HomeMy WebLinkAbout2013-07-16 Planning Board Supplemental Materials (34)
199 Newbury Street, Suite 115 ● Danvers, MA 01923 ● 978.777.7250 ● fax 978.777.8650 ● www.lynnfieldeng.com
June 26, 2013
Town of North Andover Planning Board
1600 Osgood Street
Building 20, Suite 2-36
North Andover, MA 01845
Attention: Ms. Judy Tymon, Planner
and
Town of North Andover
Conservation Department
1600 Osgood Street Suite 2035
North Andover, MA 01845
Attention: Ms. Jennifer Hughes, Conservation Administrator
Subject: Response to Comments
Proposed Pentucket Bank at the Butcher Boy Marketplace
1077 Osgood Street
LEI Job No. 480-70
Dear Ms. Tymon and Ms. Hughes:
This correspondence has been prepared on behalf of Angus Realty Corporation North
Andover, MA in response to correspondence received dated April 10, 2013 from
Lisa D. Eggleston, P.E. Eggleston Environmental Sudbury, MA regarding the Notice of Intent
submitted for the proposed Pentucket Bank at Butcher Boy Marketplace 1077 Osgood Street
North Andover.
1. The proposed project is entirely within the Zone A for the Lake
Cochichewick public water supply, defined by the Massachusetts Drinking Water
Regulations (310 CMR 22.02) as including the land area within a 400 foot lateral
distance from the upper boundary of the bank of a Class A surface water source.
The Zone A boundary should be shown on the site plans.
Response: The Zone A boundaries were placed on Drawing C-2, Existing Conditions Plan.
2. As proposed, the project does not include any recharge of runoff flows, on
the basis that the proposed development is within Zone A and the Massachusetts
Stormwater Standards require that stormwater infiltration structures be located
outside of Zone A. It does not appear that any consideration has been given to
providing compensatory recharge elsewhere on the Butcher Boy property, even
though a substantial portion of the property is located outside of Zone A. I also
Ms. Judy Tymon and Ms. Jennifer Hughes June 26, 2013
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believe that runoff from the building roof could be recharged within the Zone A,
provided the roof is not galvanized steel or copper. Both the Massachusetts
Stormwater Standards and (within the Watershed Protection District) Section
4.136(4)(g) of North Andover Zoning Bylaw do require that the runoff from
impervious surfaces be recharged onsite to the maximum extent practicable. Since
the surface runoff on this site would be diverted to the Merrimack River, any loss
of recharge would represent a net loss in the volume of water draining to Lake
Cochichewick. While the relative volume may be small, incremental losses such as
this may over time impact both the quantity and quality of water in the reservoir,
particularly during sustained drought conditions when the lake is largely
groundwater fed.
Response: A substantial portion of the property is located within a Zone A area. We have
provided infiltration of the roof area of the proposed bank. The infiltration system will treat
the one inch rainfall event. The overflow from the infiltration system will then discharge to
extended dry detention systems.
3. I have several concerns with the proposed “extended detention basins”
aimed at providing treatment and flow attenuation for runoff flows. First, there is
no indication that they will hold the water quality volume for 24 hours, as is
required for extended detention to provide 50% TSS removal through settling of
the solids. In addition, the design calls for 6-inches of stone beneath the open-
bottom chambers, making removal of any solids that do settle in the basin
virtually impossible. (I note that the O&M Plan does not even call for sediment
removal from the systems). Since the invert of the outlet pipe is at the bottom of
the stone, the accumulation of solids in the system over time will also limit the
flow of water out of the system.
Response: Refer to the revised dry detention basins design.
4. The design calls for a poly barrier on the bottom and sides of the extended
detention systems to prevent exfiltration, but does not provide any other means of
dewatering the systems below elevation 129.6. This should be reflected in the
calculation of available storage volume.
Response: The extended detention basins have been re-designed to allow for the system to
drain stormwater at all elevations.
5. The low flow orifices in the outlet control structures should be included in
the model, as they have the potential to release more water than the other
orifices.
Response: The low flow orifice has been included in the model.
6. Pavement runoff to PCB#10 is shown on the plan as discharging directly to
the extended dry detention system with no pretreatment and does not meet the
requirement for 80% TSS removal.
Response: Refer to the revised site layout and storm drain system.
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7. Pavement runoff to PCB#11 and PCB#12 will undergo pretreatment in a
CDS unit but will receive no additional treatment before being discharged to the
existing drainage system. It, too, does not meet the requirement for 80% TSS
removal.
Response: Refer to the revised Site Layout Plan and Site Grading, Drainage and Utility Plan.
8. A portion of the entrance driveway closest to Osgood Street drains to an
existing catchbasin just inside the entrance. It is unclear whether that structure is
to be upgraded or replaced as part of the driveway reconstruction.
Response: This catch basin will be replaced, if needed, and a new drain pipe will be
installed to replace the existing drain pipe.
9. Roof drains from the proposed building are shown as discharging to
proposed catchbasins #13 and #14. If the roof drains are to be tied into the
drainage system at all, they should not be connected at a catchbasin where the
additional flow could mobilize accumulated sediments. Since the roof runoff is
considered clean the connection should also be made downgradient of the CDS
units in order to maximize their effectiveness for treating pavement runoff.
Response: The roof drains will discharge to an infiltration system and then the extended
dry detention basin.
10. The project site is a busy shopping center and may well meet the DEP
threshold for a Land Use with Higher Potential Pollutant Loading (LUHPPL) of
1,000 vehicle trips per day. If so, suitable BMPs are required for all pavement
runoff associated with the proposed project and must be sized to treat a 1-inch
water quality volume.
Response: The original Butcher Boy Marketplace was constructed in the early 1990’s, more
than 20 years ago. This project is not considered to be a phased project, therefore the
entire site should not be reviewed as a whole. In addition the majority of the existing site is
located outside of the wetland buffer zone and the stormwater system discharges to the
Merrimack River. The bank traffic is estimated to be approximately 544 vehicle trips per day
which does not classify as a LUHPPL. However, the Applicant is providing improvements to
the existing stormwater system. A hydrodynamic separator is proposed, prior to the existing
storm drain system exiting the site. The hydrodynamic separator will provide Total
Suspended Solids (TSS) removal for the entire site in an effort to improve overall
stormwater quality exiting the property.
11. Due to the loss of groundwater recharge on the project site the proposed
project will necessarily increase the runoff volume discharged from the Butcher
Boy site to the town’s drainage system in Osgood Street. It should be verified that
there are no downgradient flow constrictions or related flooding problems that
could be exacerbated by this increase in flow.
Response: The existing site drainage system was mapped from the site to the outfall
located on Clark Street. There were no visible constrictions or flooding problems
encountered.
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12. Vegetative cover on the existing site should be modeled as being in “good”
rather than “fair” condition. Based on aerial photos a portion of the area could
also be considered wooded.
Response: The stormwater model was revised to include grass in good condition. The
portion of the site, parallel with Route 133, is a somewhat wooded area. There were a lot of
weeded areas along with a gravel road that accesses the utility station. In the stormwater
model, we classified this area as woods in fair condition.
13. It is difficult to read the existing conditions on Sheets C-3, C-4 and C-5 of
the project plans as they are screened too lightly. Sheet C-5 (Site Grading
Drainage and Utility Plan) also appears to be missing several grade lines and does
not show a connection from proposed DMH#1 to the existing drainage system.
Response: The screening was revised to allow the Plans to be more easily seen.
14. Per DEP requirements, the Stormwater Checklist should be stamped and
signed by a Professional Engineer.
Response: The stormwater checklist has been stamped by a Professional Engineer.
15. Per the zoning requirements for a Watershed Special Permit the application
should include a written certification by a professional engineer stating that the
project will not cause any significant degradation in the quality or quantity of
water in or entering Lake Cochichewick.
Response: Refer to the written documentation included in the Watershed Special Permit
Application.
16. The plans should show inspection ports on the subsurface detention
systems.
Response: Inspection/maintenance ports for the stormwater detention systems and the
infiltrations systems have been provided.
17. I have the following comments on the O&M Plan included with the NOI:
• Short-term, construction-related activities should be the responsibility of
the site contractor and should be removed from the O&M Plan for
inclusion in a separate Erosion and Sediment Control Plan or the
Construction SWPPP.
Comment noted. Refer to revised O&M Plan.
• The O&M plan should apply to the entire Butcher Boy Marketplace
property and should identify specific measures aimed at improving
existing conditions.
Comment noted. Refer to revised O&M Plan.
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• The plan should identify the fact that the property is within a watershed
protection zone and outline measures to minimize pollutant exposure.
Comment noted. Refer to revised O&M Plan.
• The Emergency Response Plan should also identify the fact that the
property is within a watershed protection zone and should include the
North Andover Water Department in the parties to be notified in the
event of a release.
Comment noted. Refer to revised Emergency Response Plan.
• The O&M plan should identify how the extended detention treatment
units are to be cleaned.
Comment noted. Refer to revised O&M Plan.
• Catchbasins and the CDS units should be cleaned a minimum of once per
year.
Catchbasins will be inspected four times per year during the first year of
operation and annually thereafter. Cleaning will be performed annually based on
the findings of the inspection completed.
• Table 1 (O&M Budget) is missing from the plan.
Refer to revised O&M Plan.
18. As is indicated on the Stormwater Checklist, the project is subject to the
requirements of the EPA Construction General Permit and will require a
construction Stormwater Pollution Prevention Plan (SWPPP) prepared in
accordance with EPA regulations. The SWPPP should pay particular attention to
the fact that the site is located in a water supply protection zone. The SWPPP
should be reviewed and approved by the Planning Board and/or Conservation
Commission prior to filing and prior to any disturbance on the site.
Response: A copy of the SWPPP will be submitted to the Town for review prior to the start
of construction.
19. The Erosion and Sedimentation Control Plan (Sheet C-3) should reference
the SWPPP.
Response: Drawing C-3, Erosion and Sedimentation Control Plan, has been revised to
reference the SWPPP.
20. The location of the proposed stabilized construction entrance should be
shown on Sheet C-3.
Response: Drawing C-3, Erosion and Sedimentation Control Plan, has been revised to
depict the construction entrance.
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21. The construction sequence should include construction of the retaining wall
and placement of fill.
Response: The construction sequence has been revised to include the retaining wall and fill
placement.
22. The detail for the stabilized construction entrance should specify stone
greater than 1”.
Response: The construction entrance detail was revised to specify stone greater than 1”.
If you have any questions or desire any additional information regarding this matter, please
do not hesitate to contact me at 978.777.7250 Ext. 12.
Respectfully Submitted,
Lynnfield Engineering, Inc.
Richard Barthelmes, P.E.
enclosures
c: Lisa D. Eggleston, P.E. Eggleston Environmental
Alan Yameen, Angus Realty Corporation