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Engineering Review North Country Office 100 Glen Street, Glens Falls, NY 12801 P: (518) 812-0513 F: (518) 812-2205 www.chazencompanies.com Hudson Valley Office (845) 454-3980 Engineers Environmental Professionals Capital District Office (518) 273-0055 Land Surveyors Landscape Architects Planners April 4, 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: Pushor-Spellburg 8-lot Subdivision 45 Ellsworth Road Town of Queensbury, Warren County, New York Chazen Job # 91104.30 Queensbury Ref No: Subdivision 5-2011 Dear Mr. Brown: The Chazen Companies (Chazen) has received the latest submission package for the reduced 8-lot residential subdivision at 45 Ellsworth Road. Based upon our review of the information provided, Chazen offers the following comments for the Towns consideratio Stormwater Management and Erosion and Sediment Control 1.In response to Comment 2 of Chazens February 16, 2012 letter, the Applicant states that the design and information provided demonstrates compliance with Cha-11 regulations. However, it shall be noted that the project does not comply with specific sections of this chapter, including, but not limited to, section 147-11(I)(3)(c)(1) & (2) for maintaining runoff rate & volume from pre- to post-development conditions; section 147-11(J)(3)(b) for providing protective covering within 24-hours for land with slopes greater than 15%; and section 147- 11(I)(3)(d)(2) for required period to drain practices to design l. The Applicant shall revise the design and add appropriate notes to ensure conformance with 2.In response to Comment 3 of Chazens February 16, 2012 letter, the Applicant has added additional stormwater management practices to reduce site runoff revised HydroCAD modeling, the rate & volume of runoff will be increased between pre- and post-development conditions at design point 1L, under all storm events. In addition, the rate of runoff will be increased at design point 2L for the 1- and 10-yr storm events. As such, the Applicant shall revise the design to demonstrate that post-development stormwater runoff is not increased at any design point when compared to pre-development rates. Town of Queensbury Pushor-Spellburg - Subdivision 5-2011 April 4, 2012 Page 2 3.In response to Comment 4 of Chazens February 16, 2012 letter, t from Stations 4+25 to 5+50 is being directed to retention area 1 recognized, it appears that the proposed grading may not be sufficient to direct runoff t practice. The Applicant shall provide additional grading informa will be directed to this practice and prevented from continuing Additionally, it shall be noted that 425ft of the drive is not being directed to a stormwater practice with either water quality or quantity controls. However, it appears that the adequate area on Lot 2 to implement a management practice. The Applicant shall revise the design to ensure that stormwater runoff from this section of drive is tributary to a NYSDEC acceptable stormwater management facility, designed to mitigate stormwater impacts at this location. 4.In response to Comment 5 of Chazens February 16, 2012 letter, the Applicant states that &the individual lot-specific retention areas are sized to retain both the Water Qual noted, however, that the proposed individual lot specific reten approved stormwater treatment devices. The design of these retention area such that they conform to one of the approved practices identifi treat Water Quality Volume as required by the manual. 5.In response to Comment 6 of Chazens February 16, 2012 letter, the Applicant has revised the proposed Pocket Pond and Forebay. The Detailed Pocket Pond Plan indicates within the Forebay, but does not provide any other information. The Applicant shall provide dimensional and material specifications for the sediment marker. 6.In response to Comment 7 of Chazens February 16, 2012 letter, the Applicant has indicated that a 6 layer of clay will be installed over the surfaces of the forebay and prity, the Applicant shall add a note to the pocket pond profile statin be over excavated to allow for a 6 minimum layer of clay below 7.In response to Comment 8 of Chazens February 16, 2012 letter, the Applicant states that exfiltration has been removed from all vegetated retention areas (however, it appears that an exfiltration of 2 inches/hr is still included for Retention Area 20P). With the removal of infiltration from the design of these practices, they no longer meet the criteria of a NYSDEC stormwater treatment device. As noted in comment #4, these areas shall be redesigned, if they are intended to treat stormwater, to meet NYSDEC guidelines for Any required soil testing to support design shall also be completed. It is also noted that, in accordance with Section 147-11(I)(3)(d)(2) of the Town code, vegetated depressions are required to completely drain back to design lev 8.In response to Comment 9 of Chazens February 16, 2012 letter, the Applicant has added note to the overall and detailed Subdivision Plans indicating the boundapreserved. In addition to protection of these lands during construction, the A protection of these lands after occupancy. Per Section 5.1.1 of the NYS SMDM, preservation areas shall be managed after occupancy by a responsible party able to maintain R:\9\91100-91199\91104.00_Town of Queensbury PB Engineer\91104.30-T. Queensbury -Lisa Pushor (SUB 5-2011) -Hutchins\Pushor-Spellburg-SUB 5-2011_04-04-12_L3.doc Town of Queensbury Pushor-Spellburg - Subdivision 5-2011 April 4, 2012 Page 3 natural state in perpetuity, which shall be achieved through legally enforceable deed restrictions, conservation easements, or a maintenance agreement. The applicant shall provide additional information regarding permanent protection of this land after occupancy. 9.In response to Comment 14 of Chazens February 16, 2012 letter, the Applicant has revised the lengths of overland flow (sheet flow) used in time of concentration calculations to be no more than 100ft. However, it appears that the Applicant has removed the length of has not adjusted the remaining portions of the flow path. As a rtimes of concentration are noticeably faster at most subcatchments, which may be driving the increase in runoff discussed in Comment 2. In addition, the Tc lengths depicted on the Developed Subcatchme map are not consistent with those presented in the HydroCAD modeThe Applicant shall revise the flow paths appropriately. 10.In response to Comment 19 of Chazens February 16, 2012 letter, the Applicant has revised the WQv and RRv summary table on the Detailed Subdivision Plan. However, it appears that the WQv required and the Remaining WQv are not consistent with the calculations in the Stormwater Management Report. The Applicant shall revise for consistency. 11.In response to Comment 20 of Chazens February 16, 2012 letter, the Applicant has revised Question 3 of the NOI to indicate Single Family Subdivision for Post-Development future land use. However, the Applicant has noted 9 lots, when only 8 lots are Applicant shall revise accordingly. 12.The Applicant has provided WQv and CPv calculations as an attachment to the SWPPP. However, these calculations do not include the vegetated retenti Lot 2. The Applicant shall revise the calculations to include t 13.In response to Comment 21 of Chazens February 16, 2012 letter, the Applicant states that a draft maintenance agreement is included in the SWPPP, which was taken directly from the Town code. However, this agreement shall be supplemented with a detailed list of all stormwater control measures that will be subject to said agreement. In addition, access and maintenance easements must be shown on the plans for each stormwater device and shall be reviewed and approved by the Town Highway Departmen Once approved, a maintenance easement shall also be executed and recorded in the office of the County Clerk, which shall be binding on all subsequent land owners served by t facility. The easement shall provide access to the facilities at inspection by the Town of Queensbury to ensure that they are maintained in condition. These provisions are provided such that if the applicant or their successor(s) fails adequately maintain the proposed facilities, the Town can providintenance to ensure proper function. Considering this, it is recommended that the Towns legal counse review the proposed agreement prior to approval. Further, the applicant shall furnish a description of the maintenance provi #1 of the agreement, as well as a construction cost estimate for all the agreement, and an operation and maintenance cost estimate fo shall be submitted for Town review. R:\9\91100-91199\91104.00_Town of Queensbury PB Engineer\91104.30-T. Queensbury -Lisa Pushor (SUB 5-2011) -Hutchins\Pushor-Spellburg-SUB 5-2011_04-04-12_L3.doc Town of Queensbury Pushor-Spellburg - Subdivision 5-2011 April 4, 2012 Page 4 Conclusions and Recommendations It is our opinion that the applicant should provide clarificatio changes for the next submission. If you have any questions regarding the above, please do not hesme at (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 R:\9\91100-91199\91104.00_Town of Queensbury PB Engineer\91104.30-T. Queensbury -Lisa Pushor (SUB 5-2011) -Hutchins\Pushor-Spellburg-SUB 5-2011_04-04-12_L3.doc