COMMISSION

that needs additional material (e.g., Rancho Road). Ideally, sediment that is removed from
basins is placed on trails and hills climbs within that sediment basin’s watershed.
In late July of 2015, Hollister Hills SVRA staff, with the help of other district heavy
equipment operators, completed both a large-scale road maintenance project and lake
clean out. Rancho Road, one of the oldest roads in the park, was deeply incised, roughly
eight feet in some sections, and would fail to adequately shed runoff during storm events.
Down cutting of the road’s tread occurred over several decades due to the original road
alignment and geologic setting. The San Andreas Fault, which runs almost directly beneath
and parallel to the road, juxtaposes two vastly different, yet erosive soil types. Due to the
close proximity to the fault, the original road cut was a hodgepodge of clay and sedimentary
soils.
In 2012, the annual trail assessment noted
that the road was at risk of noncompliance
with the 2008 Soil Conservation
Standard and Guidelines (Soil Standard)
because of the road’s inability to shed
water and the potential for continuous,
accelerated erosion. It was decided that
the most viable, least environmentally
Equipment operators moving sediment to project site
impactful option was to undertake a road
rehabilitation effort, and bring the road
back to grade using material from Lodge Lake, a sediment basin that drains Rancho Road.
Due to the ongoing drought, Lodge Lake, historically one of the largest bodies of water
in the park, completely dried up in 2014 and again in 2015. During the summer of 2014,
equipment operators from Hollister Hills SVRA took this opportunity to clean out the lake of
accumulated sediment and use it as the new roadbed for the rehabilitation of Rancho Road.
Equipment operators from San Andreas District,
Central Valley District, Twin Cities District, and
Monterey District moved roughly 10,000 cubic yards of
sediment to the project site. By the end of the project,
Rancho Road had been completely brought back
to grade, which greatly increased the stability and
sustainability of the road. New drainage features were
installed along the rehabilitated portions of the road
and the tread was outsloped to further promote storm
water drainage and reduce concentrated flows.
Rancho Road one year after rehabilitation
2017 Program Report 143