Piute Creek Restoration

Susanville, CA

Lassen Land and Trails Trust
Fall 2002

LLTT selected Hanford ARC to restore 1,200 feet of Piute Creek; the length of the creek in Memorial Park. Historically, the stream had been diverted to the perimeter of the land that is now a park to drain a wet meadow and floodplain. More recently, levees and sandbag berms were constructed to prevent flooding of the park. These actions channelized Piute Creek and eliminated the capacity of the stream for flood flows as well as fish habitat.

Designed by Phil Williams Associates, restoration of Piute Creek included reconstructing a set-back levee to create a 50 foot-wide flood plain, creation of a meandering channel with increased sinuosity, construction of a low flow channel with a sequence of riffles and pools, and installation of a series of soil bioengineering and fish habitat structures.

The stream required dewatering throughout construction. This included a 1,600 foot-long active bypass. Due to flow increases, we used two pumps, beginning with a 4” and ending with a 6” noise attenuated diesel pump. In addition, several trash pumps were used regularly to dewater key trenches and the channel grading areas.

The channel and floodplain grading required construction of detailed features and flexibility for field design by PWA. During demolition, the stream bed gravel was salvaged and stockpiled for placement in the new thalweg. The low-flow channel, pools, riffles, short slopes, various sized floodplain benches and existing trees (to remain) all required careful maneuvering and skilled operation of the heavy equipment by Hanford ARC operators.

The fish habitat and channel stabilization structures included four log/boulder weir structures, two log/boulder deflector structures, and a blow-down log complex on the floodplain bench. During demolition, Hanford ARC excavated the 24 mature trees, with the root wads in tact, for these structures. The log complexes included excavation of key trenches up to 10 feet deep, installation of the primary logs, installation of pin logs, backfill with a stone/soil mix, and placement of large boulders.

The soil bioengineering components to this project included a series of ten brush mattresses and 255 feet of vegetated soil lifts (in three sections). Both the brush mattresses and the soil lifts included either stone toe protection or coir log toe protection.In addition to the stream construction, Hanford ARC constructed a stormwater basin at the downstream end of the project to collect runoff from the park and release it to the stream channel through culverts with flap-gates.

The project required close coordination with the City of Susanville, the Regional Water Quality Control Board (Lahontan) and CDFG.