September-October 2000

Miners Ridge Road-to-Trail Restoration Project at Prairie Creek State Park

The Miners Ridge Road-to-Trail Restoration Project was implemented to improve a popular hiking trail and reduce erosion hazard in Prairie Creek State Park.

Article Tools

Create a Link to this Article

By Ethan Casaday

Comments

The Miners Ridge Road-to-Trail Restoration Project was implemented to improve the recreational and wilderness quality of the Squashan Creek basin. The purpose of the project was to improve the aesthetic quality and reduce the future maintenance of the Miners Ridge Trail in Prairie Creek State Park. The project involved recontouring an old road that was no longer needed as a result of a trail reroute. In addition, a road was converted into a trail using heavy equipment. The secondary purpose was to reestablish natural flow paths and geomorphic features that were disrupted by road construction prior to park ownership. A total of 2,600 ft. of road was removed, and an additional 2,600 ft. of road was converted into a narrow hiking trail. A contractor operated a 20-mt excavator for 167.5 hours over a four-week period. An estimated 4,285 yd.3 of standard roadfill and 420 yd.3 of fill from 12 stream crossings were removed. A Sweco Trail Bulldozer operated by a park employee provided compaction. Minimal damage occurred to surrounding forest and aquatic resources.

This report describes the project implementation phase and provides a postconstruction review to critically analyze the project. This report does not explain technical details of road rehabilitation; rather, it serves as a supplement to existing reports. For background information on the Squashan Creek basin, see the Summary Report for Squashan Creek Watershed Restoration Project, prepared by California State Parks in December 1997. For information on road-to-trail conversions including descriptive graphics, see Last Chance Powerline Road Restoration Project, prepared by California State Parks in April 1998. Additional information on failures and successes of road-to-trail conversions can be found in the Annadel State Park trail project review memorandum prepared by the North Coast Redwoods District. General information on road recontouring can be found in Preacher Gulch Landform Rehabilitation, prepared by California State Parks in March 1999, or the Watershed Restoration Manual, prepared by Redwood National Park in 1992.

Trail Description

The Miners Ridge Trail connects Elk Prairie with Gold Bluffs Beach campground on the coast. The trail is one of the most popular day-use and overnight hiking routes in Prairie Creek State Park. The route provides options for a loop trail connecting Fern Canyon, coastal dunes, and ancient redwood forests surrounding the park visitor center. The trail follows Squashan Creek from the beach through coastal Sitka spruce rainforest, then climbs gently through old-growth redwood forests to the ridge top separating Prairie Creek and the Pacific Ocean.

Prior to the reconstruction project, the trail followed an industrial logging road up Squashan Creek that was used for timber extraction before park ownership. The industrial logging road was sidecast construction placed adjacent to Squashan Creek and had exposed numerous springs and seeps that caused constant saturation of the road/trail tread. Humboldt-style stream crossings involving logs placed in the channel instead of in culverts existed along the alignment, causing erosion problems during winter storms. The trail then followed an old corduroy road constructed during the earliest phase of logging that crossed Squashan Creek numerous times and traversed a wetland area. The trail then followed an old mine access road that climbed steeply up through old-growth forest, crossing numerous springs, seeps, and minor drainages.

A trail reroute was constructed in late 1998 to circumvent the old mine road and the corduroy-road segment. The trail reroute was 5,000 ft. long. The heavy-equipment phase of the project described below removed the abandoned road segments by creating a full recontour to the natural slope. The most important aspect of the project was to reconstruct the lower road segment into a narrow, reduced-maintenance, curvilinear, and geomorphically stable trail.

Survey Stations

On the road segments to be removed or reconstructed, distance stations made of 24-in. redwood stakes painted white were placed every 100 ft. Stakes were placed at the top of the existing road cut, and pink flagging was hung from nearby vegetation. The project was divided into an upper and lower segment to delineate the road removal from the road-to-trail conversion. The survey of the lower road-to-trail segment began at 00+00 adjacent to the uppermost Sand Filter Water Tank used for purification of the campground water supply and ended at 26+00 at the beginning of the trail reroute. The upper road-removal segment began at 00+00 adjacent to Squashan Creek where the road begins the climb up the eastern slope and ended at 26+00 at the upper end of the trail reroute.

Volume Survey

Volume surveys were conducted using standard methods described in the Redwood National Park Watershed Restoration Manual 1992. Road prism measurements were taken at obvious changes in the road profile and used to estimate perched volume per linear foot (see Figure 1).

Figure 1. Fill Volume Estimates for Miners Ridge

Measurements included road bench-fill length, fill-slope length, and fill-slope angle. This information was not used for contract payments or sediment-reduction measurements. The volume estimate for this project is used for analysis of production rates for equipment-operator comparisons and will be used in the preparation of future contracts.

The volume survey for this project was difficult to implement because of the very thick vegetation cover on fill slopes and surrounding hillsides. Estimating the length of the fill slope was difficult because it was often unclear where the fill met the natural hillside. In the upper road segment, numerous old-growth redwood trees made fill estimates difficult. During the excavation of fill material, numerous large logs were removed, which were not visible during the initial survey that altered the actual soil volume moved. Also, in the road-to-trail conversion, some large trees growing on the fill slope were left standing to create a curvilinear trail, which altered the actual volume of material available for recontouring.

Prescriptions

Prior to the heavy-equipment work, Project Supervisor Don Beers, Geology Supervisor Patrick Vaughan, Engineering Geologist Brian Merrill, and Environmental Resources Intern Ethan Casaday hiked the project distance and developed prescriptions. Casaday noted a list of prescriptions during the field visit (see Table 1). Some misunderstanding resulted from differing viewpoints; however, a consensus was obtained for each station during the walk-through.

Table 1. Restoration Prescriptions Developed by Park Staff During Project Planning
STATION #PRESCRIPTIONS
Road to Trail
00+00Construct berm to prevent high stream flows from entering maintenance roadway.
01+00Excavate fill from stream crossing and use for berm at 00+00.
02+00Remove half of road bench through flat area to construct road to a trail.
04+50Excavate fill from stream crossing.
09+00Spring at CDF parking area; do not fill around wet area; limited storage space here.
13+00Excavate fill and large logs from stream crossing; pull fill down road toward 12+50; the existing shape is good due to some past excavations here but stream needs to be exposed; scatter woody material on steep slope above 14+00; work from downstream end of excavation toward upstream.
14+00Pull 20 ft. of trail below road; outslope fill; use bulldozer to push open for traffic.
17+00Provide ditch relief before filling against cutslope; construct a full recontour.
19+00Wet area, do not fill adjacent to springs; construct broad swale to drain spring.
21+00Excavate stream crossing.
23+00Remove large stump on road if possible.
24+00Excavate swale crossing.
25+00Push stump up toward cutslope; review road approaching from the north.
26+00Completely block old road alignment; blend trail reroute with road-to-trail work.
Road Removal
03+00Remove 18-in.-dbh spruce trees in road fill; cut through large downed redwood logs.
04+00Wet area; eliminate flow diversion with a gentle outslope.
04+50Remove puncheon and logs from turnpike; teraform the small skid trail approaching from the south; do not fill around wet area.
05+00Excavate fill from double swale; move material up road toward 06+00.
13+50Recontour through-cut area using material pushed out on ridge to the west.
14+00Do not fill over the exposed clay lens in cutslope.
16+00Outslope but do not fill over wet cutslope; limit travel through wet area; ask contractor for advice regarding puncheon.
18+00Do not remove small ferns growing on cutslope.
18+50Move wood bench to safe location using tow strap.
22+50Excavate small swale; do not fill wet area on cutslope; feather out slope breaks; go for a full recontour at all locations; protect old-growth redwoods at all cost.
24+50Use extreme caution excavating around old-growth redwoods to avoid causing root damage; place organic material on surface of recontour.
26+00Location of trail reroute at upper junction; excavate a drainage ditch from wet area to natural swale; pile material on closed road to block view of old alignment.

 

Contract Implementation

The contract work for this project was implemented between September 21 and October 14, 1999. From October 18 to October 21, 1999, state park personnel conducted additional heavy-equipment work. Because of environmental concerns regarding nesting of endangered wildlife, equipment work was scheduled to begin after September 15.

Operators and Equipment

The contractor for the implementation of the rehabilitation prescriptions was Steve Hemmingson Construction of Crescent City, CA. The equipment operator was Zeph Skeen of Hiochi, CA. Skeen has operated excavators, bulldozers, loaders, and other heavy equipment for over 20 years and has been involved in road-maintenance and road-removal contract work for state parks in the past.

The equipment used included an older Komatsu excavator, a new John Deere 200LC excavator, and a new Komatsu PC200LC excavator. The older Komatsu, owned by Hemmingson, was used only for the first two days, including the initial brush removal and construction of the ditch relief structure.

Advertisement

Equipment Move-In and Move-Out

The equipment move-in consisted of walking the two demo excavators from the construction site at the Redwood National Park mill decks, adjacent to the old Davidson Ranch, to the Gold Bluffs Beach campground. The 4-mi. move-in was required because of the narrow switchbacks on the Gold Bluffs Beach access road that were difficult in a standard low-bed transport vehicle. This part of the walk-in took three hours in the excavators. From the campground, the excavators walked 2 mi. up the Miners Ridge Road to the starting point of the road-removal project located at station 26+00. Next Page >

What Do You Think?

Post a Comment

Be the first to tell us what you think!

Post a Comment

Not a subscriber? Sign Up
 
 
*  
 




 

Get Erosion Control E-mail Updates!

Get weekly news and updates through our Erosion Control e-mail newsletter!