Frogs Leap Winery Riverbank Stabilization and Revegetation Project
Napa River
Saint Helena, California
Constructed in 1997, this project is located along the Napa River on the Frogs Leap Winery Galleron Vineyard. A 25 foot tall eroding streambank was threatening a vineyard road. The erosion was caused by a mid-channel gravel bar which was pushing the channel into the bank. The mid-channel bar was removed and the material from the bar was used to reshape the eroding bank. A live willow brush mattress was constructed on the new slope to stabilize and revegetate the actively eroding riverbank.
The 25 foot tall actively eroding riverbank.
The mid-channel gravel bar was pushing the channel into the riverbank.
The mid-channel gravel bar was bulldozed and the material was pushed up onto the riverbank to form a new slope.
The reshaped slope has had a toe trench cut at its base. The crew is preparing to pound in a line of live willow stakes. Dumped quarried boulders in foreground.
The crew has placed live willow cuttings along the slope with the cut ends of the willow stems in the toe trench. In this picture, the crew is tying the willow down to the stakes.
In the background the mattress is complete. The willow is tied down, boulders have been placed in the toe trench pinning the willow against the wet soil. A light layer of gravel has been placed over the entire completed section to increase rooting and prevent desiccation.
The first spring after an El Nino winter of heavy flooding. This area was under 12 to 15 feet of flood waters for extended periods all winter.
The live willow brush mattress has begun its rapid growth. This photograph was taken one year after construction.
The project 5 years after construction; looking upstream.
The project 5 years after construction; looking downstream.
Carpy-Connoly Vineyard Riverbank Stabilization and Revegetation Project
Napa River
Rutherford, California
This project was constructed along the Napa River on the Carpy-Connoly Vineyard. At this site, a section of riverbank just below the vineyard berm had slipped into the river during a winter storm. One of the challenges on this project was that the site was too wet to allow for heavy equipment access. A live woven willow wall was constructed by hand at the base of the slope to stabilize the eroding riverbank.
The project site just before construction.
The crew is driving live willow posts into the soil at the toe of the eroding riverbank.
Live branches are then woven between the posts.
The woven wall is complete, and live willow branches are laid against the bare bank.
Additional willow and other cut branches are packed between the woven wall and the live branches that lie against the bank.
The crew is passing rock hand to hand down to the wall where it will be hand placed to hold all the loose willow in place.
The photograph on the left is of the willow wall just after construction and the photograph on the right is the same structure one year after construction.
The project 3 years after construction.