Attachment J - Levee Ready Columbia TAS (IGA 5 and 6).pdf

Levee Ready Columbia Technical Advisory Subcommittee Certification Project Business Cases

Last updated April 19, 2021

The enclosed projects were funded in part by the Oregon State Lottery and administered by the Oregon Business Development Department.

Attachment J

IGA1: Railroad Embankment in PEN1

PROJECT OVERVIEW / BUSINESS CASE

1. PROJECT NAME

Railroad Embankment in PEN1 Reference: IGA1

2. LOCATION

Between Columbia Slough and N Pier 99 Street Portland, Oregon 97217 Peninsula 1 Drainage District (PEN1) Property Ownership: Union Pacific Railroad (UPRR), Burlington Northern Santa Fe Railroad (BNSF), Peninsula Terminal Corporation (PTC), City of Portland, Ralph Dunnington

Figure 1. Project Location Map

3. PROJECT PURPOSE AND NEED

An embankment spans 6,300 lineal feet along the western extent on the PEN 1 drainage district. The embankment functions as a levee but is situated within BNSF and UPRR property and poses complications with access and maintenance requirements. The embankment runs adjacent and to the west of Heron Lakes Golf Club for 4,900 LF. It ties into a levee at Columbia Slough to the south of PEN1.

Further north the embankment runs parallel to a BNSF railyard for 1,400 LF and ties into existing floodwall at Marine Drive. In this northern segment there is also a railroad spur that turns eastward between the Heron Lakes Golf Club and the railyard. A closure gate is installed at the entrance on the railyard to maintain access.

The existing embankment currently lies with a side slope that varies between 1.5 - 2H:1V. The railroad embankment was identified as a critical section due to a weak embankment as it was built as an ad hoc levee, backfilling material over a wooden trestle and on top of a sand foundation that results in an insufficient factor of safety for slope stability. The embankment failed during the Vanport flood in 1948 and it is considered a source of flood risk under existing conditions. The existing embankment currently meets minimum FEMA certification for flood protection elevation.

4. PROJECT PLANNING CONSIDERATONS

A. Goals

The goal is to address the vulnerability in the embankment and reduce risk of a future failure.

Due to the Feasibility Study’s recommendations to provide a uniform level of protection throughout the perimeter of the system, an alternative to provide a stable levee at an elevation of either 37.2’ or higher to 38.0’ ASL (NAVD88 datum) should also be considered.

B. Priorities The primary goal is to provide for recertification. Secondary objectives include addressing future needs due to changing climate and river operations (due to the Columbia River treaty) and better maintenance access.

C. Environmental Resources The area adjacent to the railroad embankment includes several environmental conservation zones, a blue heron rookery, and wetland areas. Avoidance and minimization of disturbance to these areas is critical. Where on-site mitigation is not available or adequate, off-site mitigation should be identified during future scoping and design efforts.

D. Cultural Resources Heron Lakes Golf Course, on the east side of the embankment, is a public golf course and has cultural significance due to the architect that designed it. Historical preservation reviews will be necessary.

E. Recreational Resources Heron Lakes Golf Course, is a public recreational feature and unique in the quality of this course, rated for professional tournament play. It is a significant revenue source for Portland Parks and

Recreation. The Columbia Slough Trail is adjacent to the south end of the project area and the Peninsula Crossing Trail is adjacent along the west edge of the project area.

5. CONSTRAINTS AND RISKS

• Additional geotechnical analysis may be provided to refine project requirement and need.

• Railroad support – Cooperation from three railroad entities, Burlington Northern Santa Fe, Union Pacific, and the Peninsula Terminal Company (PTC) (a spur and cargo/petroleum transfer facility) is required for all alternatives. Lack of support by any one of the identities would influence the implementation strategy. Railroads are concerned about avoiding precedents for new regulatory restrictions, maintaining ease of maintenance, implicitly accepting liability for the embankment as a levee, and maintaining flexibility in their corridors (e.g. Potential Columbia River Crossing changes to the area or increasing rail capacity). The Army Corps of Engineers initiated conversations in the Spring of 2020 to educate them about the alternatives they have scoped, hear their concerns, and request their cooperation to minimize project footprints and impacts. Even a parallel setback levee would require cooperation by all railroads to cross the PTC spur line and tie into the existing levee alignment.

• Alternatives that require expansion of the levee or widening of the levee into environmental or recreational areas would require more cooperation and greater permitting. It would also complicate the project through a greater effort addressing real estate concerns (i.e. easements).

The expanded footprint of this project would involve approximately 3 acres of reforestation; this would require identification of off-site reforestation and wetland mitigation areas.

• Workarounds may exist where widening of the levee into primary golf course features may be required; this includes the use of gravel toe features to permit steeper landward levee slopes, as well as rebuilding of playing surfaces on the toe of the levees, particularly where those areas are on higher ground.

6. POTENTIAL SOLUTIONS

Three alternatives are presented that aim to provide scenarios which either maintain or minimize conflicts and impacts to the BNSF property:

1. Alternative IGA1.A: The BNSF Railway and UP embankments would be flattened to a 3H:1V slope along the interior face up to elevation 37.2-feet.

2. Alternative IGA1.B: A new levee would be built up to elevation 37.2-feet, offset from the property boundary with BNSF and UP. The new levee would tie into the existing embankment at both the northern (requiring cooperation with PTC) and southern extent.

3. Alternative IGA1.C: A new levee would be built to elevation 38.0-feet, offset from the property boundary with BNSF and UP. The new levee would tie into the existing embankment at both the northern (requiring cooperation with all three railroads due to jointly held property) and southern extent.

Specifics of each alternative are provided in Figure 2. Future design will aim to minimize impacts to the adjacent golf course and natural features; and will incorporate any necessary replanting.

Figure 2. Overview of Potential Solutions (IGA1.A – IGA1.C)

Alternative IGA1.A: Improve Existing Embankment up to Elevation 37.2-FT.

Alternative IGA1.A is developed to maintain the current embankment with improvement made to the landward slope and levee height. The levee will be widened and flattened to 5H:1V up to elevation 37.2-feet in order to meet slope stability requirements and support FEMA certification. Where the levee improvement meets the BNSF railyard spur, floodwall and sheet-pile is included to continue protection and minimize disturbance to BNSF property. The existing closure gate will be abandoned in place and a new gate will be installed to maintain access to the yard and provide closure for the new wall, which will ultimately tie into existing wall at Marine Drive. See ‘Section 8 – Project Outcomes’ for discussion on project cost.

Figure 3. Alternative IGA11.A Typical Levee Section (EL. 37.2)

Figure 4. Alternative IGA1.A Typical Floodwall Section (EL. 37.2)

Alternative IGA1.B: Offset Levee at Elevation 37.2-FT.

Alternative 2 aims abandon the existing embankment, with a new levee constructed on acquired property from the neighboring golf course. Improvement within BNSF property will be identical to Alternative 1 (see Figure 4). See ‘Section 8 – Project Outcomes’ for discussion on project cost.

Figure 5. Alternative IGA1.B Typical Levee Section (EL. 37.2)

Alternative IGA1.C: Offset Levee at Elevation 38.0-FT.

Alternative 2 aims abandon the existing embankment, with a new levee constructed on acquired property from the neighboring golf course. Improvement within BNSF property will be identical to Alternative 1.B; however, all target elevations for flood protection elevations are increased from 37.2-feet to 38.0-feet to provide an increased level of protection. See ‘Section 8 – Project Outcomes’ for discussion on project cost.

Figure 6. Alternative IGA1.C Typical Levee Section (EL. 38.0)

Figure 7. Alternative IGA1.C Typical Floodwall Section (EL. 38.0)

7. ADDITIONAL FEATURES

All three alternatives would include a maintenance access road. This access path could be considered as a public use path at a later time, but currently would terminate at the NW corner of the golf course without a clear exit/connection across the industrial zone to the north. An existing pedestrian/bike path along Portland Rd serves this corridor. USACE regulations do not allow for plantings/enhancements on the face of the levee aside from herbaceous seed mixes.

8. PROJECT OUTCOMES

Improvements to the embankment will aim to provide a minimum improved condition for slope stability and seepage performance based on USACE criteria. Improvements documented in Business Case Papers for IGA1, IG2A, IGA4, and IGA 8 are consistent with project elements identified as part of the Portland Metro Levee Study (PMLS) and costs for these improvements range from $24,730,000 to $32,353,000.

Costs include a 30-50% percent contingency and include costs for real estate and additional environmental permitting.

Table 1. Project Outcomes

Alternative Reduces Flood Risk

Addresses Levee Cert.

Environmental Benefits

Cultural Benefits

Recreational Benefits

Total Cost

Alternative

IGA1.A

Yes (Improve protection to

37.2 feet)

Yes (addresses identified deficiencies)

Smallest project footprint, least impacts

Not yet scoped

(NYS)

4-season access path would be on rail property and not suitable for public access trail

N/A

Alternative

IGA1.B

Yes (Improve protection to

37.2 feet)

Yes (addresses identified deficiencies)

NYS1 NYS1

Option to convert 4-season maintenance road to pedestrian/biker path

N/A

Alternative

IGA1.C

Yes (Improved protection to

38’)

Yes (addresses identified deficiencies)

NYS1 NYS1

Option to convert 4-season maintenance road to pedestrian/biker path

N/A

9. ADDITIONAL BACKGROUND INFORMATION

• Cornforth FEMA Review

• PEN1 Levee Engineering Assessment

10. LEVERAGING OPPORTUNITIES

None identified at this time.

11. POTENTIAL FUNDING SOURCES

No clear funding sources have been identified at this time. Peninsula 1 Drainage District does not have the resources to address this project without leveraging other agency assistance in the event that this project is not authorized and funded for federal cost share following the USACE Feasibility Study. The Levee Ready Columbia partnership has dedicated funding to investigate and identify opportunities to address flood protection recertification, but it has not committed to capital investments at this time.

The new Urban Flood Safety and Water Quality District has not yet developed a revenue model that could fund large capital investments of this nature.

1 Multi-benefit scoping was completed for projects not included in the USACE Feasibility Study recommended project list. The Corps of Engineers’ study authorization did not allow for multi-benefit scoping.

IGA 2A: I-5 Floodwall and Pier 99 Street

I-5 Floodwall and Pier 99 Low Spot Reference: IGA 2A

N Pier 99 Street at Interstate-5 Portland, Oregon 97217 Peninsula 2 Drainage District (PEN2) Property Ownership: Pier West LLC, FHWA/ODOT and PBOT right-of-way

3. PROJECT PURPOSE AND NEED

The existing floodwall abruptly ends under the Interstate 5 bridge on the south side of North Marine Drive. The existing embankment currently does not meet the minimum FEMA certification for flood protection elevation. The minimum extent of improvement to correct the original problem is approximately 160 feet in the project area.

4. PROJECT PLANNING CONSIDERATIONS

A. Goals The goal is to address a prominent low spot in the perimeter levee embankment, eliminating the need to construct an emergency flood closure during a high-water event. Additional smaller flood closures can also be eliminated if the level of protection and project extent is lengthened.

The project must meet minimum requirements for recertification with FEMA and compliance with the USACE Rehabilitation and Inspection Program.

B. Priorities The project priority is recertification. If the project partners or the new drainage district are interested in following the recommendations of the Army Corps of Engineers Feasibility Study to raise the levee to address climate change, uncertainty in future river operations due to the Columbia River Treaty, and to address future resiliency, the alternative to raise the project to 38.0’ NAVD88 will be necessary.

C. Environmental Resources This project is primarily in a right-of-way under the I-5 overpass/bridge approach and there are no environmental considerations/resources in this project area aside from discharge of clean stormwater into the adjacent Oregon Slough. Where on-site mitigation is not available or adequate, off-site mitigation should be identified during future scoping and design efforts.

D. Cultural Resources N/A

E. Recreational Resources The 40-Mile Loop Pedestrian and bike trail passes adjacent to the project area.

5. CONSTRAINTS AND RISKS

Work within the project area is constrained by the presence of the Interstate-5 bridge. Exact clearance underneath the bridge is currently unknown, but evaluation of available data suggests the minimum clearance may be as low as 10-feet from the top of existing floodwall to the invert of bridge girders.

Further evaluation of clearance is required to determine constraints on equipment access and construction means and methods.

Encroachment and temporary construction easements may be required where the new floodwall ties into the existing Columbia River levee within PEN 2. Topographic and boundary survey will be required to accurately determine private property constraints.

POTENTIAL SOLUTIONS

Alternative IGA2A.A: New Floodwall Underneath Interstate-5

Alternative IGA2A.A aims to meet minimum FEMA certification requirements by installing floodwall underneath the Interstate 5 bridge that is tied into the existing floodwall to the west (PEN 1) and tied into the existing Columbia River levee to the east (PEN 2). A total of 160 linear feet of additional reinforced concrete floodwall will be installed to an elevation of 38 feet along N Pier 99 Street where it passes under I-5, as shown in plan on Figure 2 and with a profile view on Figure 3. Additional floodwall (420 LF) and automated flood gates (430 LF) are included to raise surrounding segments of N Pier 99 Street into the existing earthen embankment at both the west and eastern extents, as shown on Figure

2. Floodwall will be reinforced with a sheet pile cut-off wall installed at a depth up to 18 feet below existing grade. See ‘Section 8 – Project Outcomes’ for discussion on project cost.

Figure 2. Alternative IGA2A.A – Plan View

Figure 3. Alternative IGA2A.A – Profile View

6. ADDITIONAL FEATURES

The following additional features were identified for potential inclusion in the project during future design phases.

1. This project intersects the 40-Mile Loop, and there is potential for multi-benefits project elements along the trail in the project area. The area under the bridge presents an opportunity to include a ramp from the street grade up to the levee and floodwall alignment, connecting Bridgeton to the east. These costs are not scoped in the alternatives below.

2. There is currently a bike path that crosses through the project area that could be relocated and improved as part of the project to improve access through the study area.

7. PROJECT OUTCOMES

Improvements to the embankment will aim to provide a minimum improved condition for floodwall geotechnical stability and seepage performance based on USACE criteria. Improvements documented in Business Case Papers for IGA1, IG2A, IGA4, and IGA 8 are consistent with project elements identified as part of the Portland Metro Levee Study (PMLS) and costs for these improvements range from $24,730,000 to $32,353,000. Costs include a 30-50% percent contingency and include costs for real estate and additional environmental permitting.

Table 1. Project Outcomes

Alternative Reduces Flood Risk

Addresses Levee Cert. Environmental Impact Cultural

Impact Recreational

Impact Total Cost

Alternative

IGA2A

Yes (improved protection to

38.0 feet)

Yes (addresses identified deficiencies)

Not yet scoped (NYS)

– project within built environment/ROW

NYS1 NYS1 N/A

8. ADDITIONAL BACKGROUND INFORMATION

• PEN1 and PEN2 Levee Engineering Assessments

9. LEVERAGING OPPORTUNITIES

Additional floodwall sections and closure gates will require coordination with PBOT and private landowners to determine responsibilities for maintenance and installation during a high-water event.

10. POTENTIAL FUNDING SOURCES

No clear funding sources have been identified at this time. Peninsula 1 Drainage District does not have the resources to address this project without leveraging other agency assistance in the event that this project is not authorized and funded for federal cost share following the USACE Feasibility Study. The Levee Ready Columbia partnership has dedicated funding to investigate and identify opportunities to address flood protection recertification, but it has not committed to capital investments at this time.

The new Urban Flood Safety and Water Quality District has not yet developed a revenue model that could fund large capital investments of this nature.

1 Multi-benefit scoping was only completed for projects not included in the USACE Feasibility Study recommended project list. The Corps of Engineers’ study authorization did not allow for multi-benefit scoping.

IGA2B: Southbound I-5 and Marine Drive Interchange Low Spot

Southbound I-5 and Marine Drive Interchange Low Spot Reference: IGA2B

Interstate-5 Southbank On-Ramp Peninsula 1 Drainage District (PEN1) Property Ownership: Oregon Dept of Transportation Right-of-Way

3. PROJECT PURPOSE AND NEED

Levee elevations in the project area are below FEMA and USACE levee certification requirements. The height of the existing levee adjacent to the southbound I-5 on-ramp and I-5 could require up to ~ 10 feet in additional elevation. The total extent of required improvements are approximately 1,800 feet in the project area and would likely include a combination of levee raise (up to ~ 10 feet) and floodwall (up to ~ 3 feet).

Floodwall design currently shown is for conceptual planning purposes only. Additional analysis of site geotechnical condition will be required during a future phase of this project for floodwall design and geotechnical considerations including slope stability, seepage, and uplift.

The preferred alternative will need consideration for the Kenton to Marine Drive Trail, planned to close the trail gap between the Kenton neighborhood to the south and the Expo center and existing Marine Drive trail to the north.

The goal is to address a low spot in the cross-levee embankment, addressing a recertification issue and eliminating the need to construct an extensive and complicated flood closure for this cross-levee feature during a high-water event. The project must meet minimum requirements for recertification with FEMA and compliance with the USACE Rehabilitation and Inspection Program.

B. Priorities The project priority is recertification and was scoped to 37.2' NAVD88. As a cross-levee feature and due to the difficulty to achieve the necessary grades due to site constraints, it was not scoped with a 38' alternative to meet additional long term objectives.

C. Environmental Resources The western side of the embankment is covered in trees, a natural resource in an otherwise highly developed transportation corridor. It is also a screening measure between the I-5 corridor, the Expo Center TRIMET station and the Expo Center. Where on-site mitigation is not available or adequate, off-site mitigation should be identified during future scoping and design efforts.

D. Cultural Resources No cultural resources have been identified at this time.

E. Recreational Resources The Marine Drive section of the 40-Mile Loop passes to the north of the site and a pedestrian/bike path along Expo Road passes to the south and west of the site. This site provides potential opportunities to improve connections between these paths.

5. CONSTRAINTS AND RISKS

Any grading on the embankment to raise grade is laterally constrained by the TRIMET station and a drainage swale that runs along the east side of the station. Concerns about impacts to trees on the slope may trigger tree protection requirements. Work on this project is largely in ODOT right-of-way and care must be taken not to interfere with traffic accelerating to merge into southbound I-5, e.g., shoulder and sight distance requirements.

Two sanitary sewer force mains cross Interstate-5 and the proposed levee alignment at approximately Station 241+00. The force mains have been identified to be 20-inch and 30-inch diameter at 6-feet O.C.

and are not assumed to conflict with the proposed floodwall. Additional utility potholing will be required to verify location and depth to assess conflict during a future phase of design. A water main crossing was also identified directly south of the project but is currently outside of the project limits.

Alternative IGA2B.A: Minimize Floodwall

Alternative IGA2B.A aims to minimize the length of floodwall and use earthen levee fill to FEMA minimum requirements for flood protection (elevation 37.2-ft NAVD88 in this area). This alternative would require fill to be placed over the existing embankment with potential for impacts to a drainage swale in the proximity of STA 252+00 to STA 254+00. This alternative would include approximately 900 feet of levee improvement and approximately 900 feet of floodwall. Two typical sections are shown on and following the Alternative IGA2B.A Overview Map. As noted in Section 4.C Environmental Resources above, the western side of the existing embankment is covered in trees, and mitigation will likely be required.

Figure 2. Project Elements Overview (Alternative IGA2B.A)

Figure 3. Typical Levee Section 1 (Alternative IGA2B.A)

Figure 4. Typical Levee Section 2 (Alternative IGA2B.A)

Figure 5. Typical Floodwall Section 1 (Alternative IGA2B.A)

Table. 1 Alternative IGA2B.A Conceptual Cost

Item Quantity Unit Cost Total Cost

Levee Fill (CY) 11,000 $30 $330,000

Reinforced Concrete Floodwall (LF) 900 $650 $585,000

Construction Subtotal $915,000

Permitting $40,000

Real Estate 8% of Construction Cost $73,200

Mobilization 8% of Construction Cost $73,200

Dewatering / Diversion 3% of Construction Cost $27,450

Site Preparation 3% of Construction Cost $27,450

Planning, Engineering, Design 12% of Construction Cost $109,800

Construction Management 12% of Construction Cost $109,800

Traffic Control 5% of Construction Cost $91,500

Contingency 30% of Construction Cost $274,500

Total Project Cost (Rounded) $1,742,000

Alternative IGA2B.B: Avoid Impact to Drainage Swale

Alternative IGA2B.B aims to minimize potential impacts to the existing drainage swale by using additional floodwall to avoid placing levee over the embankment where space is limited. This alternative would include approximately 700 feet of levee improvement and approximately 1,100 feet of floodwall.

Three typical sections are called out on the Alternative IGA2B.B Overview Map. Floodwall Section 1 and Levee Section 1 are the same as shown for Alternative IGA2B.A. An additional typical section has been provided for the floodwall in the proximity on STA 252+00 to STA 254+00. As noted in Section 4.C Environmental Resources above, the western side of the existing embankment is covered in trees, and mitigation will likely be required.

Figure 6. Alternative IGA2B.B Project Elements Overview

Figure 7. Typical Floodwall Section 2 (Alternative IGA2B.B)

Table. 2 Alternative IGA2B.B Conceptual Cost

Levee Fill (CY) 8,500 $30 $255,000

Reinforced Concrete Floodwall (LF) 1,100 $650 $715,000

Construction Subtotal $970,000

Permitting $20,000

Real Estate 8% of Construction Cost $77,600

Mobilization 8% of Construction Cost $77,600

Dewatering / Diversion 3% of Construction Cost $29,100

Site Preparation 3% of Construction Cost $29,100

Planning, Engineering, Design 12% of Construction Cost $116,400

Construction Management 12% of Construction Cost $116,400

Traffic Control 5% of Construction Cost $97,000

Contingency 30% of Construction Cost $291,000

Total Project Cost (Rounded) $1,825,000

7. ADDITIONAL FEATURES

Were this project to move forward, future phases of design would consider opportunities for multi-benefit project elements to address recreation and environmental quality. One such opportunity that has been preliminarily identified, but is not included in the current analysis, to construct a connector trail improving access from the Marine Drive trail to the Trimet station. The cloverleaf provides an opportunity to provide pollinator garden/landscaping, providing environmental benefits despite the site constraints as a right-of-way.

8. PROJECT OUTCOMES

Improvements to the embankment will aim to provide a minimum improved condition for floodwall geotechnical stability and seepage performance based on USACE criteria. Opportunities for trail improvements could provide recreational improvement and public access.

Table 3. Project Outcomes

Alternative Reduces Flood Risk

Addresses Levee Cert.

Environmental Benefits

Cultural Benefits

Recreational Benefits Total Cost

Alternative

IGA2B.A

Yes (improved protection to

37.2 feet)

Yes (addresses identified deficiencies)

Pollinator garden option

Not scoped

Marine Drive to TRIMET station trail connector option

$1,742,000

Alternative

IGA2B.B

Yes (improved protection to

37.2 feet)

Yes (addresses identified deficiencies)

Pollinator garden option

Not scoped

Pedestrian/ biker path planned along project boundary by

PBOT

$1,825,000

• PEN1 and PEN2 Levee Engineering Assessments

• MCDD Flood Emergency Action Plan

Suitable fill material and grading work may leverage ODOT objectives to address excess dirt from nearby construction projects.

No clear funding sources have been identified at this time. Peninsula 1 Drainage District does not have the resources to address this project without leveraging other agency assistance. As a cross-levee feature, it is not included in the plan selected by the USACE Feasibility Study. The Levee Ready Columbia partnership has dedicated funding to investigate and identify opportunities to address flood protection recertification. The new Urban Flood Safety and Water Quality District has not yet developed a revenue model that could fund large capital investments of this nature.

Tetra Tech Revised Version - IGA3: Columbia Clubhouse in PEN2

Columbia Clubhouse in PEN2 Reference: IGA3

NE 1900 Block of Marine Drive Portland, Oregon 97211 Peninsula 2 Drainage District (PEN2) Property Ownership: Port of Portland and Portland Bureau of Transportation right-of-way

Figure 1 .Project Location Map

3. PROJECT PURPOSE AND NEED

The existing levee spanning 600 linear feet along NE Marine Drive is 6 to 12 inches lower than the minimum elevation for FEMA certification; the levee across the street from the Columbia Edgewater Clubhouse. The insufficient elevation is a result of a clubhouse fire and subsequent foundation excavations/removal that lowered the ground surface at the existing levee centerline.

The goal is to address a low spot in the perimeter levee embankment, eliminating the need to construct an emergency flood closure during a high-water event. The project must meet minimum requirements for recertification with FEMA and compliance with the USACE Rehabilitation and Inspection Program. Due to the Feasibility Study’s recommendations to provide a uniform level of protection throughout the perimeter of the system, an alternative to provide a levee height increase to 38.0’ (NAVD88 datum) should also be considered.

B. Priorities The project priority is recertification. Additional objectives to address future needs due to changing climate and river operations (due to the Columbia River treaty), and better maintenance access are important secondary objectives.

C. Environmental Resources The project faces the Columbia River, consisting of a steep bank and sandy beach with abandoned pilings and evidence of previous commercial use. Opportunities for improving upland and riparian habitat exist, including removal of legacy pavement from the old golf clubhouse and replanting of trees outside the levee prism. Where on-site mitigation is not available or adequate, off-site mitigation should be identified during future scoping and design efforts.

D. Cultural Resources None identified during scoping.

E. Recreational Resources The area lies parallel to the Marine Drive section of the 40-Mile Loop and Portland Bureau of Transportation is planning future enhancements, including a pedestrian/bike crossing on the east end of the site, as well as a bike lane on the northern shoulder.

1. The site has an environmental overlay and there are significant trees on the riverside overbuild / berm.

2. The final elevation of PEN2 will not be available until the Agency Decision Milestone is approved (it will be submitted in April 2020). The site is currently evaluated for multiple target elevations:

a. A minimum FEMA certification height of 37.2-feet NAVD88.

b. A minimum night to meet both current FEMA and USACE requirements: 39.1-feet NAVD88.

c. An elevation that meets the levee raise proposed by the USACE Feasibility Study: 38-feet

NAVD88.

3. The need to raise the levee using floodwall is expensive; however, it may be offset by the cost of environmental permitting and mitigation involved in the levee raise / widening effort.

a. This was an initial concern, but preliminary grading concepts verified that raising the levee is possible without floodwall and will not require lateral impacts to adjacent aquatic resources.

4. Site is not likely to be a significant marine access point (and it is redundant as it is close to the 42nd

Ave boat ramp operated by Metro).

a. The Port of Portland indicated that it acquired the site to meet FAA runway protection zone requirements and is not interested in encouraging any activities that would undercut the ability to meet those requirements; passive/transitory use is acceptable. Other users discussed the proximity to a full-service marine facility (the Metro-operated Gleason boat ramp), reducing the need for another facility this close.

5. There is a concern about controlling access to the site (currently fenced) due to the abundance of houseless camping activity along Marine Drive.

Two alternatives are presented that aim to provide scenarios that address project needs:

Alternative IGA3.A: Minimum Compliance for Levee Certification levee Raise to Elevation 37.2-feet

The existing levee will be raised adjacent to Marine Drive approximately 1-foot to Elevation 37.2-feet.

This alternative would require approximately 500 linear feet of new fill to be placed over the existing levee. Under this alternative there are no anticipated impacts to Marine Drive. Temporary construction easements may be required to tie the raised levee into high ground to west where the levee enters a private residence. Figure 2 presents a section view of the project elements, and Figure 3 presents a plan view of those elements. Note that the elevation scale on Figure 2 is presented in City of Portland Vertical Datum; pertinent elevations are also called out in NAVD88.

Table 1. Alternative IGA3.A Conceptual Cost

Item Quantity Unit Cost Total Cost Demolition / Removal Disposal (LS) 1 $50,000 $50,000

Borrow Fill (CY) 5,000 $31 $155,000 Levee foundation fill (CY) 1,500 $31 $46,500 Pavement Removal (SF) 50,000 $3.25 $162,500

Landscaping (LS) 1 $20,000 $20,000 Topsoil (CY) 1,234 $36 $44,424

Seeding (AC) 1.7 $4,000 $6,800 Traffic Crossing Signal (LS) 1 $200,000 $200,000

Construction Subtotal $685,224 Permitting (LS) $30,000

Real Estate 8% of Construction Cost $54,818 Mobilization 8% of Construction Cost $54,818

Dewatering / Diversion 3% of Construction Cost $20,557 Site Preparation 3% of Construction Cost $20,557

Planning, Engineering, Design 12% of Construction Cost $82,227 Construction Management 12% of Construction Cost $82,227

Traffic Control 10% of Construction Cost $68,522 Contingency 30% of Construction Cost $205,567

Total Project Cost (Rounded) $1,305,000

Figure 2. Project Elements Overview (Alternative IGA3.A): Project #3: Levee Section, Elev 37.2 NAVD88, 3:1 Landward Levee Slopes (Section 2 on Plan View Figure 3)

Figure 3. Project Elements Overview (Alternative IGA3.A): Project #3: Levee Section, Elev 37.2 NAVD88, Plan View

Alternative IGA3.B Flood Risk Reduction Levee Raise to 38-Feet

The alternative aims to increase the existing levee height using level fill to elevation 38-feet to meet any levee raise within PEN2 that is the result from the Portland Metro Levee Feasibility Study (PMLS). The levee raise will include approximately 500 linear feet of levee fill material and 250 linear feet of roadway improvements along Marine Drive. Figure 4 presents a section view of the project elements. The project element layout is similar to that presented in Figure 3. Note that the elevation scale on Figure 2 is presented in City of Portland Vertical Datum; pertinent elevations are also called out in NAVD88.

Table 2. Alternative IGA3.B Conceptual Cost

Demolition / Removal Disposal (LS) 1 $50,000 $50,000

Borrow Fill (CY) 5,800 $31 $179,800 Levee Foundation Fill (CY) 1,500 $31 $46,500

Topsoil (CY) 1,400 $36 $50,400 Pavement Removal (SF) 50,000 $3.25 $162,500

Traffic Crossing Signal (LS) 1 $200,000 $200,000 Landscaping (LS) 1 $20,000 $20,000

Seeding (AC) 1.9 $4,000 $7,600 Construction Subtotal $716,800

Permitting (LS) $30,000 Real Estate 8% of Construction Cost $57,344 Mobilization 8% of Construction Cost $57,344

Dewatering / Diversion 3% of Construction Cost $21,504 Site Preparation 3% of Construction Cost $21,504

Planning, Engineering, Design 12% of Construction Cost $86,016 Construction Management 12% of Construction Cost $86,016

Traffic Control 10% of Construction Cost $71,680 Contingency 30% of Construction Cost $215,040

Total Project Cost (Rounded) $1,364,000

Figure 4. Project Elements Overview (Alternative IGA3.B): Project #3: Levee Section, Elev 38.0 NAVD88, 6:1 Landward Levee Slopes

7. ADDITIONAL FEATURES

In addition to meeting flood protection requirements, several additional features were discussed or incorporated into current concepts (not included in current estimates).

1. 40-Mile Loop bicycle / pedestrian path elements (included in cost estimates). Reference Portland Bureau of Transportation planning memos for potential collaboration.

2. Terrestrial environmental improvement elements (general estimates included).

3. Aquatic environmental elements (not currently incorporated into estimates) – Large woody debris and / or floodplain terrace habitat features were discussed to provide marginal structure, roughness, and shade.

Projects aim to address the problem in the LRC IGA – Achieve compliance with FEMA NFIP standards, the USACE RIP Inspection program, the USACE Levee O&M Manual requirements and address deficiencies identified through the LRC-sponsored PEN2 Levee Engineering Assessment (conducted by Cornforth Engineering).

Table 3. Project Outcomes

Flood Risk

Addresses Levee Cert.

Environmental Impact

Cultural Impact

Recreational Impact Total Cost

IGA3.A Yes

Yes (raises levee segment to minimum elevation)

Not yet scoped

(NYS)

NYS NYS $1,305,000

IGA3.B Yes

Yes (raises levee segment to minimum elevation)

NYS NYS NYS $1,364,000

The port has no interest in managing and operating a park at this location and has queried MCDD / PEN2 about interest in the past.

1. Metro may have an interest in acquiring the property as an open space.

2. The City of Portland Bureau of Transportation is in the planning stages for pedestrian/bicycle trail improvements along Marine Drive, which would include development of a bicycle lane along Marine Drive along this site if implemented prior to this project. These improvements may include the pedestrian crossing element if developed prior to this project.

11. POTENTIAL FUNDING SOURCES

No clear funding sources have been identified at this time. Peninsula 1 Drainage District does not have the resources to address this project without leveraging other agency assistance in the event that this project is not authorized and funded for federal cost share following the USACE Feasibility Study. The Levee Ready Columbia partnership has dedicated funding to investigate and identify opportunities to address flood protection recertification but has not committed to capital investments at this time. The new Urban Flood Safety and Water Quality District has not yet developed a revenue model that could fund large capital investments of this nature.

It is unclear whether the Port of Portland is committed to funding for this project.

12. ASSOCIATED PROJECT

Site IGA 3 BC was one of several locations on the mainstem Columbia River that was identified as a possible shallow water habitat enhancement project. Shallow water habitat, defined by NOAA-Fisheries as waters less than 20 feet deep, is a necessary habitat element for out-migrating juvenile salmonids.

Levee construction has steepened the riverbanks in this stretch, and in combination with ongoing dredging of the navigation channel has resulted in loss of much of the shallow water habitat in this stretch of the river.

Figures 5 and 6 provide plan view and cross-section view representations of conceptual plans to enhance shallow water habitat and adjacent riparian habitat, respectively. Although the figures show proposed conditions at this site, they are considered representative of additional shallow water benches that could be developed at several locations along the south shore of the river between the Columbia Clubhouse site and the Animal Burrows project site (IGA 6 BC).

Primary project elements would include depositing fill material starting at the river’s normal operating level of 9.5 ft. NAVD 88 and extending horizontally into the water column for 50 feet at a 10 percent slope, at which point it would be sloped more steeply to tie into existing grade. Depths in the bench area at normal operating level would range from 0 feet at the river’s edge to 5 feet at the outer edge of the bench. Several small log jams would be installed approximately halfway between the levee toe and the outer edge of the habitat bench to provide additional roughness and habitat diversity. Fill material would be comprised of aggregate with a rip rap toe to stabilize the outboard edge.

The riparian zone found adjacent to the habitat bench would be treated for invasive species and revegetated with a mix of plugs and stakes intended to enhance the ground layer and canopy layer.

Mature native vegetation found at the site would be retained to the degree possible. A narrow strip of wetland vegetation would be installed at and just above the water's edge. The upland areas in the site and adjacent Port parcel could provide 3 acres of offsite replanting areas for other work areas.

Feasibility criteria were ranked from a high score of 2 to a low score of -2. As an example, a site that is publicly owned is seen as having very favorable land use status and is given a score of 2, but private property is seen as having unfavorable land use status and is given a score of -2. The proposed project scores moderately well according to the feasibility criteria and meets the habitat objective. Preliminary scores are shown in Table 4.

Primary project costs are associated with purchasing and placing gravel, pre-treatment of invasive plants, permitting, and revegetation. A preliminary estimate of project costs is provided in Table 5.

Table 4. Scoring Against Feasibility Criteria

Ownership Proximity to Flood

Project Site

Leveraging Opportunity

Cost Permitting Risks and Constraints

Objectives

2- Publicly Owned

1 - Adjacent 1 – Ability to leverage likely grant funding

0 - < $1M

2 – Project may be covered under NWP and Programmatic BiOp

• Project may require Section 408 review if considered to be in navigation channel

• Outboard structure may be needed to retain substrate

• Habitat

Table 5. Preliminary Cost Estimate for Associated Project

Item Unit Quantity Unit Cost Total Cost Bench/Toe Excavation LS 1 $1,950 $1,950

Wet Excavation - Haul Off/Disposal CY 50 $39 $1,950 Shallow Water Habitat Bench LS 1 $359,600 $359,600

In-water Placement – Long-Reach Shore Access CY 3,200 $45 $144,000 Riprap Toe CY 600 $31 $18,600

Import Gravel/Cobble Fill CY 2,600 $60 $156,000 Habitat Rootwad EA 41 $1000 41,000 Site Restoration LS 1 $34,216 $34,216

Spring Mow/Brushcut ACRE 1.4 $800 $1,120 Herbicide (Aquatic Glyphosate) Application ACRE 1.4 $600 $840

Native Riparian Seed Mix Broadcast ACRE 1.4 $1,200 $1,680 Live Stake Installation EA 3,812 $5 $19,061

Containerized Native Planting (1-gal) EA 550 $13 $7,153 Herbivore Protection EA 4,362 $1 $4,362

Contract 2-Yr. Maintenance (Plant Est.) LS 1 $25,000 $25,000 Subtotal $420,766

Permitting $45,000 Mobilization 8% of Construction Cost $33,661

Dewatering / Diversion 3% of Construction Cost $12,623

Site Preparation 3% of Construction Cost $12,623

Planning, Engineering, Design 12% of Construction Cost $50,492

Construction Management 12% of Construction Cost $50,492

Contingency 50% of Construction Cost $210,383

Total Project Cost (Rounded) $837,000

Figure 5. Associated Project Plan View

Figure 6. Associated Project Section View

IGA4: Peninsula Drainage Canal Levee Remediation

Peninsula Drainage Canal Levee Remediation Reference: IGA4

Between Columbia Slough and NE Marine Drive Portland, Oregon 97211 Peninsula 2 Drainage District (PEN2) and Multnomah County Drainage District (MCDD) West Property Ownership: Port of Portland, City of Portland, State of Oregon (Corrections), Riverside Golf & Country Club

3. PROJECT PURPOSE AND NEED

The MCDD cross-level spans 6,800 linear feet along the east edge of the Peninsula Drainage Canal at the boundary of the PEN 2 and MCDD West drainage districts. The existing cross-levee is composed of silt with clay with an existing side slope of approximately 2H:1V. Review of geotechnical boring logs indicates a near-surface 10-foot-thick clay layer located at the toe of the existing levee prism. The levee was identified for insufficient slope stability and seepage performance in 2014 (Cornforth, 2014) and 2019 (USACE, 2019). Improvement to the existing cross-levee will improve geotechnical performance to meet FEMA certification criteria.

4. PROJECT PLANNING CONSIDERATONS

A. Goals

The goal is to address the vulnerability in the embankment and reduce risk of a future failure.

Due to the Feasibility Study’s recommendations to provide a uniform level of protection throughout the perimeter of the system, an alternative to provide a levee height increase to 40.2’ ASL (NAVD88 datum) should also be considered.

B. Priorities The primary goal is to provide for recertification. Additional objectives to address future needs due to changing climate and river operations (due to the Columbia River treaty), and better maintenance access are important secondary objectives.

C. Environmental Resources The Peninsula Drainage Canal is a major resource for western painted and western pond turtles and is among the highest quality habitat in the Portland metro area for these Oregon state-protected species. Where on-site mitigation is not available or adequate, off-site mitigation should be identified during future scoping and design efforts.

D. Cultural Resources N/A

E. Recreational Resources The 40 Mile Loop and Metro are committed to development of a regional multi-modal trail along this stretch of the levee in a manner that avoids impacts to turtle habitat. The City of Portland moved the trail alignment on its Comprehensive Plan to NE 33rd Drive because of concerns about turtle habitat, but an opportunity exists to add a trail on the east side of the embankment.

No improvements are currently recommended to the PEN 2 face of the levee to avoid any fill in the Peninsula Drainage Canal.

The canal is designated by the Oregon Native Turtles Working Group as a Priority Turtle Conservation Area and is within Opportunity Area 56 of the ODFW Oregon Conservation Strategy. The canal is home to a large population of Western painted turtles and may be home to a population of Western pond turtles (Oregon Turtles and ODFW, 2020). Construction would require sequencing to avoid critical time periods for turtle breeding (typically occurs in disturbed areas on the levee face and crest). Maintenance and recreational path improvements are often built on the levee crest, but in consideration of turtle sight line issues, need to be located on the eastern side of the levee to avoid impacts.

Two alternatives are presented that make improvements on the MCDD face of the levee. No improvements are currently recommended to the PEN 2 face of the levee. Both alternatives include a pervious toe trench that will be designed to reduce subsurface pressure that results from the presence of the impervious clay layer. The two alternatives provide a varying level of improvement and are as follows:

1. The existing levee will be flattened on the MCDD face to 3H:1V up to an elevation of 42-feet.

Alternative IGA4.A: Levee Stability Improvements to 42-FT

Alternative IGA4.A aims to provide levee improvements to meet the minimum requirements for FEMA certification. The USACE Feasibility Study identified minor low spots on this levee that require fill, but the levee provides adequate protection well above FEMA requirements along with surplus to address resiliency concerns mentioned in Section 4. See ‘Section 8 – Project Outcomes’ for discussion on project cost.

Figure 2. Alternative IGA4.A Typical Section for Peninsula Canal Cross Levee (EL. 37.2) https://www.oregonturtles.com/docs/PTCA_Peninsula_Canal_One_Pager.pdf https://oregonconservationstrategy.org/conservation-opportunity-areas/

Figure 3. Alternative IGA4.B Typical Section for Peninsula Canal Cross Levee (EL. 38.0)

The following additional features were identified for potential inclusion in the project during future phases of design.

1. Pervious toe drains may be substituted with relief wells. It is recommended that additional geotechnical borings be performed to better characterize the subsurface improvement requirements including type, extent, and cost.

2. As discussed in Section 5, there may be opportunities to support native turtle conservation at the site.

3. The project has the potential to improve bike trail connectivity in the project area.

Improvements to the embankment will aim to provide a minimum improved condition for slope stability and seepage performance based on USACE criteria. Opportunities for trail improvements could provide recreational improvement and public access. Improvements documented in Business Case Papers for IGA1, IG2A, IGA4, and IGA 8 are consistent with project elements identified as part of the Portland Metro Levee Study (PMLS) and costs for the improvements range from $24,730,000 to $32,353,000.

Costs include a 30-50% percent contingency and include costs for real estate and additional environmental permitting.

Table 1. Project Outcomes

Alternative Reduces Flood Risk

Addresses Levee Cert.

Environmental Impact

Cultural Impact Recreational Impact Total

Cost

Alternative

IGA4.A

Yes (improved protection to

37.2 feet)

Yes (addresses identified deficiencies)

Potential for turtle habitat elements

Not yet scoped

(NYS)

Option to convert 4-season maintenance road to pedestrian/biker path

N/A

• PEN2 Levee Engineering Assessments (Cornforth, 2014 and 2018)

No leveraging opportunities have been identified at this time. Metro has interest in improving pedestrian/bicycle connectivity along the alignment with designs considerations to avoid turtle impacts.

No clear funding sources have been identified at this time. Peninsula 2 Drainage District and MCDD have not identified funding to address this project in the event that this project is not authorized and funded for federal cost share following the USACE Feasibility Study. The Levee Ready Columbia partnership has dedicated funding to investigate and identify opportunities to address flood protection recertification, but it has not committed to capital investments at this time. The new Urban Flood Safety and Water Quality District has not yet developed a revenue model that could fund large capital investments of this nature.

12. ASSOCIATED PROJECT

At least one environmental enhancement project has been proposed in the vicinity of the Peninsula Canal Remediation Project. This project would enhance nesting habitat for western pond turtles, an Oregon species of concern, at multiple sites on the western bank of the canal. The general project site was identified by several stakeholders who participated in the environmental project charrette held by the MCDD on November 20, 2020, as a viable site for restoring turtle habitat. Commentors cited this location due to the presence of an established pond turtle population in Peninsula Canal and adjacent land uses that are relatively compatible with establishment or enhancement of this type of habitat.

Oregon Department of Fish and Wildlife (ODFW) has developed guidance for protecting and conserving Oregon’s two native turtle species, the western painted turtle (Chrysemys picta) and the western pond turtle (Actinemys marmorata) (ODFW, 2015). This guidance identifies eight essential elements critical for the survival and long-term success of these turtle species, as follows:

1. Sunlight. Turtles require periods of direct sun exposure for proper digestion, shell development and health, and to regulate their body temperature. Turtle reproduction is also critically dependent on direct sunlight to provide the warmth needed for egg development.

2. Nesting…