HomeMy WebLinkAboutCompiled Salt Marsh Monitoring PlanTechnical Memorandum Craigville Beach Road Bridge Repair Project Salt Marsh Monitoring and Mitigation Plan To: Amanda Davis, Environmental Analyst, Massachusetts Division of Marine Fisheries Edwin Hoopes, Conservation Administrator, Barnstable Conservation Commission From: Amanda Houle, PWS, CERP, Principal Environmental Scientist, Tighe & Bond Copy: Paul Graves, PE, Town of Barnstable Department of Public Works Date: September 30, 2026 1 Introduction This Salt Marsh Monitoring and Mitigation Plan has been developed by Tighe & Bond on behalf of the Town of Barnstable (the Town) for the Craigville Beach Road Bridge Repair Project (the Project) in Barnstable, Massachusetts. The project consists of repairing an existing bridge located on Craigville Beach Road that spans the Centerville River. The project is being conducted to address multiple deficiencies including structural deficiencies (e.g. cracks, spalling), scour, vegetation overgrowth, failed bank channel protection, guard rail damage, and sidewalk deficiencies. As the bridge and riprap scour countermeasures extend into jurisdictional wetland resource areas, including Salt Marsh, permanent and temporary impacts to these areas are anticipated during the bridge repair work. 1.1 Jurisdictional Impacts Given the nature of the proposed work and the location of the existing bridge, unavoidable permanent and temporary impacts to Salt Marsh are required to conduct the bridge repairs. Total salt marsh impacts are estimated at approximately 1,760 square feet, consisting of 350 square feet of permanent impact and 1,410 square feet of temporary impact. The proposed project may result in ‘up to’ approximately 350 sf of permanent impacts to salt marsh. These impacts are limited to the previously authorized (2002) bridge footprint and are confined to areas where salt marsh has sporadically established upon the former footprint of the bridge embankment. As such, these impacts are intended to be corrective in nature and do not constitute an expansion of fill beyond the previously authorized bridge footprint. The proposed project may result in approximately 1,410 sf of temporary impacts to salt marsh. These impacts will be minimized to the extent practicable, but may be unavoidable to perform the scope of work for the project. The Town submitted a Notice of Intent (NOI; MassDEP File No. SE3-6274) to the Barnstable Conservation Commission on July 31, 2026. The Town identified the project will incorporate measures to avoid and/or minimize adverse environmental impacts to the greatest extent practicable. Project impacts have been minimized through construction-period BMPs and the limiting of proposed disturbance only to areas necessary for project completion. Additionally, the NOI identified existing vegetation in the salt marsh, including smooth cordgrass (Spartina alterniflora; OBL), maritime marsh-elder, seaside goldenrod (Solidago sempervirens; FACW), and triangle orache (Atriplex prostrata; FAC). Mitigation measures for other, unavoidable impacts are described in detail below.
Salt Marsh Restoration and Mitigation Plan 2 1.2 Massachusetts Division of Marine Fisheries NOI Review The Massachusetts Division of Marine Fisheries (MA DMF) reviewed the NOI and provided recommendations to the Barnstable Conservation Commission. As part of the recommendations, MA DMF requested the development of a salt marsh monitoring and mitigation plan which should include before and after site photos, the expected frequency of regular check-ins, and how and who will determine if more active mitigation is necessary. In response to MA DMF’s requests, Tighe & Bond has prepared this Salt Marsh Monitoring and Mitigation Plan, which outlines the steps the Town will take to address the above points. 2 Salt Marsh Monitoring and Mitigation Plan The Salt Marsh Monitoring and Mitigation Plan includes steps to be taken pre-, during, and post-construction to protect, monitor, and, if needed, have a contingency and mitigation plan in place to restore areas of salt marsh, and is described in detail below. 2.1 Pre-Construction Prior to the start of construction, the contractor will collect spot elevations in the salt marsh. These elevations will be used as a reference, if mitigation is required to guide post-construction salt marsh restoration. A qualified wetlands professional will be designated as the Environmental Monitor and will document pre-existing vegetation distribution and species. Permanent impacted salt marsh will be salvaged and stockpiled if mitigation is required. Pictures will also be taken by the contractor as a record of “pre-construction” site photos. 2.2 During Construction Erosion control barriers will be installed prior to site work and maintained throughout construction. These barriers will serve both as sediment controls and as a clearly defined visual limit of work. The Environmental Monitor will inspect erosion controls every 2 weeks and inspect the salt marsh for disturbance from the construction work. The Environmental Monitor shall notify the contractor of any issues identified immediately and the contractor shall take immediate corrective action to prevent further disturbance. 2.3 Post-Construction Mitigation If adverse construction impacts affect portions of the salt marsh beyond the identified permanent impacts, post-construction restoration will be performed to mitigate the impacts and will be reported to applicable regulatory agencies. Disturbed soils will be regraded to pre-existing contours and the site will be augmented with a high-organic loam, if fill is required. If bare patches of peat are observed post-restoration, plugs of saltmarsh grass or saltmarsh hay will be planted within an anchored coir blanket matrix as needed to provide additional vegetative stabilization and facilitate marsh recovery. Survey-grade equipment (RTK or equivalent) will be used to record post-construction elevations and verify the marsh has been restored to pre-construction reference elevations. Any impacts outside the approved limits of permanent embankment fill or impacts will need to be restored, with the potential need for plantings depending on the degree of impact.
Salt Marsh Restoration and Mitigation Plan 3 At the completion of the bridge repairs, erosion controls will be removed. Pictures will be taken by the contractor as a record of “post-construction” site photos. 2.4 Post-Construction Monitoring After initial restoration activities are complete, the salt marsh will be monitored for three subsequent (3) growing seasons by the Environmental Monitor to document salt marsh recovery. Site visits will occur once per year during the active growing season. Restoration monitoring will consist of a visual vegetation assessment, including percent cover by vegetation type (tree, shrub, vine, and herbaceous), and by native / non-native status. The Environmental Monitor will also document dominant plant species observed in the restoration area and will conduct a qualitative evaluation of soils and hydrology. This data will be recorded on the monitoring form provided in Attachment A. Each monitoring report will also include photographs from fixed, pre-established locations to document ongoing marsh restoration. 2.4.1 Monitoring Report An annual report detailing the findings of each monitoring visit will be submitted to the Conservation Commission and MA DMF no later than November 30th of each calendar year for a period of three (3) years. The first annual report (Year 1) will document initial restoration efforts during the active growing season following completion of work. The second and third reports (Years 2 and 3) will document the relative success of the restoration area over the three subsequent growing seasons. If additional remedial actions are undertaken during the monitoring phase, these will be noted in the annual report. 3 Contingency Plans Given Tighe & Bond’s experience with similar projects, we have identified several factors which may influence the restoration process as well as proposed remedial actions. 3.1 Marsh Elevation Elevation is a major driver in salt marsh recovery, as such restoring the site to the reference elevations is vital for facilitating salt marsh recovery. If subsidence is observed during the monitoring period, the site may be amended with high-organic loam to reestablish reference elevations, if deemed appropriate by a qualified wetlands specialist. 3.2 Invasive Species As with any recently disturbed soil surface, there is the potential for colonization by non-native and/or invasive plant species. The Environmental Monitor will search for and document the establishment of invasive plants within the restoration area during site visits. Furthermore, the monitor will make recommendations for their removal and propose other corrective actions, as needed. In addition, construction period invasive species control measures will be implemented, and will include proper off-site disposal of any vegetation cleared from the site. Construction vehicles and equipment are recommended to be clean and free of any plant or soil debris prior to entering the project site and are recommended to be cleaned prior to leaving the site to prevent the introduction or off-site transport of invasive plant fragments or seed.
Salt Marsh Restoration and Mitigation Plan 4 3.3 Planting Die-Off Should any plantings appear to be dead or dying, recommendations for their replacement will be made by the Environmental Monitor. It is recommended plantings are replaced within two to three weeks of the recommendation for their replacement, so that they are planted during the active growing season and have increased chances of becoming established. Timely planting replacement will also serve to offset any temporal loss in habitat value that would otherwise occur from retaining dead or dying plantings on site. 4 Two-Year Contingency Plan If restoration is unsuccessful after two years, Tighe & Bond will conduct a site investigation to characterize any factors negatively influencing site vegetation, hydrology, and/or soil structure. If salt marsh vegetation die off is observed, additional survey grade spot elevations will be collected and compared against reference elevations. Pending the results of this investigation, Tighe & Bond will update the restoration plan accordingly and recommend appropriate measures. 5 Restoration Criteria Tighe & Bond has established the following criteria to evaluate if the site has been adequately restored: 1) Restoration areas have achieved 75% native vegetative cover. 2) The salt marsh has been restored to reference elevations. 3) No evidence of ponding or soil compaction is observed within the restored salt marsh. 6 Summary This Salt Marsh Monitoring and Mitigation Plan outlines the Town’s commitment to minimize salt marsh impacts to the extent practicable. If mitigation is required, the plan outlines the steps to facilitate successful site recovery following completion of the bridge repair. The Town will submit annual monitoring reports to MA DMF and the Barnstable Conservation Commission detailing restoration progress as well as any remedial actions taken to date. If the site fails to meet adequate restoration criteria after two growing seasons, Tighe & Bond will conduct a site investigation to determine factors negatively influencing restoration success and propose additional measures to facilitate resource area restoration.
A t tach ment A
Mon itoring Form
Salt Marsh Restoration Monitoring Form Craigville Beach Road Bridge Repair Project, Barnstable, Massachusetts MassDEP File No.: SE3-6406 Project Name: Craigville Beach Road Repair Project Permittee Name: Town of Barnstable, Public Works Department Permittee Address: 382 Falmouth Road, Hyannis, MA 02601 Name of Monitor: Date of Monitoring Event: Purpose of Monitoring Event: Weather Conditions: Wetland Restoration Area ID: Vegetation Percent Cover1,2 Hydrophytic Non-Hydrophytic Trees: Shrubs: Vines: Herbaceous Vegetation: Native Vegetation: Non-Native Vegetation: Hydrology: Soils: ¹ Refer to the attached floristic inventory for a list of plant species observed during the monitoring event. ² The Replacement Area site sketch (below) depicts the observed distribution of vegetation cover types.
Floristic Inventory Craigville Beach Road Bridge Repair Project, Barnstable, Massachusetts 2 Vegetation Cover Type Species Observed During Monitoring Event Tree Shrub Vine Herbaceous Vegetation Notes