Client

District Department of Transportation

Key Services

  • Stream & Watershed Evaluation
  • Geomorphic Assessment
  • Hydrology & Hydraulic Analysis
  • Stream Restoration Design

Project Details

The District Department of Transportation (DDOT), in cooperation with the National Park Service (NPS), proposed the construction of a multi-use trail facility within a 0.7 mile stretch of Klingle Road.  For the Environmental Assessment (EA) of the project in compliance with the National Environmental Policy Act (NEPA), Coastal Resources, Inc. (CRI) staff led the field work and analysis associated with the geomorphic assessment of 3,300 linear feet of Klingle Creek, a tributary to Rock Creek.  The project included survey of channel geometry and planform, analysis of bank erosion, identification of sources of channel instability, documentation of riparian vegetation, and development of a restoration concept. CRI wrote a stream assessment and concept report, which documented the methods, analysis and results of the geomorphic assessment.  CRI also contributed sections to the EA, Finding of No Significant Impact (FONSI), and Klingle Valley Trail Design Concept Report documents.

CRI is provided stream restoration design services for the Klingle Valley Trail project. The key stream restoration design objective was to create a stable streambed and banks with improved habitat, ecological function, and aesthetics, to protect adjacent structures from flooding, as well as to result in neutral or positive impacts on downstream areas.  CRI conducted an updated stream and watershed evaluation and prepared a summary report to communicate the results to the District of Columbia and the stakeholder group.

CRI developed a stream restoration design (30%, 65%, 100% and PS&E) to achieve the design objectives while working around site constraints such as bedrock outcrops, existing infrastructure, mature trees, and retaining walls.  The stream restoration includes a series of step pools, a riffle grade control, bank protection, riparian plantings, scour protection at retaining walls, and outfall stabilization structures.  In order to protect the trail and adjacent infrastructure from flood impacts, the design approach strived to create a new active channel to convey the 25- to 50-year flood event, with an adjacent floodplain or flood-prone area to dissipate energy and convey larger storm events up to the 100-year event.

CRI provided construction phase services as well such as:

  • Revisions to the stream design plans and specifications as needed to address any changes made via addenda
  • Review of any shop drawings or proposed substitutions presented by the contractor to ensure conformance with the intent of the design, and to ensure the integrity of critical design components.
  • Responding to requests for information about the stream design during the construction phase, including questions from the Contractor.
  • Providing additional design services during construction to address any necessary design changes that are more significant than simple field changes.

After Construction