RIPARIAN RESTORATION RESEARCH PROJECT
WINTER 2012
CONTEMPORARY PLANT TECHNOLOGIES Comparison Matrix
TREE ROOT WAD direction of river flow
rip rap
logs parallel to bank for stabilization
root wad
rip rap
Root wads are an excellent reuse of fallen trees within the restoration zone or from construction sites nearby. Although they require heavy machinery and labour most likely conducted by a contractor, they are the most successful in stablizing toes of riparian slopes. Installation of root wads is a relatively quick way to provide bank stability.
Over
time, sediment accumulates within the root fans and helps create bank structure to eroding slopes as well as provide aquatic habitat.
Ideal root wads should be at
least 10 feet long (with tree canopy removed) with optimal root fans of 5 to 6 feet in diameter. The roots are usually planted in a linear series of multiple trees in a manner that undulates with the natural curvature of the watercourse. By doing so this increases the chances of capturing higher amounts of sediment. Combining this simple technique with others such as vegetative matting and brush layering duals as a riparian
yes
vegetative tool as well.
no somewhat
FASCINES
live stakes
live fascine
vegetative matting
Fascines are bundles of dormant branches bound together to create a log-like structure that roots itself into the slope. The bundle is primarily used to revegetate although it has some stabilization characteristics. These linear structures that follow a slopes contour are commonly used as a transition between other riparian revegetative techniques like brush matting and live siltation. Another revegetative use is that the coarse structure captures wind blown seeds providing habitat for their growth. Bundles of dormant willow branches 3 to 4 feet long and 8 inches in diameter are easily created, requiring little skill and/or heavy equipment. Once a sizable amount of bundles have been constructed they are dug into trenches perpendicular to the slope and only burried approximately 3 to 4 inches into the ground. Fascine rows are secured by wooden stakes although these may be substituted for dormant willows or cottonwood speices. Multiple rows can be installed giving the slope a terraced quality.
root wad