Northwood Development II Response to Comments 1.pdf
53 Southampton Road • Westfield, MA 01085-5308 • Tel 413.562.1600
www.tighebond.com
N5037001
December 19, 2019
Mr. Doug McDonald
Stormwater Manager
Northampton Department of Public Works
125 Locust Street
Northampton, MA 01060
Re: Northwood Development II Project
23 Atwood Drive, Northampton, Massachusetts
Response to Comments
Dear Mr. McDonald,
On November 12, 2019, Tighe & Bond submitted to your office an application to amend the
existing Stormwater Management Permit for the Northwood Development II Project on Atwood Drive in Northampton, Massachusetts. Comments regarding the constructed
stormwater management system were received in an email from you, dated April 3, 2019.
Sarah LaValley, Northampton Conservation Agent, 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 Sarah LaValley,
Northampton Conservation Agent, in June 2019, additional permit documents were prepared to provide the City with a new Notice of Intent filing, as well as a request to amend the
Stormwater Management Permit, as requested.
This letter summarizes Tighe & Bond’s responses to the City of Northampton’s comments
regarding As-Built plans 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 As-Built plan that was submitted are not stamped by a P.E. and do not
include all the information required. Please see the attached Amendment to Permit, Standard
Permit Condition #3 for what is required for As-Built Plans.
T&B Response 12/19/2019: New as-built plan information will be collected once
the construction of the stormwater management modifications has been
completed. Record drawings will be stamped by a Massachusetts PE.
Comment 2: The date of the As-Built plan is incorrect.
T&B Response 12/19/2019: New record drawings will be provided following
completion of the stormwater management modifications.
Comment 3: The As-Built plan was completed by a surveyor during active construction and
not at the end of construction which is not correct.
T&B Response 12/19/2019: New record drawings will be provided following
completion of the stormwater management modifications that will be stamped by
a Massachusetts PE.
Comment 4: The bioretention basins and infiltration basin are holding ponded water for
many days which does not meet the design of the system.
- 2 -
T&B Response 12/19/2019: The proposed stormwater management modifications
include language to maintain and improve the infiltrating capacity of the basins
and bioretention areas.
Comment 5: The plants in the bioretention basins were either not planted or are likely all
dead due to the ponding water.
T&B Response 12/19/2019: Additional plantings intended to provide compliance
with the design will occur in the spring.
Comment 6: The As-Built plan or another submission has not been made to verify that the
bioretention basins were constructed with the correct soil mix and with the correct depth of
soil mix.
T&B Response 12/19/2019: New record drawings will be provided following
completion of the stormwater management modifications that will include this
additional information as required.
Comment 7: The sediment posts have not been installed in the bioretention basins and the
infiltration basins.
T&B Response 12/19/2019: Sediment indicator posts are proposed and will be
installed within each basin and bioretention areas as part of the proposed
stormwater management modifications.
Comment 8: The elevation of the overflow curbs for the infiltration basins and Bioretention
Basin 1 has not been verified or specified in the As-Built plan.
T&B Response 12/19/2019: Modifications to the spillway elevations for
stormwater management facilities are proposed as part of the stormwater
management modifications.
Comment 9: The grading in the northeast section of parking lot that was designed to flow
to the wetland area to the north does not appear to be graded correctly.
T&B Response 12/19/2019: Modifications to the grading in this area of the project
are proposed as part of the stormwater management modifications.
Comment 10: The make and model of the water quality units has not been identified in the
As-Built plans.
T&B Response 12/19/2019: The make and model of the proposed water quality
units installed will be provided on future record drawings once the proposed
stormwater management modifications are constructed and additional as-built
information is collected.
Comment 11: The pipe discharging from OCS1 from Bioretention Basin 1 was specified as
18 inch in the Construction Plans and a 12-inch pipe was installed.
T&B Response 12/19/2019: The pipe discharging from Bioretention Basin 1 is
indicated to be replaced with an 18-inch culvert per the proposed stormwater
management modifications.
- 3 -
Comment 12: The bottom elevation of Bioretention Basin 1 was specified as 116 feet in the
approved plans and the As-Built plan specifies the elevation of the bottom of this basin at 118
feet.
T&B Response 12/19/2019: Modifications to the grading of Bioretention Basin 1 is
proposed to match the previously approved design.
Comment 13: The 4 backflow preventor valves installed at the outfalls of the infiltration
basins do not appear to be fully operable due to rip rap and sediment around them. The
engineer will need to confirm that these valves will function correctly.
T&B Response 12/19/2019: The proposed stormwater management modifications
require that the contractor remove any accumulated sediment and adjust installed
riprap to allow the duckbill valves to function property.
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/Associate
Copy: Travis Ward, Development Associates
Sarah LaValley, City of Northampton
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