00014024_Attachment F_Additional Documentation.pdf

For the best experience, open this PDF portfolio in

Acrobat X or Adobe Reader X, or later.

Get Adobe Reader Now!

http://www.adobe.com/go/reader

113420 - CoosCo_2024ERStormDamage_Bundle2_Justification&Figures_Letter.docx

3990 Collins Way, Suite 100 | Lake Oswego, Oregon 97035-3437 | 503-210-4750 www.shannonwilson.com

November 6, 2024

Paul Slater, Public Works Director/Roadmaster Coos County Public Works 1281 West Central Coquille, OR 97423

RE: 2024 ER STORM DAMAGE

BUNDLE 2 – MITIGATION JUSTIFICATION, GEOLOGIC SUMMARY & FIGURES

FAIRVIEW-SUMNER LN, MP 4.7 & SITKUM LN, MP 6.7 STORM DAMAGE SITES

COOS COUNTY, OREGON

Dear Mr. Slater:

Shannon & Wilson, Inc. (Shannon & Wilson), is pleased to submit this letter containing justification of the proposed mitigation alternative (tieback soldier pile walls) selected at the time of the Detailed Damage Inspection Reports (DDIR) preparation, including geologic summary and figures, for the Fairview-Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 storm damage sites. As we understand that this information has been requested by FHWA on behalf of ODOT, we have also enclosed the betterment benefit-cost analyses (and associated attachments) we transmitted to your office on September 4, 2024, for a complete record of the considerations associated with the two subject storm damage sites.

ADDITIONAL MITIGATION JUSTIFICATION DISCUSSION

The proposed landslide mitigations discussed in the DDIR prepared in late May of 2024 for both the Fairview Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 storm damage sites contemplate tieback soldier pile walls for the temporary and/or permanent repair. The DDIRs were prepared based on a desktop literature review of publicly available information and a site reconnaissance. The purpose of the DIRRs was not to provide a geotechnical causation explanation or least cost mitigation evaluation or justification.

There are a myriad of additional landslide mitigation alternatives which could be considered for these sites, including, but not limited to:

shear key buttresses;

drainage improvements;

lightweight fill;

stone columns;

shear piles/shafts;

http://www.shannonwilson.com/

Coos County Public Works

113420 Page 2 of 7 CoosCo_2024ERStormDamage_Bundle2_Justification&Figures_Letter.docx secant pile walls;

tangent pile walls;

Case 2 reticulated micropile walls;

Case 1 slope stabilization micropile;

mass balance redistribution via regrading/vertical alignment revision; and roadway realignment around the slide areas.

Not all of these mitigation alternatives are reasonably feasible, either from a geotechnical or economic perspective. For both sites, without the benefit of a geotechnical study with substantially more field data than currently exists, including subsurface explorations, a comparably geotechnically feasible and potentially cost-effective mitigation solution relative to a tieback solider pile wall is a shear key buttress.

At the time the DDIRs were prepared, tieback solider pile wall mitigations were preferred over shear key buttress mitigation alternatives for the following logistical reasons, most related to timing, in that, at the time, the intent was to have a mitigation alternative designed and under construction contract or being self-performed within 270-days of the storm event, by early to mid-October 2024:

1. Owner agency preference and experience for soldier pile walls:

a. Coos County has previous experience with self-performing deadman tieback soldier pile wall construction and stated a general preference for such mitigations where technically feasible.

2. Right-of-Way acquisition time frame days for shear key buttresses as the toe of the shear key buttress will extend beyond County Right-of-Way:

a. Fairview-Sumner Ln, MP 4.7 - Adjacent owner is the Bureau of Land Management, potential multi-year delay due to Right-of-Way acquisition or expanded easement of Federally owned land.

b. Sitkum Ln, MP 6.7 – Adjacent owner is the King Ranch, LLC, potential minimum one year delay due to Right-of-Way acquisition of privately owned land. Easement procurement for Oregon Division of State Lands also likely required.

3. Environmental permitting time frame for shear key buttresses:

a. Fairview-Sumner Ln, MP 4.7 – Environmental studies (biological and archaeological) and permitting on Federal lands, likely a multi-year delay (likely over lapping with the Right-of-Way acquisition period). Potential cumulative two- to three-year delay.

b. Sitkum Ln, MP 6.7– In-Water-Work (IWW) permitting and timing, potentially archeological survey timing.

113420 Page 3 of 7

i) IWW timing, likely the summer season of 2026, after the completion of Right-of- Way acquisition at the time the DDIRs were prepared in May of 2024. Potential cumulative two-year delay.

As a result of these time constraints, at the time the DDIRs were prepared, shear key buttress mitigations for these sites did not meet the County’s needs to be underway within 270-days of the storm event with a construction contract. At the time, it was presumed the design effort could be directly appointed by the County and the construction contracts awarded and administered by the County as emergency repairs, which would ultimately also function as permanent repairs. Previous FHWA Emergency Relief events in southern Oregon had been managed in a similar manner. As a result, shear key buttress mitigations were not submitted in the DDIRs as they were not logistically viable at the time the DDIRs were prepared.

Additionally, given the minimal geometric, geologic, and geotechnical information available at the time the DDIRs were prepared, it was presumed that soldier pile walls with tiebacks would be required. It is possible that formal design efforts may reduce, eliminate, or confirm the need for tiebacks. Several types (deadman, stranded, solid bar, hollow bar, self-drilling soil nail) of tiebacks could also be considered.

At the time the initial DDIRs were prepared in May of 2024, high-level conceptual scoping cost estimates for a shear key buttress mitigation alternative for these sites were also made.

Table 1 below summarizes these cost estimates. These cost estimates do not include Preliminary Engineering (PE) efforts for environmental permitting costs or PE efforts for Right-of-Way acquisition costs, or the cost of the Right-of-Way itself, nor do they include Construction Engineering (CE) costs for construction contract administration and inspection. The included CE costs only incorporate a moderate level of submittal and requests for information (RFIs) review and a single site visit. These additional costs could add over 50 percent to the estimates below and add at least one calendar year to the project development period. Engineering PE costs for environmental permitting or Right-of-Way acquisition are not applicable (or to a much lesser extent) to the PE estimates presented in the DDIRs for the tieback soldier pile wall alternative.

113420 Page 4 of 7

Table 1: Bundle 2 Shear Key Butress Conceptual Cost Estimate Summary Information

Location (Road Name and Milepoint) Description of Proposed Landslide Betterment Mitigation

Cost, PE/CE + Construction

(1000s of $)1

Fairview-Sumner Ln MP 4.7

Install a 215-foot-wide rock buttress approximately 25 feet high with shear key at toe. Restore the gravel surface. Remove the existing compromised roadway subgrade. Replace 24" HDPE culvert.

Replace the French drain in left ditch line.

Sitkum Ln MP 6.7 Install a 90-foot-wide rock buttress approximately 50 feet high with shear key at toe. Full-width AC overlay, 2" thick, 90 feet long, 24 feet wide.

NOTES:

Engineering PE costs do not include environmental permitting or Right-of-Way acquisition. Engineering CE costs do not include construction contract administration or inspection.

Betterment Analysis Summary

Shannon & Wilson completed a betterment benefit-cost analysis for the proposed soldier pile tieback retaining wall alternative for both sites in accordance with the FHWA Emergency Relief (ER) Manual. Our analysis results were summarized in a letter dated September 4, 2024, which is enclosed with this letter, and concluded that tieback soldier pile walls were cost effective relative to restoring the sites strictly to the pre-damage condition and risking similar repetitive failures, which have occurred at both sites in the past.

Table 2 below summarizes the results of our betterment benefit-cost analyses. In all cases, the benefit-cost ratio was greater than 1.0 for each of the three recurrence and inflationary scenarios considered, in several cases, order(s) of magnitude greater than 1.0. The complete details of the betterment benefit-cost justification, including the definition of the cases considered, are included in the enclosed letter.

113420 Page 5 of 7

Table 2: Bundle 2 Betterment Benefit-Cost Analyses–Summary Information

Location (Road Name and Milepoint)

Description of Proposed Landslide Betterment

Mitigation

Basic Cost, PE/CE +

Construction (1000s of $)

Betterment Cost, PE/CE +

Benefit- Cost Ratio, Case 1

Case 2

Case 3

Fairview- Sumner Ln

MP 4.7

Install a 215-foot-long soldier pile wall approximately 3-4 feet from the right shoulder, 15 foot design height with tiebacks.

Remove the existing compromised roadway subgrade. Replace 24" HDPE culvert. Replace the French drain in left ditch line. Restore the gravel surface.

165 2275 1.80 63.22 4.29

Sitkum Ln

MP 6.7

Install a 90-foot-long soldier pile wall approximately 3-4 feet from the right shoulder, 12 foot design height with tiebacks. Full-width AC overlay, 2" thick, 90 feet long, 24 feet wide.

165 1060 4.24 149.05 10.12

GEOLOGIC SUMMARY AND FIGURES

Geologic Summary

Fairview-Sumner Ln, MP 4.7

The project site is located on a moderately steep hillside near a sharp horizontal curve in the roadway as shown on the Site Plan, Figure 1. As shown on Figure 2, landslide deposits are depicted in the Oregon Department of Geology And Mineral Industries’ (DOGAMI) Statewide Landslide Information Database for Oregon (SLIDO) mapping approximately 100 feet south of the site. Additionally, previous landslide movement is readily apparent in the DOGAMI SLIDO mapping both up and down slope of the landslide site. Based on DOGAMI Geologic mapping, bedrock in the area is shown as Roseburg Formation (sedimentary rock) which consists of thick sequences of sandstone and siltstone with minor conglomerate and massive sandstone.

Sitkum Ln, MP 6.7

The project site is located within a bend in the Coquille River flood plain (while the local reach of the river is quite straight at the site) as shown on the Site Plan, Figure 4. As shown

113420 Page 6 of 7 on the SLIDO Map, Figure 5, previous landslide movement is readily apparent in the DOGAMI SLIDO mapping up slope of the landslide site. Based on DOGAMI Geologic mapping the site is generally underlain by Alluvium and bedrock of the Siletz River Volcanics consisting of submarine basalt, pillow basalt, and deep marine sediments.

Figures

We have included six additional figures to facilitate the understanding of the landslide sites.

A Site Plan for each site (Figures 1 and 4) which is a Google Earth image overlain by contours at 2-foot intervals produced from DOGAMI Light Detection And Ranging (LiDAR). The Site Maps show the approximate location of the presented cross-sections.

A SLIDO Map for each site (Figures 2 and 5) which is DOGAMI LiDAR overlain with historic landslide information.

A Typical Cross Section for each site (Figures 3 and 6) displaying a cross section near the center of each landslide area which is a composite of DOGAMI LiDAR and field information collected in May of 2024. The Site Maps show the approximate location of the cross sections.

CONCLUSION

Tieback soldier pile walls remain a technically feasible mitigation alternative, as they were at the time the DDIRs were prepared. At that time, tieback soldier pile walls had the potential to meet the intended timeframes for implementation and, at this juncture, can likely be implemented months to years sooner than shear key buttresses. For a formal geotechnical evaluation of various mitigation alternatives, additional studies and information are required, including site topography, landslide feature mapping, and subsurface investigations, potentially including ground movement and groundwater level monitoring, depending on the intended usage.

Thank you for your consideration of Shannon & Wilson for this project. Please contact Pete Castro directly (503-310-8058; Pete.Castro@shanwil.com) if you have any questions about this letter, or if we may be of further service to you.

113420 Page 7 of 7

Sincerely, SHANNON & WILSON

Pete Castro, PE, GE Senior Associate, Geotechnical Engineer

PTC:ECP/myw

Enc. Figure 1 – Site Plan for Fairview-Sumner Lane, MP 4.7 Figure 2 – SLIDO Map for Fairview-Sumner Lane, MP 4.7 Figure 3 – Typical Cross Section A-A’ for Fairview-Sumner Lane, MP 4.7 Figure 4 – Site Plan for Sitkum Lane, MP 6.7 Figure 5 – SLIDO Map for Sitkum Lane, MP 6.7 Figure 6 – Typical Cross Section B-B’ for Sitkum Lane, MP 6.7 Bundle 2 – Betterment Benefit-Cost Analyses Letter, September 4, 2024 (with enclosures)

A

A'

FAIRVIEW SUMNER LN

Coos County 2024 ER Storm Damage Coos County, Oregon

SITE PLAN

FAIRVIEW-SUMNER LANE MP 4.7

November 2024 113420

Fi le na m e:

P

:\G

IS

\P D

X \1

0s

0_ C oo s o

E R

S to rm am ag e\ Av xd

\S ite la n_

FV

-S 4.

7.

at

0/

/2

Lo gi n:

H

FIG. 1

0 60 12030

Scale in Feet

LEGEND

Designation and Location of Typical Cross Section

A A'

NOTES

1. 2013 aerial imagery obtained through Google Earth Pro.

2. Contours were derived from 2009 LiDAR data obtained through DOGAMI.

Fairview-Summer Ln MP 4.7

Roseburg Formation

Roseburg Formation, basalt

SLIDO MAP

FIG. 2

0 100 20050

:\C ho s\ es kt op tu dy

W or ki ng

F ile

.m

3/

L og in : S

1. LiDAR imagery obtained from DOGAMI Oregon Lidar

Consortium.

2. Geologic data obtained from the DOGAMI Oregon Geologic

Data Compilation, release 7.

3. Landslide inventory data obtained from DOGAMI Statewide

Landslide Information Database for Oregon (SLIDO), version 4.5.

Scarps

Deposits

Ground Surface from 2009 LiDAR

40.0'

10.0'

Landslide head scarp, 1.5' vertical offset

Inferred slide plane. Actual location unknown.

Reported 12" diameter x 0.375" wall natural gas main

24" diameter corrugated HDPE double-wall culvert with half pipe at outlet. Installed after January 2024 failure, then failed again. Pipe is crushed to about 1' high at headscarp.

Old damaged perforated pipe, about

4" to 6" diameter

Older 2' to 3' diameter rock fragments from previous mitigation attempt.

Approximate easement width, 40' to 50' (BLM adjacent, both sides)

FIG

. 3

TYPICAL CROSS SECTION A-A'

FIG. 3

1. LiDAR ground surface derived from 2009 LiDAR data obtained through DOGAMI.

2. Field observations based on conditions observed on

May 22, 2024.

3. All dimensions and features are approximate.

4. See Figure 1 for cross section location.

5. Property boundaries are approximate, based on On

X Offroad on November 5, 2024.

113420November 2024

File: P:\PDX\113000s\113420 Coos Co 2024 ER Storm Damage\DRAFTING\SectionFigs.dwg Date: 11/5/2024 Author: AEH

PRELIMINARY -

NOT FOR

CONSTRUCTION0 30 60

Approximate Scale in Feet

B

B'

EAST FORK COQUILLE RIVER

SITKUM LN

SITE PLAN

SITKUM LANE MP 6.7

ite la n_ itk um

6.

Lo gi n:

FIG. 4

0 60 12030

Designation and Location of Typical Cross Section

B B'

1. 2023 aerial imagery obtained through Google Maps Satellite.

2. Contours were derived from 2009 LiDAR data obtained through DOGAMI.

EAST FORK COQUILLE RIVER

Sitkum Ln, SITKUM LN

WEEKLY CRK RD

SLIDO MAP

FIG. 5

0 400 800200

LI

O _S itk um

6.

L og in

: A

Mapped Landslide Deposit

1. Hillshade was derived from 2009 LiDAR data, obtained through DOGAMI.

2. Mapped deposits provided with DOGAMI publication SLIDO-4.5.

Ground surface from 2009 LiDAR

East Fork Coquille River

40'

5'

6.0' 11.5' ℄

Two lines of recent A.C.

cracking to 0.5-inch wide.

Landslide head scarp, 4' to 5' vertical offset.

Layers of A.C. visible in head scarp to 2.5 feet deep below roadway surface.

Observed ground surface

Inferred slide plane. Actual location unknown; may continue into river bed.

Approximate R/W width 60' (private ownership both sides)

Approximate limits of private ownership

Oregon Division of State Lands ownershipPrivate ownership

. 6

TYPICAL CROSS SECTION B-B'

FIG. 6

1. LiDAR ground surface derived from 2009 LiDAR data obtained through DOGAMI.

2. Field observations based on conditions observed on

May 21, 2024.

3. All dimensions and features are approximate.

4. See Figure 4 for cross section location.

5. Property boundaries are approximate, based on On

X Offroad on November 5, 2024.

113420November 2024

File: P:\PDX\113000s\113420 Coos Co 2024 ER Storm Damage\DRAFTING\SectionFigs.dwg Date: 11/5/2024 Author: AEH

PRELIMINARY -

NOT FOR

CONSTRUCTION0 30 60

Approximate Scale in Feet

113420 - CoosCo_2024ERStormDamage_Bundle2_BettermentAnalyses_Memo.docx

3990 Collins Way, Suite 100 | Lake Oswego, Oregon 97035-3437 | 503-210-4750 www.shannonwilson.com

September 4, 2024

Coos County Public Works 1281 West Central Coquille, OR 97423

RE: 2024 ER STORM DAMAGE

BUNDLE 2 – BETTERMENT BENEFIT-COST ANALYSES

FAIRVIEW-SUMNER LN, MP 4.7 & SITKUM LN, MP 6.7 LANDSLIDE DAMAGE SITES

COOS COUNTY, OREGON

Dear Mr. Slater:

Shannon & Wilson, Inc. (Shannon & Wilson), is pleased to submit this letter containing the findings of our betterment benefit-cost analyses for the Fairview Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 landslide damage sites relative to the enclosed draft Detailed Damage Inspection Reports (DDIRs) we submitted to your office on May 31, 2024 (attachments revised, V3.0, as transmitted via email on June 19, 2024).

BETTERMENT BENEFIT-COST ANALYSES METHODOLOGY

Our betterment analyses were conducted based on the guidance provided in the Federal Highways Administration’s (FHWA) Emergency Relief (ER) Manual (Federal-Aid Highways), Updated May 31, 2013, specifically page 24 which states:

Betterments, for the purposes of the ER program, are added protective features or changes that modify the function or character of a facility from what existed prior to the disaster or catastrophic failure. Betterments can be justified for ER funding by comparing the projected cost to the ER program from potential recurring damage over the design life for the basic repair to the cost of the betterment. The analysis does not include other factors often included in highway benefit/cost evaluations, such as traffic delays costs, added user costs, motorist safety, economic impacts, etc.

The betterments contemplated are categorized on page 24 of FHWA’s manual under the headings “Betterments” “(1) Betterments Involving Added Protective Features” and “Stabilizing slide areas”. Specifically, we considered the cost of the proposed tieback soldier pile retaining wall betterment repairs discussed in the enclosed DDIRs for the landslide-damaged areas of the county roadway facility relative to the cost of re-establishing the landslide-damaged facilities to pre-damage condition (basic repair) on a recurring basis due to unmitigated and ongoing landslide movement potential.

http://www.shannonwilson.com/

113420 Page 2 of 3 CoosCo_2024ERStormDamage_Bundle2_BettermentAnalyses_Memo.docx

The premise of these betterment analyses is that if the sites are merely restored to pre-failure conditions (basic repair), subsequent landslide movement of similar magnitude may continue to occur at some periodicity, the aggregate cost of which may exceed the cost of a betterment mitigation. The periodicity for these betterment analyses were estimated on the basis that the primary causation of the landslide movement at each site was due to the heavy precipitation events which occurred in mid-January 2024. The periodicity of future similar precipitation events was evaluated on the basis of historic NOAA precipitation data, which established an analyses recurrence interval. The recurrence interval was roughly correlated to on-site observations of previous landslide movement and repair efforts as well as verbal history shared by Coos County staff. The design life of the proposed betterment mitigation at each site was then divided by the recurrence interval to determine the number of subsequent landslide movement events the betterment’s mitigation may prevent. The inputs to the betterment mitigation benefit-cost analysis include the following:

1. It was determined there were 6.78 inches of precipitation associated with the January 12- 19, 2024, storm event and there were 16.27 inches of precipitation during the month of January 2024 based on NOAA precipitation data for the nearest station to both landslide damage sites (Station USC00351836, in Coquille, Oregon), see Figure 1 attached.

Researching available NOAA precipitation data for that station, available since 1975, there have been 15 months in the last 49 years which have had 15 inches (or more) of precipitation (December and January both having five such occurrences, November having four such occurrences and March having one such occurrence, in 2012), see Figure 2 attached. Using the resulting 3.3 years as the event recurrence frequency, for a 75-year design life associated with a tieback soldier pile wall, there would be about 23 such events (22 additional events), each of which are likely to require repairs due to landslide movement if the repair were limited to restoring the pre-failure condition.

2. The tieback soldier pile wall has a 75-year design life as per AASHTO standards.

3. The summation of the costs of Preliminary Engineering (PE), Construction Engineering (CE), and construction were considered in the totals for both the basic cost and the betterment mitigation costs. The cost estimates for restoring to pre-failure conditions (basic cost) are enclosed. Coincidentally, both sites are the same at $165k ($30k for PE/CE and $135k for construction).

4. The benefit-cost ratio was computed three ways:

a. Case 1: Basic cost to betterment cost, with a 3.3-year recurrence interval, no consideration for the time value of money (i.e. inflation).

b. Case 2: Basic cost to betterment cost, with a 3.3-year recurrence interval (22 additional events in the next 75 years), with inflation for PE/CE and construction costs presumed at 7.0% per year (ODOT pre-COVID standard, likely higher in recent years).

113420 Page 3 of 4

c. Case 3: Basic cost to betterment cost, doubling the recurrence interval to 6.6 years (10 additional events in the next 75 years), with inflation for PE/CE and construction cost presumed at 3.5% per year (slightly more than the Consumer Price Index average of 3.2% for the period 1929-2023).

BETTERMENT BENEFIT-COST ANALYSES RESULTS SUMMARY

Table 1 below summarizes the results of our betterment benefit-cost analyses. In all cases, the benefit-cost ratio was greater than one.

Table 1: Bundle 2 Betterment Benefit-Cost Analyses–Summary Information

Location (Road Name and Milepoint)

Description of Proposed Landslide Betterment

Mitigation

Basic Cost, PE/CE +

Betterment Cost, PE/CE +

Case 1

Case 2

Case 3

Fairview- Sumner Ln

MP 4.7

Install a 215 ft long soldier ft from the right shoulder, 15 ft design height with tiebacks. Remove the existing compromised roadway subgrade.

Replace 24" HDPE culvert.

Replace the French drain in left ditch line. Restore the gravel surface.

165 2275 1.80

63.22

4.29

Sitkum Ln

Install a 90 ft long soldier ft from the right shoulder, 12 ft design height with tiebacks. Full-width AC overlay, 2" thick, 90 ft long, 24 ft wide.

165 1060 4.24

149.05

10.12

BETTERMENT BENEFIT-COST ANALYSES CONCLUSION

As shown in Table 1, the benefit-cost ratio for both sites was greater than one for each of the three recurrence and inflationary scenarios considered. Our conclusion is that both the Fairview Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 storm damage sites meet FHWA’s guidelines for the justification of the proposed betterment repair.

113420 Page 4 of 4

Thank you for your consideration of Shannon & Wilson for this project. Please contact Pete Castro directly (503-310-8058; Pete.Castro@shanwil.com) if you have any questions about this letter, or if we may be of further service to you.

Sincerely, SHANNON & WILSON

Pete Castro, PE, GE Senior Associate, Geotechnical Engineer

PTC:ECP/mmb

Enc. Figure 1 – Precipitation Data for January – February 2024 Figure 2 – Historical Precipitation Data 1975 to 2024 Cost Estimates to restore per-failure condition (basic repair) for Fairview Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 sites Draft DDIR Form, V3.0, revised June 19, 2024, for the Fairview Sumner Ln, MP 4.7 and Sitkum Ln, MP 6.7 sites

PRECIPITATION DATA FOR

JANUARY - FEBRUARY 2024

Geotechnical and Environmental Consultants

SHANNON & WILSON, INC.

113420September 2024

2023-2024 Storm Damage

. 1

Notes:

1. Rainfall data sourced from NOAA station USC00351836 located within

Coquille, Oregon

Pr ec ip ita tio n

(in ch

Date

2023-2024 Storm Damage

HISTORICAL PRECIPITATION DATA

1975 to 2024

August 2024 113420

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

De c-

To ta l M on th ly re ci pi ta tio n (in ch

Month - Year

Total Monthly Precipitation Coquille City, Oregon

Project No. Scope of Work Length (ft) Date 113420 Grading, Paving 215 27-Aug-24

Spec No. Item Description Unit Quantity Unit Cost ($) Total Cost ($)

210 Mobilization (rounded up to next $1000) L.S. All 10.00% 11,000.00$ 221 TP&DT (rounded up to next $1000) L.S. All 10.00% 11,000.00$ 222 Temporary Traffic Control Signs L.S. All 6,000.00$ 6,000.00$ 223 Flaggers Hours 48 112.50$ 5,400.00$ 290 Erosion Control L.S. All 3,000.00$ 3,000.00$

305 Construction Survey L.S. All 9,750.00$ 10,000.00$ 330 General Excavation C.Y. 0 67.50$ -$

Stone Embankment (240 c.y. @ 130 pcf @ $90/c.y.) Ton 420 52.50$ 23,000.00$

350 Subgrade Geotextile S.Y. 359 3.00$ 2,000.00$

445 24 Inch, Culvert Pipe, 10 Ft Depth Foot 60 337.50$ 21,000.00$

640 Aggregate Base Ton 450 75.00$ 34,000.00$

1030 Permanent Seeding ($5000 min) Acre 0.20 7,500.00$ 5,000.00$ Subtotal without Mobilization or TP&DT 109,400.00$ Total, Construction Items 131,400.00$

DDIR Reported Repair Estimate (Rounded up to $5000 Interval) 135,000.00$ Engineering (PE/CE) Cost 30,000.00$

1) Cost estimates are for a 2024 construction year.

Coos Co - 2024 ER Storm Damage - Conceptual Repairs Cost Estimate Shannon & Wilson - Lake Oswego Office / David Evans and Associates - Salem Office

County Coos

Project Name

Right of Way Development and Control

Estimate By E. Paslack/P. Castro

Mobilization and Temporary Works

Roadwork

Bases

Drainage

113420 Grading, Paving 90 27-Aug-24

210 Mobilization (rounded up to next $1000) L.S. All 10.00% 11,000.00$ 221 TP&DT (rounded up to next $1000) L.S. All 10.00% 11,000.00$ 222 Temporary Traffic Control Signs L.S. All 6,000.00$ 6,000.00$ 223 Flaggers Hours 48 112.50$ 5,400.00$ 290 Erosion Control L.S. All 3,000.00$ 3,000.00$

305 Construction Survey L.S. All 9,750.00$ 10,000.00$

Stone Embankment (93 c.y. @ 130 pcf @ $90/c.y.) Ton 250 52.50$ 14,000.00$

310 Asphalt Pavement Saw Cutting Foot 110 15.00$ 2,000.00$ 350 Subgrade Geotextile S.Y. 140 3.00$ 1,000.00$

640 Aggregate Base Ton 54 75.00$ 5,000.00$

740 Commercial Asphalt Concrete Pavement Ton 35 480.00$ 17,000.00$

810 Guardrail Terminals, Non-Flared Each 2 6,750.00$ 14,000.00$ 810 Midwest Guardrail System, Type 2A Foot 15 75.00$ 2,000.00$ 810 Midwest Guardrail System, Type 3 Foot 90 120.00$ 11,000.00$

Pavement Markings 860 Longitudinal Pavement Markings - Paint Foot 405 7.50$ 4,000.00$

1030 Permanent Seeding ($5000 min) Acre 0.10 7,500.00$ 5,000.00$ Subtotal without Mobilization or TP&DT 108,150.00$ Total, Construction Items 130,150.00$

DDIR Reported Repair Estimate (Rounded up to $5000 Interval) 135,000.00$ Engineering (PE/CE) Cost 30,000.00$

E. Paslack/P.Castro

Wearing Surfaces

Guardrail

DETAILED DAMAGE INSPECTION REPORT (DDIR)

Title 23 Emergency Relief Program

FHWA Disaster Number

OR 2024-02

Oregon Disaster ID

JAN 2024

Site Location (Name of road, milepost, coordinates, distance from nearest intersection, etc.)

Site Jurisdiction ☐ City ☒ County ☐ State

Disaster Date 1/12/2024

DDIR Site Number

Click to enter text.

Emergency Repair EA

Description of Damage (Provide specific details - Bituminous shoulder undermined, slope failure, washed out culvert, etc.)

Large slide, right lane shoulder failure, gravel surface, 215 ft long. 24" HDPE culvert pinched/pulled apart. French drain in left ditch line destroyed. Existing culvert is about 3 to 5 ft deep (inlet to outlet). BLM adjacent owner.

City (if applicable)

U.S. Congressional District District 4

SECTION 1: EMERGENCY REPAIRS COST ESTIMATE

Em er ge nc y Re pa irs

Emergency repairs include work immediately after a disaster event to minimize the extent of damage, protect the remaining facilities, and restore essential traffic to federal-aid highway facilities. Description of Work Items (Equipment, Labor, and Materials) should include quantities and costs to substantiate estimate. Include completed and remaining emergency repairs. Emergency Repair EA: Click to enter text.

Install a 215 ft long soldier pile wall approximately 3-4 ft from the right shoulder, 15 ft design height with tiebacks. Remove the existing compromised roadway subgrade. Replace 24" HDPE culvert. Replace French drain in left ditch line. Restore the gravel surface.

Mobilization and Temporary Works - $412,000 Roadwork - $51,000 Drainage - $36,000 Structures - $1,475,000 Bases - $83,000 Right of Way Development and Control - $5,000 Total Rounded to - $2,065,000

See attached spread sheet for description of construction cost estimate work items, quantities and costs.

Contracting Method ☐Force Account ☐Emergency Contract ☐Negotiated Contract ☒Standard Competitively Bid Contract a

Contracting Agency

☐STA ☐LPA

Emergency Repair Estimate $2,065,000 Engineering (PE/CE) $210,000

Right-of-Way $N/A

Emergency Repair Total $2,275,000

SECTION 2: PERMANENT REPAIRS COST ESTIMATE

Pe an en t R ep ai rs

Permanent repairs are performed after the occurrence of a disaster to restore the highway to its pre-disaster condition or make it more resilient to future damage. Description of Work Items (Equipment, Labor, and Materials) should include quantities and costs to substantiate estimate. Include completed (incidental) and remaining permanent repairs. Permanent Repair EA: Click to enter text.

Contracting Method Permanent Repair Estimate $Click to enter text.

☐Force Account ☐Emergency Contract

Engineering (PE/CE) $Click to enter text.

Right-of-Way $Click to enter text.

Permanent Repair Total $Click to enter text.

Estimated Total Repair Cost $Click to enter text.

☐ Yes ☒ No

1. Was a contracting method other than competitively bid contract used for permanent repairs? If yes, please explain how it was determined that another contracting method was cost effective (see Chapter V.M.2 of ER Manual).

2. Were permanent repairs performed concurrently with emergency repairs? If yes, please explain how it was determined to be more economical or practical per 23 CFR 668.109(a)(2) (see Chapter II.D.2 of ER Manual).

How were resilience improvements considered?

☐ Resilience improvements were considered but are not warranted or are cost or otherwise prohibited ☐ Resilience improvements will be incorporated by upgrading the highway facility to current design standards ☐ Resilience improvements will be incorporated through adding protective features that would reduce future costs to the ER program. Attach Benefit/Cost Analysis and briefly explain.

☐ Resilience improvements will be incorporated because the site was identified as a facility repeatedly requiring repair due to emergency events in the statewide evaluation as required in 23 CFR 667.

☐ Resilience improvements will be incorporated outside the ER Program.

Verify the following for DDIR approval consideration.

☒ Map of damaged site included (if adjoining locations are combined to one site, all locations must be shown) ☒ Photos of the damaged site included ☒ Damaged site on an eligible federal-aid highway (not functionally classified as a local or rural minor collector)

Signature for Local Agency Site Recommendation

Signature State DOT Site Recommendation

Name Click to enter text. Name Click to enter text.

DDIR approval does not constitute a funding authorization. An ER application must be approved by the FHWA Division Administrator before funds can be authorized (23 CFR § 668.111(c)).

FOR FHWA USE ONLY Site Eligible ☐Yes ☐No

Signature for DDIR Approval

Comments

Name Click to enter text.

113420 Structure 215 19-Jun-24

210 Mobilization (rounded up to next $1000) L.S. All 10.00% 172,000.00$ 221 TP&DT (rounded up to next $1000) L.S. All 10.00% 172,000.00$ 222 Temporary Traffic Control Signs L.S. All 6,000.00$ 6,000.00$ 223 Flaggers Hours 480 112.50$ 54,000.00$ 290 Erosion Control L.S. All 7,500.00$ 8,000.00$

305 Construction Survey L.S. All 22,500.00$ 23,000.00$ 320 Clearing and Grubbing ($5000 min) Acre 0.10 90,000.00$ 9,000.00$ 330 General Excavation C.Y. 240 67.50$ 17,000.00$

430 12-inch Drain Pipe (Subsurface) Foot 200 75.00$ 15,000.00$

596 Furnish Soldier Pile Drilling Equipment L.S. All 75,000.00$ 75,000.00$ 596 Furnish Tieback Drilling Equipment L.S. All 45,000.00$ 45,000.00$

Soldier Pile Retaining Wall (215 ft long x 15 ft design height) w/ Tiebacks

S.F. 3225 420.00$ 1,355,000.00$

640 Aggregate Base Ton 1100 75.00$ 83,000.00$

Subtotal without Mobilization or TP&DT 1,718,000.00$ Total, Construction Items 2,062,000.00$

DDIR Reported Repair Estimate (Rounded up to $5000 Interval) 2,065,000.00$ Engineering (PE/CE) Cost 210,000.00$

Structures

J. Goodall/P. Castro

DETAILED DAMAGE INSPECTION REPORT (DDIR)

Title 23 Emergency Relief Program

FHWA Disaster Number

OR 2024-02

Oregon Disaster ID

JAN 2024

Site Location (Name of road, milepost, coordinates, distance from nearest intersection, etc.)

Site Jurisdiction ☐ City ☒ County ☐ State

Disaster Date 1/19/2024

DDIR Site Number

Emergency Repair EA

Description of Damage (Provide specific details - Bituminous shoulder undermined, slope failure, washed out culvert, etc.)

Right fill slope shoulder failure, 90 ft long, slope is 40 ft high. AC cracking and sagging in right lane. East Fork Coquille Rv is adjacent.

City (if applicable)

U.S. Congressional District District 4

SECTION 1: EMERGENCY REPAIRS COST ESTIMATE

Em er ge nc y Re pa irs

Emergency repairs include work immediately after a disaster event to minimize the extent of damage, protect the remaining facilities, and restore essential traffic to federal-aid highway facilities. Description of Work Items (Equipment, Labor, and Materials) should include quantities and costs to substantiate estimate. Include completed and remaining emergency repairs. Emergency Repair EA: Click to enter text.

Install a 90 ft long soldier pile wall approximately 3-4 ft from the right shoulder, 12 ft design height with tiebacks. Full width AC overlay, 2" thick, 90 ft long, 24 ft wide.

Mobilization and Temporary Works - $196,000 Roadwork - $37,000 Structures - $574,000 Bases - $12,000 Wearing Surfaces - $17,000 Guardrail - $27,000 Pavement Markings - $4,000 Right of Way Development and Control - $5,000 Total Rounded to - $875,000

See attached spread sheet for description of construction cost estimate work items, quantities and costs.

Contracting Method ☐Force Account ☐Emergency Contract

Emergency Repair Estimate $875,000 Engineering (PE/CE) $185,000

Right-of-Way $N/A

Emergency Repair Total $1,060,000

SECTION 2: PERMANENT REPAIRS COST ESTIMATE

Pe an en t R ep ai rs

Permanent repairs are performed after the occurrence of a disaster to restore the highway to its pre-disaster condition or make it more resilient to future damage. Description of Work Items (Equipment, Labor, and Materials) should include quantities and costs to substantiate estimate. Include completed (incidental) and remaining permanent repairs. Permanent Repair EA: Click to enter text.

Contracting Method ☐Force Account ☐Emergency Contract ☐Negotiated Contract ☐Standard Competitively Bid Contract

Permanent Repair Estimate $Click to enter text.

Engineering (PE/CE) $Click to enter text.

Right-of-Way $Click to enter text.

Permanent Repair Total $Click to enter text.

Estimated Total Repair Cost $Click to enter text.

1. Was a contracting method other than competitively bid contract used for permanent repairs? If yes, please explain how it was determined that another contracting method was cost effective (see Chapter V.M.2 of ER Manual).

2. Were permanent repairs performed concurrently with emergency repairs? If yes, please explain how it was determined to be more economical or practical per 23 CFR 668.109(a)(2) (see Chapter II.D.2 of ER Manual).

How were resilience improvements considered?

☐ Resilience improvements were considered but are not warranted or are cost or otherwise prohibited ☐ Resilience improvements will be incorporated by upgrading the highway facility to current design standards ☐ Resilience improvements will be incorporated through adding protective features that would reduce future costs to the ER program. Attach Benefit/Cost Analysis and briefly explain.

☐ Resilience improvements will be incorporated because the site was identified as a facility repeatedly requiring repair due to emergency events in the statewide evaluation as required in 23 CFR 667.

☐ Resilience improvements will be incorporated outside the ER Program.

Verify the following for DDIR approval consideration.

☒ Map of damaged site included (if adjoining locations are combined to one site, all locations must be shown) ☒ Photos of the damaged site included ☒ Damaged site on an eligible federal-aid highway (not functionally classified as a local or rural minor collector)

Signature for Local Agency Site Recommendation

Signature State DOT Site Recommendation

Name Click to enter text. Name Click to enter text.

DDIR approval does not constitute a funding authorization. An ER application must be approved by the FHWA Division Administrator before funds can be authorized (23 CFR § 668.111(c)).

FOR FHWA USE ONLY Site Eligible ☐Yes ☐No

Signature for DDIR Approval

Comments

Name Click to enter text.

113420 Structure 90 19-Jun-24

210 Mobilization (rounded up to next $1000) L.S. All 10.00% 73,000.00$ 221 TP&DT (rounded up to next $1000) L.S. All 10.00% 73,000.00$ 222 Temporary Traffic Control Signs L.S. All 6,000.00$ 6,000.00$ 223 Flaggers Hours 320 112.50$ 36,000.00$

305 Construction Survey L.S. All 15,000.00$ 15,000.00$

330 General Excavation C.Y. 140 67.50$ 10,000.00$ 310 Asphalt Pavement Saw Cutting Foot 110 15.00$ 2,000.00$ 350 Subgrade Geotextile S.Y. 140 3.00$ 1,000.00$

Soldier Pile Retaining Wall w/ Tiebacks (90 ft long x 12 ft design height)

S.F. 1080 420.00$ 454,000.00$

640 Aggregate Base Ton 153 75.00$ 12,000.00$

740 Commercial Asphalt Concrete Pavement Ton 35 480.00$ 17,000.00$

810 Guardrail Terminals, Non-Flared Each 2 6,750.00$ 14,000.00$ 810 Midwest Guardrail System, Type 2A Foot 15 75.00$ 2,000.00$ 810 Midwest Guardrail System, Type 3 Foot 90 120.00$ 11,000.00$

Pavement Markings 860 Longitudinal Pavement Markings - Paint Foot 405 7.50$ 4,000.00$

1030 Permanent Seeding ($5000 min) Acre 0.10 7,500.00$ 5,000.00$ Subtotal without Mobilization or TP&DT 726,000.00$ Total, Construction Items 872,000.00$

DDIR Reported Repair Estimate (Rounded up to $5000 Interval) 875,000.00$ Engineering (PE/CE) Cost 185,000.00$

J. Goodall/P.Castro

Wearing Surfaces

Guardrail

ADDITIONAL MITIGATION JUSTIFICATION discussion

Betterment Analysis Summary geologic summary and figures

Geologic Summary

Fairview-Sumner Ln, MP 4.7

Sitkum Ln, MP 6.7

Figures

Conclusion

Fig 6 - Section_Sitkum6.7.pdf

Sheets and Views

6.7

Fig 3 - Section_FV-S4.7.pdf

Sheets and Views

4.7

CoosCo_2024ERStormDamage_Bundle2_BettermentAnalyses_Memo_Unsecured.pdf

BETTERMENT BENEFIT-COST ANALYSES METHODOLOGY

BETTERMENT BENEFIT-COST ANALYSES RESULTS SUMMARY

BETTERMENT BENEFIT-COST ANALYSES CONCLUSION

Please wait...

If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document.

You can upgrade to the latest version of Adobe Reader for Windows®, Mac, or Linux® by visiting http://www.adobe.com/go/reader_download.

For more assistance with Adobe Reader visit http://www.adobe.com/go/acrreader.

Windows is either a registered trademark or a trademark of Microsoft Corporation in the United States and/or other countries. Mac is a trademark of Apple Inc., registered in the United States and other countries. Linux is the registered trademark of Linus Torvalds in the U.S. and other countries.

ODOT Logo

.\ODOT.png

FHWA Logo

.\FHWA.png

ODOT and FHWA Oregon Division ER PCE Form

*Use this form only for PCEs that meet the criteria under 23 CFR 771.117(c)(9)

Page of

Form 734-5461 (03/2025)

WARE Melanie

6.5.0.20211215.1.13

ODOT and FHWA Oregon Division NEPA Documentation for Disaster Repair Work

Section 1: Emergency Repair

This section covers emergency repairs undertook during or immediately after a disaster to minimize the extent of damage, protect remaining facilities, or restore essential traffic (23 CFR 668.103).

Describe all emergency repair work conducted for the purpose of: minimizing the extent of the damage; protecting remaining facilities; or restoring essential traffic. This includes, but is not limited to: erection/removal of barricades and detour signs; flagging and pilot cars; temporary substitute highway traffic service; temporary detour roadway connection or bridges; removal of debris or slides; removal of drift piling on bridges; placing riprap to relieve or prevent scour; replacement of washed out embankments and approach fills; and regrading or roadway surfaces, fills, and embankments. To document compliance with other environmental laws and regulations, the “Description of work” should also summarize any emergency consultation processes with other federal/state agencies and any other federal/state approvals required.

ODOT certifies that neither significant environmental effects, as described in [23 CFR §771.117(a)] nor unusual circumstances, as described in [23 CFR §771.117(b)] resulted and that the specific conditions/criteria for an FHWA categorical exclusion under 23 CFR 771.117(c)(9) are satisfied.

Section 2: Permanent Repair

This section covers permanent repairs plans to take after a disaster to restore the damaged site to its pre-disaster condition. The permanent repair work will:

• Occur within the existing right-of-way and in a manner that substantially conforms to the preexisting design, function, and location as the original (which may include upgrades to meet existing codes and standards as well as upgrades warranted to address conditions that have changed since the original construction); and

• Commence within a 2-year period beginning on the date of the declaration.

Describe all permanent repair work planned to restore the damaged site to its pre-disaster condition, including upgrades to meet existing codes and standards and/or warranted to address conditions that have changed since the original construction. Include the date of the Presidential or Governor's emergency or disaster declaration in the project description.

A. Section 106 Compliance via ODOT’s Programmatic Agreement

Select the appropriate project level finding(s) and enter the date(s); separate Historic and Archaeology as needed:

B. Tribal Coordination

C. Endangered Species Act via ODOT’s Programmatic Agreement

Select the appropriate ESA effects determination(s) and attach all relevant documentation:

D. Other Relevant Coordination, Clearances, Approvals, or Permits (check all that apply)

Describe all relevant clearances, approvals, permits, regulatory coordination, and/or consultation for checked boxes above:

ODOT certifies that this project has been reviewed and documented following the provisions of the FHWA and ODOT Programmatic Categorical Exclusion Agreement. ODOT certifies that neither significant environmental effects, as described in [23 CFR §771.117(a)] nor unusual circumstances, as described in [23 CFR §771.117(b)] will result. This information demonstrates that the specific conditions/criteria for an FHWA categorical exclusion under 23 CFR 771.117(c)(9) are satisfied.

CurrentPage:

PageCount:

FHWADNumb:

AgencySiteNumb:

CountiesDistrictRegion:

T35:

AgencyName: Coos County infobutton1:

infobutton2:

descriptionofwork:

T97:

T150: 0

T152: 0

T161:

T7: 0

T7: 0

T7: 0

T7: 0

T7: 0

T7: 0

T9:

T28:

text7:

T90: 0

ROWcheck: 0

LandCheck: 0

SocioeconimicsCheck: 0

EJCheck: 0

Wetlandscheck: 0 floodwaycheck: 0

WQcheck: 0 visualcheck: 0 fourfcheck: 0 sixfcheck: 0

AQcheck: 0

NoiseCheck: 0

Hazmatcheck: 0

OtherCheck: 0

ROWDetails:

LandUseDetail:

SocioeconDetails:

EJDetails:

WetlandsDetails:

FloodwaysDetails:

WaterQuality:

VisualResources:

fourFdetails:

sixfdedetails:

Airqualitydetails:

Noise:

Hazardousdetails:

OtherDetails:

T36:

T60:

T61:

4/12/25

113420 Structure 215 19-Jun-24

210 Mobilization (rounded up to next $1000) L.S. All 10.00% 172,000.00$ 221 TP&DT (rounded up to next $1000) L.S. All 10.00% 172,000.00$ 222 Temporary Traffic Control Signs L.S. All 6,000.00$ 6,000.00$ 223 Flaggers Hours 480 112.50$ 54,000.00$

305 Construction Survey L.S. All 22,500.00$ 23,000.00$

330 General Excavation C.Y. 240 67.50$ 17,000.00$

430 12-inch Drain Pipe (Subsurface) Foot 200 75.00$ 15,000.00$

Soldier Pile Retaining Wall (215 ft long x 15 ft design height) w/ Tiebacks

S.F. 3225 420.00$ 1,355,000.00$

640 Aggregate Base Ton 1100 75.00$ 83,000.00$

Subtotal without Mobilization or TP&DT 1,718,000.00$ Total, Construction Items 2,062,000.00$

DDIR Reported Repair Estimate (Rounded up to $5000 Interval) 2,065,000.00$ Engineering (PE/CE) Cost 210,000.00$

J. Goodall/P. Castro

May 2024

Fairview-Sumner Lane MP 4.7

113420

SITE MAPFIG

. 1

SITE PHOTOGRAPHS

Photo 1: Looking southeast at the beginning of slide area.

Photo 2: Looking southwest near deepest point of head scarp.

Sheet 1 of 2

SITE PHOTOGRAPHS

Photo 3:Looking north from near the end of the slide.

Photo 4: Looking northwest near mid slide length, over the lower slide mass.

Sheet 2 of 2

Fairview-SumnerLn_MP4.7_ConceptualCostEstimate

Fairview-SumnerLn_MP4.7_Fig1-SiteMap

Slide Number 1

Fairview-SumnerLn_MP4.7_Fig2-SitePhotos