Sewer. ................................................................................................ 31 Figure 11- Grist Mill Trail alignment. ...........................................................................................................