This property was experiencing these higher flows in more intense flash flow events. Worse erosion was occurring each year within the creek. The channel had already been obviously tampered with by human hands, evidenced by concrete vertical channel walls, and a decomposing concrete bottom. The channel had reached bedrock where there was no concrete, and some steep cuts were forming along the channel walls, inching closer to the adjacent home structure year after year.
A couple years prior to this creek work, we removed invasive ivy, holly, blackberry, cherry laurel, and elm from the upper slopes. Then we armored the exposed soil with a coco-coir erosion control netting, branches and logs laid in woven lattice with an “on-contour” emphasis, and a thick layer of wood chips, setting the stage for the home owner to plant many Many MANY(!) fantastic native plants. But the creek still needed more attention…
So in the beginning of last winter we finally got in there! We created a series of complex woven beaver dam analogue structures within the creek, utilizing a spectrum of sticks to stumps. We armored the cut sidewalls with small stones and sticks, meshed together with branch stakes pounded into the walls. We used large logs and branches across the flow of the water, and secured these wooden elements with lag screws to ensure nothing floated away causing damage down stream. We recycled Christmas trees by shoving them into the gaps between larger branches, and secured other critical locations vulnerable to erosion with stones and small boulders. We aligned some smaller stones in the straight-aways into small one-rock-dam structures.
The result might be hard to see if you don’t know what to look for. The structures blend in, and look as if trees have simply fallen into the creek and settled themselves in log jams. The water flows more slowly now, through a series of pools with a spectrum of depths, facilitating better habitat for aquatic life. The water falls from the dams, aerating the structuring the water. The falls are armored with stone so as to avoid the cutting force of the flows.
The flooding through the rest of the season was tempered. The velocity of the flow was lower, the erosive destruction mitigated. Sediment began to accumulate within the pools immediately, and we are seeing the healthy shape of a meandering creek form atop the surface of an eroded and channelized wound. Native Wapato we planted is already established in this new sediment accumulation, and the native plant garden in the slopes above is poised to secure these new soils with their eager roots.
These types of structures will always need touch-ups, edits, and a vigilant observant eye, but if managed with care they will yield obvious and invisible benefits for many years to come.
Water is life, and we love life!
OR LCB #9872; WA# Earthel843J2
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