Some of our West Creek residents

Site 8

As previously discussed, Site 8 has been relocated and straightened to accommodate commercial development on the south bank. The site extends approximately 1,700 feet downstream from Lancaster Drive to an area stabilized with gabions. The first 500 feet of the stream valley and channel are constricted by slopes from Granger Road to the north and the commercial development to the south. The remainder of the channel is generally incised with a gradual to steep forested bank leading to Granger Road, and a short, steep embankment leading to the commercial properties. The south bank is experiencing severe erosion in several places along this site as the stream tries to create meanders within the straightened channel. This is endangering some of the buildings perched near the edge of the bank. Although the stream is actively eroding the outside meander bends, it developing stable point bars, and is beginning to establish shallow pools. The preferred concept will build upon this developing meander pattern and realign the channel away from the eroding south bank, as well as create stable riffles and pools.

The preferred concept for this reach involves realigning and slightly raising the channel invert beginning downstream of Lancaster Drive and extending approximately 1000 feet downstream. Raising the channel invert and constructing a step structures downstream of the Lancaster Drive culvert, will eliminate the existing fish blockage at the culvert. Raising the invert will also facilitate grading the banks to a stable angle. A moderately meandering step/riffle channel will be constructed to be realigned more closely to Granger Road. Realigning the channel will alleviate the south bank from erosive shear and provide more belt width to create a meandering pattern. The existing channel will be partially filled to create point bars and a floodplain for the newly constructed channel. With this option the south bank could be graded to a more stable slope and stabilized with boulder bank or toe protection, and native woody vegetation. The growing trees of a forested buffer will eventually begin to shade the stream from the sunlight which warms the channel at this site. Through the remainder of the reach, the concept will build upon the natural meander pattern that the stream is attempting to create by adjusting and stabilizing the eroding outside meander bends. On the outside meander bends, rootwads may be used in conjunction with boulder bank protection to provide additional habitat within the pools and rock vanes may be used to maintain the location of the stream thalweg.

Benefits

• Eliminate fish blockage at Lancaster Drive
• Enhanced riparian habitat and bank stability with bioengineering and native plants
• Added vegetation also will help shade the channel
• Stabilize the eroding banks
• Steps, riffles, vanes and rootwads will offer a habitat for fish
• Stable bank angles can be graded with little or no impact to adjacent properties

Risks and Constraints

• Existing slope instability along the south bank
• Realigning the stream to the north may require additional construction to stabilize the upper slope near Granger Road
• Litter may collect in the rootwads and newly established vegetation

Maintenance

• Remove debris jams
• Replace the dead or inadequately established vegetation within the first year

Project Maps and Photos

These maps are large, so download time may take a while - especially for dial-up connections. You will need to have the Adobe Acrobat Reader installed on your computer. If you do not already have it, you can download it for free at the Adobe Acrobat website.

West Creek Site Overview Project 8

West Creek site 8 concept plan

West Creek Site 8 photos