COMMISSION

in-house as a means to more adequately capture useful data about trail conditions and
sustainability while reducing subjectivity and increasing objectivity. The matrix assesses
trails based on characteristics of design sustainability and tread condition. Within those two
categories, multiple subcategories were developed that better capture what park resource
managers want to know.
The tread condition category contains subcategories
such as whoops/break bumps, ruts and rills, compaction,
etc. Generally, trails are traversed in a side-by-side
while the assessor takes note of various tread and
sustainability related issues on the trail using the Trail
Rating Matrix Field Sheet. Data is entered into the Trail
Rating Matrix and an overall rating score is provided.
Each subcategory carries a specific weight determined
by the resource managers. Category weights are based
upon how much impact certain features have on a trail.
For example, whoops on a trail are far less impactful
than having sections of trail that are incised. Sections
of trail that are incised cannot shed water, and thus
continue to worsen over time. The results of the trail
assessment are combined into an annual report that
ROV trail at Hollister Hills SVRA
is used to inform managers of the overall condition of the trail system in the park, and are
used to prioritize the annual maintenance plan.
A mutually advantageous partnership has arisen out of the Annual Trail Assessment work
completed at Hollister Hills SVRA. The park contracts with CSU Monterey Bay to perform
water quality analysis for suspended sediment in Bird Creek, the creek that drains about
two-thirds of the park. An additional component of the contract is to have CSU Monterey
Bay graduate students undertake trail erosion surveys. Using aerial photogrammetry, a
large swath of trail is surveyed. The image is used to generate raster models, which are
subtracted from year to year to get an overall net change in the tread. These models are
used to determine the amount of soil erosion or the amount of soil aggradation at a particular
site. The data is used to verify and adjust the rating scale of the Trail Rating Matrix.
Water Quality Monitoring Program
Over the last five years, Hollister Hills SVRA collaborated with faculty and students from
CSU Monterey Bay’s Division of Science and Environmental Policy to establish a Water
Quality Monitoring Program at the SVRA. This monitoring program measured the amount
of sediment coming in to and out of the SVRA’s boundaries and attempted to parse
out sediment sources and their locations of input. This program was accomplished by
2017 Program Report 97