Engineering comments 12 13 16 THE
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�� North Country Office
— 375 Bay Road, Queensbury, NY 12804
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Planners
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December 13, 2016
Mr. Craig Brown
Zoning Administrator and Code Compliance Officer
Town of Queensbury
742 Bay Road
Queensbury, New York 12804
Delivered via email only: CraigB@queensbury.net
Re: Dorman—Bonner Drive Extension Subdivision
Town of Queensbury, Warren County, New York
Chazen Project#91600.42
Queensbury Ref#SP207-2016
Dear Mr. Brown:
The Chazen Companies (Chazen) has received the latest submission responding to technical comments
offered by Chazen on August 5, 2016. Based upon our review, Chazen offers the following comments for
the Town's consideration.
Stormwater Management& Erosion and Sediment Control:
1. In response to comment 2 of Chazen's August 5, 2016 letter, the Applicant has included the 25-
year storm to the HydroCAD model. Information supporting the stormwater design and
HydroCAD model are missing (see comments 5, 7, 8, 9 and 11) and therefore a full review of the
25-year storm will occur once the changes to the design/model are made. Section 179-6-080 of
the Town Code, states that stormwater drainage plans shall analyze the impacts of a project
using at least a 25-year return interval storm with regards to both runoff rate and volume for
residential projects.
2. In response to comment 3 of Chazen's August 5, 2016 letter, EAF section E.3.f indicates the site
is located in an archeological sensitive area. It does not appear that documentation was
provided per Part I.F.8 of the SPDES General Permit concerning construction activities that may
affect historic property.The Applicant shall provide the Town with any documentation regarding
the above determination and incorporate the same into the SWPPP pursuant to Part I.F.8 of the
SPDES General Permit.
3. A response to Chazen's August 5, 2016 comment letter was not provided and therefore it is
unclear how the Applicant will address comment 4 of said letter which stated: Section 6.3.1 of
the NYS SMDM states, "The bottom of the infiltration facility shall be separated by at least three
feet vertically from the seasonally high water table or bedrock layer, as documented by on-site
soil testing. (Four feet in soil source aquifers)." It appears that the bottom of the drywells would
Chazen Engineering, Land Surveying&Landscape Architecture Co.,D.P.C.
Chazen Environmental Services, Inc.
The Chazen Companies, Inc.
Town of Queensbury
Dorman—Bonner Drive Extension
December 13,2016
Page 2
be at an elevation of 88'; and test pit #1 was performed to a depth of 87'. As such, additional
testing must be performed to confirm adequate separation from seasonally high groundwater.
Chazen would not take exception to testing being performed at the start of construction, if the
Town will allow it. However, it shall be noted that if any design changes occur because of
discovered inconsistency in soil conditions, the project may be subject to additional site plan
review. The Applicant shall notify the Town prior to advancing the soil testing; such that the
Town can witness the testing, if they so choose.
4. It is noted that the Applicant proposes to convey the proposed roadway extension to the Town
following construction. Additionally, it is assumed that the roadway drainage (drywells and
associated perforated equalization pipe) will be conveyed with the road. As such, it is
recommended that the Town Highway Superintendent review the potential use of the
perforated equalization pipe at the site. In certain circumstances, their use can lead to
differential settlement of the road, if not properly constructed/suited for the soil conditions. It is
our recollection that the Highway Superintendent typically evaluates this during construction.
5. Existing grades along Bonner Drive are not depicted on sheet S-2, therefore it is difficult to
determine what portion of the existing Bonner Drive road contributes runoff to the proposed
drywells. The Applicant to provide sufficient existing grades along Bonner Drive to show what
areas contribute to the proposed drywells.
6. It does not appear that an NOI was submitted with the SWPPP in accordance with GPO-15-002.
The Applicant to provide the NOI for review.
7. The HydroCAD model does not provide distinct inflow value depths, (as indicated by the ">"
sign) which indicates that the time span of 0-24 hours may not be sufficient. The Applicant to
revise the time span such that the full effects of each storm are realized.
8. The HydroCAD model cannot be reviewed at this time because the proposed condition
watershed map does not show any subcatchments, eave trench locations, or time of
concentration lines. The drainage routing diagram cannot be confirmed / reviewed without this
information. The Applicant to revise the proposed condition map accordingly. A full review of
stormwater rates, volumes, and WQv/RRv calculations will be performed once the HydroCAD
model can be reviewed.
9. The HydroCAD model uses arbitrary elevations for the dry wells and eave trenches. It is
requested that the Applicant to revise the HydroCAD model with actual elevations.
10. The contractors and subcontractors certification statement on the second page of the SWPPP
does not match the required certification statement in Part III.A.6 of GP-0-15-002. The Applicant
to revise the certification statement accordingly.
11. The Eave trenches aren't depicted on the site plans or proposed condition watershed plan. The
Applicant shall depict all post-construction stormwater management devices on the site plans.
Z:\projects\91600-91699\91600.00-Town of Queensbury\91600.42-PZ207-2016 Michael Dorman\ENG\REVIEW\91600.42-Dorman-BonnerDrExt_SP207-2016_2016-12-13_L2.docx
Town of Queensbury
Dorman—Bonner Drive Extension
December 13,2016
Page 3
In the event the Planning Board or Town staff have any questions or require additional information,
please do not hesitate to contact me at (518) 824-1926.
Sincerely,
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'
Sean M. Doty, P.E., LEED AP, CMS4S
Principal
Manager, Municipal Engineering Services
cc: Sunny Sweet,Town Planning Office Administrator(via email)
Laura Moore,Town Land Use Planner(via e-mail)
File
Z:\projects\91600-91699\91600.00-Town of Queensbury\91600.42-PZ207-2016 Michael Dorman\ENG\REVIEW\91600.42-Dorman-BonnerDrExt_SP207-2016_2016-12-13_L2.docx