Mitigation efforts should focus on areas above unstable inner gorge slopes that have a high potential to deliver material downstream. Leaving scattered trees may help in areas with thin soils or a history of slope movement located above steep convergent slopes feeding onto currently unstable areas. Ground disturbance should be avoided, especially along drainage lines, to prevent adding water to slopes below.

1. Mitigation above an unstable or inner gorge slope – aka area of influence
For those areas upland of the inner gorge, if soils are unusually thin, scattered leave trees may be
warranted upland of the stream-adjacent slopes. Depending on the potential for delivery, if a
steep convergent area upland of the stream-adjacent slope shows evidence of poorly drained soils
or previous slope movement or is the topographic basin above a currently unstable, high delivery
potential slope, consideration should be given to providing additional leave tree protection. In
some cases, scattered trees may be adequate. Avoid ground disturbance especially along the axis
of the convergent area which would feed water down onto the unstable area below.
S Zurenko
Inner gorge
Inner gorge
Steep convergent slope
above the inner gorge
Area of Influence