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.

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By Ethan Casaday

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Saving some trees on the outboard edge of the road allowed for the construction of a meandering trail on a previously straight road. Leaving the larger trees required that some of the roadfill remain in place. At these locations the trail alignment curved out and ran adjacent to the tree. To obtain material to replace the remaining fill, additional material was excavated in the reach between the trees. At these locations, the trail alignment curved toward the inside of the road. The problem with leaving trees in the fill slope is that excavation around the trees may leave them vulnerable to windthrow or uprooting. Only one week after this project, a tree was uprooted, leaving an undesirable mound of fill material perched above Squashan Creek.

Postconstruction Evaluation

Site Preparation

Additional site preparation would have improved productivity of this project. In the road-removal area, a few large redwood logs were bucked up to allow the excavator to move. These logs needed to be cut into shorter sections because they were difficult to move. One redwood log took almost one hour to push down the slope and out of the way.

Historical and Cultural Resources

Evidence of old corduroy roads exists throughout Squashan Creek. These roads were used in early logging efforts to skid logs using a team of oxen or a steam donkey (mechanical cable winch). The equipment for this project traveled over a short section of a corduroy road to access the upper road-removal section. The operator limited damage to this resource by carefully walking over the section and not doing any recontouring. Old logging cable and an old piece from a bulldozer were the only other evidence of historical resources found at the site. These items were left intact to the side of the road-reconstruction site.

Verbal communications with a member of the Yurok tribe indicate that the mouth of Squashan Creek was the site of an old Native American village. This project did not affect the area indicated, and no Native American historical artifacts were found.

Production Costs and Rate

The total construction cost for this project was $22,131.22 (see Table 2). This value was used to calculate a total average production rate for the project of $6.95/yd.3 (see Figure 3). The best production rate was $2.69/yd.3 during the road-to-trail perched fill removal. Production rates for crossing removal for both sections was $9.41/yd.3 The excavator averaged 31 ft./hr. or 289 ft./day.

Table 2. Production Costs for Various Aspects of Miners Ridge Restoration Project
ActionHoursRateCost
Move-in and -out  $400
Excavator + Operator168$90$15,120.00
Intern Salary256.5$10.59$2,716.33
Overtime Salary80$15.88$1,270.40
Vehicle Reimbursement2,239 mi$0.31/mi$694.09
Sweco40$48.26$1,930.40
Total  $22,131.22

 

Figure 3. Production Rate Comparison Combined With Project Costs and Volumes

 

Park Staff

Two trail crewmembers were on-site to assist with the project implementation. The main function of the crew was to transport fuel to the equipment. The crew was also responsible for removing rebar and dismantling old bridges. This crew was not motivated to work efficiently or provide additional help on brush removal.

Excavation

The road-removal section had complete excavation of fill material from the road bench. The crossing at station 5+00 in the road-removal section needed additional excavation from the left streambank.

The road-to-trail conversion had good excavation of fill material; however, a few areas should have had additional excavation. Some of the fill material left in place was the result of an attempt to protect standing trees, but these areas may have been better treated by removing the trees to favor complete excavation. The stream crossings had complete excavation; however, at the crossing at station 13+00, the active channel should have been aligned closer toward the middle of the valley.

Recontouring

The road-removal section had a complete recontouring except where springs or seeps were present in the cutslope. A complete match was obtained, including behind redwood trees where fill had to be carried in from nearby areas.

The access road between the two sections needed additional recontouring and ripping out of the old trail tread. This work was done at a fast speed but with extremely poor quality for a short distance.

The road-to-trail conversion had nearly complete recontouring except at station 21+00. This station had a large overhanging cutslope that was difficult to fill, causing the contractor to avoid completing the prescription here. The inspector should have caught this error at the time; however, it slipped by unnoticed. This area could have been fully recontoured with an additional hour of work.

Organic Material

Production data from the road-removal portion show that areas where brush removal had already been completed by park hand crews had higher production rates than areas with no prior vegetation removal.

The removal of standing trees and the handling of woody material took over 50% of the contract time (see Figure 4). This project had a heavy brush cover before construction began, and the excavated fill material was composed of 25% large woody material. In the road-to-trail conversion, trees and brush were pushed down into the surrounding forest. The project would have been improved if the excavator had pulled some of the logs back up onto the recontoured slope and placed them just below the new trail bench. Small herbaceous vegetation growing on the cutslope was left in place and buried under the recontour.

Figure 4. Percentage of Time for Each
Construction Task
Percentage of Time for each construction task

Collateral Damage

The old-growth redwood trees are the most valuable natural resource in the project area. The contractor and operator were strongly encouraged by the project supervisor and the project inspector to protect redwood trees at all costs. At the start of the project, the operator clearly understood the need to protect these trees from collateral damage and proved to be exceptionally careful when working close to them. Very little damage occurred to the bark and roots.

During crossing excavations, two active stream channels did receive some collateral damage. Both crossings were located in the road-to-trail portion of the project. The crossing located at 13+00 required removal of logs and fill from an active channel, which released fine sediment into Squashan Creek. The crossing at 01+00 was composed of sand and gravel and did not contribute much sediment to the stream.

Equipment

Excavator at work
Here, the excavator removes an abandoned road stream crossing that was diverting runoff down a road to an unstable slope.

All three excavators used on this project were well sized and performed the job efficiently. The new equipment slightly outperformed the older Komatsu because of the hydraulic controls on newer machines. The new Komatsu performed at the lowest noise decibel, which is of importance when working in habitat for sensitive wildlife. The hydraulic thumb design on all three machines was slightly different. The new Komatsu had a cantilever design that allowed the greatest range of motion. The thumb on the John Deere had a range of motion that allowed it to strike the boom when in full open position. All three thumbs, however, allowed equipment to easily move and place woody material. The thumb can also be used to rake away material from the machine on an outswing.

The use of demonstration equipment provided an opportunity to see how various machines perform in difficult terrain. The demo equipment also saved the contractor money because he was able to use his machines on other jobs and did not have to pay for time on the new machines.

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Two problems did arise from the use of demo equipment. The first problem was that the salesperson made numerous visits to the site to talk to the operator, causing delays in production. The second was that the large delays were caused by the move-in and move-out time when exchanging machines. Also, as a money-saving attempt, the operator wanted to leave the equipment with an empty fuel tank at the end of its demo period. This required a difficult fueling schedule, which involved shuttling fuel cans at less than optimal times. It also forced that equipment to end a half-hour earlier than needed because no fuel was available when its tank unexpectedly was empty. Ending a half-hour early left an oversized berm at station 00+00 adjacent to a stream crossing, which then required numerous hours in the Sweco to reshape.

For fueling, a 4x4 vehicle with a truck-bed fuel tank would probably have been more efficient. A vehicle-mount tank could have brought fuel within 3,000 ft. of the work site during the first two weeks and directly to the equipment during the third and fourth week of construction. This would have limited the need for the two additional park employees to only two weeks on the job site. Next Page >

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