Maryland Department of Transportation State Highway Administration (MDOT SHA)
- Project Management
- Natural Resources Inventories
- Field Reviews
- Stormwater Management (SWM) Design
- Erosion & Sediment Control (E&SC) Design
Coastal Resources, Inc. (CRI) provided stormwater management and erosion & sediment control design, and environmental inventories for this highway improvement project on US 50 over the Severn River in Anne Arundel County, Maryland. The project consisted of the median barrier replacement and lane reconfiguration of the US 50 steel girder bridge over the Severn River and the roadway approaches on either side of the bridge from MD 70 to MD 2, a distance of 1.34 miles. Most of the proposed roadwork consisted of wedge-and-level and resurfacing of existing pavement. However, the proposed work also included full-depth reconstruction of the outside shoulders east of the bridge and full-depth reconstruction where the median was being moved toward the westbound lanes. Water Quality Maps were developed to show the existing impervious area and the proposed impervious reconstruction, new impervious, and impervious removal for the project site. CRI also prepared drainage area maps that showed the land uses within the existing and proposed drainage areas. The land uses within the project site consisted of impervious area, open area, residential area greater than 1-acre, residential area greater than 2 acres, and wooded area. All the proposed work was within the Chesapeake Bay Critical Area.
Design efforts for this project were constrained heavily by noise abatement walls spanning large portions of US 50. In addition to serving as physical barriers the walls heavily influence existing drainage patterns. Typically, the existing storm drain system conveyed flows from drainage ditches along open roadway sections, under the noise walls directly to the Severn River or vegetated outfalls outside the ROW. On the bridge, SHA Type II Scuppers conveyed flows from the eastbound and west bound lanes directly onto the Severn River.
To support the project design, CRI developed the stormwater management and erosion & sediment control plans for the Site Development Plan submission to the SHA Plan Review Division (PRD) in order to satisfy the Environmental Site Design (ESD) requirements of this roadway improvement project. CRI prepared electronic submittal materials for the Anne Arundel Soil Conservation District for review based on PI Plans and prepared the SWM and E&SC design report, as well as the Site Development applications, checklist, and transmittal forms and letters.
CRI prepared concept SWM documents for approval and updated the following items in the concept SWM documents to Site Development Plans for submission to PRD for approval.
- Update mapping (Site Resources, Pre/Post Construction D.A.)
- Update ESD volume (ESDv) required / provided & hydrology calculations for POI (6 POI’s)
- Update layout / grading of BMPs (6 facilities)
- Update ESDv required/provided & hydraulic calculations for ESD facility (6 facilities)
- Update and compile SWM report
- Prepare Engineer’s Estimate for SWM
- Continue refinement of E&S controls, LOD and sequence of construction
- Update E&S plans and details
CRI prepared a report that presented the findings of preliminary studies that determined and addressed the SWM needs of the roadway project. This project included identification, analysis, design, and permitting of SWM best management practices (BMPs) that are proposed to meet the Maryland Department of the Environment (MDE) requirements of this project. Therefore, as required by MDE, the design of the proposed BMPs needed to meet the strict requirements of the latest MDE ESD criteria. Any facilities designed under the criteria of the Chapter 5 (May 2009) revisions to the MDE 2000 Maryland Stormwater Management Design Manual Volumes I & II was designed in accordance with these criteria and/or as approved by the appropriate plan approval authority.
CRI also conducted natural resources inventories and developed a natural resources map and report for the project site. Existing published resources and available data were reviewed and summarized to describe environmental resources within the study area. A field review was conducted in order to verify the findings of the desktop research. In addition, CRI coordinated with MD DNR Wildlife and Heritage Service to determine if there were state or federal records for rare, threatened, or endangered species within the boundaries of the study area.