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COMMUNITY VISIONING WORKSHOP DOCUMENTATION + PRELIMINARY CONCEPT PLAN

AUGUST 17, 2026

CONTENTS About the Project Key Vulnerabilities and Coastal Resources Community Planning Workshop Preliminary Concept Plan Pathway to Implementation

ABOUT THE PROJECT

CHALLENGES AND PROJECT APPROACH The Town of Manchester-by-the-Sea has been regularly experiencing impacts from coastal flood events along Ocean Street – especially the low-lying segment of the roadway between Summer Street (in the east) and the western end of White Beach. Annual storms frequently wash out portions of the dunes along Black Beach and the parking lot at White Beach, leading to increased effort and expenditures for annual cleanup, restoration, and maintenance. Recent storms have even undermined the structural integrity of the roadway along White Beach, near an old public boat launch, and have come close to exposing the new water main that was installed in 2019. Accessibility is also a challenge to maintain, as the sidewalk along Ocean Street is routinely damaged each year and will no longer be feasible to maintain in its current state.

The purpose of this project was to: 1. Conduct a vulnerability assessment to evaluate current and future coastal flood risk 2. Facilitate a proactive public workshop to co-develop preliminary resilience strategies with the community 3. Develop a conceptual plan to help position the Town to pursue funding to implement long-term risk reduction solutions

KEY VULNERABILITIES AND COASTAL RESOURCES

COASTAL HAZARDS AND VULNERABILITIES Ocean Street is directly exposed to coastal storm surge and tidal flooding. While larger present-day coastal storms have also been known to overtop the road, frequent meanhigh-water (MHW) flooding is not expected to become a consistent roadway issue until approximately the 2070 planning horizon, when the area around the existing culvert area and Ocean Street west of it are projected to experience daily tidal inundation.

MC-FRM AEP 2050

What is Mean High Water (MHW)? Mean High Water (MHW) is the average of all high tides recorded at a specific location over a 19-year cycle.

The culvert and surrounding marsh add another layer of vulnerability. Tide-gauge data collected during the project indicate that the marsh does not currently experience a full tidal range: low-water elevations remain near 2.7 feet (NAVD88) because of elevated streambed elevations and culvert inverts, while the culvert restricts some incoming flow during spring high tide events. Although this currently provides some attenuation of the highest tides, projected 2070 MHW elevations may be sufficient to flow over Ocean Street and directly inundate the marsh. This makes the culvert crossing and adjacent low-lying roadway area a particularly important point of failure under future modeled conditions. Coastal erosion and wave-driven beach change are also significant concerns, especially along White Beach and Black Beach. At White Beach, Ocean Street is protected only by a rough boulder revetment, and at Black Beach, protection consists of seawalls of varying ages and construction types. Storm waves already erode the beaches and deposit sand on the road, and continued erosion could eventually undermine the roadway. Although the shoreline has been relatively stable over the long term, recent data show average erosion rates of approximately 0.78 feet per year at White Beach and 0.6 feet per year at Black Beach. See the attached vulnerability assessment for full descriptions of current and projected flood vulnerabilities identified for the area.

Projected Mean High Water

Existing Culvert

What is Annual Exceedance Probability (AEP)? Annual exceedance probability (AEP) is the probability that a storm of that magnitude will be met or exceeded within a given year. A storm causing coastal flooding with an AEP of 50% has a 1 in 2 chance of occurring at any point within a given year.

COASTAL RESOURCES AREAS Black Beach and White Beach are both barrier beaches directly exposed to storm surge and waves. Continued and increased impacts to these barrier beaches could result in loss of usable beach, additional sand transport across Ocean Street, reduced public access and recreational use, and greater exposure of the revetment, seawall, culvert, parking, and roadway. The coastal dunes, salt marsh, bordering vegetated wetlands, and coastal banks form the landward natural system surrounding Ocean Street. Dunes occur on both sides of the road and make up much of the barrier system. Near White Beach, road runoff follows a defined drainage path through the dune toward the salt marsh. The upstream salt marsh appeared healthy during a 2025 field survey conducted by the Project Team; however, future modelled conditions project that much of it could transition from irregularly flooded marsh to regularly flooded marsh and eventually estuarine beach, with limited ability to migrate inland because of steep banks. Bordering vegetated wetlands and coastal banks, totaling approximately 20,500 square feet (sf), provide transition areas between the marsh and surrounding uplands. More regular flooding impacts to these areas could result in habitat and vegetation loss, altered drainage and tidal conditions, and reduced buffer between the marsh, roadway, and nearby properties. Seaward of the beaches, approximately 78,500 sf of rocky intertidal shore was identified, with macroalgae covering about 90% of the boulders. Offshore waters are also mapped as spawning and settlement habitat for softshell clam, sea scallop, and blue mussel, although no living shellfish were observed during the survey. Changes in shoreline structures, sediment movement, water quality, or tidal exchange could affect these habitats. All documented resource areas lie within land subject to coastal storm flowage and should therefore be considered together when evaluating Ocean Street resilience improvements, as changes to one resource area may impact another. See p. 19 for additional notes on regulatory implications related to mapped coastal resources.

COASTAL RESOURCES AREAS 1 Salt Marsh Bordering Coastal Bank

4 Rocky Intertidal Shore

Black Beach and White Beach are both barrier beaches, and coastal dunes, salt marsh, bordering vegetated wetlands, and coastal banks form the landward natural system surrounding Ocean Street

1 2 Barrier Beach – Coastal Dune

5 Border of Salt Marsh and Barrier Beach

2 3 Barrier Beach – Coastal Beach

Bordering Vegetated Wetland Bordering Salt Marsh and Barrier Beach

5 3 4

COMMUNITY PLANNING WORKSHOP

THE “WALKSHOP” As a complement to the data collected through the vulnerability assessment, Town-supplied drawings and utility information, and past studies, a walkshop was held on June 1, 2026. The walkshop provided the Project Team an opportunity to walk the site with community members and hear firsthand which aspects of the site are most important to them, what challenges they have experienced, and what changes they believe could help transform Ocean Street into a more resilient roadway. Walkshop participants described recurring road closures and maintenance issues after storms, including substantial sand accumulation, sand moving into the salt marsh, and the loss or narrowing of usable beach and parking areas. Access was a major discussion item throughout the walkshop. As an alternative to Singing Beach, White Beach and Black Beach are often easier to access when wanting to avoid crowds during peak season, though concerns over parking limitations were also noted. Walkshop participants also emphasized the need to maintain ADA access, pedestrian and bicycle safety, beach access, and the boat launch. Former amenities and operations were also discussed, including lifeguards, a portable toilet, a water fountain, and beach and parking attendants. Near Black Beach, questions were raised about the culverts, tidal flushing, drainage, salt marsh water quality and health, and applicable federal and state regulations – in addition to ideas on potential upgrades to the existing culvert, extending and improving the structural integrity of the existing seawall, and improvements for better access to the beach. The input received during the walkshop was translated into a series of sketch alternatives, which were displayed at a public pin-up the following evening at Town Hall for participants and other community members to review and provide additional feedback.

1. Project Background

10 10

WHAT WE HEARD Seawall Dunes

Salt Marsh

Boat Launch

Sand Bicycles Amenities

Parking

ACCESS Storms

Road Closures

Culverts

Pedestrians

Wa t e r Q u a l i t y Shared Path

Initial Sketches

PUBLIC PIN-UP OF CONCEPTUAL ALTERNATIVES

Collecting Feedback

1. Project Background

12 12

Concept Alternatives

Identifying Key Opportunities

1. Project Background

13 13

IDENTIFIED AREAS FOR POTENTIAL IMPROVEMENT

PRELIMINARY CONCEPT PLAN

PRELIMINARY CONCEPT PLAN – WHITE BEACH

PATHWAY TO IMPLEMENTATION

PATHWAY TO IMPLEMENTATION Implementation of actions to improve the long-term resilience of Ocean Street will require a phased program led by the Town and coordination across various Town departments (e.g., DPW), boards and commissions (e.g., Select Board, Planning Board, and Conservation Commission), public and private landowners, and community stakeholders, with early engagement from state agencies (e.g., CZM, MassDEP). Near-term investigations and maintenance actions should refine performance objectives, confirm permitting pathways, and position the Town for funding to support larger mid- and long-term projects. Because several actions are interdependent – particularly the proposed structural assessment and limited hydrologic and hydraulic (H&H) study, potential structural repairs and culvert upgrade, roadway reconfiguration – the Town should advance them as a coordinated program rather than isolated projects, soliciting feedback from the community along the way. Design assumptions, climate scenarios, survey and geotechnical data, permitting commitments, and operations and maintenance requirements should be carried forward from one phase to the next.

IMPLEMENTATION CHALLENGES

REGULATORY CONSIDERATIONS

Constrained corridor and competing uses

Local and state wetlands review

Ocean Street has limited right-of-way between the beach and dune system, salt marsh, existing shoreline protection, utilities, parking, and adjacent properties. Accommodating resilient roadway sections, a shared-use pathway, ADA access, parking, drainage, and emergency access will require tradeoffs and may require easements, localized narrowing, or changes in circulation and parking supply.

Work in coastal beach, dune, barrier beach, salt marsh, bordering vegetated wetland, coastal bank, land under water, or land subject to coastal storm flowage is likely to require a Notice of Intent and Order of Conditions from the Conservation Commission under the Wetlands Protection Act and any local wetlands bylaw. Depending on actions taken over time, MassDEP Section 401 Water Quality Certification and review by DMF or NHESP may also be needed.

Construction access and continuity Major future construction projects may require temporary road closures, detours, restricted beach or boat-launch access, and carefully timed work windows. The Town will need a phasing and communication plan that maintains emergency response and resident access, provides safe pedestrian routes, and accounts for limited staging and material-storage areas. Interdependent technical decisions Culvert capacity, marsh hydrology, roadway elevation, shoreline protection, beach nourishment, and dune performance are linked. Changing one element may affect flood levels, sediment movement, erosion, or habitat conditions elsewhere. Future designs should be tested under current and future conditions and structured for adaptive implementation as monitoring data and coastal conditions evolve. Delivery, cost, and long-term maintenance Planning-level costs will need refinement through survey, geotechnical investigation, design, and permitting, and grant programs may require local match and shovelready documentation. The Town should also budget long-term for recurring nourishment, dune repair, pavement maintenance, monitoring, and post-storm response so future capital investments retain their intended performance.

Waterways and federal authorizations Activities below or near mean high water, including revetment or seawall work, boatlaunch improvements, culvert work, dredging or fill, and beach nourishment, may require Chapter 91 authorization. Work in navigable waters or discharge of dredged or fill material may also require USACE Section 10 and/or Section 404 authorization. Section 401 certification is issued by MassDEP, not USACE. State and federal environmental review Massachusetts Environmental Policy Act (MEPA) review may be triggered when a project involves state funding, permits, land, or applicable environmental thresholds. Projects requiring a federal permit or federal funding in the coastal zone may also require CZM federal consistency review, and federal involvement may trigger NEPA, endangered-species, or essential-fish-habitat consultation. Early agency coordination The final permitting pathway will depend on the selected actions and impact limits. A coordinated pre-application process with the Conservation Commission, MassDEP, CZM, USACE, DMF, and other relevant agencies should begin during future preliminary design phases so avoidance, minimization, mitigation, and 19 application sequencing can be incorporated before final plans are completed.

PATHWAY TO IMPLEMENTATION Potential Phased Implementation Actions

Near-Term “Enabling” Actions 1-3 Years

Mid-Term “Contingent” Actions 3-10 Years

Long-Term “Transformative” Actions 10+ Years

Conduct a structural assessment of the existing seawall, revetment sections, and culvert to document the existing wall geometry, materials, toe and crest conditions, drainage, settlement, and evidence of undermining or displacement (est. range: $75,000 to $250,000). The assessment should identify immediate safety or maintenance needs, evaluate performance under present and projected coastal flooding, and establish repair, replacement, or monitoring priorities to inform subsequent design and grant applications. Convene an early coordination meeting with regulators, including the Massachusetts Office of Coastal Zone Management, MassDEP, the U.S. Army Corps of Engineers, and other agencies (as appropriate) to review the preliminary resilience ideas developed through the community planning workshop and design charrette (est. range: $2,000 to $5,000). The meeting should identify likely permitting pathways, resource-area concerns, and potential design constraints before the Town advances with other potential near-term actions. Agency feedback should be documented in a coordination memorandum and used to establish a preliminary regulatory roadmap, refine future scopes of work, and strengthen grant applications. Complement the structural assessment with a limited hydrologic and hydraulic (H&H) analysis of the existing crossing connecting Kettle Cove and the adjacent marsh system to quantify tidal exchange, drainage conveyance, backwater effects, and flood pathways under current and future sea-level and storm conditions (est. range $150,000 to $200,000+). The study should also compare crossing upgrade alternatives for culvert size, invert elevation, potential tidal control, and roadway-crossing configuration, while also evaluating potential effects on marsh hydrology, water quality, habitat, and adjacent properties. Pilot a one-way, one-lane drive aisle configuration from White Beach to the intersection of Ocean Street and Summer Street for at least six (6) months to capture distinct traffic shifts (e.g., seasonal changes in roadway usage, potential traffic diversion patterns, and pedestrian safety metrics) and community feedback on the potential change (est. range: $25,000 to $50,000). Formalize parking along White Beach to include new signage and encourage angle-in parking that can accommodate potential shared-use pathway configurations in the future (pending a determination being made on the future conversion of the Ocean Street segment to a one-way, one-lane drive aisle) (est. range: $10,000 to $20,000). Make near-term roadway repairs to mill and repave deteriorated portions of Ocean Street as an interim assetmanagement measure to improve road quality, correct localized drainage deficiencies, and reduce water intrusion into the pavement (est. Range: $250,000 to $400,000). Resurfacing should be coordinated with near-term utility, drainage, parking, and pathway work so new pavement is not disturbed by later construction and does not preclude a future resilient roadway reconstruction. This could also be the opportunity to more formally convert the roadway to a one-way (pending the feedback on the six-month pilot).

PATHWAY TO IMPLEMENTATION Potential Phased Implementation Actions

Near-Term “Enabling” Actions 1-3 Years

Mid-Term “Contingent” Actions 3-10 Years

Long-Term “Transformative” Actions 10+ Years

Implement targeted structural repairs and stabilization measures for the existing seawall and revetment based on the findings and recommendations of the near-term structural assessment (est. range: TBD). The work should address identified deficiencies, restore structural integrity, and extend the service life of the coastal protection system, while reducing near-term vulnerability to erosion, wave action, and coastal flooding. Design and construct a dedicated shared-use pathway along Ocean Street to separate pedestrians and bicyclists from moving (and parked) vehicles and maintain safe public access (est. range: $30,000 to $50,000). The pathway alignment, surface, width, crossings, and transitions should be coordinated with parking changes, beach access points, drainage, utilities, and future roadway adaptation. Reinforce, reconfigure, and formalize small boat launches using a durable, low-profile surface that is more resilient to repeated use and coastal exposure, while limiting erosion and rutting (est. range: $60,000 to $75,000). The designs should maintain safe public access, incorporate edge stabilization and maintenance provisions appropriate to launch paddle craft (e.g., kayaks, canoes, paddleboards) and emergency vehicles and vessels. Restore and reinforce targeted dune areas using compatible sand, native vegetation, sand fencing, and access management, with selective revetment improvements only where necessary to protect critical infrastructure (est. range: $750,000 to $1M+). The work should function as an adaptive shoreline system that reduces overwash and erosion, while preserving beach processes, habitat, public access, and the ability to add sand or shift treatments landward over time. Following the long-term pavement schedule, consider reconstructing vulnerable roadway segments with reinforced concrete pavement sections designed for longer-term repeated wave overtopping, saltwater exposure, and heavy maintenance or emergency loads (est. range: $1.5M to $2M+). Detailed design should integrate subgrade stabilization, drainage, utility protection, joints and transitions, and constructability, while confirming that the investment remains viable under long-term sea-level rise and shoreline change. Replace or substantially upgrade the Ocean Street crossing to increase hydraulic capacity, improve structural reliability, and support future tidal exchange and marsh adaptation (est. range: $500,000 to $1M+). The preferred configuration should be selected through the H&H study and geotechnical and structural design, with careful consideration of invert elevations, scour protection, aquatic passage, utility conflicts, roadway grade, and impacts to adjacent wetlands and properties. Implement a long-term beach nourishment program to place compatible sediment at White and Black Beaches to restore beach volume, widen the storm buffer, and reduce exposure of the roadway, revetment, seawall, and parking areas (est. range: $1M+ per nourishment). A nourishment plan should define sediment characteristics, target profiles and volumes, placement methods, environmental work windows, monitoring, and a repeatmaintenance strategy because future storms and long-term erosion will continue to redistribute material.

PATHWAY TO IMPLEMENTATION The following tables identify several potential local, state, and federal funding mechanisms that may support implementation of the various actions included in the preliminary concept plan shown above. Funding opportunities are organized by action type and summarized in terms of program purpose, general eligibility criteria, and the types of activities typically supported. Because the preliminary actions are interrelated and expected to advance in phases and change over time with additional community input, individual projects may require a combination of funding sources; eligibility, match requirements, application timing, and project-readiness criteria should therefore be confirmed as actions are refined and advanced as a series of phased projects over time.

PRELIMINARY ACTION TYPES

Code

Action Type

Potential Actions Included in Type

Planning, assessment, design & permitting

Structural assessment; early regulatory coordination and permitting roadmap; H&H analysis; preliminary/final design and supporting studies

Roadway operations, parking & interim pavement

One-way pilot; parking formalization; mill/repave; localized drainage corrections and near-term asset management

Seawall/revetment & coastal protection

Targeted structural repairs, stabilization, and selective improvements to existing seawall and revetment systems

Shared-use path & public water access

Dedicated pedestrian/bicycle pathway, ADA/public access, and reinforced small boat launch improvements

Dunes & beach nourishment

Dune restoration with compatible sand, native vegetation, fencing and access management; recurring beach nourishment

Resilient roadway reconstruction

Long-term reconstruction of vulnerable roadway sections with reinforced pavement, drainage, subgrade and utility protection

Culvert, tidal crossing & marsh connectivity

Replace or upgrade the crossing to improve hydraulic capacity, structural reliability, tidal exchange, aquatic passage and marsh adaptation

Note: Funding mechanisms – and related details and eligibility requirements – change over time. It is best to confirm the details of current solicitations prior to applying for funding to support the implementation of specific actions.

PATHWAY TO IMPLEMENTATION LOCAL FUNDING MECHANISMS Funding Mechanism

Town capital appropriation

Manchester Community Preservation Act (CPA)

Brief Description

Eligibility/Key Criteria

Types of Work Typically Funded

Potential Links to Action Types

Flexible local source that can serve as the primary funding source, grant match, or bridge funding

Town-controlled project; requires inclusion in the capital/budget process, Town Meeting and any borrowing authorization, plus ownership/right-of-way and procurement compliance

Studies, design, permitting, grant match, repairs, construction, long-term maintenance, monitoring and poststorm response

A-G

Local surcharge and state trust distributions dedicated to community preservation purposes

The proposal must qualify under open space/recreation, historic preservation, or housing; CPC recommendation and Town Meeting approval are required. Recreation/open-space land protections may apply.

Eligible trails/shared-use paths, public beach or water access, dune/openspace restoration, land interests, and related planning/design (Not routine roadway maintenance)

A, D, E

Eligibility/Key Criteria

Types of Work Typically Funded

Potential Links to Action Types

Competitive grants for local and regional projects addressing coastal flooding, erosion and sea-level rise

Massachusetts coastal-zone municipality, Tribal government, or certified 501(c)(3) (Public resilience benefit and climate basis required; generally 10% match, with limited exceptions)

Risk/vulnerability studies; outreach and planning; design/permitting; retrofit of seawalls, critical roads and culverts; beach/dune/marsh restoration; construction and monitoring

A, C, E, F, G

Implements community-identified priority climate adaptation actions

MVP-designated community; older MVP plans are subject to MVP 2.0 participation rules (Current round requirements typically emphasize best climate data, engagement/equity, nature-based solutions and local match)

Assessments, design, permitting, resilient infrastructure, flood/stormwater/culvert upgrades, wetland/dune restoration, outreach and on-the-ground implementation

A, C, E, F, G

STATE FUNDING MECHANISMS Funding Mechanism

CZM Coastal Resilience Grant

MVP Action Grant

Brief Description

PATHWAY TO IMPLEMENTATION STATE FUNDING MECHANISMS (CONT.) Eligibility/Key Criteria

Types of Work Typically Funded

Potential Links to Action Types

Capital grants and loans for aging floodcontrol and coastal-protection infrastructure

Local government body or nonprofit; eligible publicly/nonprofit-owned structure (Construction proposals generally need advanced permitting and MEPA review or an explanation of exemption; match/readiness vary by round)

Inspection, design, permitting, repair, removal and construction for seawalls, levees, dams and other protective structures

A, C

Formula transportation capital aid distributed to every municipality

Municipal project on locally controlled public transportation assets; must meet eligible capital-purpose, documentation and reimbursement requirements

Milling and paving, roadway/bridge repair or reconstruction, drainage, sidewalks and bike paths, accessibility, curbing, lighting and traffic improvements

B, D, F, G

MassTrails

Reimbursement and matching grants for recreational trails and shared-use pathways

Municipalities, public agencies, Tribal governments and nonprofits; documented landowner permission and recreational/trail nexus (Current program generally requires a 20% match)

Planning, engineering, permitting, new path/trail construction, restoration/maintenance, trailheads and supporting amenities

A, D

MassDOT Community Culvert Program

Competitive grants to modernize and improve resilience of small municipal culverts

Municipal or Tribal government; culvert must be on a public way and have an existing span of 10 feet or less (New or ongoing design and construction may be eligible)

Culvert investigation and design; repair, replacement or removal; hydraulic and structural resilience improvements

A, G

Capital investment in coastal communities’ maritime economy and resilient public waterfront assets

One of Massachusetts’ 78 coastal communities or another eligible public entity; competitive proposal should demonstrate maritime, recreational boating, tourism/economic and public benefits

Boat ramps and launches, harborwalks/public access, shoreline and revetment work, waterfront planning, design/permitting and construction

A, C, D, E

Funding Mechanism

Dam and Seawall Repair or Removal Program

MassDOT Chapter 90

Seaport Economic Council Grant

Brief Description

PATHWAY TO IMPLEMENTATION FEDERAL/NATIONAL FUNDING MECHANISMS Funding Mechanism

FHWA Transportation Alternatives Set-Aside (through MassDOT/MPO)

NFWF National Coastal Resilience Fund

USACE Continuing Authorities Program — Sections 103 / 206

USDOT PROTECT Discretionary Grants

Eligibility/Key Criteria

Types of Work Typically Funded

Potential Links to Action Types

Federal-aid funding for smaller-scale bicycle, pedestrian and nonmotorized transportation projects

Eligible local/public sponsor through the state or MPO competitive process; transportation nexus, programming, right-of-way, environmental review, federal-aid procedures and local match

Planning, design and construction of shared-use paths, pedestrian/bicycle facilities, crossings, ADA and safety improvements; some stormwater/habitat mitigation tied to transportation

A, D

National grants for nature-based coastal resilience that benefit both communities and fish/wildlife habitat

Local/state/Tribal governments, nonprofits, educational institutions and for-profits; eligible coastal geography; project must deliver riskreduction and habitat benefits and fit a defined planning-to-implementation pipeline

Capacity/planning, site assessment and preliminary design, final design/permitting, and implementation/monitoring of dunes, marshes, living shorelines and other natural or hybrid systems

A, E, G

Federal-local partnership for limited-scope water-resources projects without projectspecific congressional authorization

Nonfederal public sponsor; federal interest, technical/economic feasibility, environmental acceptability, cost share, lands/easements and long-term operation/maintenance commitment

Section 103: beach erosion and coastal storm-damage reduction. Section 206: aquatic ecosystem and salt-marsh restoration, hydrologic/tidal connectivity, design and construction.

A, C, E, G

FHWA program for surface transportation resilience, evacuation routes and at-risk coastal infrastructure

Local/state governments, MPOs, transportation authorities and Tribes; eligible surface transportation asset, benefit-cost analysis, federal cost share and programspecific readiness

Resilience planning; roadway and crossing hardening; drainage and flood protection; coastal transportation resilience; evacuation-route improvements

A, C, F, G

Brief Description

Note: FEMA hazard-mitigation funding is unlikely to be a fit for the preliminary actions identified in the concept plan above. FEMA generally requires mitigation projects to demonstrate cost-effectiveness, typically through a FEMA-approved benefit-cost analysis with a benefit-cost ratio of at least 1.0. Based on the current planning-level information, the substantial costs associated with roadway reconstruction, culvert replacement, seawall and revetment repairs, dune restoration, and recurring beach nourishment may be difficult to offset with sufficiently quantifiable avoided losses.

ADDITIONAL PARKING CONFIGURATIONS – WHITE BEACH

MEMORANDUM DATE

May 13, 2026

Ariel Sasser, AICP Fuss & O’Neill, Inc (617) 405-5325 Ariel.Sasser@fando.com

FROM

Brittany Hoffnagle Woods Hole Group (508) 495-6227 bhoffnagle@woodsholegroup.com

JOB NO. 2023-0262

Technical Memo: Ocean Street Resiliency Ocean Street is a low-lying road running along Black Beach and White Beach in Manchester-by-the-Sea, Massachusetts. A culvert providing drainage to Wolf Trap Brook and the surrounding salt marsh is located at the western end of Black Beach, and various types of revetments and seawalls support the seaward edge of the road. Ocean Street is vulnerable to coastal hazards such as flooding and erosion, and its level of vulnerability is expected to increase as sea levels continue to rise and coastal storms continue to become stronger. The following technical memo summarizes the various field investigations and climate change vulnerability assessment for Ocean Street. The memo lays the groundwork for understanding the existing conditions of the study area and the potential future climate change impacts ahead of developing resilient roadway alternatives for Ocean Street.

Tige Gauge Deployment Woods Hole Group Coastal scientists deployed two tide gauges in Manchester-by-the-Sea (Figure 1, Table 1). Station WL1 was deployed on a piling of Magnolia Pier to capture the full tidal range and act as a reference. WL2 was deployed on a pipe anchor in Wolf Trap Brook, just upstream of the culvert into the system, under Ocean Street. The tide gauge sensors were in-situ Aqua TROLL 200 CTDs (Conductivity, Temperature and Depth sensors), configured to record absolute pressure, temperature, and conductivity at six-minute intervals. Absolute pressure is a combination of atmospheric pressure and water pressure. Local atmospheric pressure was obtained from Beverly Municipal Airport. Water pressure (and level) above the tide gauge is calculated by subtracting the atmospheric pressure record from absolute pressure. Precipitation data was obtained from station MA-ES-99 in Beverly, part of the Community Collaborative Rain, Hail, & Snow Network (COCORAHS). During both deployment and recovery, the gauges were surveyed using a real-time kinematic global positioning system (RTK GPS) connected to a virtual reference station network (Leica Smartnet VRS network) for centimeterlevel vertical and horizontal accuracy. These survey data were used to convert the water level record (depth or distance to water surface) to a water surface elevation relative to the North American Vertical Datum of 1988 (NAVD88) in units of feet (ft).

Figure 1.

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Wolf Trap Brook Tide Gauge Deployment Locations

All stations were recovered on January 23, 2026 for a total of thirty-eight (38) total deployment days. Data were downloaded, assessed for quality and completeness, and processed, resulting in a time-series of water surface elevations in feet relative to NAVD88, temperature, and salinity. Complete time-series were recorded at nearly all stations. Surface ice was observed upstream of the culvert under Ocean Street during both deployment and recovery. Table 1.

Wolf Trap Brook System Tide Gauge Deployment Locations Station WL1 WL2

Latitude (N)

Longitude (W)

42.574508

70.715890

42.578221

Description

Piling at Magnolia Pier 70.735112 Upstream of culvert into Wolf Trap Brook

Water surface elevations at both tide gauge locations are shown in Figure 2 and calculated tidal datums in Table 2. Water surface elevations had the largest variability in Kettle Cove (WL1- blue line) with a tide range of 8.04 feet (Figure 2, Table 2). The tide range was calculated by subtracting the average Mean Low Water (MLW) elevation from the average Mean High Water (MHW) elevation over the full time-series dataset. Additionally, the station recorded mixed semi-diurnal tides, with two unequal high and low tides every day. In contrast, the Wolf Trap Brook signal (WL2- red line) showed a reduced tidal range of 1.48 feet. However, the consistent maximum low tide elevation (MLW and Mean Lower Low Water (MLLW)) at around 2.7 feet NAVD88 indicated that the Wolf Trap Brook never fully drains or exhibits a full tidal range – likely due to elevated streambed elevations and culvert inverts. The existing culvert seems to limit some tidal flow through the culvert during the spring tidal cycle, when tidal ranges are the largest and result in higher high tides. This can be seen in Figure 2, where the blue line (WL1) reaches elevations higher than 5 feet NAVD88 compared to the red line (WL2) that remains at or lower than 5 feet NAVD88 in elevation during the first week of January 2026.

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Figure 2.

Water surface elevation at all tide gauge locations (top) and precipitation in Beverly, MA at station MA-ES-99 (bottom)

Table 2. Tidal Datums at all Stations. MHHW refers to Mean Higher High Water and MTL refers to Mean Tide Level, all other acronyms are previously defined. Tidal Datums (feet, NAVD88)* MHHW MHW MTL MLW MLLW Range

Magnolia Pier WL1 4.63 3.82 -0.20 -4.22 -4.83 8.04

Wolf Trap Brook Marsh WL2 4.52 4.20 3.47 2.73 2.71 1.48

* These datums are calculated using the Woods Hole Group 38-day record and are not comparable to standard NOAA tidal benchmarks, which are computed over a 19-year tidal epoch.

Salinity at both tide gauge locations is shown in Figure 3. Salinity at WL1 was saline, ranging from 31 to 32 PSU, and was largely unaffected by precipitation, other than a slight decrease in salinity during the December 29, 2025 precipitation event. Salinity at WL2 was slightly fresher, ranging from 27 to 31 PSU. Similar to WL1, the largest decrease in salinity at WL2 was observed during the December 29, 2025 precipitation event. Despite cold temperatures and ice formation during the deployment period, neither tide gauge appeared to be impacted by ice.

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Figure 3.

Salinity at all tide gauge locations (top) and precipitation in Beverly, MA at station MA-ES-99 (bottom)

In summary, high tides in the Wolf Trap Brook (WL2) system were obstructed only during spring high tides. Low tides in the system were elevated due to higher streambed elevations and culvert inverts. Water surface elevation and salinity in the system were largely unresponsive to precipitation, though this may be due to snow versus rain. Neither station appeared to be affected by ice formation.

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Climate Change Vulnerability Assessment The Massachusetts Coast Flood Risk Model (MC-FRM) was used to assess the potential impacts of future daily tidal and coastal storm surge flooding along Ocean Street with 1.3, 2.5, and 4.3 feet of sea level rise (i.e., the sea level rise projections for the 2030, 2050, and 2070 time horizons). The MC-FRM is a probabilistic hydrodynamic model that is used as the state standard for coastal climate change planning in Massachusetts.1 The MC-FRM considers a variety of factors such as sea level rise projections, historical and projected future tropical and extratropical systems, elevation data, and land cover data to provide an accurate representation of potential flood impacts along the state’s coast. The outputs of the model include storm surge flooding projections for the three time horizons (2030, 2050, and 2070) and a range of annual exceedance probabilities (AEPs). The AEP of a point refers to that point’s probability of flooding at least once in a given year. A point with a 1% AEP is considered relatively unlikely to experience coastal flooding, while a point with a 100% AEP is expected to flood at least once each year. This vulnerability assessment evaluated future flood risk to the project area using MC-FRM data and asset elevations gathered on site. Sea Level Rise Scenario A uniform sea level rise scenario, or predicted rate of sea level rise in the future, is used for statewide planning efforts in Massachusetts. Various sea level rise scenarios include different levels of greenhouse gas emissions and different contributions from global ice sheet melt, and therefore yield different rates of sea level rise.2 Local sea level rise projections are established by downscaling future mean sea level elevations from global climate projections.3 The Commonwealth of Massachusetts uses the High scenario for climate change planning, which for the nearby Boston tide gauge corresponds to 1.3 feet of sea level rise from a 2008 baseline as soon as 2030, 2.5 feet as soon as 2050, and up to 4.3 feet as soon as 2070 (Figure 4). Use of the High scenario is deliberately conservative and ensures that future sea levels are not underpredicted for large infrastructure and planning projects. This sea level rise projection is used to calculate local tidal datums for 2030, 2050, and 2070 planning horizons and is also incorporated into MC-FRM, which is used for this vulnerability assessment. Figure 2 shows how the “High” scenario compares to other scenarios, as well as the probability that it is not underpredicting sea level rise under RCP 4.5, RCP 8.5, and both of those scenarios with additional contributions from ice sheet melt. In the near term, most of the projected relative sea level rise comes from thermal expansion and land subsidence, and there is little uncertainty in projections. After 2050, contributions from ice sheet melt are uncertain, and the scenarios diverge significantly. The choice to use the “High” scenario for MC-FRM flood modeling and MHW projections means that vulnerability and flooding predicted by these data products may occur later than their corresponding year. In interpreting results, 2030, 2050, and 2070 are generally treated as the soonest that corresponding flood probabilities could be projected, and a 20-year range is applied. In practice, 2030 projections are treated as occurring sometime between 2030 and 2050, and the same applies to 2050 and 2070.

https://eea-nescaum-dataservices-assets-prd.s3.amazonaws.com/cms/GUIDELINES/MC-FRM_FAQ_04-06-22.pdf https://doi.org/10.1038/nature17145 3 https://doi.org/10.1002/2017EF000663 1 2

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Figure 4.

Massachusetts Executive Office of Energy and Environmental Affairs (MA EOEEA) Probabilistic Sea Level Rise Projections

Tidal Benchmarks The “High” scenario sea level rise projections incorporated into the MC-FRM were also used as the basis for developing local tidal benchmarks, which were used to evaluate potential high-tide (nuisance) flooding along Ocean Street. Based on MC-FRM projected tidal benchmarks, MHW at Ocean Street could reach 5.8 feet NAVD88 as soon as 2030, 7.0 feet NAVD88 as soon as 2050, and 8.9 feet NAVD88 as soon as 2070 (Table 3). However, if the sitespecific tide data shows a restriction in tidal flow, the future MC-FRM tidal benchmarks are no longer considered representative of actual water levels upstream and require adjustments. The tide data from Wolf Trap Brook does not show a full tide range as water does not drain below approximately 2.7 feet (NAVD88). Therefore, MHW and MHHW for Wolf Trap brook were estimated using the tide data collection and assumes culvert stays in place at its current dimensions and inverts. By 2070, it was projected that the MHW and MHHW would be high enough to flow over Ocean Street and flood Wolf Trap Brook marsh, thus removing the need to adjust the 2070 values within Farm Pond. Table 3:

MHHW MHW MLW MLLW

MC-FRM Projected Tidal Benchmarks and Adjustments for Ocean Street. Kettle Cove MC-FRM Tidal Benchmarks (ft, NAVD88) 2030 2050 2070 6.2 7.4 9.3 5.8 7.0 8.9 -3.3 -2.1 -0.4 -3.5 -2.3 -0.7

Wolf Trap Brook Adjusted for Attenuation (ft, NAVD88) 2030 2050 2070 6 7.2 9.3 5.7 6.9 8.9 N/A* N/A* N/A* N/A* N/A* N/A*

*Tidal datums don't exist upstream of culvert as the water doesn't drain below approximately 2.7 ft NAVD88

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MC-FRM Flood Exposure Future inundation risks from mean high water and coastal storm surge flooding are shown in Figure 5. The first three panels show the Level 1 MC-FRM probability of inundation rasters for 2030-, 2050-, and 2070-time horizons. Exposure risks to storm surge flooding indicate that the roadway is vulnerable to sea level rises and coastal storms as they become more frequent and more intense. The Ocean Street roadway has an annual chance of flooding between 1-100% as early as 2030. Ocean Street increases in elevation towards Victoria Road thus reducing overall vulnerability (0.1-0.5% annual chance). Additionally, Summer Street is vulnerable to flooding with an annual chance of flooding between 0.1-5% as early as 2030. Flooding along western Ocean Street and Summer Street highlights the challenge of accessing the main Ocean Street thoroughfare. The exposure risks to storm surge flooding increase through 2050 and 2070 as indicated by the expansion of the flooding and darkening of the legend colors (purples and blues). The annual chance of flooding along Ocean Street increases to 10-100% in 2050 and 20-100% in 2070. Figure 6 shows the projected water depth with a 1% AEP as soon as 2030, 2050, and 2070. Woods Hole Group developed GIS (Geographic Information Systems) representations of these projected future MHW extents by extracting corresponding elevation contours from the most current terrain elevation measurements available from the MassGIS LiDAR (Light Detection and Ranging) Terrain Data. The GIS extents reflect the MHW values along Kettle Cove and the adjusted MHW values within Wolf Trap Brook. The last (bottom right) panel shows the adjusted MHW flooding extents with 2030 MHW in the darkest shade of blue and 2070 the lightest shade of blue. Daily flooding over the road is not expected to be a significant challenge until 2070 when a small area around the culvert and Ocean Street west of the culvert is at risk of daily tidal flooding. Note that the MHW extents are visual representations of still water elevations and do not incorporate the increased risks from exceptionally high tide events and other oceanographic conditions that may have impacted Ocean Street previously.

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MC-FRM AEP 2030

MC-FRM AEP 2050

MC-FRM AEP 2070

Projected Mean High Water

Figure 5.

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MC-FRM results and Mean High Water shorelines as soon as 2030, 2050, and 2070

MC-FRM 1% AEP Depths 2030

MC-FRM 1% AEP Depths 2050

MC-FRM 1% AEP Depths 2070

Figure 6.

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MC-FRM 1% AEP Flood Depths as soon as 2030, 2050, and 2070

Vulnerability Assessment To assess the probability of flooding for a given point in the project area, water surface elevations corresponding with different AEPs obtained from the MC-FRM are compared to the elevation of the point. Woods Hole Group conducted a topographic survey of the site on December 11, 2025. Elevation points were surveyed using a Leica Real-Time Kinematic Global Positioning System (RTK-GPS) and in-field measurements. An RTK-GPS is a type of GPS instrument that uses a network of reference stations to collect highly accurate elevation position measurements. The elevation points were compiled into a GIS database and then compared to the projected water surface elevations from MC-FRM across different time horizons (as soon as 2030, 2050, and 2070, or 1.3, 2.5, and 4.3 feet of sea level rise) and for different flood probability levels (AEPs ranging from 0.1% to 5% annually). The points were also compared to projected Mean High Water (MHW) elevations for those time horizons. Points were then assigned an AEP based on the highest probability water level that would exceed their elevations in a given projected year. While MC-FRM has a high resolution (<20m) for a statewide model, these methods allow for an even higher resolution understanding of the flood vulnerability of thin features such as roads and buildings. However, water surface elevation data is not available for this area for AEPs higher than 5%, limiting the ability of this analysis to distinguish between points that are moderately and severely vulnerable to flooding. Points that are expected to flood daily are placed into the MHW category, helping to distinguish between daily inundation and common storm flooding. Figure 7 shows the results of the coastal flood vulnerability assessment in the project area for conditions expected with 1.3 (as soon as 2030), 2.5 (as soon as 2050), and 4.3 (as soon as 2070) feet of sea level rise, including annual chance of flooding per year and vulnerability to daily tidal inundation. Elevation points were collected along the roadway center line during the topographic survey and analyzed using the process described above. Points are colored according to the highest AEP (lowest water level) that would exceed their elevation. To be assigned an AEP, the point must be within the flood extent of a given AEP and have an elevation lower than the associated water surface elevation. The highest probability water surface elevation data available for this area corresponds to the 50% AEP. As described in the introduction to sea level rise projections, 2030, 2050, and 2070 are generally treated as the soonest that corresponding flood probabilities could be projected, and a 20-year range is applied. In practice, 2030 projections are treated as occurring sometime between 2030 and 2050, and the same applies to 2050 and 2070.

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MC-FRM Road Point AEPs 2030

MC-FRM Road Point AEPs 2050

MC-FRM Road Point AEPs 2070

Road Point Mean High Water

Figure 7.

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Coastal Flood Probability and Mean High Water vulnerability as soon as 2030, 2050, and 2070

Road Point Elevations (feet, NAVD88)

Figure 8.

Annual Coastal Flood Exceedance Probability

Water Surface Elevation (feet, NAVD88) 2030

2050

2070

0.1%

10.7

12.3

14.1

0.2%

10.4

12.0

13.8

0.5%

10.0

11.5

13.3

9.7

11.2

13.0

9.4

10.8

12.6

9.0

10.3

12.2

10%

8.6

10.0

11.8

20%

8.3

9.6

11.4

50%

7.8

9.1

10.9

HAT

7.6

8.8

10.6

MHW

5.8

7.0

8.9

Road point elevations and associated water surface elevations for each AEP level

Additional information related to depths of flooding can be determined by using the specific water surface elevations along Ocean Street as seen in Figure 8. The general road point elevations along Ocean Street are labeled in the aerial map in the left panel. On the right-hand side of Figure 8 are the representative water surface elevations for each Annual Coastal Flood Exceedance Probability derived from the Level 2 MC-FRM projected water surface elevation data, as well as Highest Annual Tide (HAT) and MHW elevations derived from projected tidal datums.

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Coastal Erosion Vulnerability In addition to coastal flooding, Ocean Street is vulnerable to damage from erosion. Although it is located on a southfacing shoreline and is therefore sheltered from nor’easters, storm-driven waves still erode the beach and deposit sand on the road. If erosion advances far enough, the road could be undermined. The stretches of Ocean Street along White Beach and Black Beach are most vulnerable to erosion. At White Beach, Ocean Street is the most seaward piece of infrastructure, buffered only by a rough revetment of large boulders on the beach. At Black Beach, a seawall of varying ages and construction types separates Ocean Street from the beach. Ocean Street also crosses a culvert at the western end of Black Beach. The shoreline in this area has been relatively stable over the past two centuries. Figure 9 demonstrates the similarity between the shoreline on an 1869 map and in a 2023 aerial. A slight thinning of the high tide beach is apparent between the 1990s and 2023. Analysis of other recent aerials indicates that these beaches have likely been nourished, and that sand that washes over on to the road is plowed into piles on the landward edge of the beach. There is no evidence of undermining at the road’s edge or along the seawall in any aerials analyzed. The influence of coastal processes in the project area was quantified through an analysis of historical shoreline change. Valuable insights can be drawn on the dominant trends of sediment transport using shoreline change transects provided by the Massachusetts Office of Coastal Zone Management (CZM). The data can also be used to evaluate the influence of anthropogenic alterations, such as armoring, on the evolution of the shoreline. In the project area, CZM historical shoreline position data traces the local high-water line based on historical coastal surveys and maps for eight time periods between 1846 and 2018. A series of shore normal transects spaced every 50 feet along the coastline are used to measure historical rates of shoreline change. Rates of change are given in feet per year; negative values indicate erosion while positive values indicate accretion. Figure 10 shows the short-term and long-term rates of shoreline change. The long-term data shows a generally stable shoreline, aligning with the trend observed in historic aerials and maps. The short-term shoreline change rates, which focus on the most recent 50 years of data, show a general trend of gradual erosion at both beaches. At White Beach, the average rate of erosion is 0.78 feet/year, and at Black Beach it is 0.6 feet/year. This indicates that beach nourishment is either not fully effective in these locations or that it has not been going on long enough to sway the data set. A visual analysis of shorelines from 2008-2018 does not show a clear trend of erosion or accretion.

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1919

1990s

Figure 9:

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Historic maps and aerials for the project area

2023

1970-2018 Shoreline Change

1840s-2018 Shoreline Change

Figure 10:

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Short-term (top) and long-term (bottom) rates of shoreline change in the project area (Data from the Massachusetts Shoreline Change Project)

Marsh Migration Figures 11-14 show the results of the Sea Level Affecting Marshes Model (SLAMM) High sea level rise scenario for 2030, 2050, 2070, and 2100. Much of the wetland area behind Ocean Street is currently classified as Irregularlyflooded Marsh. Over time, it is projected to convert to Regularly-flooded Marsh and then Estuarine Beach. The wetlands in the project area are not projected to expand significantly beyond their current footprint because they are limited by steep banks.

Figure 11:

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SLAMM results for 2030 in the SLAMM High sea level rise scenario

Figure 12:

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SLAMM results for 2050 in the SLAMM High sea level rise scenario

Figure 13:

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SLAMM results for 2070 in the SLAMM High sea level rise scenario

Figure 14:

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SLAMM results for 2100 in the SLAMM High sea level rise scenario

Resource Area Delineation Coastal resource area delineations were conducted on December 9th, 2025, and January 23rd, 2026, by one Woods Hole Group Wetland Professional in Training and one Woods Hole Group Coastal Scientist. The delineations occurred at low tide and were completed to observe relevant site topography, indicators of hydrology, and any vegetation assemblages that may indicate potential impacts (if any) on proposed alternative designs. An array of topographical points (illustrated in Figure 15) was taken both up and downstream of the culvert to characterize the existing conditions and map the wetland resources areas. The study area extended approximately 5,000 linear feet along Ocean Street between Victoria Road and Magnolia Avenue. To delineate the extent of resource areas and capture changes in topography, a survey-grade RTK GPS was used to collect data at subcentimeter accuracy in both horizontal and vertical datums. Horizontal data were recorded in Massachusetts State Plane 2001 (Island, US survey feet) and vertical data were collected in North American Vertical Datum of 1988 (NAVD88, US survey feet). Overall, this survey covered two barrier beach systems separated by Crow Island and marsh habitat separated by Ocean Street to the west (Figure 15). The edge and center of Ocean Street and Route 127 were also surveyed. All resource areas were defined in accordance with CZM definitions to the highest degree possible. Frozen soil prevented digging test pits to identify the most accurate edge of wetland resources, but changes in elevation and vegetation often made the determination apparent. Land Subject to Coastal Storm Flowage (LSCSF) was also included in this study as mapped by the Federal Emergency Management Agency (FEMA). While the study area consisted of barrier beaches, individual resource areas within the barrier system were delineated for this study. Resource areas surveyed included coastal beach, coastal dune, salt marsh, bordering vegetated wetland, rocky intertidal shore, and coastal bank. Extents of paved surfaces associated with Beach Road were also surveyed. Figure 16 visualizes the natural resources surveyed within the study area. Descriptions of each resource area are included in the following sections. Figure 15.

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Total survey coverage

Black

Crow Island

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Figure 16. Coastal resource areas delineated within the study area Barrier Beaches – Coastal Beach Black Beach was located on the eastern side of the Crow Island peninsula and was approximately 1,200 linear feet long and 300 feet wide (northern, tan-colored area, Figure 16). The beach was composed of a mix of various sediment grain sizes between sand and boulder. This Barrier Beach - Coastal Beach was gently sloping and terminated at the landward edge at either Ocean Street, Barrier Beach – Coastal Dune or a coastal engineering structure (e.g. seawall). Its seaward limit was defined by Kettle Cove or Rocky Intertidal Shore (RIS). A culvert lies in the middle of the barrier beach connecting to the salt marsh west of Ocean Street. South of the culvert, a transition to more rocky ground cover dominated by sand, gravel, cobble, boulders and exposed bedrock was observed, which continues south until terminating at Crow Island. Adjacent to the downstream side of the culvert is an approximately 2,500 sqft. area of salt marsh and degraded salt marsh platform. A sea wall protecting and elevating Ocean Street borders roughly 600 ft of the southern section of the barrier beach. On the western side of the Crow Island peninsula is White Beach (Figures 16 & 17), approximately 600 feet long and 90 feet wide. White Beach was very similar to Black Beach, gently sloping and terminated into a small rock and sand revetment bordering a parking lot along Ocean Street. White Beach was sandier, with fewer cobbles and boulders than Black Beach. The beach was confined by Crow Island in the east and a combination of boulders and bedrock to the west. Both beaches were unvegetated.

Figure 17.

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White Beach, Barrier Beach – Coastal Beach

Barrier Beach – Coastal Dune Coastal dune was identified on both sides of Ocean Street (Figure 16). Seaward of Ocean Street, the barrier beach – coastal dune was vegetated with American beach grass (Ammophila breviligulata), seaside goldenrod (Solidago sempervirens) and beach rose (Rosa rugosa), with few observations of evening primrose (Oenothera biennis). On the west side of Ocean Street (Figure 18), a more complex barrier beach – coastal dune exists, which makes up almost the entirety of the barrier system. Along Black Beach, the barrier beach – coastal dune was occupied by managed lawns of private residences abutting the salt marsh, eventually becoming unmanaged sand and gravel near the Ocean Street culvert vegetated mainly with eastern red cedar (Juniperus virginiana) and American beach grass. This section of coastal dune was mostly flat and similar elevation as the roadway but had a steep transition to salt marsh in the west, with approximately 3 feet of elevation difference between the two. Vegetation in the managed lawns was unidentified turf grass, common reed (Phragmites australis), staghorn sumac (Rhus typhina), black cherry (Prunus serotina), plus oaks and maples. Adjacent to White Beach and beginning at a stone wall along the western edge of Ocean Street, was a gently-sloping barrier beach – coastal dune heavily vegetated with poison ivy (Toxicodendron radicans), beach rose, eastern white pine (Pinus strobus), northern bayberry (Myrica pennsylvanica), and eastern red cedar but also many invasives such as shrub honeysuckle (likely Lonicera tatarica), Asiatic bittersweet (Celastrus orbiculatus), and Japanese knotweed (Reynoutria japonica). Near the edge of the salt marsh the vegetation switched to common reed and marsh elder (Iva frutescens). Road runoff appears to be directed into this area, with a clearly defined drainage pathway leading to the salt marsh.

Figure 18.

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Barrier Beach – Coastal Dune, adjacent to the Ocean Street culvert

Salt Marsh Upstream of the Ocean Street culvert is a large salt marsh bordered by residential properties, plus small sections of Bordering Vegetated Wetland and Coastal Bank (Figure 19). The northern, southern, and eastern borders of the marsh were surveyed in the field by Woods Hole Group, but the western edge was created using data available on MassGIS. Despite being surveyed in winter, the salt marsh appeared healthy, vegetated with smooth cordgrass (Spartina alterniflora), salt marsh hay (Spartina patens) and spike grass (Distichlis spicata) on the marsh platform. There was evidence of previous growing season growth and seed formation. The marsh had a moderate amount of mosquito ditches and few observations of ponding on the marsh surface, which were frozen at the time of observation.

Figure 19.

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Border of Salt Marsh and Barrier Beach – Coastal Dune near White Beach

Bordering Vegetated Wetland (BVW) Bordering vegetated wetland (BVW) was observed in three locations between the salt marsh and upland resource areas (coastal bank, barrier beach – coastal dune). A small area was observed in the far south bordering the salt marsh and was vegetated with non-halophyte sedges and seaside goldenrod, before transitioning to coastal bank (Figure 20). The second BVW observed was between the White Beach barrier beach - coastal dune and the salt marsh, vegetated with seaside goldenrod, common reed and switchgrass (Panicum virgatum). The third and largest BVW area was between the salt marsh parallel to Route 127 (Figure 16). This BVW area was wider than the others and had similar vegetation present, with the addition of broad-leaf cattail (Typha latifolia), eastern red cedar, mosses, and few white oak (Quercus alba). The landward boundary of this BVW area deviated from the bank with Route 127 at the property located at 395 Summer Street and followed the border of this property. This section of BVW was dominated by thick growth of common reed and Asiatic bittersweet and eventually transitioned to only common reed in the far northern corner of the survey area.

Figure 20.

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BVW bordering salt marsh and Barrier Beach – Coastal Beach

Coastal Bank Two Coastal Banks totaling 20,519 sqft were identified within the survey area, bordering the salt marsh and BVW. The larger of the two Coastal Banks was surveyed on the northern edge (Figure 21) of the survey area, occupying the space between Route 127 and BVW (Figure 16). This bank was short and steep and was vegetated by poison ivy, seaside goldenrod, arborvitae (Thuja occidentalis), red oak (Quercus rubra) and an unidentified grass. Another Coastal Bank was surveyed in the southeastern corner of the resource area. This smaller bank had a more gradual slope and was positioned between BVW and upland that bordered private residences. Red oak and eastern red cedar trees were the primary vegetation on this bank, along with upland grasses.

Figure 21.

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Salt marsh bordering coastal bank (right, along road), northern edge of study area

Rocky Intertidal Shore Rocky Intertidal Shore (RIS) was observed seaward of the barrier beach systems, totaling 78,504 square feet (Figure 16). Approximately 90% of boulders in this area were covered with macroalgae, the largest of which were >6 feet in their largest dimension (Figure 22). Patches of RIS were scattered seaward of Black Beach amongst a rock and cobble dominated ground cover. Areas of RIS were also observed bordering coastal engineering structures on both sides of the Crow Island peninsula and were confined to the eastern and western edges of White Beach. Stones and boulders that showed signs of anthropogenic origin or modification (cut marks, drill holes, very angular edges) were not included as RIS. The westernmost section of RIS abuts a large swath of exposed bedrock which borders a private residence.

Figure 22.

Rocky Intertidal Shore with attached macroalgae along Crow Island / White Beach

Land Subject to Coastal Storm Flowage Land subject to coastal storm flowage (LSCSF) is land subject to any inundation caused by coastal storms up to and including that caused by the 100-year storm, surge of record or storm of 100-year storm, surge of record or storm of record, whichever is greater. LSCSF was inclusive of the AE and VE zones designated by FEMA and encompassed all resource areas that were documented on site (gray hatched area on Figure 16). This includes the small uncategorized area in the far east near the intersection of Route 127 and Ocean Street, which did not appear to meet definitions for CZM resource areas seen elsewhere. It was a flat area, slightly higher elevation than the salt marsh, vegetated with Black Oak (Quercus velutina), grasses and white pine. This area had a small (<20 ft long) frozen pool with unidentified sedges or grass around it, but no other signs of hydrology. The forested area opposite Crow Island was upland, vegetated by upland trees and shrubs, was much higher elevation than the surrounding area, and was not part of the survey.

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Natural Heritage Estimated & Priority Habitat and Massachusetts Division of Marine Fisheries Shellfish Suitability Areas According to the Massachusetts Department of Environmental Protection, areas offshore were identified as spawning and settlement habitat for soft shell clam (Mya arenaria), sea scallop (Placopecten magellanicus), and blue mussel (Mytilus edulis), shown in Figure 23. No living shellfish were observed during the delineation. Furthermore, no Estimated and Priority Habitat for Rare or Endangered Species were identified within the study area by the Massachusetts Natural Heritage and Endangered Species Program. Mass DEP also did not illustrate any mapped eelgrass offshore of the survey area nor any historical beds.

Figure 23.

Shellfish suitability areas

Thank you for the opportunity to work with your team on Ocean Street Resiliency efforts. If you have any questions regarding the results of this work, please do not hesitate to reach out to me via email bhoffnagle@woodsholegroup.com or by phone (508) 495-6227. I look forward to continuing working collaboratively to increase the resilience of Ocean Street.

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Sincerely,

Brittany Hoffnagle Climate Resiliency Specialist Woods Hole Group

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