Engineering Comments
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
January 12, 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 12 Site Plan Review
Town of Queensbury, Warren County, New York
Chazen Project # 91204.01
Queensbury Ref. No: Site Plan 1-2012
Dear Mr. Brown:
The Chazen Companies (Chazen) received a submission package from your office for a site p
for the above referenced project. Submitted information include
Plans entitled, William Threw, prepared by Hutchins Engineering, dated September 30, 2011;
A Stormwater Management Report, prepared by Hutchins Engineering;
A Site Plan Application with supporting documentation.
Your office has requested that we limit our review to the design
and sediment control items as it relates to compliance to local, state or relevant codes and r
Based on our review of the information provided, Chazen offers t
consideration:
Stormwater Management & Erosion and Sediment Control:
1.The proposed commercial development disturbs approximately 4.8 acres of land and therefore
requires the preparation of a Stormwater Pollution Prevention Plthat includes post-
construction stormwater management practices, in accordance with General Permit GP-0-10-001.
Additionally, Section 179-6-080 of the Town Code states that stormwater drainage plans shall
analyze the impacts of a project using a 50-year return interval storm for commercial projects. The
Applicant has provided stormwater analysis, but has not included the 50-year storm event. The
Applicant shall provide additional analysis in accordance with tThe Town of
Queensbury Requirement section of the SWPPP shall also be revised to reference the 50-yr storm
requirement.
Town of Queensbury
Site Plan 1-2012 William Threw Lot 12
January 12, 2012
Page 2
2.Section 6.3.1 of the NYSSMDM states that geotechnical testing must be performed within the
limits of each infiltration facility to determine the infiltrati
separate distance from seasonally high groundwater (minimum 3-feet). The applicant has
provided only a single test pit and percolation test in support
systems. However, no testing was provided in support of the infies, dry wells or
retention area designs. The applicant shall advance testing as required by the NYSSMDM to verify
the assumed infiltration rates of 10 and 30 inches per hour.
3.Section 6.3.3 of the NYSSWDM states that a minimum pretreatment
shall be provided prior to entry into an infiltration facility. If the infiltration rate is greater than 5
in/hr, as assumed, then 100% of the WQv shall be pretreated prio
facilities. The Applicant shall ensure that pretreatment requirements are be
supporting calculations for all infiltration devices.
4.Section 6.3.6 of the NYSSWDM requires that an observation well bevery dry well. The
Applicant shall revise the plans & details for conformance.
5.It is noted that the proposed dry wells appear to be receiving r
are not limited to only roof runoff. According to New York State
Manual (NYSSMDM) Section 6.3.1, the drainage area to dry wells sould include roof runoff only.
As such the applicant shall revise the design to demonstrate compliance with the refer
standard.
6.The Area Listing in the existing conditions HydroCAD model indic
impervious surface. However, the existing total non-permeable areas listed in the site plan
applications for Lots 12 & 13 indicate a total of 3.29 Acres. In
increases in impervious area are 1.536 and 0.211 Acres for Lots
would indicate an increase of 1.747 Acres of impervious surface, wh
increase of 2.278 Acres. The Applicant shall revise these values
7.The overall watershed boundary should not be limited to the subj, but shall
include the entire watershed tributary to each Subcatchment/Desi
applicant should revise the boundaries appropriately. USGS topog
used for offsite areas.
8.The intent of stormwater quantity control is to prevent an increase in stormwater runoff at each
discharge point from the site, or design point. In comparing the
Link 5L actually has increased runoff volumes at the 10-, 25-, and 100-year storm events under
proposed conditions. The increased runoff must be mitigated at this design point such that the
value is less than or equal to the existing rate.
9.Per Section 4.4 of the NYSSWDM, the length of overland flow used
calculations is limited to no more than 100ft for post development conditions. The
HydroCAD model presents sheet flow lengths greater than 100ft for subcatchments 1S, 2S, 3S, 5S,
and 7S. The Applicant shall revise the time of concentrations apion, the
minimum allowed time of concentration, per NYSDEC regulations, i-minutes. The applicant shall
revise the calculations to use a minimum time of concentration of 6-minutes where appropriate
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Town of Queensbury
Site Plan 1-2012 William Threw Lot 12
January 12, 2012
Page 3
(i.e. in subcatchments were the time of concentration is less th
revised calculations in the SWPPP.
10.The Applicant indicates a total disturbance of 4.8 Acres betweenPlease note, per
Part II.C.3 of the General Permit, the owner or operator of a construction activity shall not disturb
greater than five (5) acres of soil at any one time without prio
Department or the MS4. It is recommended that notes are added to the drawings indicating to the
Contractor that the five acre limit cannot be exceeded.
11.It appears that the proposed grading at the eastern portion of the project site may be directing
runoff toward the two subsurface wastewater systems and creating low points in those areas. To
protect the integrity of the systems, the Applicant shall consid
runoff away from these systems.
12.The Applicant states that an inquiry has been made to the NYSDEC regarding an endangered
species impact determination. Once a determination has been made
the Town with supporting documentation and revise the SWPPP to i summary of such
documents, to ensure compliance with Part I.D.4 of the General Permit.
13.The Applicant states that there are no nationally registered hist
project and has included a screening map from the OPRHP website. Based upon this map, it is
evident that the entire site falls within a designated Archeologically Sensitive Area, which is
defined by OPRHP as areas within the state where the discovery of archeological sit
predicted. Per Part III (A) (8) b of the General Permit, areas of archeolog
indicate the need for a survey. As such, the Applicant shall coordinate with the Office of Parks,
Recreation, and Historic Preservation (OPRHP) to determine the n
potential for impact to historic or archeological resources. Add
ensure compliance with this section of the General Permit.
14.A stabilized construction entrance shall be indicated on the Ero
a detail shall be added in accordance with the NYS Specification
Control.
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Town of Queensbury
Site Plan 1-2012 William Threw Lot 12
January 12, 2012
Page 4
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 (518) 824-1926.
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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