Stream Habitat Restoration Projects

COAL CREEK

Coal Creek passed through a perched culvert. An attempt to address this condition using wooden stream spanning straight weirs had failed. The stream had subsequently down cut to a hard clay sub-strate offering minimal habitat features and no spawning opportunities for the Coho salmon known to occupy Coal Creek.

A bottomless culvert was our designed solution. The perched condition (drop at the culvert outlet) was alleviated through a series of wood vanes. The vanes provided pool habitat and created riffles composed of spawning gravel.

Coho were seen using the improvements and successfully passing the mitigated barrier within months of project completion.

SPRINGBROOK CREEK

Springbrook Creek runs through the fully developed urban community of Lake Oswego, OR. The stream then empties into a lake. In order for the local fishery to fully utilize Springbrook Creek, the cutthroat trout had to pass through a 170 foot long flat bottom concrete culvert running under a 25 foot deep railroad fill. The culvert spilled out into a two feet high drop. Summer flows through the culvert ran about an inch deep. When sufficient depth for fish passage existed in the culvert, the velocity was too high to allow passage.

StreamFix designed a modification to the bottom of the culvert to allow fish to pass during summer low flows. The perched conditions at the outfall of the culvert were mitigated by constructing a series of stone vanes that created pools and habitat conditions. A couple of months later, a resident fish biologist reported seeing 14" cutthroat spawning in his reach of Springbrook Creek for the first time in the 35 years he had lived there.

Habitat needs vary by species and location in the watershed. In the Sycan River, the stream restoration work included constructing log jams that would provide overhanging cover as well as in-stream habitat. That same project included pool developing structure with large wood incorporated into the structure in such a manner that it provides year round habitat.

HITEON CREEK

Hiteon Cr., in Englewood Park (Tualatin OR), was a classic urbanized stream. Incised, running through a well developed park, disconnected from its supporting wetlands.directly receiving waters for a major arterial storm drainage.

The goal for this project was to reconnect wetlands, rectify the incision, re-establish aquatic habitat, creating mitigation for the storm run-off, all the while preserving the community park setting.

This was accomplished through removal or relocation of asphalt walkways through wetlands,removal of unnecessary culverts, stabilizing the stream while re-establishing habitat features, re-routing arterial storm drainage through wetlands specifically created for that purpose and re-establishing riparian and wetland vegetation throughout.

Stream and river projects seldom address only one problem. They are usually associated with a combination of problems such as excessive lateral channel migration, habitat loss, loss of riparian vegetation, erosion problems, flooding and water safety.

All of these issues must be considered in the development of river restoration plans. Understanding this variety of interdependent issues takes a great deal of data collection and analysis, computer modeling and interpretation of results. Successful projects are seldom the result of a 'good gut feel' or the consensus of group of well meaning citizens. The science of stream restoration is still evolving, however, we have come a long way in the past decade.

Excessive bank erosion results in the loss of adjoining lands, increases in sediment load, shallower rivers, loss of riparian vegetation and increases is water temperatures, all undesirable traits from the perspective of the landowner and aquatic habitat. Successful bank erosion remediation addresses all of these factors to the benefit of increased over-all river health.

Long term, successful stream restoration is invariably the result of the collection and interpretation of relevant data. This is often an arduous process being performed by well trained and experienced practitioners.

Long term successful stream restoration is seldom the result of poorly trained practitioners working from a 'good gut feel'.

Streamfix offers the review of stream and wetland restoration plans as an independent third party. The project plan reviewers will usually include well trained and experienced geomorphologists, land surveyors, hydraulic modelers, fish biologists, wetland scientists, riparian vegetation specialists and others as needed.

The review will ensure critical issues such as:

• Basic data collection
• Stream/reach Hydrology
• Sediment characterization, load and transport competence
• Flood impacts
• Bank erosion hazards
• Geomorphic analysis
• Riparian planting
• Project related erosion control

are addressed in terms of the provided project goals and objectives.

The review offered will offer suggestions for the project sponsor and designer to consider as they move forward. The ultimate decisions regarding the projects design will, of course, rest with the project designer and sponsor.