MD 32 Design-Build from Linden Church Road to I-70 Stream and Wetland Mitigation

The Maryland Department of Transportation’s State Highway Administration (MDOT SHA) is proposing roadway improvements along MD 32 from MD 108 to I-70 in Howard County, MD.  Phase II of the project includes dualization of MD 32 from Linden Church Road north to I‑70 and will require the relocation of two stream channels as well as 1,443 LF of stream restoration/enhancement and 2.27 aces of palustrine forested wetland mitigation.

Coastal Resources, Inc. (CRI) is part of a design-build team as the primary environmental design consultants. CRI was responsible for the wetland mitigation design, the stream restoration/enhancement and relocation design and supporting regulatory documentation as well as Designated Specialist construction oversight services.

CRI performed a geomorphic evaluation, aquatic habitat assessment, and bank stability analysis for three stream reaches on Terrapin Branch, Tributary at Rosemary Lane, and Middle Patuxent River, approximately 5,200 LF total. CRI completed hydrology and hydraulics studies for the existing conditions in the study reaches. These studies provided the basis for design.

CRI developed Final designs (100%) for each of the three stream reaches. The Terrapin Branch and Middle Patuxent River reaches were designed solely for relocation and were considered mitigation in-kind. The designs focused on stability upstream and downstream of the new MD 32 crossings as well as floodplain connectivity and functional improvements.  The proposed work at the Rosemary Lane Tributary will serve as mitigation for unavoidable impacts caused by the MD 32 Phase II project. The Rosemary Lane Tributary design will provide fish passage through the proposed 243 LF culvert under MD 32 and provide functional uplift by meeting the ecological uplift goals set by CRI. The fish passage design aimed to provide fish passage for specific low flow conditions using the US Forest Service program Fish Xing. The final designs were approved by MDOT SHA, MDE, and USACE.

CRI conducted a site investigation at the 2.27 acres Gossage Farm wetland mitigation site to verify the potential of the site. The team installed new groundwater monitoring loggers in the existing well locations and will continue to collect groundwater data until construction begins. CRI analyzed the new survey data and groundwater data obtained and develop a water budget that will support the wetland design. The water budget was calculated using the Pierce/Wetland Training Institute methodology (Pierce, 1993). CRI prepared a final (100%) design, report, and construction documents.

Along with design documents, CRI prepared the Phase II Final Mitigation Plans for Rosemary Lane Tributary Stream restoration/enhancement site and the Gossage Farm Wetland Mitigation site in accordance with the design guidelines outlined in MDE’s Phase II Mitigation Checklist, as well as any other requirements requested by the USACE and MDE. CRI is also responsible for preparing JPA Modification(s) documentation, as necessary, for the Rosemary Lane Tributary Phase II Stream Mitigation Plans, Gossage Farm Wetland Mitigation Phase II Wetland Mitigation plans, final construction plans, and any other information requested in the MDE and USACE permits to receive the required final corridor and wetlands and waterway permits.

CRI prepared the pre-construction monitoring protocols and conducted pre-construction activities such as photographs and invasive species identification.  CRI was also responsible for preparing a Monitoring Plan that detailed proposed post-construction conditions. The Monitoring Plan was approved by the MDOT SHA, MDE, and USACE.

CRI is providing a Wetland and Stream Specialist (WSS) during stream and wetland construction. The WSS has provided on-site inspection services that consist of site reviews of on-going construction activities related to wetland and stream construction. The contractor’s activities continue to be reviewed to determine if they meet the design intent. Inspection includes review of erosion sediments control measures, grading operations and planting of wetland vegetation. Written logs and photo-documentation of construction and inspection activities will continue to be completed.


Howard County, MD


MDOT State Highway Administration

Key Services:

  • Geomorphic Assessment
  • Hydrology and Hydraulics
  • Groundwater Monitoring
  • Stream and Wetland Mitigation Design
  • Agency Coordination
  • Permitting