Glebe Branch Stream Restoration (Glebe Creek) South River Watershed Project No. B559700 Contract No. B559701
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GLEBE BRANCH STREAM RESTORATION (GLEBE CREEK) SOUTH RIVER WATERSHED PROJECT NO. B559700 CONTRACT NO. B559701 Watershed and Site Assessment Report December 2016 Prepared For: Anne Arundel County Department of Public Works Watershed Protection & Restoration Program 2662 Riva Road Annapolis, MD 21401 Prepared by: Biohabitats, Inc. / Century Engineering, Inc. A Joint Venture (this page intentionally left blank) Glebe Branch Stream Restoration Watershed and Site Assessment Report Anne Arundel County DPW Table of Contents 1 Introduction ................................................................................................................................ 1 1.1 Project Study Area and Background .............................................................................. 1 1.2 Project Goals and Objectives ......................................................................................... 3 2 Environmental Resources Inventory .......................................................................................... 3 2.1 Overview of Assessment Methods ...................................................................................... 4 2.2 Stream Classification ........................................................................................................... 4 2.3 Watershed Characterization ................................................................................................ 4 2.4 Historic and Present Land Use ............................................................................................ 5 2.5 Geology and Soil ................................................................................................................. 5 2.6 Wetlands and Surface Waters ............................................................................................. 7 2.7 Preliminary Hydrology ......................................................................................................... 8 2.8 Riparian Vegetation ............................................................................................................. 9 2.9 Biological and Cultural Resources .................................................................................... 10 3 Constraints Analysis ................................................................................................................ 10 3.1 Limited Environmental Assessment .................................................................................. 10 3.2 Existing Utilities and Infrastructure .................................................................................... 1 1 3.3 Forest Impacts ................................................................................................................... 14 3.4 Property Ownership, Easements, and Construction Access Opportunities ...................... 14 3.5 FEMA Floodplain and Hydrologic Trespass ...................................................................... 15 3.6 Forest Conservation Priority Areas ................................................................................... 16 3.7 RTE and In-Stream Work Restrictions .............................................................................. 16 4 Reference Reach Characterization .......................................................................................... 16 5 Existing Stream Conditions ...................................................................................................... 17 5.1 Site Assessment ................................................................................................................ 17 5.2 Stream Geomorphology .................................................................................................... 17 5.3 Stream Stability Evaluation ............................................................................................... 26 5.4 Bank Stability Analysis and Erosion Estimate ................................................................... 29 6 Preliminary Conceptual Design ................................................................................................ 31 6.1 Restoration Approach Alternatives Analysis ..................................................................... 31 6.2 Restoration Techniques .................................................................................................... 32 6.3 Approaches by Reach ....................................................................................................... 34 6.4 Roadway Culvert Analysis ................................................................................................. 4 3 6.5 Stormwater Management Basin D1 Analysis .................................................................... 45 6.6 Functional Assessment and Ecological Uplift Evaluation .................................................. 47 6.7 Water Quality Credits ........................................................................................................ 48 6.8 Recommendations ............................................................................................................ 49 Glebe Branch Stream Restoration Watershed and Site Assessment Report Anne Arundel County DPW 6.9 Future Design Development .............................................................................................. 49 7 References and Correspondence ............................................................................................ 51 7.1 References ........................................................................................................................ 51 Appendix A: Existing Conditions and Drainage Area Map, Geomorphic Assessment Data And Soils Report Appendix B: Historical Imagery and Mapping Appendix C: Natural Resource Inventory Report Appendix D: Agency Correspondence Letters Appendix E: As Built Drawings Appendix F: Reference Reach Search Appendix G: Photographic Log7 Appendix H: SEM Model Tables Appendix I: BANCS Results Appendix J: Roadway Culvert Analysis Appendix K: SWM Basin D1 Analysis Appendix L: Functional Assessment Tables List of Figures: Figure 1: Project Location Map Figure 2: FEMA FIRM Map Figure 3: Stream Evolution Model (SEM) List of Tables: Table 1: Soil Map Units and Associated Hydric Soil Components Table 2 Stream Stats Flow Statistics Table 3 Stream Segments Table 4: Geomorphic Data and Stability Summary Table 5: Bankfull Region Regression Results Table 6: Summary of BEHI predictions Table 7: Stormwater Management Basin Analysis Results Table 8: Pond Inflow Rates for 2-year, 10-year, and 100-year storms Table 9: Pond Outflow Rates for 2-year, 10-year, and 100-year storms Table 10: Removal Rate Predictions Glebe Branch Stream Restoration Watershed and Site Assessment Report Anne Arundel County DPW 1 INTRODUCTION 1.1 Project Study Area and Background The Anne Arundel County (County), Maryland, Watershed Preservation and Restoration Program (WPRP) is initiating the development of projects that were identified in the comprehensive assessment of the South River Watershed. These projects are being implemented to provide ecological enhancement and support the requirements of the National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit issued to the County by the Maryland Department of the Environment (MDE) and to assist the County in meeting pollutant load reductions associated with the Chesapeake Bay Total Maximum Daily Load (TMDL). The stream under evaluation, referred to as Glebe Branch by the County for this project, but known as multiple names (Glebe Creek on some mapping and West Glebe Branch on development stormwater as built plans) begins as one of the headwater branches to the tidal portion of Glebe Creek. Its origin is located within the South River Colony Golf Course Community at the northeast side of Antiqua Place. The evaluation reach continues in a northeasterly direction, crossing under several roads including Colony Crossing Road, Central Avenue East (MD 214) and Mayo Road (MD 253), before ending at the tidal water confluence of Glebe Creek. These stream segments collectively comprise an estimated 8,500 linear feet of degraded channels within approximately 48 acres of stream valley, referred to throughout this report as the Study Area and illustrated in Figure 1. This full length was evaluated as part of the site assessment, but the length of stream below Mayo Road was not included in the preliminary conceptual designs per County direction because it was determined to not warrant restoration. The project Study Area is approximately 48 acres (see Figure 1). © Biohabitats, Inc 1 Glebe Branch Stream Restoration Watershed and Site Assessment Report Anne Arundel County DPW Figure 1: Project Location Map © Biohabitats, Inc 2 Glebe Branch Stream Restoration Watershed and Site Assessment Report Anne Arundel County DPW 1.2 Project Goals and Objectives The stream restoration design work entails preliminary environmental analysis and feasibility study, field surveys, preliminary and final design, permitting, acquisition of easements, and construction documents. The design goals for this project are: 1. Provide stream valley restoration, including the re-connection of the stream channel with riparian wetlands and optimizing floodplain reconnection of stormflows. 2. Provide design features that promote denitrification during base flow. 3. Provide significant reduction in annual mass of sediments and attached nutrients originating from on-site channel degradation and upstream loss being