Robbin B. Sotir & Associates, Inc.

Case Study: Johnson Creek/span>

Location: Portland, Oregon
Client: Oregon DOT
Objectives: Relocate and stabilize a stream channel and associated cut and fill banks. Restore aquatic and riparian habitat, and water quality lost during the construction of a new bridge and interchange.

• Channel reach 400 feet long
• Stream length shortened by 20% and commensurate slope increase by the relocation
• Enhance anadromous fishery
• Soil bioengineering designed to provide overhanging cover for fish and restore riparian habitat
• Highly visible location

Nature of Firm's Resonsibility
Our Expanded Scope Included:

• Redesign of the realigned channel
• Soil bioengineering plans and specifications
• Provide aquatic and riparian habitat
• Permit assistance
• Prebid and preconstruction training
• On site construction observation
• Evaluation and monitoring for three years

Johnson Creek is a well developed urban watershed with land use from low-density residential to heavy industry. It is a third-order stream with a 100 year flood discharge at the project site of about 5,000 cfs.
Public concern over degraded water quality, riparian habitat and an interest in restoring an anadromous fishery prompted the creation of a citizen's committee known as the Johnson Creek Corridor Committee (JCCC) to monitor the stream corridor. The ODOT initially commissioned our firm to evaluate the potential impacts on water quality, fish, riparian habitat value and channel stability, with their trapezoidal channel design and proposed riprap rock lining.

The recommendations were presented to ODOT, Johnson Creek Corridor Committee, Oregon Fish & Game and Oregon Department of Fish and Wildlife to explain the rationale for the design changes and to resolve any remaining concerns. The recommendations were embraced and approved by the JCCC, the Client and the agencies. The modified design was constructed. Robbin B. Sotir & Associates, Inc. acted as the liaison between ODOT, the permitting agencies and the JCCC throughout the 1993 construction phase.

This project has experienced numerous floods with long duration flows. It continues to perform well and improve in environmental function each year.

We worked with Beak Consultants to evaluate the performance of the installed systems from a mechanical and plant diversity perspective as well as their effect on restoring habitat values.

This project appears in several papers and articles.