Engineering_2nd review
North Country Office
100 Glen Street, Glens Falls, NY 12801
P: (518) 812-0513 F: (518) 824-8391
www.chazencompanies.com
Hudson Valley Office (845) 454-3980
Engineers
Environmental Professionals Capital District Office (518) 273-0055
Land Surveyors
Landscape Architects
Planners
March 14, 2012
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: William Threw Lot 13 Site Plan Review
Town of Queensbury, Warren County, New York
Chazen Project # 91204.02
Queensbury Ref. No: Site Plan 1-2012
Dear Mr. Brown:
The Chazen Companies (Chazen) has received the latest submission package from your office for the
above referenced project. Based upon our review of the information provided, Chazen offers the fol
comments for the Towns consideration:
Stormwater Management & Erosion and Sediment Control:
1.In response to Comment 2 of Chazens January 12, 2012 letter, ads been
performed on-site, which shows consistently deep and well drained sandy soils. However, testing
was not performed within the limits of each infiltration facility, a
particular, testing was not performed within infiltration basins/trenches 7, 8, 13, or 14AP.
Additional testing must be performed to confirm adequate separation distance from seasonally
high groundwater (minimum 3-feet), as well as infiltration rates. Chazen would not take exception
to testing being performed at the start of construction. However, it shall be not design
changes that occur because of discovered inconsistency in soil conditions, may be subject to
additional site plan review.
2.The Applicant has included Water Quality Volume and Channel Prot
the SWPPP, as well as a combined table on drawing S3 Grading & Drainage Plan. There are
inconsistencies in the values presented within these tables. In
clarify the table presented on the plan. It is unclear whether t
required or those provided. It appears that the values vary between these two types within the
same column. It is recommended that these values be presented in
inconsistency.
Town of Queensbury
Site Plan 1-2012 William Threw Lot 13
March 14, 2012
Page 2
3.The storage volumes provided for the forebays, and the volumes i
facilities for the 100-yr storm, which are listed in the table on drawing S3 Grading & Drainage
Plan, are not consistent with the values generated from the HydroCAD modeling. It is
recommended that these values be presented in a single location
4.In response to Comment 3 of Chazens January 12, 2012 letter, the Applicant has shifted the
absorption field to provide exactly 25-feet of separation from the proposed infiltration trench.
However, the absorption field appears to be located less than 20-feet from the proposed drywell
located adjacent to the field. Pursuant to Section 147-11.I.2(c) of the Town code, a minimum
separation of 20-feet shall be provided between the absorption facility and the infiltration device.
The Applicant shall revise the drawing to demonstrate compliance
the Applicant shall provide a dimension on the plan indicating required separation distances to
the infiltration devices, to guarantee that separation is preserved when constructed.
Additionally, pursuant to Section 6.3.1 of the NYS SWDM all infi
minimum of 25-feet down gradient from structures. It is noted that basin 7AP is located within 10-
feet of the existing westerly 125x200 warehouse. This basin sh
compliance with the noted provision.
5.In response to Comment 4 of Chazens January 12, 2012 letter, the Applicant states that forebays
have been sized to provide 100% of the WQv as pretreatment. Howe
there is no pretreatment provided for infiltration trench 9P. Also pretreatment must be provided
prior to stormwater entering the proposed drywells intended to treat runoff from the proposed
80x120 warehouse building. It appears on the plan that pretrea
stormwater runoff generated from the southern half of the the referenced building. Pretreatment
must be provided for all infiltration facilities in accordance wi
6.In response to Comment 5 of Chazens January 12, 2012 letter, thsediment
basins will be constructed in the locations of the proposed infiltration basins, and will be installed
a minimum of 1-foot above the final elevations of the infiltration facilities.
indicates that the accumulated sediment will be removed from the
restoration will be performed prior to the infiltration trenches being installed. Chazen does not
take exception to this method of conversion. However, based upon
infiltration rates on-site, 1-foot of soil may be insufficient to prevent clogging of the underlying
soil with construction sediment. It is recommended that the Applicant reduce the excavation
depth for these sediment basins. Based upon the required volumes calculated, it appears that
most sediment basins have been oversized, which would allow for this reduction in excavation
depth. The Applicant shall adjust the volumes appropriately, and ensure that they are consistent
with the NYS Standards and Specifications for Erosion and Sediment Control for sediment basins.
7.In response to Comment 6 of Chazens January 12, 2012 letter, the Applicant has provided a
general detail for the proposed infiltration trenches. However, the detail does not include a pea
gravel filter layer and fabric above the main stone layer, as required by the NYS SMDM. The
Applicant shall revise the detail appropriately.
8.In response to Comment 9 of Chazens January 12, 2012 letter, th
drywells are no longer proposed as part of the stormwater management practices and has
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Town of Queensbury
Site Plan 1-2012 William Threw Lot 13
March 14, 2012
Page 3
removed the drywell detail. However, the Grading & Drainage Plan and SWPPP still indicate the
proposed drywells adjacent to the new 80x120 warehouse building. If the drywells are no longer
being proposed, the plans and SWPPP shall be revised to include an alternate practice to treat the
proposed 80x120 warehouse. If drywells are being proposed at this location, then the Applicant
shall add the construction detail back to the plan set, and revi
requirements of the NYS SMDM.
9.In response to Comment 18 of Chazens January 12, 2012 letter, the Applicant indicates that an
inquiry has been made to NYSDEC regarding Endangered Species as
of the site. In accordance with Part I(D)(4) of the General Permit, the SWPPP must contain
documentation supporting the determination of permit eligibility. Once a determination has been
made, the Applicant shall provide the Town with supporting docum
to include a summary of such documents to support permit eligibility.
10.In response to Comment 19 of Chazens January 12, 2012 letter, the Applicant indicates that an
inquiry has been made to OPRHP regarding Archeological Resources
relates to the development of the site. In accordance with Part (8) of the General Permit, the
SWPPP must contain documentation supporting the determination of permit eligibility. At a
minimum the criteria outlined in Part III(A)(8) a through d must to support permit
eligibility. Once a determination has been made, the Applicant shall provide the Town with
supporting documentation and revise the SWPPP to include a summary of such documents to
support permit eligibility.
11.The weir elevation between practices 14P & 14AP is incorrectly lshall be
revised to elevation 377 based on grading and the HydroCAD mode
Conclusions and Recommendations
It is our opinion that the applicant should provide clarificatio
changes in subsequent plan submissions.
If you have any questions regarding the above, please do not hes-1926.
Sincerely,
Sean M. Doty, P.E., LEED AP
Senior Project Engineer
cc: Pam Whiting, Town Planning Office Administrator (via email)
Keith Oborne, Town Planner (via email)
Joel Bianchi, P.E., Senior Director - Municipal Engineering (via email)
File
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