HomeMy WebLinkAboutCorrespondence - 58 COUNTRY CLUB CIRCLE 4/13/2017 Atlantic Engineering&Survey Consultants,Inc. John B.Paulson,P.L.S.President
97 Tenney Street Georgetown,MA 01833 George J.Zambouras,P.E.
978-352-7870 •978-352-9940(fax) etlantic84@gmail.com
April 13, 2017
Town of North Andover
Planning Board
120 Main Street
North Andover, MA 01845
Re: Special Permit Application
58 Country Club Circle, North Andover
Dear Planning Board Members:
Attached please find a copy of the revised site plan for the Special Permit Application for 58
County Club Circle. The revisions depict the relocation of the proposed poll outside of the
Watersheds Non-Disturb Zone, as requested by the Zoning Board of Appeals, and the
elimination of the rain gardens. In lieu of the rain gardens a stoned infiltration trench is now
being proposed to capture and infiltrate runoff from the added impervious surfaces. The change
from rain gardens to an infiltration trench is to address the concerns indicated in the email review
comments prepared by Lisa Eggleston of Eggleston Enviromnental dated March 21, 2017.
Below please find a summary of my response to the review comments prepared by Lisa
Eggleston of Eggleston Environmental dated March 21, 2017.
1. As indicated above, to mitigate for the loss of annual recharge resulting from the added
impervious surfaces the proposed improvements now incorporate the use of stoned
infiltration trenches rather than the rain gardens. The stoned trenches are proposed along
the perimeter of the pool and pool deck to eliminate the concern that that of receiving
suitable run-off from the impervious surfaces. The trenches have been sized to capture
and provide infiltration in excess of the required 1"volume from the added impervious
surface area. The calculations indicating the required infiltration volume and supporting
trench volume calculations are attached to this memo.
2. The intent of the methods of de-chlorination of the pool water section of the Pool
Maintenance Plan was to cover the discharge of pool water for any purposes.
1
Additional wording has been added to the attached modified Pool Maintenance Plan to
clarify that de-chlorination is required for discharges that occur during pool maintenance,
end of the season draw down and drawn down for major storm events.
Sincerely,
I Zambouras, P.E.
Cc: Don D. Stanley
2
Recharre Volume Calculations
Change in Impervious Surfaces
Existing Impervious Surfaces - Patio,walkway&walls 1,660 s.f.
Proposed Impervious Surfaces—
Patio,walkways,walls, retaining wall,pool & spa,poll deck 4,001 s.f.
Net Increase Impervious Surfaces 2,341 s.f.
Required Recharge Volume (Based on 1" Run-off)
Recharge Volume Calculation
Target Depth: 1 Inches
REQUIRED
Impervious Area
2,400 S.F. = 0.06 Acres
Volume Required 1 FT.
2,400 S.F. X 1 inches X ---------- = 200 C.F.
12 inches
Required Recharge Storage Volume=200 c.f,
Proposed Stoned Trench Drain
Length of trench drain provided= 120 feet
Trench Drain Dimensions: Width= 1.5 ft.
Depth=4 ft.
Trench Volume (@ 40% stone void space)
Trench Drain Volume: 120 x 1.5 x 4 =720 c.f. x 40% =288 c.f
Provided Volume 288 c.f, >Required Volume 200 c.f.
3
Atlantic Engineering&Survey Consultants,Inc. John B.Paulson,P.L.S.President
97 Tenney Street Georgetown,MA 01833 George J.Zambouras,P.E.
978-352-7870 •978-352-9940(fax) atlantic84@gmail.com
Swimming Pool& BMP Maintenance Requirements
58 Country Club Circle
North Andover, Ma 01845
April 13, 2017
STORAGE OF CHEMICALS
Pool Chemicals shall be stored inside the basement or inside garage to ensure containment of any
spill or drips.
POOL DRAINDOWN MAINTENANCE AND OVERFLOW PROTECTION
At the time of pool closure for the season or anytime the pool water needs to be drained for
maintenance or to protect form overflows during major storm events; the chlorine levels shall be
reduced to undetectable levels of<0.1 mg/l. This shall be accomplished by utilizing either of the
two (2)methods listed below:
• Prior to discharging the no chlorine shall be added to the pool for approximately ten days
to allow chlorine levels to dissipate.
• Discharge water shall be de-chlorinated utilizing sodium thiosulphate or other approved
pool de-chlorination chemicals approved by DEP for use in watershed areas.
• The de-chlorinated water shall then be discharged over the grassy lawn surfaces or
planting areas prior to entering into the wooded portion of the yard.
POOL OVERFLOWS
To prevent the overtopping of chlorinated pool water during a 100-year storm event; whenever a
severe storm event is predicted the pool level shall be drained to a level to permit the collection
of 7-inches of rain. All discharged pool water shall be de-chlorinated in accordance with the
above methods.
1
BMP MAINTENANCE
INFILTRATION TRENCHES
Trenches shall be inspected every 6 months and after major storms. Debris shall be removed and
the top layer of pea stone shall be inspected for sedimentation. Areas found to be clogged shall
be removed and replaced to a depth necessary to assure proper functioning of the trench.
2