Final_Project_Scoping_Report.pdf

FINAL PROJECT SCOPING REPORT

Goose Lake Road Reconstruction

January 16, 2015

Final Project Scoping Report Project No. ID PFH 98(1) Goose Lake Road Reconstruction 1

PURPOSE OF THE REPORT

Goose Lake Road, located west of McCall, Idaho, is an important route connecting State Highway (SH) 55 with recreational areas in the Payette National Forest. See Figure 1 for the project location.

With improving safety as the focus of Goose Lake Road Reconstruction project, this Project Scoping Report fully identifies key issues and summarizes observations made by the consultant team during the site visit and documents information necessary for the development of a Preliminary Plans package suitable for solicitation as a Design-Build (DB) contract.

This report provides a general project introduction and consultant team’s observations during the site visit. Observations were provided in several areas including:

Roadway and roadside features Utilities Environmental Geotechnical Storm Drainage and hydraulics

The traffic discipline performed desk surveys to gather existing traffic volume data and available accident history.

Key project issues were identified and summarized from background information, site visit observations, and stakeholder input. A listing of future design needs is also provided.

The report is supported by reconnaissance reports for Geotechnical, Hydraulics and Traffic, as well as notes from the November 19, 2014 meeting with the US Forest Service. These can be found in the reports appendix.

Figure 1. Goose Lake Road Project Vicinity

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INTRODUCTION

Goose Lake Road provides recreational access to the Payette National Forest, with the primary destination being the Brundage Mountain Ski Area. Goose Lake Road however, is also a narrow winding mountainous road with the highest accident rate in the Payette National Forest. The intent of the Goose Lake Road Reconstruction Project is to improve safety by widening the existing roadway, from an approximate 22 foot paved width to a 26-foot paved width. Additionally, spot improvements will be provided to select substandard curves as well as intersection improvements at SH 55.

The identified project limits begin at the intersection of SH 55 and Goose Lake Road and extend approximately 3.8 miles to the entrance of the Brundage Mountain Ski Area.

SITE VISIT

A site visit was conducted on November 18-19, 2014, in order to familiarize the project team with the site and gather first hand observations of the constraints and issues of the location.

The following is a brief description of observations made by project team members.

Roadway Observations:

Roadway Width: Goose Lake Road currently consists of a 22 foot paved section within the limits of the project. This mountainous road consists of steep side slopes adjacent to both sides for much of the corridor. With a desired cross section consisting of 26-feet of paved roadway width (two 11-foot lanes with 2-foot shoulders), there is limited space for expansion on the existing roadway prism. US Forest Service staff (USFS) indicated a desire to lay slopes back to allow for growth of vegetation on “gentler” stabilized slopes that would also increase stopping sight distance through the existing blind curves. It was noted that the lack of centerline pavement markings in the corridor presents dangerous scenarios for motorists traveling in the middle of the roadway on a bi-directional facility. In addition, the absence of edge lines makes it difficult for motorists to stay on the roadway when edge of pavement is not visible or buried by snow or

Figure 2 Goose Lake Road Reconstruction Project Limits

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Project No. ID PFH 98(1) Goose Lake Road Reconstruction 3 earth. Incorporating dedicated bike lanes would be extremely difficult due to space constraints in the corridor.

Horizontal Alignment: Goose Lake Road is classified as a rural major collector with a current posted speed of 30 miles per hour (mph) with the exception of a few hairpin turns where the advisory speed is posted at 15 mph. Several of these substandard curves have minimal exposure to the sun during winter, creating icy conditions that are dangerous to motorists. USFS requested that the alternative horizontal alignments with larger radii to be considered. It was observed that the first right curve exiting from Brundage Mountain Ski Area is a compound curve configuration that is not ideal to maneuver in slippery road conditions.

Vertical Profile: The mountainous terrain of this corridor could limit the ability for major profile adjustments. It was noted during the field visit that several existing cross culverts would require minor roadway profile modifications to provide minimum cover.

SH 55 Intersection: The existing Goose Lake Road intersection at SH 55 presents several challenges that would need further investigation to address. The intersection sight distance is substandard when observing northbound (NB) SH 55 traffic approaching the intersection. The intersection lacks the concentric turning lane for left turning traffic from Goose Lake Road to southbound (SB) SH 55 for acceleration and merging with SB SH 55 traffic. USFS indicated that traffic turning right from Goose Lake Road to NB SH 55 is frequently backed up from queuing with the left turn traffic from Goose Lake Road to SB SH 55.

Other Roadway Observations: In addition to lacking pavement markings, centerline rumble strips were also lacking, but are typically used for this type of facility. It was noted that the majority of the existing signage in the project corridor are within the anticipated clear zone and are not on breakaway supports. The field visit indicated that most of the signage was installed in 2001.

Utilities Observations:

Existing underground and overhead utilities were observed along the roadway for approximately the first mile of the proposed project as indicated in the November 2011 Project

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Identification Report (PIR). There is one additional overhead utility crossing located near the snowmobile parking area. It was noted in the PIR that, if necessary, the utility providers would be required to relocate its facility at its own expense prior to construction.

Environmental Observations:

The site visit generally confirmed the environmental conditions presented in the PIR with the following exceptions and clarifications:

1) The wetlands section of the PIR has the names and locations of the unnamed tributary to Little Goose Creek and Little Goose Creek reversed compared to the Hydraulics/Hydrology appendix of the PIR. This Scoping Report will be consistent with the Hydraulics/Hydrology appendix such that the crossing of the unnamed tributary to Little Goose Creek occurs at mile post (MP) 0.07 while the crossing of Little Goose Creek occurs at MP 0.22.

2) Upstream of the crossing of the unnamed tributary to Little Goose Creek at MP 0.07, the unnamed tributary crosses under SH 55, southeast of Goose Lake Road. The culverts of this crossing appear to be perched during low-flow conditions that were occurring during the site visit. This crossing is in the same vicinity of the crest vertical curve on SH 55 that creates a concern for sight-line distance at the intersection of SH 55 and Goose Lake Road.

3) The riparian portion of the unnamed tributary to Little Goose Creek between SH 55 and Goose Laked Road is likely all jurisdictional wetlands. Other potential wetlands identified in the PIR were confirmed.

Geotechnical Observations:

Geotechnical reconnaissance was performed during the site visit. Observations and recommendations developed from the site visit are included in Appendix A - Geotechnical Reconnaissance Report

Storm Drainage and Hydraulic Observations:

The project site is located within the Payette River Basin, which generally drains from the northeast to the southwest. Along the approximately 3.8 miles of roadway within the project limits, the existing drainage pattern on the east side alternates between steep areas sloped toward the roadway, areas sloped away from the roadway and areas of roadside ditches that are drained by the cross-road culverts described below. Alternatively, on the west side, medium to steep slopes send sheet flow away from the roadway along most of the length with no defined roadside ditches.

There are three major drainage crossings, including five cross-road culverts that convey the unnamed tributary of Little Goose Creek (MP 0.07), Little Goose Creek (MP 0.22) and Thorn Creek (MP 3.00) from the east side to the west side of the roadway. Two of the three major

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Project No. ID PFH 98(1) Goose Lake Road Reconstruction 5 drainage crossings (one 48 inch CMP at the unnamed tributary of Little Goose Creek (MP 0.07)and dual 54 inch CMP at Little Goose Creek (MP 0.22)), are currently being designed to be aquatic organism (fish) passage (AOP) culverts by the USFS. The plans for these designs will be incorporated into the project during the preliminary design phase. The two culverts (36 inch and 24 inch CMP) located at the crossing at Thorn Creek (MP 3.00) were not deemed practical for AOP design due to the steep gradient of Thorn Creek downstream of the culverts.

Additionally, as mentioned in the Environmental Observations section of this scoping report, south of MP 0.0, there are dual culverts (36 inch CMP) located upstream of the MP 0.07 crossing that convey the unnamed tributary underneath SH 55.

There are also 32 other minor cross road culverts along the roadway that were not verified at the site visit and are not further discussed in this report due to weather and time constraints.

Hydraulic reconnaissance was performed during the site visit. Observations and recommendations developed from the site visit are included in Appendix B – Hydraulic Reconnaissance Report.

Traffic The traffic discipline was not part of the site visit, but separately performed tasks that included reviewing available information, such as the PIR and collecting:

Existing traffic volume data Available accident history data

This information is summarized in Appendix C- Traffic Reconnaissance Report, which presents the various data collected.

USFS MEETING

During the morning of November 19, 2014, project team members met with Will Perry, PE, USFS Supervisory Civil Engineer, to discuss the project and gather his insights to the key issues.

Key project issues discussed during the meeting include:

Construction staging schemes for the maintenance of traffic during construction will be critical to the success of the project.

Addressing key safety issues at the intersection of SH 55 and Goose Lake Road while keeping within the project’s budget.

See Appendix D for a meeting attendee list and meeting notes.

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SUMMARY OF KEY PROJECT ISSUES

Based on the review of existing documentation, a site visit, and meeting with USFS staff, the following is a summary of the key project issues:

Maintenance of Traffic during Construction. The narrow 22 foot existing pavement width and the lack of feasible alternative routes place a greater emphasis on the development of a maintenance of traffic plan that key stakeholders and the traveling public can support.

Extent of Safety Improvements. Safety concerns exist, not only for the project’s limits of Goose Lake Road, but also for the intersection of SH 55 and Goose Lake Road. Available project funding will need to be efficiently allocated to maximize the overall safety improvements.

Pavement Design. The pavement was resurfaced in 2010 and presently is in good condition. A key issue for pavement design will be able to develop a cost efficient design that addresses a 20 year window need.

Environmental Considerations. Corridor tree removal to daylight the road will need to be performed to visual Partial Retention standards to meet Payette Forest Plan standards and guidelines. The USFS will develop a Tree Removal Plan that will meet the Visual Quality Objectives as presented in the Payette Forest Plan. Consideration should be given to separating out all tree removal into a separate contract from the design-build road widening contract, as the DB contractor may not have the necessary expertise to perform the Tree Removal Plan to the USFS requirements.

IDENTIFICATION OF FUTURE DESIGN NEEDS

From the project reconnaissance work, several items were identified as being needed in the future, as the project progresses through the design phase.

Preliminary Plans Package: With the design and construction of this project determined to be through a Design-Build (DB) procurement, the preliminary plans package needs to serve the purpose of informing the contractor of the work to be performed, restrictions that must be adheared to and provide a clear understanding of the non-negotiable standards to be followed.

Primary elements of a preliminary plans package include roadway design, pavement design, fish passage and maintenance of traffic.

Roadway Design: Certain items such as the roadway width, a range for horizontal curve alignment, striping configuration/ material and signage are recommended to be contract requirements, but other design items such as the location of the roadway centerline and specific horizontal curve alignment can be left to the DB contractor.

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Pavement Design: Pavement design criteria should be developed to allow the DB contractor to produce a pavement design that obtains the recommended design life while minimizing the required maintenance to be performed by Adams County. A pavement and subgrade investigation should be performed to support this work.

Rehabiltation methodolgies should be researched to determine feasible alternatives for this effort.

Fish Passage: Two of the existing culverts that cross underneath Goose Lake Road will be replaced and improved for fish passage. The specific hydraulic opening requirement, “fish friendly” requirements, and acceptable structure material are recommended to be contract requirements, but type of structure, length of structure and construction method could be left to the DB contractor.

Traffic Data: Sufficient data is not available at this time to determine project design hourly volume or directional distribution. On a daily basis, this type of facility would typically have a directional distribution that is very close to 50/50 because it is most likely being used for recreational trips that would come and go within the same day.

Furthermore, it can often be assumed that the design hour volume on a rural road is approximately 15 percent of the average daily traffic (ADT). However, it may be considerably higher for Goose Lake Road given the ski area and other recreational uses that it accesses. It is recommended that additional traffic counts be conducted to determine the design hour volume and directional distribution in order to verify the 2014 projections presented in the traffic reconnaissance report.

Maintenance of Traffic (MOT): It is recommended to describe MOT requirements in a performance specification manner and not in a perscriptive manner. This will allow the DB contractor to use his experience and innovation in developing an acceptable MOT.

Preliminary Plan Schedule: The schedule will need to be developed with respect to the seasonal usage and associated restrictions for Goose Lake Road. At this point in time, information is pending regarding this usage and restrictions.

Survey Needs: Additional survey needs are pending receipt and review of recently completed topographic survey.

Environmental Needs:

Wetland delineations in the areas identified for culvert replacement need to be performed during the growing season (beginning in May 2015). Due to the project schedule, it may be necessary to perform wetland determinations based upon survey

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Project No. ID PFH 98(1) Goose Lake Road Reconstruction 8 data, existing wetland mapping, and a site visit to map approximate wetland boundaries but the responsibility for full wetland delineation may need to be on the DB contractor.

Cultural and historic resource surveys need to be completed along the entire corridor if the USFS has not done these already. This is also weather dependent as these surveys would need to occur after the snow has melted.

Documentation from the USFS of Section 7 Endangered Species Act and USFS sensitive species surveys supporting their effects determination (No Effect) under the Endangered Species Act will be needed.

Geotechnical Needs: A geotechnical investigation is recommended to assist in the preliminary design of cut and fill slopes. An investigation would also assist in the development of DB procurement documents. Due to the project schedule, a geotechnical investigation may not be feasible prior to DB procurement. In this case, data should be obtained from current slope performance, survey information, available geologic and geotechnical documents, and any pavement/subgrade investigations that are performed.

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APPENDIX A

Geotechnical Reconnaissance Report

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Geotechnical Reconnaissance Report

INTRODUCTION

The purpose of this Geotechnical Reconnaissance Report is to summarize the results of the following tasks performed under this phase of work and to develop recommendations for future phases including:

Literature review of available reports, maps, assessments, and plans;

Site visit and geotechnical reconnaissance;

Develop preliminary understanding of the geologic features that may be important to design and construction of the proposed project;

Identify potential geotechnical/geological issues related to design and construction.

LITERATURE REVIEW

A literature review of available documentation was performed to obtain background information of the existing bridge and project vicinity. The following documentation was reviewed:

ID PFH 98, Goose Lake Road Project Identification Report (PIR), Adams County, Idaho, Robert Peccia & Associates, November 2011

Breckenridge, R. M. and Othberg, K. L. (2005). Surficial Geologic Map of the McCall Quadrangle, Valley and Adams Counties, Idaho. Idaho Geological Survey.

Schiappa, T. and Link, P. K. (2002a). Adams County Geologic Units, Idaho. Retrieved from http://imnh.isu.edu/digitalatlas/counties/adams/geomap.htm

Schiappa, T. and Link, P. K. (2002b). Valley County Geologic Units, Idaho. Retrieved from http://imnh.isu.edu/digitalatlas/counties/valley/geomap.htm

Glacial Geology Near McCall, Idaho. Retrieved from http://www.idahogeology.org/FieldWorkshops/WestCentralIdaho/McCall.htm

Lund, K. (2005). Geology of the Payette National Forest and Vicinity, West-Central Idaho.

U.S. Geological Survey Professional Paper 1666

Idaho Department of Water Resources (IDWR) Well Logs

GEOTECHNICAL RECONNAISSANCE

A site visit was conducted on November 18-19, 2014 in order to familiarize the project team with the site and gather first hand observations of the constraints and issues of the project.

Goose Lake Road is a narrow winding mountainous road that provides recreational access to the Payette National Forest. The identified project limits start at the intersection of SH 55 and Goose

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Lake Road and extend approximately 3.8 miles to the entrance of the Brundage Mountain Ski Area.

General Site Topography and Geologic Setting The project site is located approximately 5 miles north of McCall, Idaho, beginning at the intersection of Goose Lake Road and SH 55. Payette National Forest personnel have indicated the roadway was originally constructed as a logging road and has been widened/upgraded incrementally over time as recreation use increased. The roadway was first paved in the 1990s and a chip seal was performed in 2010. Design records from these activities are not available at this time. Goose Lake Road is situated along the west facing slope of Brundage Mountain.

Elevation of the roadway ranges from slightly less than 5,000 feet at MP 0.0 to approximately 5,920 feet at MP 3.8.

The geology of the region is complex. Goose Lake Road is located along the Idaho Suture Zone (ISZ) – a region of two different tectonic units with distinguishing stratigraphy, structure, and geologic history. To the west of the ISZ are Columbia River basalts underlain by a complex volcanic and sedimentary layered rock structure (Schiappa, 2002a). To the east of the ISZ are gneissic and granitic rocks of the Idaho batholith (Schiappa, 2002b).

Surficial geology of the vicinity is heavily influenced by the Pinedale Glaciation (which resulted in the formation of Payette Lake, among other surface features). Previously, the high mountain regions were covered by an ice cap. Meltwater streams, from the Pinedale and other glaciations, deposited sands and gravels throughout the region (Glacial Geology Near McCall, Idaho).

The majority of the roadway alignment is located on the Salmon River Suture, a heterogeneous orthogneiss, and foliated granodiorite and granite while the remaining southern portion of roadway (approximate MP 0.0 to 1.0) overlies alluvial, landslide and glacial deposits (Lund, 2005), consisting of silty sands with gravel, cobbles, and boulders (Breckenridge and Othberg, 2005). Surficial soil deposits consisting of silty sands with gravels, cobbles and boulders were observed along the entirety of the alignment. Rock outcroppings with variable amounts of weathering are visible along the roadway alignment. Boulders larger than 10 feet in diameter were observed along the alignment.

A review of well logs available from the Idaho Department of Water Resources was performed. Well logs generally indicate soils consisting of gravels and boulders overlying variable bedrock. Bedrock was encountered between 4 feet and 30 feet of depth within the reviewed well logs and is expected to be vary in depth along the roadway.

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Roadway Conditions The roadway appears to have been constructed using side-cast fill, with cut slopes generally to the right or the roadway and fills to the left. Geotechnically, the roadway appears to be performing well. Although there are locations within fill slopes that pistol but trees are present, no indications of roadway slumps were observed. Cut slopes appear to be performing well with observed instability limited to shallow, raveling type failures on non-vegetated slopes.

The soils observed along the roadway generally consist of silty sands with gravel, cobbles and boulders. Based on geologic mapping rock outcrops are expected to consist of orthogneiss, however given the complex geologic history of the region bedrock composition is likely to vary along the alignment. Boulders observed ranged from highly weathered to fresh. Conventional earth moving equipment will be sufficient to remove many boulders along the alignment, however, given the size and hardness of several observed boulders blasting will likely be required to facilitate widening and removal.

Fill slopes are generally located to the left of the roadway and range from approximately 6 to 50 feet in height with slopes less than 1H:1V. Most fill slopes along the alignment are vegetated with grasses, bushes, and coniferous trees. The fill slopes appeared to be performing well. Pistol butt trees are present at several locations along the alignment, however, roadway instability was not observed. Boulders up to approximately 4 feet in diameter are present along the face of large fill slope near MP 3.2, it is unknown if the boulders are present throughout the fill. The fill slope at this location is approximately 1H:1.5V.

Cut slopes are generally located to the right (east side) of the roadway and range from approximately 5 to 20 feet with slopes ranging from 2H:1V to 1H:2V. The largest cut slope reaches approximately 30 feet in height. Most cut slopes are vegetated with grasses, bushes, and coniferous trees. Generally, cut slopes are performing well. Minor erosion and sloughing that potentially impacted the drainage ditch but not the roadway was observed at sporadic locations along the alignment. The large cut near MP 3.2 was observed to be experiencing minor to moderate erosion and surficial raveling. A vertical scarp of approximately 5 feet in height is present along a portion of the cut. The portions of the cut experiencing this erosion and raveling is south facing and unvegetated. Native slopes above cuts are generally heavily vegetated and flatter than the cut slopes. The majority of cut slopes could be widened or flattened without having to “chase” the slopes up the hillside extensively, however there are locations were the natural slope above the cuts approaches the cut slope angle. Table A-1 presents slope conditions along the alignment.

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Table A-1 – Observed slope conditions and materials.

Milepost Existing Conditions Observed cut slope material Begin End

0.0 0.1 Cut slopes on right, fill slopes on left Soil

0.1 0.3 Fill slopes both sides Soil

0.3 0.6 Cut slopes on right, fill slopes on left Soil

0.6 0.8 Fill slopes both sides

0.8 0.9 Cut slopes on right, fill slopes on left Soil

0.9 1.0 Cut slopes on right, fill slopes to at grade on left

Soil/weathered rock

1.0 1.1 Cut slopes on right, fill slopes on left Soil/weathered rock

1.1 1.2 Fill slopes both sides

1.2 3.0 Cut slopes on right, fill slopes on left Soil/boulders/bedrock

3.0 3.2 Large cut slope on right, large fill slope on left

Soil/boulders

3.2 3.6 Cut slopes on right, fill slopes on left Soil/boulders

3.6 3.8 Cut slopes on left, fill slops on right Soil/boulders

Note – Many of the cut slopes were obscured with snow and only what was observed is reported in the table above. However, boulders are likely to be encountered in all slopes along the alignment.

Subgrade soils below the pavement likely consist of silty sands with gravel, cobbles, and boulders originating as cut material from side-cast construction. The pavement base and subgrade appear to be performing well. Areas of settlement were not observed during the site visit, however approximately 3-4 inches of snow cover was on present and the roadway was partially obscured. The PIR indicates two locations of settlement (approximately 2-3 inches in depth, 15 feet in length) were observed at MP 1.0 and MP 2.7 in 2011. Brundage Mountain personnel have reported a few locations of frost heave are present along the roadway in the spring.

A chip seal was performed in 2010 and the pavement appears to be in good condition given it is approximately 20 years old. Full width transverse cracking was observed along the entirety of the alignment. Additional pavement distress that was observed along the roadway includes longitudinal cracking, alligator cracking at the pavement edge, and minor rutting. Observed pavement distress appears primarily related to the age of the pavement, rather than an inadequate or poorly performing roadway structure.

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Extensive surficial gouging (approximately 1/2 inch deep) of the pavement has occurred near MP 1.0 at a heavily used snowmobile crossing (the Bear Basin crossing). Figure A-8 displays observed damage at this location.

CONCEPTUAL DISSCUSSION OF IDENTIFIED GEOTECHNICAL DESIGN ISSUUES

Cuts and fills will likely be required to widen and adjust the alignment of the roadway.

Existing cut slopes are generally performing well along the roadway. Cut slope design should be performed to determined slope angles that will result in adequate factors of safety regarding stability analysis. Cut slopes should be designed so that revegetation will occur following construction. Potential locations where laying back an existing cut slope would allow for direct sunlight to reach the roadway during the winter should be identified and studied to determine if feasible. Locations where new/adjusted cut slopes could result in the slope extending a significant distance up the mountainside should be identified and potential alternatives analyzed, such as retaining walls or fills rather than cuts. Cut material will likely be acceptable as embankment fill; a balanced earthwork design will likely result in construction cost savings. Areas of the alignment where conventional equipment will not be able to perform earthwork should be identified (i.e. blasting required).

Fill slopes should be designed to an adequate factor of safety regarding stability. It appears feasible to place fill slopes in some locations to facilitate roadway straightening. Fill design should account to the potential usage of cut materials; a balanced earthwork design will likely result in construction cost savings. A geotechnical investigation will assist with the potential design of cut and fill slopes.

The existing pavement appears to be performing adequately, however, the pavement may be nearing the end of its design life. The pavement structure thickness and condition should be investigated to determine feasible rehabilitation/construction methods. Design of the pavement structure should be performed such that the desired design life is obtained requiring minimal initial maintenance. Rehabilitations consisting of overlays or mill and inlays are unlikely to result in the required design life and minimal maintenance. In-place recycling should be studied but may not be practical. Full-depth reclamation (CRABS) should be studied. Performing a pavement and subgrade investigation will assist in the identification of potential rehabilitation methods. Potential designs should account for the possibility of full subgrade excavation and replacement in isolated areas along the alignment to remove unstable soils.

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Methods to protect the pavement at the Bear Basin snowmobile crossing should be investigated. A Portland Cement Concrete (PCC) section could provide a more durable/resistant surface at the crossing, however, the PCC/asphalt concrete (AC) interface could settle differentially. This could result in a “bump” in the road or result in a lip that is hit by plows during snow removal operations. A potential way to mitigate this “bump” would be to construct a tapered section where the PCC extends below the AC surface, helping to smooth the transition between the materials of differing stiffnesses. Other mitigation alternatives including adjusting AC mix designs or adding a polymer coating, should be investigated. These methods have been attempted in other locations with limited success but continued development of materials and methodologies may result in a cost effective solution.

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Figure A-1 – Approach of Goose Lake Road from SH 55.

Figure A-2 –SH 55 embankment with culverts south of intersection with Goose Lake Road.

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Figure A-3 – Facing down station on Goose Lake Road near MP 0.1.

Figure A-4 – Transverse pavement crack near MP 0.2.

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Figure A-5 – Facing down station near MP 0.2.

Figure A-6 – Embankment with twin culverts near MP 0.22. Facing upstream (east), gabion baskets placed along drainage.

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Figure A-7 – Typical roadway MP 0 to 1. Facing down station.

Figure A-8 – Damaged pavement at Bear Basin snowmobile crossing near MP 1.0

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Figure A-9 – Facing up station near MP 1.5. Large boulder in the background.

Figure A-10 – Large boulder near MP 1.5. Maximum dimension is approximately 15 feet.

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Figure A-11 – Facing up station near MP 1.5 showing typical terrain beyond MP 1.0.

Figure A-12 – Typical terrain showing slope bench above roadway. Near MP 1.6.

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Figure A-13 – Facing up station near MP 1.7. Roadway distress not noted, however pistol butt trees are present in side case fill.

Figure A-14 – Boulders/outcrop near MP 1.7.

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Figure A-15 – Facing down station from pullout area near MP 2.4.

Figure A-16 – Outcrop/boulders near MP 2.5.

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Figure A-17 – Facing up station near MP 3.0.

Figure A-18 – Hairpin curve at MP 3.2.

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Figure A-19 – Example of pistol butt tree on slope below roadway. MP 3.0-3.2.

Figure A-12 – View of fill slope with boulders below roadway near MP 3.2.

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Figure A-21 – Fill material consisting of boulders near MP 3.2.

Figure A-22 – Facing down station from MP 3.2.

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Figure A-23 – Facing up station from MP 3.2.

Figure A-24 – Slope above curve near MP 3.2. Note scarp, raveling, and erosion of unvegetated slope.

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Figure A-25 – Slope above MP 3.2. Raveling/erosion present on unvegetated areas.

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APPENDIX B

Hydraulics Reconnaissance Report

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Hydraulics Reconnaissance Report

OVERVIEW

As mentioned in the body of this scoping report, the project limits extend north from the intersection of Goose Lake Road and SH 55, defined as MP 0.0 to approximately MP 3.80, at the entrance of the Brundage Mountain Ski Area. There are three major creek crossings located within the project limits that convey main creek flow or tributary creek flow from the east to the west side of the roadway. Conversely, the dual culverts located south of MP 0.0 convey tributary flow from the west to the east side of SH 55. More specifically, seven cross-road culverts ranging from 24 inches to 54 inches in size are included in the four major creek crossings defined above and will be explained in more detail in the next section. Please refer to Figure B-1 below for the approximate locations of the three major drainage crossings within and the one major drainage crossing outside of the project limits.

Additionally, there are 32 other minor cross-road culverts throughout the 3.8-mile stretch that serve to drain the roadway ditches and areas of sheet flow that are tributary to Goose Lake Road from the east to the west side of the roadway. Based on the hydraulic importance, weather and time constraints, only the three major drainage crossings were evaluated and verified during the site visit. During the site visit, no major adverse drainage issues were observed. Furthermore, no observed drainage concerns were reported by USFS and WFLHD staff when the design team met on November 19, 2014. The only drainage issue on record is described in the PIR: the missing minor culvert at MP 1.20 and the need for a replacement culvert. Further site evaluation is recommended prior to design development to verify the characteristics and conditions of the minor cross-road culverts.

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EXISTING CONDITIONS

The three major drainage crossings are identified below as they are labeled in Figure B-1, according to their location on Goose Lake Road as defined by the project limits. Photographs of the major cross road culverts taken during the site visit are included for reference at the end of each crossing description.

1. MP 0.07: 48-inch CMP culvert The 48-inch corrugated metal pipe (CMP) culvert located at MP 0.07 is approximately 20 feet long and conveys the unnamed tributary of Little Goose Creek from the east to the west side of the roadway approximately 0.2 miles upstream of where the tributary joins with Little Goose Creek.

The crossing at MP 0.07 can be classified as a small stream as the channel width does not exceed 10 feet. As shown in Figure B-1.1, the floodway or main channel of the creek meanders upstream of the culvert with random variation and vegetation is approximately 20 to 100 feet from the channel on either bank. As stated in the PIR, there is no defined channel downstream of the culvert as water collects in a small pond directly downstream of the outlet during low flow events (see Figures B-1.5, B-1.6 and B-1.7). In addition, it was confirmed during the site visit that the channel slope upstream and downstream of the culvert is generally less than one percent in the vicinity the culvert.

No apparent creek bed aggradation or degradation was noticed during the site visit.

With the exception of the corrosion along the bottom of the barrel to about 24 inches from the invert and the slight misshapenness on the top, the 48-inch CMP culvert appeared to be in fair condition (see Figure B-1.4).

After evaluating the creek bed material as primarily cobble and coarse gravel, the Manning’s ‘n’ value was determined to be approximately 0.030 according to Table 3.1 of FHWA’s Hydraulic Engineering Circular No. 20: Stream Stability at Highway Structures (HEC-20). From observation at the site visit, the median bed particle diameter, D50 value, was estimated to be approximately six inches.

At the site visit, no major debris was observed as obstructing creek flow upstream or downstream of the culvert. Visible in Figures B-1.2 and B-1.3, there were large rocks located in front of the inlet that seemed to successfully function as inlet protection.

Pending verification from the maintenance foreman with the Idaho Transportation Department assigned to the site, it seems that there has been no significant issue with debris within the project area. Further field reconnaissance and interviews with the

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Figure B-1.1: Upstream of the 48-inch CMP culvert at MP 0.07 (standing on the roadway shoulder on the east side and looking upstream/east).

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Figure B-1.2: Upstream of the 48-inch CMP culvert at MP 0.07 (standing beyond the east side of the roadway and looking downstream/west).

Figure B-1.3: Upstream of the 48-inch CMP culvert at MP 0.07

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Figure B-1.4: Upstream of the 48-inch CMP culvert at MP 0.07

Figure B-1.5: Downstream of the 48-inch CMP culvert at MP 0.07 (standing on the roadway shoulder on the west side and looking downstream/southwest).

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Figure B-1.6: Downstream of the 48-inch CMP culvert at MP 0.07 (standing beyond the west side of the roadway and looking southeast).

Figure B-1.7: Downstream of the 48-inch CMP culvert at MP 0.07 (standing beyond the west side of the roadway and looking south).

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Figure B-1.8: Downstream of the 48-inch CMP culvert at MP 0.07 (standing beyond the west side of the roadway and looking upstream/southeast).

2. MP 0.22: Dual 54-inch CMP culverts The dual 54-inch CMP culverts located at MP 0.22 are approximately 23 feet in length and convey Little Goose Creek from the east to the west side of the roadway upstream of its confluence with Thorn Creek.

The crossing at MP 0.22 can be classified as a small stream as the channel width does not exceed 10 feet. The main channel of the creek is relatively straight upstream of the culvert with a bend immediately upstream of the existing gabion basket on the south bank (see Figures B-2.2 and B-2.3). As expressed in the PIR, a realignment of the culverts to better line up with the natural channel would encourage more stable conditions at the crossing and prevent potential bank erosion and scouring and would also reduce the need for and cost of implementing countermeasures. A feasibility analysis is recommended during design development.

At the site visit there appeared to be a berm or small dam about 50 feet downstream of the outlet (see Figure B-2.6), which was not identified in the PIR. This structure could be a level spreader installed to dissipate energy during high flow conditions. During the low flow event at the time of the site visit the berm/dam did not seem to obstruct flow, but

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Project No. ID PFH 98(1) Goose Lake Road Reconstruction 41 further site evaluation is needed to verify drainage patterns during a high flow event. In addition, it was confirmed that the channel slope upstream and downstream of the culvert is generally about two percent.

The culverts appeared to be in fair condition but corrosion was observed inside the barrels to about 24 inches from the invert (see Figure B-2.5).

The overlay of ice on the channel bottom made it difficult to accurately determine the Manning’s ‘n’ and D50 values at the site visit. However, because general site conditions are similar to the culvert at MP 0.07, a suggested Manning’s ‘n’ of 0.03 has been deemed appropriate for this location as well.

No major debris was observed as obstructing creek flow upstream or downstream of the culverts.

Figure B-2.1: Upstream of the dual 54-inch CMP culverts at MP 0.22

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Figure B-2.2: Upstream of the dual 54-inch CMP culverts at MP 0.22

Figure B-2.3: Upstream of the dual 54-inch CMP culverts at MP 0.22

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Figure B-2.4: Downstream of the dual 54-inch CMP culverts at MP 0.22 (standing beyond the west side of the roadway and looking downstream/west).

Figure B-2.5: Downstream of the dual 54-inch CMP culverts at MP 0.22 (standing beyond the west side of the roadway and looking downstream/west).

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Figure B-2.6: Downstream of the dual 54inch CMP culverts at MP 0.22 (standing beyond the west side of the roadway and looking upstream/east).

3. MP 3.00: 36-inch CMP and 24-inch CMP culverts At the hairpin curve at approximately MP 3.00, the 36-inch CMP culvert is located on the north side of the roadway bend and the 24-inch CMP culvert is located on the south side of the bend (see Figure B-3.1). Both culverts are approximately 35 feet in length and join the unnamed tributary of Thorn Creek on the north side with the main channel of Thorn Creek on the south side from the east side to a ravine inside the bend on the west side of the roadway.

Both crossings can be classified as small streams as the channel widths do not exceed 10 feet. On the north side of the roadway bend at the 36-inch CMP culvert crossing, the upstream channel of the unnamed tributary of Thorn Creek is very shallow with a depth not greater than one foot as no defined banks were visible underneath the snow during the site visit (see Figure B-3.3). Conversely, upstream of the 24-inch CMP culvert crossing, the main channel of Thorn creek is clearly defined with a slight meander (see Figure B-3.5).

The two culverts discharge to the ravine on the west side of the roadway, shown in Figures B-3.6 and B-3.7, where the flow joins and Thorn Creek continues west.

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The culverts appeared to be in good condition and no corrosion was observed.

The creek bed material at both culvert crossings can be identified as mostly cobble and coarse gravel and therefore, the Manning’s ‘n’ value was determined to be approximately 0.030 according to the HEC-20 publication and the D50 value was estimated to be approximately 12 inches.

No major debris was noticed as obstructing creek flow upstream or downstream of the culverts.

Figure B-3.1: Hairpin curve over Thorn Creek at approximately MP 3.00 (standing next the inlet of the 36-inch culvert and looking downstream/southwest).

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Figure B-3.2: Upstream of the 36-inch CMP culvert at MP 3.00

Figure B-3.3: Upstream of the 36-inch CMP culvert at MP 3.00 (standing beyond the east side of the roadway and looking upstream/east).

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Figure B-3.4: Upstream of the 36-inch CMP culvert at MP 3.00

Figure B-3.5: Upstream of the 24-inch CMP culvert at MP 3.00 (standing beyond the east side of the roadway and looking upstream/east).

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Figure B-3.6: Downstream of the 24-inch CMP culvert at MP 3.00 (standing on the roadway shoulder on the west side and looking upstream/southeast).

Figure B-3.7: Downstream of the 36-inch CMP culvert at MP 3.00 (standing on the roadway shoulder on the west side and looking upstream/northeast).

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4. Upstream of MP 0.0: Dual 36-inch CMP culverts The dual 36-inch CMP culverts are approximately 45 feet long and convey the unnamed tributary underneath SH 55 at the crest vertical curve location before the flow reaches the 48-inch CMP culvert at MP 0.07.

The crossing upstream of MP 0.0 can be classified as a small stream as the channel width does not exceed 10 feet. As shown in Figures B-4.2 and B-4.4, the floodway or main channel of the creek is relatively straight both upstream and downstream of the culverts.

No apparent creek bed aggradation or degradation was noticed during the site visit.

The culverts appeared to be in fair condition, except for the corrosion noticed along the bottom of the barrel to about 24 inches from the invert, visible in Figure B-4.3. Further investigation is recommended to determine the remaining service life for the culverts.

Similar to the creek crossing at MP 0.07, the creek bed material at the creek crossing upstream of MP 0.0 was determined to be primarily cobble and coarse gravel with a Manning’s ‘n’ value of approximately 0.030 according to the HEC-20 publication. In addition, the D50 value was estimated to be approximately six inches.

At the site visit, no major debris was observed as obstructing creek flow upstream or downstream of the culverts.

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Figure B-4.1: Upstream of the dual 36-inch CMP culverts located south of MP 0.0 (standing beyond the west side of the roadway and looking downstream/east).

Figure B-4.2: Upstream of the dual 36-inch CMP culverts located south of MP 0.0 (standing beyond the west side of the roadway and looking downstream/east).

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Figure B-4.3: Downstream of the dual 36-inch CMP culverts located south of MP 0.0 (standing beyond the east side of the roadway and looking upstream/west).

Figure B-4.4: Downstream of the dual 36-inch CMP culverts located south of MP 0.0 (standing beyond the east side of the roadway and looking upstream/west).

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APPENDIX C

Traffic Reconnaissance Report

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MEMORANDUM

To: Mark E. Hirota, PE, Parsons Brinckerhoff

From: Danielle Scharf, PE, PTOE, LEED AP, Sanderson Stewart

Date: December 10, 2014

Reference: ID PFH 98, Goose Lake Road – Traffic Reconnaissance Report

The purpose of this memorandum is to summarize the preliminary traffic findings relative to the Goose Lake Road project in McCall, Idaho. It addresses the data sources and analysis procedures used to complete the Traffic Reconnaissance Report, summarized into the following categories:

Traffic Volume Data Vehicle Crash Data Design Recommendations

TRAFFIC VOLUME DATA

New traffic volume data was not collected for this particular phase of the evaluation of Goose Lake Road. The Project Identification Report (PIR) for ID PFH 98, Goose Lake Road (2011) was a resource that was utilized for review of historic traffic data and volume projection information.

The PIR reported a USFS-provided average daily traffic (ADT) volume of 328 vehicles per day in 2007 and 762 vehicles per day in 2010.