Turkey Branch Stormwater Management Retrofit and Stream Restoration Project

Reference

Dan Harper, Senior Engineer

Project Highlights

  • Stream Assessment and Restoration Design
  • Bioengineering Design
  • Natural Resources Inventory/Forest Stand Delineation
  • Environmental Permitting
  • GIS Analysis

Project Details

Turkey Branch is a severely degraded urban stream located in the Rock Creek Watershed in Montgomery County, Maryland. The Montgomery County Department of Environmental Protection contracted with Coastal Resources, Inc to design treatments to stabilize stream conditions and when feasible restore natural channel form and function to enhance aquatic habitat. This project was a continuation of the Rock Creek Watershed Study, which included 30% concept designs for SWM facilities, outfall mitigation, and stream restoration/stabilization alternatives.

The stream project limits included over 15,000 linear feet of stream along the Turkey Branch mainstem from Georgia Avenue to Rock Creek and along the Aspen Hill Tributary from Independence Road to the confluence with Turkey Branch. CRI developed an alternatives analysis, assisted Whitman, Requardt & Associates with final design plans and construction bid documents, and developed cost estimates. CRI also is under contract to provide construction management services once the stream restoration is underway.

During the field assessment and data collection phases of project, CRI completed cross-sectional surveys of the stream channels and performed hydrologic analyses to verify bankfull field indicators. Data regarding existing conditions of the riparian zone, stream channel, and streambanks within each reach were noted. Care was taken to detect potential public safety issues, infrastructure conflicts, and property damage resulting from stream conditions. CRI reviewed the existing data provided in the Rock Creek Watershed Study, field-identified new and additional areas in need of restoration and streambank stabilization, and developed remedial designs. The designs addressed issues throughout the project area:

  • eroding streambanks
  • floodplain access
  • head-cutting
  • sediment transport
  • habitat degradation.

Designs included the following techniques:

  • channel realignment
  • native material revetments
  • step pools
  • imbricated rock
  • cross vanes
  • coir logs
  • rock vanes
  • streambank grading
  • live staking
  • branch layers
  • fascines
  • wing deflectors
  • cut off sills
  • linear deflectors

CRI prepared a Natural Resources Inventory, including a jurisdictional wetland delineation and forest stand delineation. CRI also prepared the Section 404/401 Joint Permit Application for the project and attended and presented project information at public meetings. Since a portion of the project area is located within Matthew Henson State Park, CRI participated in significant coordination with Maryland National Park and Planning Commission staff. Comments from the community, property owners, and regulatory agencies that were received throughout the field investigation, design, and construction process were incorporated into the restoration designs.