Interfluve, Inc. of Hood River, Oregon was hired to formulate a biostabilization design, to conduct bioengineering seminars for City staff and to provide training in the necessary construction processes. The channel was stabilized using 2 basic methods. Where possible, steep banks were cut back to make them less steep. A series of pools and riffles were also designed for the channel. Riffles also add oxygen to water making it possible to support more life.
Pools are areas where water moves much more slowly and is therefore less erosive.
In the riffles, water moves fast and is more erosive so rock is placed in the channel and stream banks to resist the erosive force. In pools, water moves slowly enough that vegetation alone is often able to withstand the erosive force and no rock is needed. The height to which this lining was extended up the sides of the channel was determined by analyzing the force that the water from a 100-year storm exerts on the bank. Where that force was such that vegetation alone could withstand it, rock was stopped and vegetation was used to protect the banks. Live willow stakes were placed below the wrapped soil on 1-foot centers and grass seed was spread on the soil before the fabrics were wrapped over it.