Mill Creek Watershed Rehabilitation Project
Saving streams by decommissioning abandoned logging roads.
Located 45 miles south of Eureka, CA, Humboldt Redwoods State Park is California's largest redwood state park. This article describes work completed in the park's Mill Creek Watershed Rehabilitation Project during the summers of 2001 and 2002 by the North Coast Redwoods District (NCRD) Roads, Trails, and Resources Maintenance section. The project involved the removal of 20.4 miles of abandoned logging skid and haul roads. The 2001 work was located on the east side of the Mill Creek Watershed and the 2002 work on the west slopes. The project was located within the Bull Creek Watershed, a tributary to the South Fork Eel River.
The California State Parks (CSP) Natural Heritage Program and the California Department of Fish and Game (CDFG) Coastal Salmon Recovery Program jointly funded the Mill Creek Watershed Rehabilitation Project. In May 1999, the NCRD submitted a grant application to the CDFG requesting $27,200 in matching funds to help complete work on the eastern slopes. These funds were granted to NCRD and expended during the summer of 2001. In May 2002, DFG announced additional funding for Mill Creek totaling over $300,000 to implement work on the western slopes. These funds were expended in 2002. The project was selected for CDFG funding due to the fact that sediment reduction is a primary factor affecting salmonid recovery in the Bull Creek Watershed. The Roads, Trails, and Resources section, under the supervision of Maintenance Chief Don Beers, implemented the project.
The 2001 road removal required 480 excavator hours and 480 dozer hours over a 13-week period. General engineering contractor Wendt Construction of Fortuna, CA, performed the year 2001 work using an excavator and bulldozer. An estimated 53,387 cubic yards of material were recontoured, including 32,757 cubic yards of forest road fill, 2,350 cubic yards of prairie road fill, 1,150 cubic yards of landing fill, and 17,130 cubic yards of fill from 41 stream crossings on 8.1 miles. The average production rate for the road removal project was $2.74 per cubic yard. The project cost for 2001 was $189,500.
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| Starting in foreground, a forest road constructed using a cut-and-fill approach. |
The 2002 construction phase required approximately 1,000 excavator hours and 1,000 dozer hours over a 15-week period. Wendt Construction performed the year 2002 work using two excavators and two bulldozers, complemented by a CSP excavator and bulldozer for a portion of the work. An estimated 98,722 cubic yards of material were recontoured, including 17,089 cubic yards of road fill and 8,390 cubic yards of fill from 94 stream crossings on 12.3 miles of roads. An additional 4,130 cubic yards of material were prevented from entering streams in the Connick Cut-Block with funding from this project. The average project production rate for 2002 was $3.30 per cubic yard of sediment saved, and the implementation rate was $2.76 per cubic yard. The project cost for 2002 was approximately $325,772.
Setting
Erosion and Sediment Problems
The most severe problem on the eastern slopes involved a stream diversion that contributed flow into an active landslide measuring 150 feet wide, 500 feet long, and 50 feet deep. The diverted flows were actively expanding this landslide. Another major problem was a large gully traversing a hill slope for 800 feet, caused by the active diversion of five small stream crossings. The gully formed in the inside ditch of a road that was constructed with no drainage structures. The gully ended at Bull Creek, where it was actively contributing tons of sediment directly into the stream during each major runoff event. A third major problem was a road adjacent to Mill Creek that had four active diversions at each stream crossing. Each diversion created a gully ranging from 2 by 2 by 100 feet to a gully 6 by 8 by 250 feet down the road, each of which eventually cut across the road and dropped downslope to end in the Mill Creek channel. Numerous additional smaller gullies, rills, and slope failures—directly or indirectly related to roads—also existed within the project area.
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| A bulldozer shapes the recontoured slopes, and an excavator spreads mulch. |
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| The stream-crossing fill has been removed and the slope mulched. |
The most severe problem on the western slopes involved three stream diversions on a single traversing road that caused a large gully down the road, which then contributed flow into an active landslide measuring 120 feet wide, 400 feet long, and 40 feet deep. The diverted flows were actively expanding this landslide and causing continued failure into Mill Creek. Another major problem on the western slope was a diversion caused by a small skid trail, which caused a large gully descending 300 feet down a ridge-top road before cutting downslope 400 feet to a small tributary channel. A third problem was runoff concentrations on a traversing road that had no drainage for more than 1,000 feet before cutting downslope in a large gully. Numerous other stream channel diversions were also present on the western slopes that were causing active gully erosion and landslide activity.
Background
Mill Creek has experienced severe erosion problems on the upland slopes since logging and road building were conducted in the 1940s through the 1960s. Fill-slope failures, stream-crossing diversions, and runoff concentrations along the old logging roads are typical causes of the problems that contribute sediment directly to Mill Creek. Since CSP acquired the property, many of the roads have developed a cover of vegetation. However, serious and persistent erosion problems still exist on many of the roads, and most of the stream crossings have a high risk of failure.
A sediment-source road inventory was conducted in April and May 2000 on the east side of the Mill Creek Watershed as part of a larger effort to analyze problems throughout Humboldt Redwoods State Park. During the winter of 2001, the road inventory was continued in the western portion of the watershed. The assessments identified road-related sediment sources contributing material directly into stream channels. The assessments documented current erosion problems including active stream diversions, as well as potential future problems such as stream-crossing failures and road-related landslides. The road problems in the watershed included numerous in-board ditch and road tread diversions that intercepted and diverted runoff via gullies to unstable slopes and inner-gorge areas.
Objective
The objective was to decommission abandoned logging roads that delivered or had the potential to deliver sediment to streams. CSP watershed rehabilitation goals call for decommissioning of abandoned roads that are causing accelerated sediment delivery or have the potential to accelerate sediment delivery to the drainage network in the Bull Creek Watershed. Because CSP management goals do not include reentry for future resource extraction or similar purposes, rehabilitation projects are single-entry, and all erosion sites are treated in areas entered by heavy equipment.
The work involved using heavy equipment to retrieve fill from the outboard edge of the road and place it against the cut slope to achieve a full recontour on the former road surface. Stream crossings were fully excavated and fill material was exported away from the stream onto stable upland road sections. Heavy equipment used on the project consisted of three excavators and three bulldozers. The dozers pushed fill into the cutbank, shaped it, and compacted it. The excavators were used to retrieve fill from outboard and downslope areas and to remove fill from the stream channels at crossing sites.
CSP geology staff have developed effective decommissioning techniques using a combination of technologies developed by Pacific Watershed Associates, Redwood National Park, the US Department of Agriculture Forest Service, the Natural Resources Conservation Service, the Redwood Community Action Agency, and others involved in road rehabilitation. All operations are conducted as described in the NCRD's Best Management Practices and Field Techniques for Forest and Range Road Removal.
Project Planning
Geomorphic Mapping
Aerial photos taken in 1963 were scanned at high resolution and stored on recordable CDs as JPEG images. The images were then spatially rectified using ArcView extensions that allow points on the photo to be manually assigned to points on a topographic map with known geographic coordinates. These rectified air photos were then enlarged and printed on 16- by 23-inch photo-quality inkjet paper. Twelve enlargements were produced to cover the entire project area. The enlargements were then laminated to make them waterproof and attached to thin plywood to create "map boards" with a Mylar sheet covering. The boards could be carried into the field, and geomorphic features could be directly drawn onto the Mylar coating.
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| Removing a failed stream crossing in Redwoods State Park. |
Geomorphic mapping of the project area took place beginning February 2000 on the eastern slopes and February 2001 on the western slopes. Environmental Resources Interns Sarah Balster, Erik Rogers, and I conducted the geomorphic mapping and road inventory. Geomorphic information observed in the field was mapped onto the map boards using a standard set of mapping symbols. Field staff followed protocols detailed in the Geomorphic Assessment and Mapping—California State Parks, Watershed Rehabilitation Technical Memorandum Series. The mapping resulted in identification of 8.1 miles of roads on the eastern slopes and 8.6 miles on the western slopes with high erosion hazard and related problems such as gulling and landsliding. Fill-slope failures, swale diversions, and runoff concentrations on these abandoned logging roads were contributing sediment directly into Mill Creek. Road segments were digitized onto the base map and other features of the landscape were added as separate layers, including landslides, streams, and gullies. A final map was prepared and used as the construction specification.
Prescriptions
All roads with 1 cubic yard per linear foot or more of fill material were selected for removal. Other roads were selected for removal if they had any significant erosion problems or potential for problems—regardless of their fill volume. Some roads with very low road-fill volume were also selected for removal because of active stream diversions. The prescriptions were entered into the geographical information system database developed for the project. The prescriptions included written construction specifications for all sites having special concerns outside of the typical best management practices for road treatments.
Before the heavy-equipment work began, engineering geologist Brian R. Merrill, R.G.; engineering geologist Patrick Vaughan, C.E.G.; senior resource ecologist Jay Harris; and the environmental resources interns hiked the project distance and reviewed the prescriptions.
Volume Survey
Road prism measurements were taken at obvious changes in the road profile and used to estimate volume per linear foot. Measurements included road-bench fill length, fill-slope length, and fill-slope angle. This information was not used for contract payments or for sediment reduction measurements. The volume estimate for this project was used for preparation of grant applications, and analysis of production rates for equipment operator comparisons and in the preparation of future contracts. All of the roads in this area were of similar size and for the most part separated out into 0.5 cubic yard per linear foot, 1 cubic yard per linear foot, 1.5 cubic yards per linear foot, and 2.0 cubic yards per linear foot. Roads with large gullies descending down the road length had a road-fill volume much less than the actual amount of material moved to achieve out-sloping. In these cases more than 3 cubic yards of material were moved per linear foot.
Crossing volumes were calculated using an end-area formula, which entails delineating triangular sections along both the upstream and downstream ends of the fill prism and averaging their volumes to reveal the feature's total volume along the entire length.
Environmental Analysis
Plants.Before the environmental documents were prepared, the project area was surveyed for threatened and endangered species using California Native Plant Society (CNPS) protocol. Humboldt State University (HSU) staff botanists—guided by Sarah Balster—surveyed the entire area for threatened and endangered plants. Three species of uncommon plants on List 4 of the CNPS Inventory of Rare and Endangered Plants of California were encountered. List 4 of the CNPS inventory is a watch list of limited-distribution plants. These species are not considered threatened and no mitigation was necessary. Piperia candida (white-flowered rein orchid), Listera cordata (heart-leaved twayblade), and Pityopus californicus (California pinefoot) were identified within the Mill Creek Watershed.
Amphibians. The roads on the eastern slopes were surveyed for the presence of potential amphibian habitat. No populations of federally or state-listed threatened or endangered species were identified in the eastern portion of the project. Potential habitat was flagged and mapped by Balster and HSU staff biologist Don Ashton. The consultant-trained CSP staff provided a field amphibian identification card including color images and key features used to identify amphibians. During a field consultation, the consultant reiterated his previous biological opinion that road removal projects would have an overall benefit to amphibians by increasing potential habitat. Roads on the western portion of the project were not surveyed for amphibians based on the results of the surveys from the eastern areas.
Cultural Review. Historical and cultural review as required by the California Public Resources Code (PRC) section 5024 was included in the California Environmental Quality Act (CEQA) process. NCRD archeologist Karin Anderson reviewed the project evaluation and negative declaration for the 2001 work. The Center for Indian Community Development at HSU conducted field investigations, which included walking all roads proposed for removal. Archeologists Jamie Roscoe and numerous assistants examined the entire project area and mapped significant resources. No significant historical and cultural sites were located in areas where road removal operations were to occur. Some significant objects were located and construction was conducted to avoid disturbance to these objects. The 2002 cultural survey was described in a report titled "A Cultural Resource Investigation of the Humboldt Redwoods State Park Road Reengineering Project."
CEQA. The NCRD was the lead agency for this project and prepared documents required by CEQA. Because funding for the western portion was unknown at the time of the first CEQA analysis, the project was included in two separate CEQA reviews. The first CEQA document for the project was initiated in November 2000 with the preparation of a Project Evaluation/Initial Study. The first negative declaration was filed at the State Clearinghouse on April 10, 2001. Following public review of the negative declaration a notice of determination was issued that the project would not have a negative effect on the environment.
On February 21, 2002, a second initial study was sent to the CEQA coordinator. A negative declaration was prepared and a notice of determination was signed on June 21, 2002.
Construction Implementation
The contract work for the east side of the watershed was implemented between July 16 and October 10, 2001. The contract work for the west side of the watershed was implemented between July 15 and October 30, 2002. Heavy-equipment work took place Monday through Thursday from 6:00 a.m. to 5:30 p.m.
In 2001 the CDFG funded stream-crossing removal and road-bench decommissioning on the main road up the east side of the Mill Creek Watershed known as Big Madrone Road. Two spur roads used to access the upper portion of Big Madrone Road, which had been cut off by a massive landslide following logging, were also treated with CDFG funds. Additional CSP funds were used to construct a full recontour on Big Madrone Road and all remaining roads.
In 2002, the CDFG funded stream-crossing removal and road-bench decommissioning on all roads in the western watershed that were identified for removal in the road inventory and in the SB271 grant/contract. Additional CSP funds were used to supplement the project budget to allow for construction of a full recontour at all sites. Additional CSP funds were necessary to do full recontouring because the CDFG does not typically fund full recontouring.
Park Staff
Merrill, Balster, Rogers, and I were responsible for the construction oversight and implementation. Roads, Trails, and Resources crew members were at the project site to repair trails and monitor equipment while regular inspectors were absent. CDF fire crews were also onsite to assist with trail repairs.
Operators and Equipment
Equipment used by Wendt Construction during the 2001 season included a John Deere 790 excavator and a John Deere 650 dozer. The equipment utilized during the 2002 season included a John Deere 790 excavator, a John Deere 690 excavator, and two John Deere 650 dozers. During the last week of the project in 2002 Wendt's 650 dozer broke down and was replaced with another 650. Use of this equipment was funded by the CDFG.
During the 2002 season, park operators were onsite using a John Deere 750 excavator and a John Deere 750 dozer. The park operators, Brian Hall and Glyne Johnson, were funded by State Parks NCRD Roads and Trails.
Equipment Move-In and Move-Out
The equipment move-in during the 2001 season consisted of walking the two pieces of equipment from Mattole Road to the project site. The walk-in took half an hour on the Hamilton Barn Environmental Camp access road.
During the 2002 season, equipment was walked into the Hamilton Barn parking area where the treatment roads began. For four days, the first crew removed brush and opened roads before beginning recontouring in the upper watershed. Move-in for the second crew involved walking in on Hamilton Barn Road and then walking 1 mile up the newly opened roads to a spur road where they began recontouring. During the final two weeks of the 2002 season, one equipment crew was moved to the Connick Cut-Block area to implement road removal and reengineering. Move-in to Connick required eight hours of dozer time and 10 hours of excavator time.
Road Removal
Decommissioning work requires a crew of one excavator and one bulldozer working in tandem. During the first half of the 2001 season, one crew was involved in the road removal work. The last four weeks of the construction had two crews working a few miles apart. During the 2002 season, two crews worked in the watershed for the majority of the time and three crews were present during the middle of the project.
Stream-Crossing Removal
Stream-crossing removal typically began with the dozer cutting into the upper surface of the crossing and pushing it out to adjacent stable road sections. The dozer continued to dish out the crossing until it could no longer achieve a suitable pushing angle. Once the dozer had completed its work, the excavator recovered the remaining fill material, culverts, logs, etc., from the stream channel and fed fill to the dozer. The dozer pushed the material away from the crossing, compacted it, and shaped it along adjacent road sections. Stream crossings were excavated to original width, depth, and slope to expose natural channel armor. The excavation of stream crossings involved locating buried stumps, boulders, logs, and black, organic-rich soil as indicators of the location of the natural stream channel. Sideslopes generally matched original contours above and below the road. Additional logs were placed against the upper banks of stream crossings to prevent soil detachment from overland flow. Material excavated from streams and other watercourses was moved to stable locations along adjacent road sections. Occasionally, excavated material needed to be pushed or transported to more distant locations if no stable sites were located near the crossing.
Road Recontouring
Treatment of roads and skid trails began with removal of organics from the in-board ditch and ripping of the road cut-bench. The dozer then cut outboard fill and pushed into the cutbank in lifts, compacting it with each pass. When the dozer finished, the excavator completed the recovery of unstable fill and placed it in the cutbank where the dozer completed the shaping. During the 2001 and 2002 seasons, a full recontour to the natural slope was obtained along 95% of the road removal length.
Export Outslope
Where groundwater was present, recovered fill was not placed into the cutbank as it is typically done. Instead, fill was exported to a stable location away from the unsuitable site. Export outslope was also used where mass wasting was present or suspected. At those sites, fill was exported to avoid loading the unstable feature.
Mulch
Organic material was separated from the fill and placed as mulch on the recontoured surface to protect against raindrop splash and sheet erosion. Logs and large pieces of organic material were placed on the slope surface and tamped down to provide contact with the soil surface. In numerous crossings organic material was placed on the final surface to obtain 100% coverage and was up to 3 feet thick. No straw mulches were used at this project because of the potential to introduce non-native species and pathogens to the backcountry areas.
Post-Construction Analysis
Brush Removal
The most efficient method for brush removal appears to be piloting the road with a dozer and then sending in the excavator to remove additional material and stack it in piles to the edge of the road. The contract operators preferred to leave as many trees standing as possible during initial brushing, pushing them over when ready to use them as mulch. The park operator preferred to remove as much organic material as possible during the initial entry, making piles of material upslope from the road at intervals along the road. The park operator's technique is the preferred method and is specified in contracts. Future projects would benefit greatly by enforcement of the contract specifications requiring brush to be placed upslope from roads.
Organic Material
Five different people operated the excavator during this project and each had a different approach to spreading organic material. Some operators tended to spread organics randomly, sometimes leaving material bunched together with areas of non-mulched soil in between piles. Operators were asked on numerous occasions to spread organic material more evenly across the surface. One operator appeared to have difficulty handling organic material. He dropped material from the bucket numerous times before moving it to the desired location; this may have been due to the bucket/thumb configuration. He caused damage to the machine on a weekly basis from organic material. Other operators were good at spreading mulch and breaking larger pieces.
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. No old-growth trees were damaged during this project; however, some larger trees between 12 and 20 inches' diameter at breast height did sustain damage to the bark. Damaged bark may not be bad ecologically because it adds diversity and can lead to hollows that are similar to burned-out trees in a mature forest. Damage mainly occurred to tree bark when the excavator was limbing the branches off trees that were within the swing radius of the machines, and in attempting to recover woody material that had been pushed downslope during the initial brushing phase. This is another reason why brush generated during initial entry should be placed upslope in piles.
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| Road before removal with capture of groundwater in the inboard ditch. |
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| The same road after removal with restored groundwater hydrology. |
During the 2001 construction season, all but two stream crossings were dry and remained dry into November. This eliminated resource damage to streams due to turbidity. In the crossings that had stream flow, a 300-foot plastic pipe was used to divert flow around the construction site. The diversions took approximately one hour to install using bags filled with dirt to temporarily dam the stream. The diversion pipe forced the dozer to push in one direction at a time, rather than the usual dishing-out technique. It was difficult to move the pipe to the opposite side of the excavation as work progressed because the pipe was cumbersome and heavy.
Only one stream had flowing water during the 2002 construction season, at a crossing that had already completely failed. The crossing was located on a road that was used to access a large portion of the project. Instead of placing a temporary culvert and using fill to cover the pipe to provide access, onsite materials were used to create a drivable surface to cross over the channel. The excavator placed numerous small logs and brush into the active channel to protect the bed and banks. The dozer then ran back and forth across the woody material to pack it down and create a drivable surface. Because no excavations were planned for the crossing because it had already completely failed, it was desirable to avoid rebuilding the crossing with fill material. Using the brush allowed for access without placing any fill into the channel. And during the removal phase, the excavator simply removed the brush and small trees and placed them on the banks as mulch.
Equipment
During the 2001 season, equipment downtime was 28 hours on the excavator and eight hours on the dozer. The downtime on the dozer was due to a leak in a hydraulic hose that caused early shutdown, and later in the season, downtime was due to a broken drive plate. During the hottest week mid-project, the dozer overheated every few hours, forcing 10-minute delays to allow for cooling. The inspector requested a replacement machine after two days of constant overheating, and a newer dozer was brought out that weekend. Downtime on the excavator was due to numerous hydraulic hose breaks, and later in the season a failed hydraulic pump. During the last few weeks of the project, the excavator had to be replaced with a different machine because hoses were rupturing almost daily. The excavator also overheated and needed water added to the radiator two to four times each day, causing brief delays in production.
During the 2002 season, equipment downtime was over 40 hours on the excavators and approximately 16 hours on the dozer. Downtime occurred on equipment at least once a week. Downtime was not included in payments to the contractor; however, it causes inefficiency in production rate. When downtime occurs, in many cases both machines must stop work until a repair can be made. Also, the park inspector continues to be paid during the day while waiting for repairs. Downtime was high on this project due to the thick trees and brush growing at the site, and due to old, poorly maintained equipment.
Operators
Five equipment operators were involved with the 2001 work, and eight equipment operators worked during 2002. All operators conducted themselves as professionals and demonstrated a high level of skill in operating heavy equipment. Equipment operators reacted quickly to avoid hydraulic oil leaks to the environment by shutting down immediately and by utilizing spill kits when the equipment was damaged.
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| Road before removal. |
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| Road after recontouring. |
Operator skill level varied greatly. On the dozer, some operators have higher standby time because they prefer to work closely with the other machine and will wait nearby as the other machine completes a task. Other operators do not like to sit idle at all and will move ahead and start the next phase of work while waiting for the second machine to complete a task. Some dozer operators prefer to back down the slope and make all the pushes up the slope into the cutbank. Others travel back and forth along the road in a series of U-turns to push material into the cutbank.
On the excavator, some operators masticate and place organic material efficiently, while others have a difficult time placing logs or brush and cause damage to the machine hoses, windows, and doors. Some of the operators can travel across steep slopes and work on sites that have been previously outsloped by the dozer, while others prefer to work on a level surface and spend extra time building a flat pad to work from.
Excavation
In past projects, stream crossings were under-excavated, leading to over-steepened slopes adjacent to watercourses. To avoid this, operators were regularly reminded of this past problem during project safety/progress meetings. Operators were asked how they could help ensure that crossings were not under-excavated during this project. In general, all crossing fill was placed 30 to 150 feet away from the channel. Cutbanks adjacent to crossings were not matched; rather, they were blended by laying them back to try to disguise the bank visually and to reduce the slope steepness. Also, the dozer finished dry crossings where possible, because this forced the operators to lay the banks back to a slope that the dozer could push out of. This also left much less loose material than on crossings finished by the excavator.
Park construction crews found that implementing full recontouring was only slightly more time-consuming than partial recontouring in areas where equipment is the maximum size that can work on a road segment. On this project, only a few of the roads had a large enough prism that could have used larger-size-class equipment. Most of the roads were narrow and located on steep slopes, and the excavator was large enough to access the entire cut-and-fill slope from one position. This makes full recontouring essentially the same cost as partial recontouring or decommissioning. From a cost-benefit perspective, partial recontouring has very little cost savings in these situations. Partial recontouring may be beneficial where the excavator cannot access the entire road prism or if fully recontoured slopes have a higher potential for post-treatment failure than partially recontoured slopes.
Full recontouring, however, may not always be the best treatment for a road located lower in the watershed. During a monitoring visit to the site in January 2003, it became clear that full recontouring could have some problems during high rainfall events in locations where runoff is high and groundwater is pumping out of the old cutslope. Lower Mill Creek Road suffered numerous failures of recontoured fill. The problem appeared to be related to surface and subsurface water movement that was not anticipated even during the inventory and planning conducted during the prior winter. In many locations along the lower portion of the road, surface runoff from small untreated skid roads concentrated and saturated sections of recontoured fill, causing the material to become a small mudflow—in one case entering a tributary channel. The majority of slip-outs did not contribute to streams. The problem is not related to over-steepened slopes; many steep recontoured slopes remained stable during high rainfall.
In the few cases where an inspector was not onsite during the excavation of a crossing, the sites were under-excavated, and the potential for post-construction stream channel adjustments was high. The general tendency for equipment operators, no matter how excellent their skill level, is to not remove enough material from a crossing. On the majority of sites, the inspector requested additional soil removal before mulching was allowed. By the end of the project, equipment operators developed the habit of asking for inspector approval of excavation depth prior to mulching.
Stream Alteration Permits
An application for a streambed alteration agreement (SAA) from the California Department of Fish and Game was submitted prior to the completion of the CEQA documents. An attempt was made during the planning process to obtain a memorandum of understanding (MOU) between the CDFG and CSP to allow for a more streamlined SAA process. An MOU would allow for considerable cost savings by avoiding the duplicated environmental review that both departments implement. Because of the efficiency in which the CDFG processes SAAs, this permit process is a minor factor in project planning and implementation. The process in this case, however, is a duplication of effort because of the extensive review conducted by CSP staff during the CEQA process.
Inspector
The inspector found that telling the operators what he wanted the final product to look like and asking the operators during a brief planning break what they planned to do obtained the best results. It is much better to stop briefly before the equipment gets to a crossing to discus the plan of attack than to just stand back and let them move onto the site and start working.
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Difficulties occurred during the project between some operators and an inspector. The problems occurred when the inspector made requests of the operator regarding actual methods of operating the machine. In one case the operator saw a very inefficient action being implemented by the excavator that was going to move the same dirt twice. The inspector could see a better place to position the machine where only one motion would be required; however, the operator resisted making the change. The inspector was informed that due to contracting procedure he could not make requests on operation of the machine, only on what the finished product should be.
Conclusion
The Mill Creek Watershed Rehabilitation Project was implemented to reduce erosion hazard in Humboldt Redwoods State Park. The project removed all roads with the potential to deliver sediment to streams in the Mill Creek Watershed. DFG Salmonid Restoration Federation grant funds from SB271 were used to remove stream-crossing fill and stabilize sites with direct influences on streams. CSP funds were used to perform full recontouring to completely remove all roads used to access the crossings. The project was implemented as designed with no accidents or deviations from specifications detailed in the Initial Study and Mitigated Negative Declaration prepared for the project. The continuous onsite presence of qualified project inspectors allows for efficient use of equipment and operators that results in high production rates. In the future, monitoring will be implemented on an annual basis to assist with adaptive management and to continually improve construction standards.
September-October 2005
Mill Creek Watershed Rehabilitation Project
Saving streams by decommissioning abandoned logging roads.
Located 45 miles south of Eureka, CA, Humboldt Redwoods State Park is California's largest redwood state park. This article describes work completed in the park's Mill Creek Watershed Rehabilitation Project during the summers of 2001 and 2002 by the North Coast Redwoods District (NCRD) Roads, Trails, and Resources Maintenance section. The project involved the removal of 20.4 miles of abandoned logging skid and haul roads. The 2001 work was located on the east side of the Mill Creek Watershed and the 2002 work on the west slopes. The project was located within the Bull Creek Watershed, a tributary to the South Fork Eel River.The California State Parks (CSP) Natural Heritage Program and the California Department of Fish and Game (CDFG) Coastal Salmon Recovery Program jointly funded the Mill Creek Watershed Rehabilitation Project. In May 1999, the NCRD submitted a grant application to the CDFG requesting $27,200 in matching funds to help complete work on the eastern slopes. These funds were granted to NCRD and expended during the summer of 2001. In May 2002, DFG announced additional funding for Mill Creek totaling over $300,000 to implement work on the western slopes. These funds were expended in 2002. The project was selected for CDFG funding due to the fact that sediment reduction is a primary factor affecting salmonid recovery in the Bull Creek Watershed. The Roads, Trails, and Resources section, under the supervision of Maintenance Chief Don Beers, implemented the project.
The 2001 road removal required 480 excavator hours and 480 dozer hours over a 13-week period. General engineering contractor Wendt Construction of Fortuna, CA, performed the year 2001 work using an excavator and bulldozer. An estimated 53,387 cubic yards of material were recontoured, including 32,757 cubic yards of forest road fill, 2,350 cubic yards of prairie road fill, 1,150 cubic yards of landing fill, and 17,130 cubic yards of fill from 41 stream crossings on 8.1 miles. The average production rate for the road removal project was $2.74 per cubic yard. The project cost for 2001 was $189,500.
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| Starting in foreground, a forest road constructed using a cut-and-fill approach. |
The 2002 construction phase required approximately 1,000 excavator hours and 1,000 dozer hours over a 15-week period. Wendt Construction performed the year 2002 work using two excavators and two bulldozers, complemented by a CSP excavator and bulldozer for a portion of the work. An estimated 98,722 cubic yards of material were recontoured, including 17,089 cubic yards of road fill and 8,390 cubic yards of fill from 94 stream crossings on 12.3 miles of roads. An additional 4,130 cubic yards of material were prevented from entering streams in the Connick Cut-Block with funding from this project. The average project production rate for 2002 was $3.30 per cubic yard of sediment saved, and the implementation rate was $2.76 per cubic yard. The project cost for 2002 was approximately $325,772.
Setting
Erosion and Sediment Problems
The most severe problem on the eastern slopes involved a stream diversion that contributed flow into an active landslide measuring 150 feet wide, 500 feet long, and 50 feet deep. The diverted flows were actively expanding this landslide. Another major problem was a large gully traversing a hill slope for 800 feet, caused by the active diversion of five small stream crossings. The gully formed in the inside ditch of a road that was constructed with no drainage structures. The gully ended at Bull Creek, where it was actively contributing tons of sediment directly into the stream during each major runoff event. A third major problem was a road adjacent to Mill Creek that had four active diversions at each stream crossing. Each diversion created a gully ranging from 2 by 2 by 100 feet to a gully 6 by 8 by 250 feet down the road, each of which eventually cut across the road and dropped downslope to end in the Mill Creek channel. Numerous additional smaller gullies, rills, and slope failures—directly or indirectly related to roads—also existed within the project area.
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| A bulldozer shapes the recontoured slopes, and an excavator spreads mulch. |
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| The stream-crossing fill has been removed and the slope mulched. |
The most severe problem on the western slopes involved three stream diversions on a single traversing road that caused a large gully down the road, which then contributed flow into an active landslide measuring 120 feet wide, 400 feet long, and 40 feet deep. The diverted flows were actively expanding this landslide and causing continued failure into Mill Creek. Another major problem on the western slope was a diversion caused by a small skid trail, which caused a large gully descending 300 feet down a ridge-top road before cutting downslope 400 feet to a small tributary channel. A third problem was runoff concentrations on a traversing road that had no drainage for more than 1,000 feet before cutting downslope in a large gully. Numerous other stream channel diversions were also present on the western slopes that were causing active gully erosion and landslide activity.
Background
Mill Creek has experienced severe erosion problems on the upland slopes since logging and road building were conducted in the 1940s through the 1960s. Fill-slope failures, stream-crossing diversions, and runoff concentrations along the old logging roads are typical causes of the problems that contribute sediment directly to Mill Creek. Since CSP acquired the property, many of the roads have developed a cover of vegetation. However, serious and persistent erosion problems still exist on many of the roads, and most of the stream crossings have a high risk of failure.
A sediment-source road inventory was conducted in April and May 2000 on the east side of the Mill Creek Watershed as part of a larger effort to analyze problems throughout Humboldt Redwoods State Park. During the winter of 2001, the road inventory was continued in the western portion of the watershed. The assessments identified road-related sediment sources contributing material directly into stream channels. The assessments documented current erosion problems including active stream diversions, as well as potential future problems such as stream-crossing failures and road-related landslides. The road problems in the watershed included numerous in-board ditch and road tread diversions that intercepted and diverted runoff via gullies to unstable slopes and inner-gorge areas.
Objective
The objective was to decommission abandoned logging roads that delivered or had the potential to deliver sediment to streams. CSP watershed rehabilitation goals call for decommissioning of abandoned roads that are causing accelerated sediment delivery or have the potential to accelerate sediment delivery to the drainage network in the Bull Creek Watershed. Because CSP management goals do not include reentry for future resource extraction or similar purposes, rehabilitation projects are single-entry, and all erosion sites are treated in areas entered by heavy equipment.
The work involved using heavy equipment to retrieve fill from the outboard edge of the road and place it against the cut slope to achieve a full recontour on the former road surface. Stream crossings were fully excavated and fill material was exported away from the stream onto stable upland road sections. Heavy equipment used on the project consisted of three excavators and three bulldozers. The dozers pushed fill into the cutbank, shaped it, and compacted it. The excavators were used to retrieve fill from outboard and downslope areas and to remove fill from the stream channels at crossing sites.
CSP geology staff have developed effective decommissioning techniques using a combination of technologies developed by Pacific Watershed Associates, Redwood National Park, the US Department of Agriculture Forest Service, the Natural Resources Conservation Service, the Redwood Community Action Agency, and others involved in road rehabilitation. All operations are conducted as described in the NCRD's Best Management Practices and Field Techniques for Forest and Range Road Removal.
Project Planning
Geomorphic Mapping
Aerial photos taken in 1963 were scanned at high resolution and stored on recordable CDs as JPEG images. The images were then spatially rectified using ArcView extensions that allow points on the photo to be manually assigned to points on a topographic map with known geographic coordinates. These rectified air photos were then enlarged and printed on 16- by 23-inch photo-quality inkjet paper. Twelve enlargements were produced to cover the entire project area. The enlargements were then laminated to make them waterproof and attached to thin plywood to create "map boards" with a Mylar sheet covering. The boards could be carried into the field, and geomorphic features could be directly drawn onto the Mylar coating.
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| Removing a failed stream crossing in Redwoods State Park. |
Geomorphic mapping of the project area took place beginning February 2000 on the eastern slopes and February 2001 on the western slopes. Environmental Resources Interns Sarah Balster, Erik Rogers, and I conducted the geomorphic mapping and road inventory. Geomorphic information observed in the field was mapped onto the map boards using a standard set of mapping symbols. Field staff followed protocols detailed in the Geomorphic Assessment and Mapping—California State Parks, Watershed Rehabilitation Technical Memorandum Series. The mapping resulted in identification of 8.1 miles of roads on the eastern slopes and 8.6 miles on the western slopes with high erosion hazard and related problems such as gulling and landsliding. Fill-slope failures, swale diversions, and runoff concentrations on these abandoned logging roads were contributing sediment directly into Mill Creek. Road segments were digitized onto the base map and other features of the landscape were added as separate layers, including landslides, streams, and gullies. A final map was prepared and used as the construction specification.
Prescriptions
All roads with 1 cubic yard per linear foot or more of fill material were selected for removal. Other roads were selected for removal if they had any significant erosion problems or potential for problems—regardless of their fill volume. Some roads with very low road-fill volume were also selected for removal because of active stream diversions. The prescriptions were entered into the geographical information system database developed for the project. The prescriptions included written construction specifications for all sites having special concerns outside of the typical best management practices for road treatments.
Before the heavy-equipment work began, engineering geologist Brian R. Merrill, R.G.; engineering geologist Patrick Vaughan, C.E.G.; senior resource ecologist Jay Harris; and the environmental resources interns hiked the project distance and reviewed the prescriptions.
Volume Survey
Road prism measurements were taken at obvious changes in the road profile and used to estimate volume per linear foot. Measurements included road-bench fill length, fill-slope length, and fill-slope angle. This information was not used for contract payments or for sediment reduction measurements. The volume estimate for this project was used for preparation of grant applications, and analysis of production rates for equipment operator comparisons and in the preparation of future contracts. All of the roads in this area were of similar size and for the most part separated out into 0.5 cubic yard per linear foot, 1 cubic yard per linear foot, 1.5 cubic yards per linear foot, and 2.0 cubic yards per linear foot. Roads with large gullies descending down the road length had a road-fill volume much less than the actual amount of material moved to achieve out-sloping. In these cases more than 3 cubic yards of material were moved per linear foot.
Crossing volumes were calculated using an end-area formula, which entails delineating triangular sections along both the upstream and downstream ends of the fill prism and averaging their volumes to reveal the feature's total volume along the entire length.
Environmental Analysis
Plants.Before the environmental documents were prepared, the project area was surveyed for threatened and endangered species using California Native Plant Society (CNPS) protocol. Humboldt State University (HSU) staff botanists—guided by Sarah Balster—surveyed the entire area for threatened and endangered plants. Three species of uncommon plants on List 4 of the CNPS Inventory of Rare and Endangered Plants of California were encountered. List 4 of the CNPS inventory is a watch list of limited-distribution plants. These species are not considered threatened and no mitigation was necessary. Piperia candida (white-flowered rein orchid), Listera cordata (heart-leaved twayblade), and Pityopus californicus (California pinefoot) were identified within the Mill Creek Watershed.
Amphibians. The roads on the eastern slopes were surveyed for the presence of potential amphibian habitat. No populations of federally or state-listed threatened or endangered species were identified in the eastern portion of the project. Potential habitat was flagged and mapped by Balster and HSU staff biologist Don Ashton. The consultant-trained CSP staff provided a field amphibian identification card including color images and key features used to identify amphibians. During a field consultation, the consultant reiterated his previous biological opinion that road removal projects would have an overall benefit to amphibians by increasing potential habitat. Roads on the western portion of the project were not surveyed for amphibians based on the results of the surveys from the eastern areas.
Cultural Review. Historical and cultural review as required by the California Public Resources Code (PRC) section 5024 was included in the California Environmental Quality Act (CEQA) process. NCRD archeologist Karin Anderson reviewed the project evaluation and negative declaration for the 2001 work. The Center for Indian Community Development at HSU conducted field investigations, which included walking all roads proposed for removal. Archeologists Jamie Roscoe and numerous assistants examined the entire project area and mapped significant resources. No significant historical and cultural sites were located in areas where road removal operations were to occur. Some significant objects were located and construction was conducted to avoid disturbance to these objects. The 2002 cultural survey was described in a report titled "A Cultural Resource Investigation of the Humboldt Redwoods State Park Road Reengineering Project."
CEQA. The NCRD was the lead agency for this project and prepared documents required by CEQA. Because funding for the western portion was unknown at the time of the first CEQA analysis, the project was included in two separate CEQA reviews. The first CEQA document for the project was initiated in November 2000 with the preparation of a Project Evaluation/Initial Study. The first negative declaration was filed at the State Clearinghouse on April 10, 2001. Following public review of the negative declaration a notice of determination was issued that the project would not have a negative effect on the environment.
On February 21, 2002, a second initial study was sent to the CEQA coordinator. A negative declaration was prepared and a notice of determination was signed on June 21, 2002.
Construction Implementation
The contract work for the east side of the watershed was implemented between July 16 and October 10, 2001. The contract work for the west side of the watershed was implemented between July 15 and October 30, 2002. Heavy-equipment work took place Monday through Thursday from 6:00 a.m. to 5:30 p.m.
In 2001 the CDFG funded stream-crossing removal and road-bench decommissioning on the main road up the east side of the Mill Creek Watershed known as Big Madrone Road. Two spur roads used to access the upper portion of Big Madrone Road, which had been cut off by a massive landslide following logging, were also treated with CDFG funds. Additional CSP funds were used to construct a full recontour on Big Madrone Road and all remaining roads.
In 2002, the CDFG funded stream-crossing removal and road-bench decommissioning on all roads in the western watershed that were identified for removal in the road inventory and in the SB271 grant/contract. Additional CSP funds were used to supplement the project budget to allow for construction of a full recontour at all sites. Additional CSP funds were necessary to do full recontouring because the CDFG does not typically fund full recontouring.
Park Staff
Merrill, Balster, Rogers, and I were responsible for the construction oversight and implementation. Roads, Trails, and Resources crew members were at the project site to repair trails and monitor equipment while regular inspectors were absent. CDF fire crews were also onsite to assist with trail repairs.
Operators and Equipment
Equipment used by Wendt Construction during the 2001 season included a John Deere 790 excavator and a John Deere 650 dozer. The equipment utilized during the 2002 season included a John Deere 790 excavator, a John Deere 690 excavator, and two John Deere 650 dozers. During the last week of the project in 2002 Wendt's 650 dozer broke down and was replaced with another 650. Use of this equipment was funded by the CDFG.
During the 2002 season, park operators were onsite using a John Deere 750 excavator and a John Deere 750 dozer. The park operators, Brian Hall and Glyne Johnson, were funded by State Parks NCRD Roads and Trails.
Equipment Move-In and Move-Out
The equipment move-in during the 2001 season consisted of walking the two pieces of equipment from Mattole Road to the project site. The walk-in took half an hour on the Hamilton Barn Environmental Camp access road.
During the 2002 season, equipment was walked into the Hamilton Barn parking area where the treatment roads began. For four days, the first crew removed brush and opened roads before beginning recontouring in the upper watershed. Move-in for the second crew involved walking in on Hamilton Barn Road and then walking 1 mile up the newly opened roads to a spur road where they began recontouring. During the final two weeks of the 2002 season, one equipment crew was moved to the Connick Cut-Block area to implement road removal and reengineering. Move-in to Connick required eight hours of dozer time and 10 hours of excavator time.
Road Removal
Decommissioning work requires a crew of one excavator and one bulldozer working in tandem. During the first half of the 2001 season, one crew was involved in the road removal work. The last four weeks of the construction had two crews working a few miles apart. During the 2002 season, two crews worked in the watershed for the majority of the time and three crews were present during the middle of the project.
Stream-Crossing Removal
Stream-crossing removal typically began with the dozer cutting into the upper surface of the crossing and pushing it out to adjacent stable road sections. The dozer continued to dish out the crossing until it could no longer achieve a suitable pushing angle. Once the dozer had completed its work, the excavator recovered the remaining fill material, culverts, logs, etc., from the stream channel and fed fill to the dozer. The dozer pushed the material away from the crossing, compacted it, and shaped it along adjacent road sections. Stream crossings were excavated to original width, depth, and slope to expose natural channel armor. The excavation of stream crossings involved locating buried stumps, boulders, logs, and black, organic-rich soil as indicators of the location of the natural stream channel. Sideslopes generally matched original contours above and below the road. Additional logs were placed against the upper banks of stream crossings to prevent soil detachment from overland flow. Material excavated from streams and other watercourses was moved to stable locations along adjacent road sections. Occasionally, excavated material needed to be pushed or transported to more distant locations if no stable sites were located near the crossing.
Road Recontouring
Treatment of roads and skid trails began with removal of organics from the in-board ditch and ripping of the road cut-bench. The dozer then cut outboard fill and pushed into the cutbank in lifts, compacting it with each pass. When the dozer finished, the excavator completed the recovery of unstable fill and placed it in the cutbank where the dozer completed the shaping. During the 2001 and 2002 seasons, a full recontour to the natural slope was obtained along 95% of the road removal length.
Export Outslope
Where groundwater was present, recovered fill was not placed into the cutbank as it is typically done. Instead, fill was exported to a stable location away from the unsuitable site. Export outslope was also used where mass wasting was present or suspected. At those sites, fill was exported to avoid loading the unstable feature.
Mulch
Organic material was separated from the fill and placed as mulch on the recontoured surface to protect against raindrop splash and sheet erosion. Logs and large pieces of organic material were placed on the slope surface and tamped down to provide contact with the soil surface. In numerous crossings organic material was placed on the final surface to obtain 100% coverage and was up to 3 feet thick. No straw mulches were used at this project because of the potential to introduce non-native species and pathogens to the backcountry areas.
Post-Construction Analysis
Brush Removal
The most efficient method for brush removal appears to be piloting the road with a dozer and then sending in the excavator to remove additional material and stack it in piles to the edge of the road. The contract operators preferred to leave as many trees standing as possible during initial brushing, pushing them over when ready to use them as mulch. The park operator preferred to remove as much organic material as possible during the initial entry, making piles of material upslope from the road at intervals along the road. The park operator's technique is the preferred method and is specified in contracts. Future projects would benefit greatly by enforcement of the contract specifications requiring brush to be placed upslope from roads.
Organic Material
Five different people operated the excavator during this project and each had a different approach to spreading organic material. Some operators tended to spread organics randomly, sometimes leaving material bunched together with areas of non-mulched soil in between piles. Operators were asked on numerous occasions to spread organic material more evenly across the surface. One operator appeared to have difficulty handling organic material. He dropped material from the bucket numerous times before moving it to the desired location; this may have been due to the bucket/thumb configuration. He caused damage to the machine on a weekly basis from organic material. Other operators were good at spreading mulch and breaking larger pieces.
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. No old-growth trees were damaged during this project; however, some larger trees between 12 and 20 inches' diameter at breast height did sustain damage to the bark. Damaged bark may not be bad ecologically because it adds diversity and can lead to hollows that are similar to burned-out trees in a mature forest. Damage mainly occurred to tree bark when the excavator was limbing the branches off trees that were within the swing radius of the machines, and in attempting to recover woody material that had been pushed downslope during the initial brushing phase. This is another reason why brush generated during initial entry should be placed upslope in piles.
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| Road before removal with capture of groundwater in the inboard ditch. |
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| The same road after removal with restored groundwater hydrology. |
During the 2001 construction season, all but two stream crossings were dry and remained dry into November. This eliminated resource damage to streams due to turbidity. In the crossings that had stream flow, a 300-foot plastic pipe was used to divert flow around the construction site. The diversions took approximately one hour to install using bags filled with dirt to temporarily dam the stream. The diversion pipe forced the dozer to push in one direction at a time, rather than the usual dishing-out technique. It was difficult to move the pipe to the opposite side of the excavation as work progressed because the pipe was cumbersome and heavy.
Only one stream had flowing water during the 2002 construction season, at a crossing that had already completely failed. The crossing was located on a road that was used to access a large portion of the project. Instead of placing a temporary culvert and using fill to cover the pipe to provide access, onsite materials were used to create a drivable surface to cross over the channel. The excavator placed numerous small logs and brush into the active channel to protect the bed and banks. The dozer then ran back and forth across the woody material to pack it down and create a drivable surface. Because no excavations were planned for the crossing because it had already completely failed, it was desirable to avoid rebuilding the crossing with fill material. Using the brush allowed for access without placing any fill into the channel. And during the removal phase, the excavator simply removed the brush and small trees and placed them on the banks as mulch.
Equipment
During the 2001 season, equipment downtime was 28 hours on the excavator and eight hours on the dozer. The downtime on the dozer was due to a leak in a hydraulic hose that caused early shutdown, and later in the season, downtime was due to a broken drive plate. During the hottest week mid-project, the dozer overheated every few hours, forcing 10-minute delays to allow for cooling. The inspector requested a replacement machine after two days of constant overheating, and a newer dozer was brought out that weekend. Downtime on the excavator was due to numerous hydraulic hose breaks, and later in the season a failed hydraulic pump. During the last few weeks of the project, the excavator had to be replaced with a different machine because hoses were rupturing almost daily. The excavator also overheated and needed water added to the radiator two to four times each day, causing brief delays in production.
During the 2002 season, equipment downtime was over 40 hours on the excavators and approximately 16 hours on the dozer. Downtime occurred on equipment at least once a week. Downtime was not included in payments to the contractor; however, it causes inefficiency in production rate. When downtime occurs, in many cases both machines must stop work until a repair can be made. Also, the park inspector continues to be paid during the day while waiting for repairs. Downtime was high on this project due to the thick trees and brush growing at the site, and due to old, poorly maintained equipment.
Operators
Five equipment operators were involved with the 2001 work, and eight equipment operators worked during 2002. All operators conducted themselves as professionals and demonstrated a high level of skill in operating heavy equipment. Equipment operators reacted quickly to avoid hydraulic oil leaks to the environment by shutting down immediately and by utilizing spill kits when the equipment was damaged.
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| Road before removal. |
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| Road after recontouring. |
Operator skill level varied greatly. On the dozer, some operators have higher standby time because they prefer to work closely with the other machine and will wait nearby as the other machine completes a task. Other operators do not like to sit idle at all and will move ahead and start the next phase of work while waiting for the second machine to complete a task. Some dozer operators prefer to back down the slope and make all the pushes up the slope into the cutbank. Others travel back and forth along the road in a series of U-turns to push material into the cutbank.
On the excavator, some operators masticate and place organic material efficiently, while others have a difficult time placing logs or brush and cause damage to the machine hoses, windows, and doors. Some of the operators can travel across steep slopes and work on sites that have been previously outsloped by the dozer, while others prefer to work on a level surface and spend extra time building a flat pad to work from.
Excavation
In past projects, stream crossings were under-excavated, leading to over-steepened slopes adjacent to watercourses. To avoid this, operators were regularly reminded of this past problem during project safety/progress meetings. Operators were asked how they could help ensure that crossings were not under-excavated during this project. In general, all crossing fill was placed 30 to 150 feet away from the channel. Cutbanks adjacent to crossings were not matched; rather, they were blended by laying them back to try to disguise the bank visually and to reduce the slope steepness. Also, the dozer finished dry crossings where possible, because this forced the operators to lay the banks back to a slope that the dozer could push out of. This also left much less loose material than on crossings finished by the excavator.
Park construction crews found that implementing full recontouring was only slightly more time-consuming than partial recontouring in areas where equipment is the maximum size that can work on a road segment. On this project, only a few of the roads had a large enough prism that could have used larger-size-class equipment. Most of the roads were narrow and located on steep slopes, and the excavator was large enough to access the entire cut-and-fill slope from one position. This makes full recontouring essentially the same cost as partial recontouring or decommissioning. From a cost-benefit perspective, partial recontouring has very little cost savings in these situations. Partial recontouring may be beneficial where the excavator cannot access the entire road prism or if fully recontoured slopes have a higher potential for post-treatment failure than partially recontoured slopes.
Full recontouring, however, may not always be the best treatment for a road located lower in the watershed. During a monitoring visit to the site in January 2003, it became clear that full recontouring could have some problems during high rainfall events in locations where runoff is high and groundwater is pumping out of the old cutslope. Lower Mill Creek Road suffered numerous failures of recontoured fill. The problem appeared to be related to surface and subsurface water movement that was not anticipated even during the inventory and planning conducted during the prior winter. In many locations along the lower portion of the road, surface runoff from small untreated skid roads concentrated and saturated sections of recontoured fill, causing the material to become a small mudflow—in one case entering a tributary channel. The majority of slip-outs did not contribute to streams. The problem is not related to over-steepened slopes; many steep recontoured slopes remained stable during high rainfall.
In the few cases where an inspector was not onsite during the excavation of a crossing, the sites were under-excavated, and the potential for post-construction stream channel adjustments was high. The general tendency for equipment operators, no matter how excellent their skill level, is to not remove enough material from a crossing. On the majority of sites, the inspector requested additional soil removal before mulching was allowed. By the end of the project, equipment operators developed the habit of asking for inspector approval of excavation depth prior to mulching.
Stream Alteration Permits
An application for a streambed alteration agreement (SAA) from the California Department of Fish and Game was submitted prior to the completion of the CEQA documents. An attempt was made during the planning process to obtain a memorandum of understanding (MOU) between the CDFG and CSP to allow for a more streamlined SAA process. An MOU would allow for considerable cost savings by avoiding the duplicated environmental review that both departments implement. Because of the efficiency in which the CDFG processes SAAs, this permit process is a minor factor in project planning and implementation. The process in this case, however, is a duplication of effort because of the extensive review conducted by CSP staff during the CEQA process.
Inspector
The inspector found that telling the operators what he wanted the final product to look like and asking the operators during a brief planning break what they planned to do obtained the best results. It is much better to stop briefly before the equipment gets to a crossing to discus the plan of attack than to just stand back and let them move onto the site and start working.
Difficulties occurred during the project between some operators and an inspector. The problems occurred when the inspector made requests of the operator regarding actual methods of operating the machine. In one case the operator saw a very inefficient action being implemented by the excavator that was going to move the same dirt twice. The inspector could see a better place to position the machine where only one motion would be required; however, the operator resisted making the change. The inspector was informed that due to contracting procedure he could not make requests on operation of the machine, only on what the finished product should be.
Conclusion
The Mill Creek Watershed Rehabilitation Project was implemented to reduce erosion hazard in Humboldt Redwoods State Park. The project removed all roads with the potential to deliver sediment to streams in the Mill Creek Watershed. DFG Salmonid Restoration Federation grant funds from SB271 were used to remove stream-crossing fill and stabilize sites with direct influences on streams. CSP funds were used to perform full recontouring to completely remove all roads used to access the crossings. The project was implemented as designed with no accidents or deviations from specifications detailed in the Initial Study and Mitigated Negative Declaration prepared for the project. The continuous onsite presence of qualified project inspectors allows for efficient use of equipment and operators that results in high production rates. In the future, monitoring will be implemented on an annual basis to assist with adaptive management and to continually improve construction standards.