Washington Suburban Sanitary Commission (WSSC)

Key Services

  • Wetland Delineation
  • Forest Stand Delineation/Natural Resources Inventory
  • Forest Conservation
  • Assist with Permitting Process
  • Stream Restoration

Project Details

Coastal Resources, Inc. (CRI) provided environmental assessment, environmental design, and permitting services for this large sewer rehabilitation project. CRI has conducted environmental assessments for over 140 assets in approximately 60 project areas that Washington Suburban Sanitary Commission (WSSC) has identified for rehabilitation or repair to manholes and/or pipe segments, mostly located along streams, within the Beaverdam Creek watershed.  CRI conducted wetland delineations and forest stand delineations, including specimen tree surveys, within each of the project areas.  These resources were surveyed by CRI using a Trimble Global Positioning System (GPS).  CRI prepared Natural Resource Inventory (NRI) Maps in GIS detailing all natural resources such as steep slopes, 100-year floodplains, wetland, streams, soils, and the findings from the forest stand delineations as required by Maryland Department of Natural Resources (MDNR) for each project area.  CRI will prepare a Forest Conservation Plan (FCP) for each project area once MDNR has approved the forest stand delineations.  CRI coordinated with the U.S. Fish and Wildlife Service (USFWS), MDNR Wildlife and Heritage Division, National Marine Fisheries, and MDNR Environmental Review Unit (ERU) to determine if any federal or state listed rare, threatened, or endangered species are present within the project areas.

CRI prepared a Joint Permit Application (JPA) to submit to the U.S. Army Corps of Engineers and the Maryland Department of the Environment (MDE) for review.  As part of the JPA submittal, CRI prepared the wetland delineation report, including wetland mapping, detailed impact plates, and impact summary tables based on rehabilitation design and access plans.  CRI also conducted a jurisdictional determination (JD) for all wetlands and waterways located within the project areas.

WSSC Beaverdam Stream 1CRI also prepared permit ready design plans for 9 channel relocations associated with stream impacts or infrastructure conflict resolution.  These designs aim to protect infrastructure in an environmentally sensitive way, while also improving the ecosystem where possible.  To support the design development, CRI conducted stream assessments that included the collection of geomorphic parameters such as cross sectional area, bankfull elevation, water-surface and streambed slopes and streambed particle sizes and class.  CRI collated and analyzed the geomorphic data and prepared appropriate remedial designs for each of the impacted sites. HEC-RAS and other hydraulic modeling were performed to support the design.   The permit ready design package includes a final design report, proposed grading plans, stream profile, stream cross sections, typical sections, stream stabilization details, erosion and sediment control notes and details, specifications, and construction cost estimates.  The final permit ready design package was submitted to WSSC.