EMAIL REGARDING ANNOUNCEMENT OF OPERABLE UNIT (OU) 3 OXBOW SITE WALK, 04/01/2021 (03/31/2021 TECHNICAL MEMO AND CORRECTED FIGURE ATTACHED)OU3_Mitigation_TechMemo_20210331.pdf
Reminder: Today at 1pm is the Centredale OU3 Sitewalk! Details below are for both in-person and remote participants. See you out there!
Location: Allendale Avenue (east end), Johnston, RI – (for navigation directions, use 100 Allendale Avenue and be sure route takes you through Johnston!)
When: Thursday, April 1 @ 1:00 – 3:00 PM ET
Purpose: Site walk to view, visit and discuss Oxbow area cleanup and restoration plans in the field.
Agenda:
1pm - Meeting at site trailer for overview and health & safety orientation (decontamination protocols required) Key question to ask during orientation: Are there specific agenda items, features to see or habitat restoration ideas you’d want to discuss in the field?
1:15 pm - tour/discuss upland site area and location of treatment facility
1:45 pm - Tour/discuss Oxbow forested area with views and access to wetlands
2:45 pm - Return to site trailer and discuss conceptual mitigation design
Proportions of each habitat type
Channel habitat
Sitewalk Materials
The attached PDF file titled “OU3_Mitigation_TechMemo_20210331.pdf” is a short memo with some tables and figures that provides the reader with a broad description of the following:
* ecological predesign investigation work conducted in OU3 * existing habitats characteristics of OU3 * two concepts for mitigating OU3 after this portion of the site has been remediated.
The PDF file titled”Figure_Centredale_OU3_SiteWalk_corrected_11x17.pdf” is a 3-panel figure that will be used as a guide for tomorrow’s tour. The first panel (left-most) shows where we will meet for the tour, including GPS coordinates to the trailer, and specific numbered locations in OU3 that we will visit as part of the tour. The first panel also shows the locations of the existing wetland habitats. The other two panels show the specific numbered locations, but the locations are superimposed on the two concept mitigation plans.
20 copies of the two PDF attachments will be available to hand out to in–person participants.
Video Livestream:
For those not able to join in person I am providing the following Microsoft Teams meeting invite. We will be livestreaming the site walk via this teams meeting so folks can come with us virtually. The numbers on the second PDF figure can be used by those joining remotely to orient themselves. We will likely only transmit video at the specific numbered locations because transmitting the image while walking from location to location is too jarring for viewing.
Microsoft Teams meeting
Click here to join the meeting <https://gcc02.safelinks.protection.outlook.com/?url=https%3A%2F%2Flinkprotect.cudasvc.com%2Furl%3Fa%3Dhttps%253a%252f%252furldefense.proofpoint.com%252fv2%252furl%253fu%253dhttps-3A__teams.microsoft.com_l_meetup-2Djoin_19-253ameeting-5FYTIzNzM1ZjUtMWYzYy00YTY5LTliMDYtNWJlYjM1MWFkNGY5-2540thread.v2_0-3Fcontext-3D-257b-2522Tid-2522- 253a-2522546d1b85-2Dec51-2D40dd-2D9280-2D873298a3c3f0-2522-252c-2522Oid-2522-253a-2522f2059f07-2D0b8d-2D40eb-2D89af-2D7682e6e0c746-2522-257d%2526d%253dDwMFAg%2526c%253deuGZstcaTDllvimEN8b7jXrwqOf- v5A_CdpgnVfiiMM%2526r%253d4LH_Sdst5So3MOkRVICfx5IeXSf2DcCxPVRWI71faig%2526m%253dgARglpZCbI23yqp4pfGkq0H7WcCElguuOxymsq8dkCA%2526s%253dL5IKA4sYGXmRh7LgnWUyFWqqeUeAM23XcvlKa6URwsk%2526e%253d%26c%3DE%2C1%2CjZzGv31Py9L9Lfnfe7qMC9OB- 5UewiQQdvo2R8vsHFJGaFMKq0gViuM40yF0kDU2wlkiu6u0ydHy1N7m3twqd4w3kXkHjAIPE31qwdDVTq7k- 5XyVO8%2C%26typo%3D1&data=04%7C01%7Ckrasko.anna%40epa.gov%7Cadbe75de2b034c1fd6f008d8f512254d%7C88b378b367484867acf976aacbeca6a7%7C0%7C0%7C637528805947724130%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=yaCC9mPLwMEEBH3c3e0cDMrQWKq0yl%2FEkIAZVLQN6Jw%3D&reserved=0>
+1 207-352-4072,,549572376# <tel:+12073524072,,549572376> United States, Portland
Phone Conference ID: 549 572 376#
Feet
Lyman Mill Reach
Meeting Point: 41.8504°, -71.4839° Approx. 100 Allendale Ave, Johnston, RI 02919 Access via Johnston - no bridge at Lyman Mill Reach
ALLENDALE AVE
WARREN AVE
Notes: Centredale Manor Restoration Project Operable Unit 3 (OU3) wetland delineation and habitat assessments are preliminary and were performed by Normandeau in 2019 and 2020. Habitat mitigarion concepts are preliminary and are for discussion purposes only. Aerial imagery is courtesy of LEA and is dated April 2018.
Figure. Centredale Manor Restoration Project OU3 Site Walk April 1, 2021
Site Walk 1 - Meeting Point 2 - Lyman Mill Reach 3 - Area of overland flow during flood events 4 - Former oxbow channel 5 - Palustrine forested (PFO) wetland north of former oxbow channel 6 - Vernal pool 7 - Northeastern extent of palustrine scrub shrub (PSS) wetland 8 - PFO/PSS wetland 9 - Upland forested area 10 - Braided stream channel 11 & 12 - Potential viewpoints for palustrine emergent (PEM) wetland
1 2
CONCEPT 1 CONCEPT 2
Habitat Type: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) Palustrine Emergent (PEM) Water Flood Passage
ALLENDALE AVE 1 2
120 100 200 Feet
Integral Consulting Inc. 45 Exchange Street Suite 200 Portland, ME 04101 telephone: 207.874.9000 facsimile: 207.874.7800 www.integral-corp.com
MEMORANDUM
To: Jeff Loureiro, Loureiro Engineering Associates, Inc.
From: Patrick Gwinn and Sara Barbuto, Integral Consulting Inc. Lee Carbonneau, Normandeau Associates, Inc.
Date: March 31, 2021
Subject: Preliminary Habitat Summary and Conceptual Mitigation Plans for OU3 – Centredale Manor Restoration Project Superfund Site, North Providence Rhode Island
Project No.: CF1958
On July 9, 2018, the U.S. Environmental Protection Agency (EPA) lodged a consent decree with the U.S. District Court for the District of Rhode Island. The consent decree and its accompanying statement of work (USEPA 2018) described the remedial design/remedial action activities to be performed for the Centredale Manor Restoration Project (CMRP) Superfund Site in North Providence, Rhode Island (“Site”) (Comprehensive Environmental Response, Compensation and Liability Information System No. RID981203755). Emhart Industries, Inc. and Black & Decker Inc. (collectively, “Settling Defendants” or “SDs”) are currently undertaking the remedial design/remedial action activities. Integral Consulting Inc. (Integral) and Normandeau Associates Inc. (Normandeau), on behalf of Loureiro Engineering Associates, Inc. (LEA) (the SD’s remedial contractor), are supporting the design of habitat mitigation elements for Lyman Mill Reach and the former Oxbow Area (hereafter referred to collectively as Operable Unit 3 [OU3]).
This technical memorandum presents a summary of preliminary findings resulting from wetland delineation and habitat surveys performed in OU3 and two conceptual mitigation plans for OU3. This information is being provided in advance of the April 1, 2021 Site walk coordinated by EPA’s consultant, Skeo, to provide attendees (both in-person and virtually) a broad view of the habitats that exist in OU3 and how the conceptual mitigation plans strive to return OU3 to a wetland system that provides functions similar to those that presently exist. It is important to note that the conceptual mitigation plans are not a final design. They will be refined over the course of the coming months by input from
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 2 of 4
Integral Consulting Inc.
OU3 ECOLOGICAL BASELINE PRE-DESIGN INVESTIGATION
An EPA-approved ecological baseline pre-design investigation (Eco PDI) was performed in OU3 to inform remedial design, compensatory mitigation planning, habitat design, and post-remedial monitoring of habitat recovery.1 Eco PDI data collection activities for OU3 included the following:
• wetland delineation
• vernal pool assessment
• terrestrial vegetation survey
• aquatic vegetation survey
These studies were performed at OU3 in 2019 and 2020 in accordance with the approved Eco PDI Part I field sampling plan.2 The results of the Eco PDI Part I field activities are to be provided in the Draft Ecological Baseline Pre-Design Investigation—Part I, OU3 Study Results (Integral & Normandeau 2021, in preparation), and will be included as a supporting document to the OU3 remedial design.
As shown in Table 1, approximately 20 acres of palustrine wetlands were identified during the Eco PDI investigation. Approximately 47% of the OU3 palustrine wetlands were classified as forested (PFO), while the remaining were classified as either scrub shrub (PSS – 21%) or emergent (PEM – 31%). General characteristics of each wetland type including acreage, dominant plant species identified, and water regime are provided in Table 1. Figure 1 shows the locations of the existing wetlands identified during the PDI survey.
A single vernal pool was identified in OU3. This vernal pool did not contain any primary indicator breeding evidence during any of three visits, but contained abundant secondary indicators in the form of fingernail clams and spire snails. The presence of two secondary indicators in the pool is considered sufficient evidence for classification as a vernal pool by federal standards. Additionally, on the first visit a single male wood frog was observed
1 Integral. 2019. Quality Assurance Project Plan for the Ecological Baseline Pre-Design Investigation—Part I, Site Wetland, Floodplains, and Aquatic Zones, Centredale Manor Restoration Project Site. Integral Consulting Inc. July. 2 Integral. 2019. Field Sampling Plan for the Ecological Baseline Pre-Design Investigation—Part I, Site Wetland, Floodplains, and Aquatic Zones, Centredale Manor Restoration Project Site. Integral Consulting Inc. July.
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 3 of 4
Integral Consulting Inc.
singing from the site. This pool may be too isolated from other suitable pools to provide sustainable breeding habitat for primary vernal pool organisms.
There is generally limited upland floodplain within the OU3 project area. Vegetation in the uplands was typically dominated by red maple as well as black and white oaks in the tree stratum, and glossy buckthorn in the shrub stratum. Much of the upland has been converted into walking paths, and were observed to contain a limited herb stratum.
As part of the PDI surveys, biologists noted the presence of wildlife while performing wetland delineation and habitat survey activities in OU3. Table 2 summarizes the list of wildlife species that were noted in OU3. Table 2 is not intended to represent a complete list of wildlife that may reside in or transit OU3. Rather it simply identifies the wildlife observed within OU3 while biologists were present.
CONCEPTUAL HABITAT MITIGATION PLANS
Two conceptual habitat mitigation plans were developed by Integral and Normandeau based on information collected as part of the Eco PDI, topography, potential remediation strategies, input from stakeholders, professional judgement and experience. The plans, Concept 1 and Concept 2, were developed to facilitate further discussion on the OU3 mitigation process. For both concept plans, the goal was to mitigate the wetland habitats and to provide an open channel on Lyman Mill Reach to allow small boat (e.g., canoe or kayak) access to the reach from Lyman Mill Pond. Neither concept plan attempts to replace the existing vernal pool.
Concept 1
Concept plan 1, shown in Figure 2, was developed based on the grades that may result following soil and sediment excavation. The areas identified as sediment will be excavated to the depth of contamination (i.e., to a depth where contaminant concentrations are below sediment cleanup levels) while the areas designated as soil will be excavated to the water table. While PDI investigations that will more explicitly define excavation depths are pending, it is anticipated that the depth of excavation in sediment will be greater than the depth of excavation for soil. The potential extents of soil and sediment excavation in OU3 are shown in Figure 1.
Concept 1, shown in Figure 2, places mitigated forested wetlands primarily in areas currently identified as soil excavation areas, and the mitigated scrub shrub and emergent wetlands in areas currently identified as sediment excavation areas. Concept 1 does not retain the former oxbow channel feature, but allows for flood flow from Lyman Mill Reach
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 4 of 4
Integral Consulting Inc.
at the approximate location where flood water presently enters the Oxbow Area and allows for drainage through the wetland complex via a drainage system shown as emergent wetland on the western side of the system. Concept 1 also retains the channelized feature of Lyman Mill Reach with an engineered berm running the length of the reach.
Concept 1 also retains the relatively large upland forested area in the central portion of the system. Public access to the upland area could be provided via the upland forested western edge of Lyman Mill Reach.
Concept 2
Concept plan 2, shown in Figure 3, also took into account potential post-excavation grades in OU3, but envisions a larger floodplain along the western shore of Lyman Mill Reach, which will allow more frequent flooding of the scrub shrub wetlands. Concept 2 locates the emergent wetland feature closer to the southwestern end of Lyman Mill Reach than Concept 1. Compared to Concept 1, the Concept 2 mitigated emergent wetland does not extend as far west into the wetland system.
The upland feature in the central portion of the former oxbow area is smaller in Concept 2 than Concept 1, and would have limited access because it is surrounded by scrub shrub wetland.
In terms of total wetland area, both concepts replace the existing wetland on a 1:1 basis, but the percentage of each wetland type varies. Figure 4 shows the percentages of forested, scrub shrub, and emergent wetland for the existing system and for each of the concepts.
In each concept presented in this memo, the plantings currently being considered are the same. Table 3 presents a planting list organized by habitat type. Where feasible, native plant species observed in OU3 during the wetland and vegetation surveys were selected.
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
Integral Consulting Inc. Page 1 of 1
Palustrine Forested (PFO)
Palustrine Scrub-Shrub (PSS)
Palustrine Emergent (PEM)
Red Maple, Glossy Buckthorn, Skunk Cabbage, Highbush Blueberry, Winterberry, Bluejoint, Sweet Pepperbush
Silky Dogwood, Buttonbush
None Purple Loosestrife
Permanently or Semi permanently Flooded
OU3 Wetland Type
Table 1. Summary of OU3 Wetland Characteristics
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
Integral Consulting Inc. Page 1 of 1
Table 2. Incidental OU3 Wildlife Observations (2019-2020)
Class Species Common Name Lithobates palustris Pickerel Frog Lithobates sylvatica Wood Frog Accipiter cooperi Cooper’s Hawk Anas platyrhynchos Mallard Anas rubripes American Black Duck Baeolophus bicolor Tufted Titmouse Branta canadensis Canada Goose Buteo jamacensis Red-tailed Hawk Colaptes auratus Northern Flicker Cyanocitta cristata Blue Jay Dryobates pubescens Downy Woodpecker Dryobates villosus Hairy Woodpecker Dumatella carolinensis Gray Catbird Empidonax traillii Willow Flycatcher Geothlypis trichias Common Yellowthroat Melanerpes carolinensis Red-bellied Woodpecker Myiarchus crinitus Great Crested Flycatcher Poecile atricapilla Black-capped Chickadee Sayornis phoebe Eastern Phoebe Setophaga coronata Yellow-rumped Warbler Setophaga petechia Yellow Warbler Setophaga ruticilla American Redstart Setophaga striata Blackpoll Warbler Sitta carolinensis White-breasted Nuthatch Spinus tristis American Goldfinch Thyrothorus ludovicianus Carolina Wren Turdus migratorius American Robin Tyrannus tyrannus Eastern Kingbird Vireo gilvus Warbling Vireo Vireo olivaceous Red-eyed Vireo Chelydra serpentina Snapping Turtle Nerodia sipedon Common Water Snake Thamnophis sirtalis Common Garter Snake Odocoileus virginianus White-tailed deer Ondatra zibethicus Muskrat Sciurus carolinensis Eastern Gray Squirrel Tamias striatus Eastern Chipmunk Procyon lotor Raccoon Vulpes vulpes Red Fox
Insect Vespula sp. Yellowjacket
Amphibian
Bird
Reptile
Mammal
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
Integral Consulting Inc. Page 1 of 1
Table 3. Plant List for Habitat Mitigation Areas
Habitat Type Species Common Name Carya ovata Shagbark Hickory Quercus rubra Red Oak Quercus alba White Oak Betula populifolia Gray Birch Nyssa sylvatica Black Gum Acer rubrum Red Maple Prunus virginiana Chokecherry Hamamelis virginiana Witch Hazel Viburnum dentatum Arrowwood Clethra alnifolia Sweet Pepperbush Carpinus caroliniana Ironwood
Betula populifolia Gray Birch Nyssa sylvatica Black Gum Acer rubrum Red Maple Acer saccharinum Silver Maple Viburnum dentatum Arrowwood Clethra alnifolia Sweet Pepperbush Carpinus caroliniana Ironwood Vaccinium corymbosum Highbush Blueberry Cornus amomum Silky dogwood Thelypteris palustris Marsh Fern Onoclea sensibilis Sensitive Fern
Alnus incana Speckled alder Cornus amomum Silky dogwood Ilex verticillata Winterberry Sambucus nigra Black elderberry Salix discolor Pussy Willow Vaccinium corymbosum Highbush Blueberry Cephalanthus occidentalis Buttonbush Salix discolor Pussy Willow Cornus amomum Silky Dogwood Thelypteris palustris Marsh Fern Onoclea sensibilis Sensitive Fern Decodon verticillatus Swamp Loosestrife
Peltandra virginica Arrow Arum Sagittaria latifolia Arrowhhead Pontederia cordata Pickerelweed Decodon verticillatus Swamp Loosestrife Alisma subcordatum Am. Water Plantain Schoenoplectus tabernaemontani Soft-stem Bulrush Sparganium americanum American Burreed Cephalanthus occidentalis Buttonbush Salix discolor Pussy Willow Sambucus nigra Elderberry Cornus amomum Silky Dogwood Salix nigra Black Willow Cephalanthus occidentalis Buttonbush
Palustrine Emergent Wetland
Palustrine Forested Wetland Floodplain /
Palustrine Scrub Shrub Wetland
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Notes: Preliminary elevation contours, soil and sediment excavation extents were provided by LEA on February 12, 2021. Centredale Manor Restoration Project Operable Unit 3 (OU3) wetland delineation and habitat assessments were performed by Normandeau in 2019 and 2020. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
ALLENDALE DAM
Preliminary Cover Type: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) PSS/Riverine Palustrine Emergent (PEM) Aquatic Bed Water
Johnston Oxbow Property Lines
Allendale Pond
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Notes: Preliminary soil and sediment excavation extents were provided by LEA on February 12, 2021. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
W AR
RE N
AV EN
Pond
Conceptual Habitat Mitigation Area: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) Palustrine Emergent (PEM) Water Flood Passage Shoreline Stabilization Bioengineered Shoreline
Johnston Oxbow Property Lines Outer Extent of OU3 Excavation
EXTENT OF OU3
PM
Notes: Preliminary soil and sediment excavation extents were provided by LEA on February 12, 2021. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
W AR
RE N
AV EN
EXTENT OF OU3
Investigation
Notes: PFO = palustrine forested wetland PSS = palustrine scrub-shrub wetland PEM = palustrine emergent wetland
The total OU3 wetland area from the ecological pre-design investigation and each habitat mitigation concept is approximately 20 acres.
Habitat mitigation concepts are preliminary and for discussion purposes only.
Conceptual OU3 Habitat Mitigation Areas
Concept 1 Concept 2
Conceptual Habitat MItigation Plans
Slide Number 1
Integral Consulting Inc. 45 Exchange Street Suite 200 Portland, ME 04101 telephone: 207.874.9000 facsimile: 207.874.7800 www.integral-corp.com
MEMORANDUM
To: Jeff Loureiro, Loureiro Engineering Associates, Inc.
From: Patrick Gwinn and Sara Barbuto, Integral Consulting Inc. Lee Carbonneau, Normandeau Associates, Inc.
Date: March 31, 2021
Subject: Preliminary Habitat Summary and Conceptual Mitigation Plans for OU3 – Centredale Manor Restoration Project Superfund Site, North Providence Rhode Island
Project No.: CF1958
On July 9, 2018, the U.S. Environmental Protection Agency (EPA) lodged a consent decree with the U.S. District Court for the District of Rhode Island. The consent decree and its accompanying statement of work (USEPA 2018) described the remedial design/remedial action activities to be performed for the Centredale Manor Restoration Project (CMRP) Superfund Site in North Providence, Rhode Island (“Site”) (Comprehensive Environmental Response, Compensation and Liability Information System No. RID981203755). Emhart Industries, Inc. and Black & Decker Inc. (collectively, “Settling Defendants” or “SDs”) are currently undertaking the remedial design/remedial action activities. Integral Consulting Inc. (Integral) and Normandeau Associates Inc. (Normandeau), on behalf of Loureiro Engineering Associates, Inc. (LEA) (the SD’s remedial contractor), are supporting the design of habitat mitigation elements for Lyman Mill Reach and the former Oxbow Area (hereafter referred to collectively as Operable Unit 3 [OU3]).
This technical memorandum presents a summary of preliminary findings resulting from wetland delineation and habitat surveys performed in OU3 and two conceptual mitigation plans for OU3. This information is being provided in advance of the April 1, 2021 Site walk coordinated by EPA’s consultant, Skeo, to provide attendees (both in-person and virtually) a broad view of the habitats that exist in OU3 and how the conceptual mitigation plans strive to return OU3 to a wetland system that provides functions similar to those that presently exist. It is important to note that the conceptual mitigation plans are not a final design. They will be refined over the course of the coming months by input from
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 2 of 4
Integral Consulting Inc.
OU3 ECOLOGICAL BASELINE PRE-DESIGN INVESTIGATION
An EPA-approved ecological baseline pre-design investigation (Eco PDI) was performed in OU3 to inform remedial design, compensatory mitigation planning, habitat design, and post-remedial monitoring of habitat recovery.1 Eco PDI data collection activities for OU3 included the following:
• wetland delineation
• vernal pool assessment
• terrestrial vegetation survey
• aquatic vegetation survey
These studies were performed at OU3 in 2019 and 2020 in accordance with the approved Eco PDI Part I field sampling plan.2 The results of the Eco PDI Part I field activities are to be provided in the Draft Ecological Baseline Pre-Design Investigation—Part I, OU3 Study Results (Integral & Normandeau 2021, in preparation), and will be included as a supporting document to the OU3 remedial design.
As shown in Table 1, approximately 20 acres of palustrine wetlands were identified during the Eco PDI investigation. Approximately 47% of the OU3 palustrine wetlands were classified as forested (PFO), while the remaining were classified as either scrub shrub (PSS – 21%) or emergent (PEM – 31%). General characteristics of each wetland type including acreage, dominant plant species identified, and water regime are provided in Table 1. Figure 1 shows the locations of the existing wetlands identified during the PDI survey.
A single vernal pool was identified in OU3. This vernal pool did not contain any primary indicator breeding evidence during any of three visits, but contained abundant secondary indicators in the form of fingernail clams and spire snails. The presence of two secondary indicators in the pool is considered sufficient evidence for classification as a vernal pool by federal standards. Additionally, on the first visit a single male wood frog was observed
1 Integral. 2019. Quality Assurance Project Plan for the Ecological Baseline Pre-Design Investigation—Part I, Site Wetland, Floodplains, and Aquatic Zones, Centredale Manor Restoration Project Site. Integral Consulting Inc. July. 2 Integral. 2019. Field Sampling Plan for the Ecological Baseline Pre-Design Investigation—Part I, Site Wetland, Floodplains, and Aquatic Zones, Centredale Manor Restoration Project Site. Integral Consulting Inc. July.
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 3 of 4
Integral Consulting Inc.
singing from the site. This pool may be too isolated from other suitable pools to provide sustainable breeding habitat for primary vernal pool organisms.
There is generally limited upland floodplain within the OU3 project area. Vegetation in the uplands was typically dominated by red maple as well as black and white oaks in the tree stratum, and glossy buckthorn in the shrub stratum. Much of the upland has been converted into walking paths, and were observed to contain a limited herb stratum.
As part of the PDI surveys, biologists noted the presence of wildlife while performing wetland delineation and habitat survey activities in OU3. Table 2 summarizes the list of wildlife species that were noted in OU3. Table 2 is not intended to represent a complete list of wildlife that may reside in or transit OU3. Rather it simply identifies the wildlife observed within OU3 while biologists were present.
CONCEPTUAL HABITAT MITIGATION PLANS
Two conceptual habitat mitigation plans were developed by Integral and Normandeau based on information collected as part of the Eco PDI, topography, potential remediation strategies, input from stakeholders, professional judgement and experience. The plans, Concept 1 and Concept 2, were developed to facilitate further discussion on the OU3 mitigation process. For both concept plans, the goal was to mitigate the wetland habitats and to provide an open channel on Lyman Mill Reach to allow small boat (e.g., canoe or kayak) access to the reach from Lyman Mill Pond. Neither concept plan attempts to replace the existing vernal pool.
Concept 1
Concept plan 1, shown in Figure 2, was developed based on the grades that may result following soil and sediment excavation. The areas identified as sediment will be excavated to the depth of contamination (i.e., to a depth where contaminant concentrations are below sediment cleanup levels) while the areas designated as soil will be excavated to the water table. While PDI investigations that will more explicitly define excavation depths are pending, it is anticipated that the depth of excavation in sediment will be greater than the depth of excavation for soil. The potential extents of soil and sediment excavation in OU3 are shown in Figure 1.
Concept 1, shown in Figure 2, places mitigated forested wetlands primarily in areas currently identified as soil excavation areas, and the mitigated scrub shrub and emergent wetlands in areas currently identified as sediment excavation areas. Concept 1 does not retain the former oxbow channel feature, but allows for flood flow from Lyman Mill Reach
Preliminary Habitat Summary and Conceptual Mitigation Plan for OU3 March 31, 2021 Page 4 of 4
Integral Consulting Inc.
at the approximate location where flood water presently enters the Oxbow Area and allows for drainage through the wetland complex via a drainage system shown as emergent wetland on the western side of the system. Concept 1 also retains the channelized feature of Lyman Mill Reach with an engineered berm running the length of the reach.
Concept 1 also retains the relatively large upland forested area in the central portion of the system. Public access to the upland area could be provided via the upland forested western edge of Lyman Mill Reach.
Concept 2
Concept plan 2, shown in Figure 3, also took into account potential post-excavation grades in OU3, but envisions a larger floodplain along the western shore of Lyman Mill Reach, which will allow more frequent flooding of the scrub shrub wetlands. Concept 2 locates the emergent wetland feature closer to the southwestern end of Lyman Mill Reach than Concept 1. Compared to Concept 1, the Concept 2 mitigated emergent wetland does not extend as far west into the wetland system.
The upland feature in the central portion of the former oxbow area is smaller in Concept 2 than Concept 1, and would have limited access because it is surrounded by scrub shrub wetland.
In terms of total wetland area, both concepts replace the existing wetland on a 1:1 basis, but the percentage of each wetland type varies. Figure 4 shows the percentages of forested, scrub shrub, and emergent wetland for the existing system and for each of the concepts.
In each concept presented in this memo, the plantings currently being considered are the same. Table 3 presents a planting list organized by habitat type. Where feasible, native plant species observed in OU3 during the wetland and vegetation surveys were selected.
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
Integral Consulting Inc. Page 1 of 1
Palustrine Forested (PFO)
Palustrine Scrub-Shrub (PSS)
Palustrine Emergent (PEM)
Red Maple, Glossy Buckthorn, Skunk Cabbage, Highbush Blueberry, Winterberry, Bluejoint, Sweet Pepperbush
Silky Dogwood, Buttonbush
None Purple Loosestrife
Permanently or Semi permanently Flooded
OU3 Wetland Type
Table 1. Summary of OU3 Wetland Characteristics
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
Integral Consulting Inc. Page 1 of 1
Table 2. Incidental OU3 Wildlife Observations (2019-2020)
Class Species Common Name Lithobates palustris Pickerel Frog Lithobates sylvatica Wood Frog Accipiter cooperi Cooper’s Hawk Anas platyrhynchos Mallard Anas rubripes American Black Duck Baeolophus bicolor Tufted Titmouse Branta canadensis Canada Goose Buteo jamacensis Red-tailed Hawk Colaptes auratus Northern Flicker Cyanocitta cristata Blue Jay Dryobates pubescens Downy Woodpecker Dryobates villosus Hairy Woodpecker Dumatella carolinensis Gray Catbird Empidonax traillii Willow Flycatcher Geothlypis trichias Common Yellowthroat Melanerpes carolinensis Red-bellied Woodpecker Myiarchus crinitus Great Crested Flycatcher Poecile atricapilla Black-capped Chickadee Sayornis phoebe Eastern Phoebe Setophaga coronata Yellow-rumped Warbler Setophaga petechia Yellow Warbler Setophaga ruticilla American Redstart Setophaga striata Blackpoll Warbler Sitta carolinensis White-breasted Nuthatch Spinus tristis American Goldfinch Thyrothorus ludovicianus Carolina Wren Turdus migratorius American Robin Tyrannus tyrannus Eastern Kingbird Vireo gilvus Warbling Vireo Vireo olivaceous Red-eyed Vireo Chelydra serpentina Snapping Turtle Nerodia sipedon Common Water Snake Thamnophis sirtalis Common Garter Snake Odocoileus virginianus White-tailed deer Ondatra zibethicus Muskrat Sciurus carolinensis Eastern Gray Squirrel Tamias striatus Eastern Chipmunk Procyon lotor Raccoon Vulpes vulpes Red Fox
Insect Vespula sp. Yellowjacket
Amphibian
Bird
Reptile
Mammal
Preliminary Habitat Summary and Conceptual Mitigation Plan - OU3 March 31, 2021
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Table 3. Plant List for Habitat Mitigation Areas
Habitat Type Species Common Name Carya ovata Shagbark Hickory Quercus rubra Red Oak Quercus alba White Oak Betula populifolia Gray Birch Nyssa sylvatica Black Gum Acer rubrum Red Maple Prunus virginiana Chokecherry Hamamelis virginiana Witch Hazel Viburnum dentatum Arrowwood Clethra alnifolia Sweet Pepperbush Carpinus caroliniana Ironwood
Betula populifolia Gray Birch Nyssa sylvatica Black Gum Acer rubrum Red Maple Acer saccharinum Silver Maple Viburnum dentatum Arrowwood Clethra alnifolia Sweet Pepperbush Carpinus caroliniana Ironwood Vaccinium corymbosum Highbush Blueberry Cornus amomum Silky dogwood Thelypteris palustris Marsh Fern Onoclea sensibilis Sensitive Fern
Alnus incana Speckled alder Cornus amomum Silky dogwood Ilex verticillata Winterberry Sambucus nigra Black elderberry Salix discolor Pussy Willow Vaccinium corymbosum Highbush Blueberry Cephalanthus occidentalis Buttonbush Salix discolor Pussy Willow Cornus amomum Silky Dogwood Thelypteris palustris Marsh Fern Onoclea sensibilis Sensitive Fern Decodon verticillatus Swamp Loosestrife
Peltandra virginica Arrow Arum Sagittaria latifolia Arrowhhead Pontederia cordata Pickerelweed Decodon verticillatus Swamp Loosestrife Alisma subcordatum Am. Water Plantain Schoenoplectus tabernaemontani Soft-stem Bulrush Sparganium americanum American Burreed Cephalanthus occidentalis Buttonbush Salix discolor Pussy Willow Sambucus nigra Elderberry Cornus amomum Silky Dogwood Salix nigra Black Willow Cephalanthus occidentalis Buttonbush
Palustrine Emergent Wetland
Palustrine Forested Wetland Floodplain /
Palustrine Scrub Shrub Wetland
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Notes: Preliminary elevation contours, soil and sediment excavation extents were provided by LEA on February 12, 2021. Centredale Manor Restoration Project Operable Unit 3 (OU3) wetland delineation and habitat assessments were performed by Normandeau in 2019 and 2020. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
ALLENDALE DAM
Preliminary Cover Type: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) PSS/Riverine Palustrine Emergent (PEM) Aquatic Bed Water
Johnston Oxbow Property Lines
Allendale Pond
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Notes: Preliminary soil and sediment excavation extents were provided by LEA on February 12, 2021. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
W AR
RE N
AV EN
Pond
Conceptual Habitat Mitigation Area: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) Palustrine Emergent (PEM) Water Flood Passage Shoreline Stabilization Bioengineered Shoreline
Johnston Oxbow Property Lines Outer Extent of OU3 Excavation
EXTENT OF OU3
PM
Notes: Preliminary soil and sediment excavation extents were provided by LEA on February 12, 2021. Aerial imagery is courtesy of LEA and is dated April 2018.
Lyman Mill Reach
W AR
RE N
AV EN
EXTENT OF OU3
Investigation
Notes: PFO = palustrine forested wetland PSS = palustrine scrub-shrub wetland PEM = palustrine emergent wetland
The total OU3 wetland area from the ecological pre-design investigation and each habitat mitigation concept is approximately 20 acres.
Habitat mitigation concepts are preliminary and for discussion purposes only.
Conceptual OU3 Habitat Mitigation Areas
Concept 1 Concept 2
Feet
Lyman Mill Reach
Meeting Point: 41.8504°, -71.4839° Approx. 100 Allendale Ave, Johnston, RI 02919 Access via Johnston - no bridge at Lyman Mill Reach
ALLENDALE AVE
WARREN AVE
Notes: Centredale Manor Restoration Project Operable Unit 3 (OU3) wetland delineation and habitat assessments are preliminary and were performed by Normandeau in 2019 and 2020. Habitat mitigarion concepts are preliminary and are for discussion purposes only. Aerial imagery is courtesy of LEA and is dated April 2018.
Figure. Centredale Manor Restoration Project OU3 Site Walk April 1, 2021
Site Walk 1 - Meeting Point 2 - Lyman Mill Reach 3 - Area of overland flow during flood events 4 - Former oxbow channel 5 - Palustrine forested (PFO) wetland north of former oxbow channel 6 - Vernal pool 7 - Northeastern extent of palustrine scrub shrub (PSS) wetland 8 - PFO/PSS wetland 9 - Upland forested area 10 - Braided stream channel 11 & 12 - Potential viewpoints for palustrine emergent (PEM) wetland
1 2
CONCEPT 1 CONCEPT 2
Habitat Type: Upland Forest Palustrine Forested (PFO) Palustrine Scrub Shrub (PSS) Palustrine Emergent (PEM) Water Flood Passage
ALLENDALE AVE 1 2