Attachment_2_-_Appendices_A-E__Regulatory_Permits.pdf

Appendices A - E, Regulatory Permits

PROJECT MANUAL

FOR

CONSTRUCTION

FOR THE

NATIONAL PARK SERVICE

SALMON HABITAT ENHANCEMENT

AT MUIR WOODS, PHASE 2

100% Construction Documents

PMIS-GOGA 312237

October 2022

Civil Engineers and Geomorphologists:

Northern Hydrology and Engineering

PO Box 2515 McKinleyville, CA 95519

PH/FAX: (707) 839-2195

GOGA – 312237 1 Table of Contents

TABLE OF CONTENTS

APPENDICES

A - U.S. Fish and Wildlife Service Biological Opinion, Aug. 10, 2022.

B - National Marine Fisheries Service, Biological Opinion, Sept. 20, 2017.

C - U.S. Army Corps of Engineers Nationwide Permit 27, Section 404, July 13, 2022.

D - Regional Water Quality Control Board, Clean Water Act Section 401 Water Quality Certification, July 2022.

E - State Historic Preservation Office, Memorandum of Agreement, July 2018.

Separate File

F - Storm Water Pollution Prevention Plan, Oct. 2022

GOGA – 312237 2 Table of Contents

In Reply Refer to:

2022-0004734-S7-003

August 10, 2022

Memorandum

To: General Superintendent, Golden Gate National Recreation Area, Fort Mason, San Francisco, California, GOGA_superintendent@nps.gov

From: Field Supervisor, Sacramento Fish and Wildlife Office, Sacramento, California

Subject: Second Reinitiation of Formal Consultation on the Muir Woods Water and Sewer Line Rehabilitation Project, Salmon Habitat Enhancement and Bridge Replacement Project, and the Sustainable Access Project at Muir Woods National Monument (MWNM) in Marin County, California (National Park Service (NPS) file number 1.A.2 (GOGA-NR))

Dear General Superintendent:

This memorandum is in response to the NPS’s June 24, 2022, request for reinitiation of formal consultation with the U.S. Fish and Wildlife Service (Service) on the proposed Muir Woods Water and Sewer Line Rehabilitation Project, Salmon Habitat Enhancement and Bridge Replacement Project, and Sustainable Access Project (Service file number 08ESMF00-2017-F- 2376-R001, Service 2018) (the three projects collectively referred to as the proposed project) at MWNM in Marin County, California (NPS file number 1.A.2 (GOGA-NR)). Your request was received by the Service on June 24, 2022. NPS is requesting the reinitiation of formal consultation due to three additional years of construction (a total of eight years) proposed during the marbled murrelet’s core breeding season to complete the proposed project. At issue are the proposed project’s effects on the federally threatened California red-legged frog (Rana draytonii), threatened northern spotted owl (Strix occidentalis caurina), and threatened marbled murrelet (Brachyramphus marmoratus) and its designated critical habitat. Critical habitat has been designated for the California red-legged frog and northern spotted owl but does not occur within the action area for the proposed project. This response is provided under the authority of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.) (Act), and in accordance with the implementing regulations pertaining to interagency cooperation (50 CFR 402).

The federal action we are consulting on is the NPS rehabilitating water and sewer lines, enhancing habitat for salmon, removing riprap from (or strategically burying riprap within) the creek channel, and replacing four pedestrian bridges over Redwood Creek at the MWNM in Marin County, California. NPS will also conduct in-channel construction activities to repair an emergency stabilization of a 2015 culvert blowout on a tributary to Redwood Creek. NPS will

General Superintendent 2 also implement the Sustainable Access Project to improve visitor access and arrival facilities at MWNM to better manage visitor demand and transportation services, improve visitor experience and safety, realign trails, and enhance preservation of natural and cultural resources. These facilities include parking areas, bus and/or shuttle areas, stormwater management infrastructure, restrooms, and interpretive media. Pursuant to 50 CFR 402.12(j), you submitted a biological assessment for our review and requested concurrence with the findings presented therein. These findings along with further communications between NPS and the Service conclude that the proposed project may affect, but is not likely to adversely affect the California red-legged frog and northern spotted owl, is likely to adversely affect the marbled murrelet, and is not likely to adversely affect marbled murrelet critical habitat.

In considering your request, we based our evaluation on the following: (1) your memoranda requesting the initiation of informal consultation on the MWNM Water and Sewer Line Replacement Project and the Salmonid Habitat Enhancement and Bridge Replacement Project, dated May 3, 2017, and August 30, 2017; (2) the March 2017 Muir Woods National Monument Water/Wastewater Service Rehabilitation Draft Environmental Assessment (NPS 2017a); (3) the April 2017 Salmon Habitat Enhancement and Bridge Replacement Project at Muir Woods Draft Environmental Assessment (NPS 2017b); (4) the Service’s informal consultation concurrence letter on the MWNM Water and Sewer Line Replacement Project and Salmonid Habitat Enhancement and Bridge Replacement Project, dated October 4, 2017 (Service file number 08ESMF00-2017-I-2376, Service 2017b); (5) your memorandum requesting informal consultation on the MWNM Sustainable Access Project, dated November 4, 2016; (6) your memorandum updating the project description for the MWNM Sustainable Access Project, dated February 24, 2017; (7) the November 2016 Muir Woods National Monument Sustainable Access Project Biological Assessment (Horizon and Environment, LLC 2016); (8) the Service’s informal consultation concurrence letter on the MWNM Sustainable Access Project, dated March 28, 2017 (Service file number 08ESMF00-2017-I-0839, Service 2017a); (9) your memorandum requesting the reinitiation of formal consultation on the proposed project, dated February 6, 2018, (L. Joss Golden Gate National Recreation Area [GGNRA], in litt. 2018); (10) a site visit to the MWNM Sustainable Access Project site on January 26, 2017; (11) the Service’s July 9, 2018, biological opinion for the proposed project (Service file number 08ESMF00-2017- F-2376-R001, Service 2018); (12) your memorandum requesting the second reinitiation of formal consultation on the proposed project, dated June 24, 2022; (13) surveys conducted for the northern spotted owl and marbled murrelet within the action area between 2018 and 2021 (Conservation Metrics, Inc. 2019, 2020, 2021, 2022; NPS 2022a, 2022b); (14) proposed project monitoring reports (NPS 2020); (15) conversations and electronic mail messages between NPS and the Service; and (16) other information available to the Service.

The Service concurs that the proposed project is not likely to adversely affect the California red-legged frog because: (1) no suitable breeding habitat for the California red-legged frog occurs within the action area; (2) no California red-legged frogs have been observed within the MWNM; (3) suitable aquatic foraging and dispersal habitat for the California red-legged frog will be restored and enhanced within the action area along Redwood Creek; (4) the proposed project will result in a net increase in riparian habitat along Redwood Creek due to the relocation of parking spaces away from the creek and revegetation with suitable native riparian plant species; (5) the avoidance of work at night, during dawn and dusk, during rain events, and within 24 hours after a rain event when California red-legged frogs are most likely to disperse through the action area; (6) a Service-approved biologist will conduct pre-construction surveys and will supervise construction activities within suitable habitat along Redwood Creek; (7) all proposed project construction personnel will be trained by a Service-approved biologist in the

General Superintendent 3 identification of the California red-legged frog and NPS will implement avoidance and minimization measures; (8) NPS will prevent the inadvertent entrapment of the California red-legged frog during construction by thoroughly inspected steep-walled holes or trenches more than 2 feet deep for trapped animals and covering them at the close of each working day with plywood or similar materials or installing one or more escape ramps; and (9) the implementation of water quality best management practices (BMPs) will minimize the potential for the degradation of aquatic habitat for the California red-legged frog.

The Service concurs that the proposed project is not likely to adversely affect the northern spotted owl because: (1) annual monitoring for northern spotted owls will be conducted during each year of proposed project construction following the Service’s northern spotted owl survey protocol (Service 2011) in and adjacent to MWNM to determine the location of northern spotted owl activity centers and nest sites; (2) NPS will follow the Service’s survey protocol (Service 2011) to determine if a northern spotted owl nest site is still active; (3) all proposed project actions that would raise noise levels above ambient background levels at an active northern spotted owl nest site will be delayed until a Service-approved biologist has determined that the nest is no longer active and that all the fledgling northern spotted owls have left the natal grove;

(4) for any unsurveyed areas, any work that would raise noise levels above ambient background levels within suitable northern spotted owl habitat will occur outside the owl’s February 1 – July 31 breeding season; (5) northern spotted owls within the action area are likely acclimated to the high ambient background levels of noise (50-70 decibels (dB), see Figure 5) and disturbance at MWNM from high park visitation levels and vehicle traffic; (6) NPS will implement BMPs to further reduce noise levels from proposed project construction activities; (7) construction is not likely to affect northern spotted owl foraging activities because northern spotted owls mostly hunt at night and construction would be restricted to the daytime; (8) no large coniferous trees that could potentially support nesting northern spotted owls (i.e., coniferous trees with greater than 18 inches diameter at breast height or trees with large cavities or deformities that enhance nesting substrate) will be removed; (9) within northern spotted owl habitat, disturbance to native trees greater than 10 inches in diameter at breast height will be avoided where feasible; (10) all habitat for northern spotted owls and their prey species that is temporarily disturbed will restored; (11) NPS will implement BMPs to prevent the introduction and spread of the exotic plant pathogen Phytophthora (i.e., Working Group for Phytophthoras in Native Habitats 2016 (enclosed), https://www.suddenoakdeath.org/wp-content/uploads/2016/04/Restoration_guidance_FINAL-111716.pdf) that threatens the northern spotted owl’s nest trees; and (12) NPS will conduct inventory work for the invasive barred owl in potential habitat areas inside and within two miles of the MWNM boundary for five years and coordinate with the Barred Owl Science Team.

The Service concurs that the proposed project is not likely to adversely affect marbled murrelet critical habitat because: (1) disturbance to native trees greater than 10 inches in diameter at breast height will be avoided where feasible; (2) no suitable nest trees (i.e., tall coniferous trees with greater than 18 inches diameter at breast height or trees with large cavities or deformities that enhance nesting substrate) will be removed; and (3) suitable nesting habitat for marbled murrelets will remain within the action area.

The remainder of this document provides our biological opinion on the effects of the proposed project on the marbled murrelet.

https://www.suddenoakdeath.org/wp-content/uploads/2016/04/Restoration_guidance_FINAL-111716.pdf

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Consultation History

November 4, 2016: The Service received from NPS the request for the initiation of informal consultation on the MWNM Sustainable Access Project.

January 26, 2017: The Service attended a site visit for the MWNM Sustainable Access Project.

March 13, 2017: The Service received from NPS the addendum to the project description for the MWNM Sustainable Access Project.

March 28, 2017: The Service sent NPS the informal consultation concurrence letter for the MWNM Sustainable Access Project (Service file number 08ESMF00- 2017-I-0839, Service 2017a).

May 16, 2017: The Service received from NPS the request for the initiation of informal consultation on the effects of the MWNM Water and Sewer Line Rehabilitation, Salmon Habitat Enhancement, and Bridge Replacement projects on the northern spotted owl, marbled murrelet, and marbled murrelet critical habitat.

July 25, 2017: The Service sent via electronic mail to NPS comments and a request for additional information on the MWNM Water and Sewer Line Rehabilitation, Salmon Habitat Enhancement, and Bridge Replacement projects. The Service stated that NPS should also consult on the California red-legged frog and include conservation measures for the California red-legged frog.

August 3, 2017: The Service participated in a conference call with NPS.

August 8, 2017: The Service received via electronic mail from NPS the proposed conservation measures for the California red-legged frog.

August 9, 2017: The Service sent via electronic mail to NPS comments on the proposed conservation measures for the California red-legged frog.

August 14, 2017: The Service received from NPS the estimates of California red-legged frog habitat disturbance and restoration.

August 30, 2017: The Service received from NPS the revised memorandum requesting informal consultation on the effects of the MWNM Water and Sewer Line Rehabilitation, Salmon Habitat Enhancement, and Bridge Replacement projects on the California red-legged frog, northern spotted owl, marbled murrelet, and marbled murrelet critical habitat. The revised memorandum included the proposed conservation measures for the California red-legged frog.

October 4, 2017: The Service sent NPS the informal consultation concurrence letter for the MWNM Water and Sewer Line Rehabilitation, Salmon Habitat Enhancement, and Bridge Replacement projects (Service file number 08ESMF00-2017-I-2376, Service 2017b).

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November 8, 2017: The Service received and responded to an electronic mail message from NPS requesting information on the process for reinitiating consultation if proposed project work were allowed to begin on June 1 during the breeding seasons for the northern spotted owl and marbled murrelet.

February 15, 2018: The Service received from NPS the memorandum requesting the reinitiation of formal consultation on the MWNM Water and Sewer Line Rehabilitation, Salmon Habitat Enhancement, and Bridge Replacement projects and the MWNM Sustainable Access Project to allow construction work to begin on June 1 during the breeding seasons for the northern spotted owl and marbled murrelet (L. Joss, GGNRA, in litt. 2018). The memorandum also added to the proposed project in-channel construction activities to repair an emergency stabilization of a 2015 culvert blowout on a tributary to Redwood Creek.

February 21, 2018: The Service sent via electronic mail to NPS comments and requests for additional information on the proposed project.

February 26, 2018: The Service participated in a conference call with NPS to discuss the effects of the proposed project on the northern spotted owl and marbled murrelet and the proposed conservation measures.

March 15, 2018: NPS informed the Service during a conference call of potential revisions to the project description and construction schedule. NPS and the Service also discussed the proposed marbled murrelet inventory program.

April 2, 2018: The Service received from NPS the revised project description and construction schedule.

June 26, 2018: The Service requested information from NPS on the potential for “take” of northern spotted owls since the proposed project would avoid increases in noise above ambient background levels at an active nest site. The Service also requested how NPS would determine whether a northern spotted owl nest was still active.

June 27, 2018: The Service received the requested information from NPS on the effects of the proposed project on northern spotted owls due to work conducted during the breeding season after June 1. NPS said they will follow the Service’s survey protocol (Service 2011) to determine whether a northern spotted owl nest was still active and would avoid any construction activities that would raise noise levels above ambient background levels at an active nest site until monitoring conducted by a Service-approved biologist had determined that all the fledgling northern spotted owls had left the natal grove. The revised effects analysis provided by NPS demonstrates a change in the conclusion from “likely to adversely affect” to “not likely to adversely affect” the northern spotted owl based on the high ambient background levels of noise within the action area and the implementation of monitoring and avoidance measures to avoid disturbing any breeding northern spotted owls and their fledglings. The Service provided NPS with BMPs to prevent the introduction of the exotic plant

General Superintendent 6 pathogen Phytophthora within the action area that threatens northern spotted owl nest trees (Working Group for Phytophthoras in Native Habitats 2016).

July 3, 2018: The Service received via electronic mail from NPS approval to include in the proposed project conservation measures the BMPs to prevent the introduction of the exotic plant pathogen Phytophthora within the action area (Working Group for Phytophthoras in Native Habitats 2016).

July 9, 2018: The Service issued the biological opinion for the proposed project (Service file number 08ESMF00-2017-F-2376-R001).

March 25, 2019: The Service received from NPS the “Draft Proposed Inventory Plan Options for Marbled Murrelets in Muir Woods National Monument” (Point Blue Conservation Science 2019) that was a requirement of the biological opinion for the proposed project.

March 27, 2019: The Service provided comments on the “Draft Proposed Inventory Plan Options for Marbled Murrelets in Muir Woods National Monument” (Point Blue Conservation Science 2019).

January 13, 2022: The Service requested from NPS the northern spotted owl and marbled murrelet survey reports and annual monitoring reports that were a term and condition in the biological opinion for the proposed project.

February 7, 2022: The Service received from NPS the requested northern spotted owl and marbled murrelet survey reports and proposed project monitoring reports.

Some of the required marbled murrelet surveys were not implemented due to COVID-19 restrictions.

February 14, 2022: The Service requested additional information on the status of construction of the proposed project and whether additional northern spotted owl and marbled murrelet surveys would be conducted.

March 17, 2022: The Service met with NPS to discuss the status of the proposed project and implementation of the conservation measures (e.g., the required five years of marbled murrelet surveys). NPS stated they will reinitiate formal consultation to cover three additional years of work during the marbled murrelet’s core breeding season through 2027 that are required to complete the proposed project. NPS agreed to conduct additional years of acoustic surveys for the marbled murrelet during the years in which construction would occur during the marbled murrelet’s core breeding season.

June 24, 2022: The Service received from NPS the request to reinitiate formal consultation on the proposed project due to three additional years of work proposed during the marbled murrelet’s core breeding season beyond the five years covered by the Service’s July 9, 2018, biological opinion.

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June 29, 2022: The Service requested clarification on the activities covered by the biological opinion and the number of years work would occur during the marbled murrelet’s core breeding season.

July 7, 2022: The Service received from NPS the requested information.

BIOLOGICAL OPINION

Description of the Proposed Action

Water Service (Waterline) Rehabilitation and Wastewater (Sewer Line) Rehabilitation Projects

The purpose of this part of the proposed project is to provide reliable water and wastewater services at the MWNM to meet current codes for water and waste water collection services; and to address fire flow demands, potable water quality issues, visitor and employee health and safety, and locating wastewater infrastructure out of the Redwood Creek corridor. The portion of the existing wastewater collection system south of the visitor center is in close proximity to Redwood Creek making it susceptible to erosion or scour from flood flows. Relocation of the wastewater line will ensure it is a safe distance from Redwood Creek and will safeguard public health and protect water quality important to sensitive natural resources including Coho salmon and steelhead trout. Eighty percent of the wastewater collection system that runs parallel to Redwood Creek is in a critical risk area for future exposure and damage due to the changing creek watershed if all creek riprap was removed. Several sections of the gravity sewer main are within feet of the current Redwood Creek bank, and there are several locations where the sewer main is exposed having no cover over the piping. Nearly the entire gravity sewer main located upstream of Manhole #13, situated adjacent to the lower parking area, is located within the channel migration and erosion hazard zone. The project area extends from the point of the Marin Municipal Water District (MMWD) connection at the Tourist Club, to Mount Tamalpais State Park land west of the Tourist Club, and from the existing tank site above the historic Superintendent’s Residence to the southern end of the MWNM. Although the total project area is approximately 32 acres, the actual ground disturbance from construction activities and staging associated with the water line and sewer line rehabilitation will be approximately 2 acres (Figures 1A and 1B).

Water Line Rehabilitation The water line rehabilitation in the proposed project includes the following: removing the existing water tank and providing a new 6-inch domestic service connection from MMWD;

constructing a single 6-inch water main down hillside to connect to the existing 6-inch water main; separating the fire flow water main from the domestic water main at the road below tank site; and installing a supplementary disinfection pump in an existing shed to be rehabilitated.

Sewer Line Rehabilitation The proposed project will not change the overall flow from the MWNM to the Tamalpais Community Services District. Instead, it only increases the capacity of the MWNM’s gravity collection system pipes based on modeling of existing usage, i.e., the current wastewater lines are undersized. In order to eliminate aged and poorly functioning components, the proposed project will relocate sewer line infrastructure to provide sewer separation located farther from Redwood Creek to help safe guard public health and protect sensitive natural resources including Coho salmon and steelhead trout.

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Figure 1A. Project area for the MWNM Waterline and Sewer Line Rehabilitation Projects (copied from Figure 1 in NPS 2017a).

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Figure 1B. Project area for the MWNM Waterline and Sewer Line Rehabilitation Projects (copied from Figure 2 in NPS 2017a).

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To maintain the current sewer alignment within the greater surrounding critical infrastructure, the new wastewater lines will include the following wastewater elements: (1) pipe burst (a method of inserting pipe without excavating) the existing 6-inch sewer main located between the road corridor up by the NPS residence down to the MWNM’s visitor center with an 8-inch high-density polyethylene pipe then with an open cut trench install a new 8-inch sewer main over to the road corridor to connect with Zone 2 sewer improvements; (2) rehabilitate, replace, or install new manholes; (3) perform spot repairs to address pipe sags; (4) install an 8-inch polyvinyl chloride sewer main; (5) abandon in place the existing gravity sewer main except the portion used for connection to the lower comfort station; and (6) install new sewer mains and lateral connections.

Construction is anticipated to begin in the summer of 2019 and be completed by the winter of 2019. Water and wastewater construction actions are anticipated to begin in the summer of 2019, approximately June 1, 2019. Work will be completed by the start of the rainy season or mid- November 2019. As required, vegetation removal will occur prior to nesting season.

Salmon Habitat Enhancement and Bridge Replacement

This part of the proposed project includes the replacement of four existing non-historic wooden pedestrian bridges that cross Redwood Creek within the MWNM; these bridges are aging and constraining the stream channel. One of the goals of the proposed project is to restore natural geomorphic processes where possible, given constraints to channel function such as the existing trail system and the need to maintain much of the channel bank revetment as a cultural resource.

The proposed project also includes enhancing winter/spring habitat for Coho salmon fry and juveniles and summer habitat for Coho salmon and steelhead juveniles in Redwood Creek through in-stream actions, floodplain enhancement, bank revegetation, removal (or strategic burial) of riprap, and placement of large woody debris. The project area is shown in Figures 2A- 2E.

Salmon Habitat Enhancement The proposed salmon habitat enhancement project will include the following features:

1. NPS will conduct revegetation on creek banks and areas of the forest floor impacted by implementation. Revegetation on creek banks will only use native species and will include species that would provide overhanging branches for cover for fish;

2. Grade control will be installed in a small incised tributary on the east side of the creek just downstream of Bridge 3. Broken pieces of riprap removed during other project actions will be installed by hand in a series of check dams extending over approximately 150 linear feet of the tributary. Slash may be placed in the tributary between the check dams to help trap sediment. The purpose of the grade control is to help reverse the incision that has occurred in this reach and potentially raise groundwater elevations on a very localized scale, which may help protect instream flows. The check dams may also capture sediment behind them; this is a small-scale experimental action;

3. Heavy equipment will be used to excavate pools and build adjacent bars/riffles at wood jams. These actions will create immediate summer rearing habitat (pools) and enhance winter rearing depth as well as velocity;

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4.

Figure 2A. Project area for the MWNM Salmon Habitat Enhancement and Bridge Replacement Project (copied from Figure 2-3 in NPS 2017b).

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Figure 2B. Project area for the MWNM Salmon Habitat Enhancement and Bridge Replacement Project (copied from Figure 2-4 in NPS 2017b).

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Figure 2C. Project area for the MWNM Salmon Habitat Enhancement and Bridge Replacement Project (copied from Figure 2-4 in NPS 2017b).

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Figure 2D. Project area for the MWNM Salmon Habitat Enhancement and Bridge Replacement Project (copied from Figure 2-4 in NPS 2017b).

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Figure 2E. Project area for the MWNM Salmon Habitat Enhancement and Bridge Replacement Project (copied from Figure 2-5 in NPS 2017b).

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4. An undermined bank adjacent to the entrance boardwalk extending approximately 20 linear feet will be filled with riprap to prevent erosion or further undermining. A sewer line under the adjacent boardwalk will remain in place even after other segments of the sewer line will be moved further from the creek; the entrance boardwalk is essential infrastructure for visitor resources. The rock will be placed so as to remain in a smooth line with other riprap both upstream and downstream of this feature; Erosion control methods may integrate the use of existing rock backing material (the 6-12-inch rock behind the riprap) to protect bank slopes without the use of erosion control fabric where there is sufficient banking material and the bank slope is adequate;

5. Any toe material that occurs as part of a riprap segment will be removed along with the other riprap rock, and the creek bed will be rebuilt to the existing grade with suitable native material (instead of removing the riprap and hauling it to disposal sites, riprap will be buried strategically in the creek channel)

6. A total of 1,731 linear feet of riprap (51 percent of the existing total) will be removed (or strategically buried in the creek channel);

7. An alcove will be added near the Bridge 1.5 area. The right bank at the entry plaza will be lowered to floodplain elevation; and

8. Large woody debris will be added at 23 locations.

Pedestrian Bridge Replacement Four existing pedestrian bridges in the MWNM (Figures 2A-2E) are deteriorating due to age and will be replaced by bridges which will be designed to provide improved flood conveyance while enhancing the rustic and historic character of the MWNM. Designs for Bridges 2 and 3 will require trail rerouting, while designs for Bridges 1 and 4 will not. All of the forested areas proposed for new trail segments are flat, extend more than a channel width from the top of the bank, can avoid impacts to redwood trees, and present good options for smooth connections to the existing trail alignment. The proposed pedestrian bridge replacement project will include the following features:

1. NPS will replace Bridges 1 and 4 to pass a 100-year storm flow. This action will require minor increases to the bridge span to ensure passage of a 100-year storm flow with 18 inches of freeboard. Bridge 1 will have an approximately 50 linear-foot span, and Bridge 4 will have an approximately 45 linear-foot span.

2. NPS will replace Bridge 2 with a bridge that accommodates a 25-year storm. This action will require a bridge span of 52 linear feet to ensure passage of a 25-year storm flow with 15 inches of freeboard at the peak of the arch.

3. NPS will replace Bridge 3 with a bridge that accommodates a 100-year storm. This action will require a bridge span of 45 linear feet to ensure passage of a 100-year storm flow with 13 inches of freeboard at the peak of the arch.

4. Bridges will be of a clear span design over the stream channel, able to accommodate from 25- to 100-year flood flows (based on existing channel conditions). New abutments will be relocated farther from the creek but still in the 100-year floodplain. Existing abutments for Bridges 1 through 4 will be removed. Historic riprap surrounding the Bridge 1 abutments and riprap in the vicinity of the Bridge 2 left bank abutment will not be

General Superintendent 17 removed. Non-historic riprap surrounding the Bridges 2, 3, and 4 abutments will be retained, replaced in-kind, or replaced with other bank protection measures.

5. The approaches to all new bridges will be designed to connect the existing trail network with the new bridges. No trail reroutes will be required for Bridges 1 and 4. Approaches to the bridges will require minor new trail construction and adjusted grades within the existing alignment. At Bridge 2, approximately 120 linear feet of new boardwalk will be installed on the east side of the creek and 20 linear feet of new boardwalk on the west side of the creek. At Bridge 3, approximately 120-160 linear feet of new trail and 50 linear feet of boardwalk will be installed on the east side of creek and 50 linear feet of new boardwalk on the west side of the creek.

6. Bridge designs and associated redesigned trail approaches will meet the Architectural Barriers Act Accessibility Standard for outdoor areas, and all grades will aim to be less than 5 percent.

7. Bridges will be a steel stringer design with wood decking and guardrails. Guardrails are needed to comply with current safety codes. Bridges 1 and 4 will include a minor arched camber. Bridges 2 and 3 will include a more significant arched camber.

8. Bridge 2 will have a small, approximately 20-foot x 20-foot gathering area on the east side of the creek.

9. The gathering area and existing trail alignment at Bridge 2 will be restored to habitat. The trail will be outside of the 100-year floodplain. The trail on the east side of Bridges 2 and 3 will be restored to habitat.

10. New/rerouted trails will either be boardwalk or flexible paving, which could include asphalt, compacted shale, or other materials. The lengthened boardwalks/transitions between bridge and trails may require piers placed within the 100-year floodplain; and

11. Areas of existing trail removal will be decompacted, restored, and revegetated with native plants.

Creek restoration actions could begin as early as summer or fall 2019 if permitting is complete (placing of large trees in the creek could occur as early as late summer/fall 2018). Phase 1 riprap removal (or burial) is anticipated to occur over about an eight-week on-the-ground work period, and Phase 2 is anticipated to occur over a similar duration in a later year (possibly as late as 2023). Bridge construction is scheduled to start in 2020 and 2022 with two bridges removed and replaced each of the construction years. Construction is anticipated to occur over an approximately 4.5-month period within each construction year.

Repair of Emergency Stabilization Measures in Tributary of Redwood Creek

In-channel construction activities are needed to repair an emergency stabilization of a 2015 culvert blowout on a tributary to Redwood Creek. Currently, Class 2 riprap is lying on top of the tributary headcut. Under most flow conditions, water flows through the riprap matrix rather than on top which creates a movement barrier for aquatic organisms. The location of this proposed action is on Conlon Avenue in an unnamed tributary to Redwood Creek at MWNM (Figure 3).

Actions will include removing two existing headwall structures from the channel, and reshaping and reinstalling existing armoring for up to 40 feet of tributary channel to allow the site to act as

General Superintendent 18 an armored fill stream crossing (e.g., allowing surface flow of water as well as a stable driving surface for infrequent crossings by vehicles). The construction schedule is not known at this time but will occur sometime between 2018 and 2023 depending on the receipt of funding.

Figure 3. Location of the proposed in-channel construction activities for the repair of emergency stabilization measures on Conlon Avenue in an unnamed tributary of Redwood Creek at MWNM (copied from Figure 1 in L. Joss, GGNRA, in litt. 2018).

Sustainable Access Project

The Sustainable Access Project will modify the footprints of the Entry Plaza, Main Lot, Annex Lot, Conlon Lot, and the former Nursery Area, but will maintain the same number of parking spaces for privately owned vehicles as currently exists (i.e., 232 spaces) (Figure 4). Though administrative access will be maintained in the Entry Plaza, existing parking spaces will be relocated further away from Redwood Creek, and approximately 0.4 acre will be rehabilitated with native riparian vegetation. Parking for persons with disabilities will be relocated to the Main Lot, with approximately 11 spaces available and an access point for passenger drop-off. The Main Lot will also maintain its existing footprint and contain approximately 18 parking spaces for buses, shuttles, and commercial use vehicles. The Main Lot will likely need to be restriped to meet disability parking requirements and to accommodate two additional bus spaces.

The Annex Lot will be reconfigured and restriped to accommodate approximately 125 parking spaces for privately owned vehicles. The Annex Lot will be designed with one-way aisles and a single entry and exit at the southern end of the lot to promote efficient vehicular circulation.

The Conlon Lot will be widened 6 to 8 feet to accommodate a two-way driveway and approximately 48 parking spaces for privately owned vehicles. A pedestrian trail will be developed on the perimeter of the lot near Conlon Creek. Visitors parking in the Conlon Lot will cross Muir Woods Road at the Conlon Avenue intersection by way of a delineated footpath.

Existing roadside parking will be eliminated on the east side of Muir Woods Road between Conlon Avenue and the Muir Woods Road bridge, and the area will be revegetated with plants native to MWNM.

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Figure 4. Action area for the Sustainable Access Project (copied from Figure 2 in Horizon and Environment, LLC 2016).

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A new lot will be developed in the former Nursery Area (an existing maintenance and storage area also referred to as the Nursery Lot) and contain parking spaces for up to 48 privately owned vehicles. The structures in the former Nursery Area will be removed, and the area will require less than 0.3 acre of development. Because the MWNM aims to work within the existing footprint of the former Nursery Area, minimal filling and grading will be necessary to construct former Nursery Area, minimal filling and grading will be necessary to construct the Nursery Lot.

One culvert will be installed during construction to accommodate an existing drainage on site.

Impervious asphalt will be used to surface the Nursery Lot, and the lot will be designed to promote one-way traffic with one entrance, one exit, and a single driveway.

Construction activities for the parking areas will involve dumping rock and other material, grading parking area base to match proposed grades, spreading aggregate base across the surface, and using paving and roller machines to install asphalt to the surface. Work at the Nursery Lot will also include clearing and grubbing of vegetation including some trees. Other construction equipment will include front-end loaders, excavators, skid steers, and bulldozers. Construction staging and material storage will be located on the existing parking areas within MWNM and at the Nursery Lot following preparation of the staging and lay down area. Sand, rock, and gravel and paving materials will be obtained from NPS-approved commercial sources near MWNM.

Engineered stormwater management facilities will be used to treat the runoff from the Entry Plaza and all parking lots. Shallow excavated ditches lined with filter strip sand and topped with stone to form a subsurface basin (where water is stored until it infiltrates into the soil) will be used to treat stormwater. This system is commonly known as an infiltration trench. The infiltration trenches will be designed and sized in accordance with U.S. Environmental Protection Agency guidance. The largest infiltration trenches will be associated with the Main and Annex Lots. These trenches will be approximately 0.04 acre. The Entry Plaza, Conlon Lot, and Nursery Lot will have infiltration trenches covering approximately 0.012 to 0.016 acre. The infiltration trenches will be installed near the parking lots.

The trail between the Main and Annex Lots will be improved and widened to 10 to 12 feet.

Improvements to the trail will include minor realignments and grading to improve accessibility and replacement of deficient culverts at three locations with larger culverts or footbridges to correct drainage problems. The trail will be designed to incorporate drainage and erosion control measures, including stabilizing the downstream drainage channel to stop further downcutting and bank sloughing near the two crossings. The drainages at the trail crossings will receive additional riprap to armor the channel and possibly larger rocks or logs for grade control. The disturbed soil areas along the trail and drainage crossings will be planted with native plant material to help minimize soil erosion. If heavy equipment access is needed for the trail work, the contractor will access the site using the existing trail prism. The proposed project will remove the restroom near Redwood Creek in the Entry Plaza. The restroom will remain in the Entry Plaza but be relocated outside of the erosion hazard area and will be sized to accommodate peak season visitation levels. The relocated restroom will not impede access to the Entry Plaza. A second restroom will be constructed near the former Nursery Area to accommodate visitors’ parking at the southern end of the project area and will also be sized to meet peak season visitation levels.

The segment of existing pedestrian trail along Muir Woods Road between the Main and Nursery Lots will be decommissioned and revegetated with plants native to MWNM. The proposed project will develop a new woodland pedestrian trail between the Annex Lot and Nursery Lot.

Approximately 1,200 linear feet of disturbance will be required to construct the trail at a width of 6 to 8 feet. The trail will pass along the Redwood Creek side of the Annex and Nursery Lots, and

General Superintendent 21 will tie into the Dipsea Trail. Portions of the trail within or adjacent to the Annex and Nursery Lots will be developed within the existing footprint of the lots. If this alignment is not feasible, the trail will follow the perimeter of the two lots, which may require building the trail on fill. The segment of trail connecting the Annex and Nursery Lots will be approximately 570 feet and pass through arroyo willow riparian forest, buckeye-bay laurel forest, and coast live oak woodland. A total of approximately 0.2 acre of vegetation will be disturbed. To minimize disturbance, retaining walls may be constructed with handrails. Small footbridges or boardwalks will be built over any intermittent drainages along the trail route, and the trail will be no steeper than a 2 percent running slope. New interpretive media will be located along this new trail.

The portion of the Dipsea Trail passing through the Annex Lot will be realigned to the northwest perimeter of the lot, and a new pedestrian footbridge will be installed at the Redwood Creek crossing. The pedestrian footbridge will likely be installed in the location of the existing wooden plank and placed roughly 14 feet above the creek bed so that the north side of the bridge will be at the same grade as the Annex Lot. Figure 4 shows the changes that will occur under the proposed project. No trees will need to be removed, and the existing Dipsea Trail will retain a similar alignment.

The proposed project will establish additional signs directing visitors to the Entry Plaza and to local trails as a means to improve wayfinding at MWNM. The Entry Plaza will be furnished with new interpretive media telling the story of natural, historic, and cultural resource stewardship at MWNM. The segment of trail between the Main Lot and Annex Lot will also be furnished with interpretive media.

The proposed project will also remove two lift stations located in the former Nursery Area and northeast of the Conlon Lot, which will be replaced with a single modern 40,000 gallon lift station located near the Nursery Lot entrance. The replacement lift station will be more efficient than the existing units and eliminate the need for double pumping waste water. An underground power line and sewer lines will be installed to connect the lift station to the existing lines. The new lift station will be designed to accommodate the new restroom. The structures in the former Nursery Area will be removed, and the area will require less than 0.4 acre of development.

Project and Channel Access Construction activities will require the use of trucks to haul materials from sources outside of MWNM to work and staging areas in the project area. Vehicle access to the project area is available using Muir Woods Road via Panoramic Highway or State Highway 1. The main entrance to MWNM lies on the west side of Muir Woods Road. Parking areas associated with the proposed project are situated on both sides of Muir Woods Road. Construction crews can access the Dipsea bridge location through the existing Annex Lot. An earthen ramp will need to be constructed on the left bank to allow for equipment access required for installation of new bridge abutments on the upper banks of Redwood Creek. Equipment will access the north (right) bank using a temporary, free spanning bridge over the wetted channel. Access to the channel will not require the removal of any existing trees.

Construction Schedule The proposed construction schedule for the majority of proposed project spans from June 2019 through 2027 during the breeding seasons for the northern spotted owl (February 1 and July 31) and the marbled murrelet (March 15 – September 15). However, the sewer and water lines rehabilitation will occur beginning as early as August 1, 2018, outside of the breeding season for the northern spotted owl but during the late breeding season for the marbled murrelet (August 1 –

General Superintendent 22

September 15). The Sustainable Access Project will be phased over this period to accommodate visitor parking and allow for some space to be available for construction staging. Timing restrictions to protect federally listed species, as described in the Conservation Measures section below will be applied to construction activities during this period. Table 1 below shows the work that was completed 2018-2021. Table 2 below shows the work that will be completed between 2023 and 2027.

Table 1. Proposed project work completed 2018-2021.

Year Constructed

Project Location Description

2018 Sewer/Water/Telecom (Phase 1)

Nursery Area

Scoping, initial work at nursery area, outside northern spotted owl nesting season

2019 Salmon Restoration Phase 1 Redwood Creek

Creek dewatering, restoration for salmon habitat

2019/2020 Sewer/Water/Telecom (phase 1)

From Conifer Classroom to Lift Station

Trenching for new water and sewer lines. Install new manholes. This moved significant portions of sewer away from Redwood Creek.

2019 Lift Station

Nursery Lot Removal of sheds and garden areas of Nursery Lot. Grading.

Construction of new lift station.

2020 Lift Station Demo

Conifer Lot Demo of old lift station.

Grading and site stabilization.

Included in Lift Station Contract but work conducted in 2020.

2021 Install Water Main (remaining work on private property not completed)

From Tourist Club to Water Tank

8-inch waterline installed from Tourist Club to below MWNM Water Tank

2021 Entry Boardwalk

Entry NPS Trail Crew replaced boardwalk from entry to circle

General Superintendent 23

Table 2. Proposed project work scheduled for 2023-2027.

Year to be Constructed

Project Location Description

2023 Salmon Restoration Phase 2

Redwood Creek

Creek dewatering, restoration for salmon habitat

2023 Culvert Repair Conlon Lot tributary

Repair of Redwood Creek tributary

2024 Sustainable Access Project Phase 1

Main Lot/Entry Plaza

Construction of entry plaza, bathroom, demo of lower bathroom (Main Lot)

2024 Bridges Phase 1 Over Redwood Creek

Replacement of two pedestrian bridges and associated boardwalk

2025 Conlon and Nursery Lots

Conlon and Nursery Lots

Replacement of two lots.

Construction of bathroom in Nursery Lot next to lift station

2025 Bridges Phase 2 Over Redwood Creek

Replacement of remaining two bridges and associated boardwalk

2026 Annex Lot Annex Lot Replacement of Annex Lot

2027 Main Lot Main Lot Replacement of Main Lot

Conservation Measures

The NPS and their contractors will implement the following conservation measures and BMPs to avoid and minimize the effects of the proposed project on the marbled murrelet, northern spotted owl, California red-legged frog, and their habitats, and other environmental resources:

Marbled Murrelet BMPs

1. Implement a Service-approved monitoring plan for marbled murrelet inventory work to better understand their status in and around MWNM. Four years of acoustic recording unit (ARU) monitoring, from 2018 through 2021, were implemented at MWNM (NPS 2022a). This work included 16 ARUs deployed, 1,410 trap nights surveyed, and over 6,100 hours of recordings over four years. One year of shore-based monitoring for marbled murrelets was conducted in 2019 consisting of 11 surveys at two survey sites totaling over 22.5 observation hours (NPS 2022a). During the remaining proposed project construction years from 2023 to 2027, NPS will implement ARU monitoring for marbled murrelets at 28 northern spotted owl long-term monitoring sites and nine additional ARU locations in and surrounding MWNM. These ARUs will be deployed and analyzed under

General Superintendent 24 the protocol for the Passive Acoustic Monitoring within the Northwest Forest Plan Area Project. The U.S. Forest Service Pacific Northwest Research Station will analyze acoustic data using a neural network they developed for the project. Marbled murrelet “hits” from the neural network will need to be verified by a qualified biologist. NPS will report any confirmed marbled murrelet detections from the 28 northern spotted owl long-term monitoring ARU sites. If a marbled murrelet detection is confirmed at one of the nine detector locations in and surrounding MWNM, the Service will be notified immediately and all noise-generating activities during the marbled murrelet’s breeding season (March 15 – September 15) will be restricted to the daytime hours from two hours after sunrise to two hours before sunset.

2. During the first year of construction (2018), all proposed project work in or near marbled murrelet habitat will occur after July 31 (outside of the core breeding season (March 15 – July 31) but during the late breeding season (August 1 – September 15) for the marbled murrelet).