Atwood North_Comment Response Conservation 2-27-20 (1).pdf
53 Southampton Road • Westfield, MA 01085-5308 • Tel 413.562.1600
www.tighebond.com
N5037001
February 27, 2020
Sarah I. LaValley
Conservation, Preservation, Land Use Planner
Northampton Office of Planning and Sustainability
City Hall, 210 Main Street, 2nd Floor
Northampton, MA 01060
Re: Northwood Development II Project
23 Atwood Drive, Northampton, Massachusetts
Response to Comments
Dear Sarah,
On January 28, 2020, Tighe & Bond submitted to your office a revised Notice of Intent,
Stormwater Management Report and Permit Drawings for the Northwood Development II
Project located at 23 Atwood Drive in Northampton, Massachusetts. Comments regarding the
constructed stormwater management system were received in an email from you, dated
February 18, 2020. It was indicated in an email dated April 5, 2019 that since the previous
Order of Conditions was expired, that a new Notice of Intent was required to complete the
project. Following a site visit with yourself and Mr. Doug McDonald, Stormwater Manager, in
June 2019, new permit documents were prepared to provide the City with a new Notice of
Intent filing, as requested.
This letter summarizes Tighe & Bond’s responses to the City of Northampton’s comments
regarding the revised Notice of Intent, Stormwater Management Report, and Permit Drawings
for the above referenced project. The City’s comments are listed below in Italics, followed by
the response in bold font.
Project Description
Comment 1: The legal notice for next week’s meeting is attached, this will need to be placed
in a yellow sign on the site.
T&B Response: Comment acknowledged.
Comment 2: The Section 1 introduction indicates that the amended Order of Conditions
lapsed in August 2019. Please note that it actually expired on November 13, 2017.
Amendments cannot extend Orders, as noted in that permit.
T&B Response: Comment acknowledged.
Comment 3: Please clarify what Table 4-1, BLSF Existing and Proposed, represents. As we
discussed, utilizing accumulated flood storage capacity from the project as a whole, including
the demolition of the Clarion is fine if necessary to meet performance standards, but the
figures do not match those presented as part of that review (attached).
T&B Response: The vertical datum, NAVD88, is indicated on Sheet G-100 of the
permit drawings. Limits of 100-year flooding established by the flood insurance
study of the Connecticut River are at elevation 123 feet NGVD29. This value was
converted from 123 feet NGVD29 to 122.33 feet for use in the NAVD88 datum.
Additional clarification of the required datum and elevation conversions will be
provided on the revised drawings. The elevations reported in the June 2017 letter
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did not account for the conversion of the flood elevation from 123 feet NGVD29 to
122.33 feet NAVD88. Table 4-1, as presented in the revised NOI, considers the
conversion.
Comment 4: Function of the infiltration basins will need to be restored through excavation
of existing soils, these have been holding water consistently.
T&B Response: As discussed with Doug McDonald on February 26, 2020, the goal
of the proposed modifications to the infiltration and bioretention basins is full
functionality. This will be achieved through an initial attempt, similar to the
remediation work associated with the Northwood Development I project, which
includes removal of the top 3-6 inches of soil, scarification of the subgrade surface,
and replacement of loam and seed. As previously experienced as part of the
Northwood Development I project, the top layer of soil is likely blinded by fines
during construction efforts, and a larger excavation is not necessary. We request
the Commission consider a condition of approval that revised Site Plans be
submitted by within 10 days of issuance of the Order of Conditions which provide
additional instruction for the infiltration basin remediation work required.
We note that the Stormwater Operation and Maintenance (O&M) Plan approved for
the Northwood Development II project on file with the Northampton Stormwater
Manager includes language requiring mitigation efforts should any of the basins
not function as designed.
Comment 5: Please address DEP’s file number notification comments, and confirm that DEP
was provided the revised submittal.
T&B Response: DEP’s file number notification comments have been addressed in
a separate letter dated February 27, 2020.
Comment 6: The engineered soil mix has changed from the mix that was originally
presented. Please explain.
T&B Response: Following the November 2019 NOI submittal, Tighe & Bond met
with the Northampton Stormwater Manager and yourself at City Hall. During this
meeting, the engineered soil mix was identified as potentially too heavily organic,
thus limiting water transmissivity. The mix that is currently proposed meets the
requirements of the MassDEP Stormwater Handbook.
Comment 7: Both the overall totals and number of species of shrubs have decreased from
the 2017 preconstruction plans. These will need to match the planset approved by the
Planning Board, and the stormwater permit, which is still valid.
T&B Response: Permit Drawings were approved in May 2017, which included the
full build out of the project. Those drawings required 114 trees and 195 shrubs.
Phase I has since been constructed, and a portion of the required trees and shrubs
have been planted. Tighe & Bond performed a site visit on February 26, 2020 to
confirm the status of tree and shrub plantings. As of the date of this letter, 74
trees and 182 shrubs exist on site. As such, 40 trees and 13 shrubs will be required
to be installed as part of this permit application to comply with approved land use
permits.
We request the Commission consider a condition of approval requiring that the
previously approved quantity of trees and shrubs be met, and that revised Site
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Plans be submitted by within 10 days of issuance of the Order of Conditions
showing the locations and species of the required plantings.
Comment 8: The planting plan for the native habitat feature is different than the original
submittal, please explain proposes shifts in species and locations.
T&B Response: The planting plan for the native habitat feature was revised to
avoid the existing flared end sections. The proposed quantities of plantings
remains as previously permitted.
Comment 9: If provisions specific to the bioretention area plantings were not included in
the O&M for the project, please provide for review inclusion in the Order of Conditions.
T&B Response: The O&M Plan approved for the project as part of the Stormwater
Management Permit continues to be effective for the proposed design and includes
provisions for the maintenance and replacement of bioretention area plantings.
Comment 10: Permit drawings refer to bioretention basins as detention basins. Please
correct for consistency on construction drawings.
T&B Response: The project consists of two bioretention basins and two
infiltration/detention basins. The bioretention basins are located in the
northernmost and easternmost portions of the project. The infiltration/detention
basins are located in the westernmost portion of the project. We request the
Commission consider a condition of approval requiring that revised Site Plans be
submitted by within 10 days of issuance of the Order of Conditions and will provide
additional clarification relative to bioretention basin labeling.
If you have any questions, or if you require additional information, please contact me at (413)
875-1301.
Very truly yours,
TIGHE & BOND, INC.
Brian Huntley, P.E.
Senior Project Manager/Senior Associate
Copy: Travis Ward, Development Associates
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north_comment response conservation 2-24-20.docx