Degraded Stream
The Teedyuskung Creek
Restoration Project
In-Stream
Restoration
|
|
The project area is located within a heavily shaded, narrow ravine. Together with many state, local, and federal agency partners, F.X. Browne, Inc. conducted a preliminary site assessment to determine the cause of the problem and to develop a conceptual strategy for designing the restoration project. The site assessment showed evidence of both tractive erosion at the bank toe and subsequent mass failure. Increased stormwater runoff from the golf course and associated development was thought to be responsible for the increase in tractive erosive forces. |
| Despite the fact that the streambank was well armored with trees, shrubs and riparian ground cover, the increased erosive forces were causing catastrophic and rapid channel changes. |
|
|
| In other locations, large deposits of aggraded material were causing multiple channels to develop. |  |
|
A need for a natural yet structural approach was the driving force behind the bank stabilization design approach. F.X. Browne Inc. surveyed the restoration site and collected geomorphic and hydraulic data. |
| F.X. Browne, Inc. used Rosgen classification and geomorphic assessment techniques to aid in the design process. HEC-RAS hydraulic modeling system was used to model channel hydraulics throughout the project reach and to design stable individual structures. |
|
|
The design approach consisted of using a boulder toe stabilization system to prevent further undermining of the streambanks. This system was augmented in several locations with cedar tree revetments single and double wing stone deflectors, and single log deflectors to deflect and moderate flow and enhance fish habitat. |
|
