The last week of November 2012 brought three consecutive storms and plenty of rain to Napa County.
By Sunday, Dec. 2, property owners along Dry Creek just south of Hwy 29 noticed that a large tree, downed by the storms had fallen into the creek and a lot of woody debris, brought downstream by these first large storms of the season, had combined to pose a very real flood threat to the neighboring properties.
Ordinarily, flood district crews would work to dislodge and remove the tree and the debris to open the waterway.
This time, they did that, but also much more.
The results:
Before
After
Sat. Dec.1: Property owners noticed a large
California Black walnut tree had uprooted from
the stream bank and fallen into and across
the creek. By Sunday, Dec., 2, a large debris jam
had accumulated behind the tree, alarming
neighbors and potentially threatening property.
the property owner to evaluate the situation and
discuss strategies. First order of business:
Remove the debris jam.
Contractor Mark Dixon Engineering had been
staged at the Dry Creek Railroad Bridge, ready
to help if necessary during the storm.
Using an excavator, crews removed 93 cubic yards
of material that been clogging the waterway.
16 cubic yards was chipped and used onsite;
75 yards was hauled away.
Flood District staff knew that tree, however, was a
valuable ecological resource.
Monday morning, with the property owner's
permission, crews from Pacific Tree Care
pulled the tree from the waterway and laid it
down on the bank, roots facing upstream,
to help keep the bank stable and to provide
more natural "complexity" in the creek.
When the tree uprooted a large portion of the stream
bank was destabilized. To restore the bank and
streambed, the downed tree was positioned with
the rootwad facing upstream, the chipped flood debris
was spread along the top of bank, erosion control
fabric was installed along the bank, a willow mattress
was constructed at the toe of the stream bank, and
an assortment of native plants were installed to
stabilize the bank.
The project would not have been a restoration success without the willing cooperation and
support of the property owner. The Flood District considers downed trees (and their woody
debris) a highly valuable ecological resource to stream channels. The District works with
landowners to turn downed tree issue into habitat enhancement opportunities. In this
case the rootwad and 25 foot section of the main stem were preserved to protect
the streambank from future erosion and enhance instream habitat and
physical processes.