HomeMy WebLinkAboutCorrespondence - 180 MARBLERIDGE ROAD 10/10/2002 52 Washington Street
=nze Newburyport, Massachusetts 01950
Voice : (978)462-4171
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Civil/Site and Environmental Engineering
Land Development and Permit Acquisition
October 10, 2002
Town of North Andover
Community Development& Services
Planning Department
146 Main Street
North Andover, MA 01845
RE: 180 Marbleridge Road, North Andover, MA
Mary Ellen Fennessy McDermott
Required infiltration sizing for house addition
Dear Board Members:
Assessing compliance under the local Special Permit requirements can proceed via many
pathways. Rather than prove capacity of existing systems to absorb the increase in runoff it was
decided to proposed and design a new"Infiltrator" (or equivalent competitor) subsurface
stormwater trench and storage system. Such a system can be sized for the net change in site
runoff volume during the 100-year, 24-hour storm event incurred by the proposed addition. This
system can also be constructed simply and fairly inexpensively.
I have attached a construction detail and potential layout given the proposed site plan provided
to me by you. Please keep in mind that so long as the construction detail remains unchanged the
only deciding factors will be the approximated rooftop inflow area to be served and the calculated
number of required infiltration units. Thus, changes in layout and footprint can be made in the
future without compromising these calculations so long as the approximated rooftop inflow area
is not exceeded or the calculated number of required units decreased.
I have included a few hundred square feet extra of approximated rooftop inflow area over that
calculated by measuring the proposed addition off the site plan. This extra area should more
than compensate for pavers and other impervious surfaces being proposed in the landscape
about the new addition.
Calculate Required Infiltration Volume
Given an approximated rooftop inflow area= 1,500 square feet
Given a parent hydrologic soil grouping= Group D (determined by inspection of
N.R.C.S. Soils Survey of Essex County Northern Part)
Given an existing Cover Curve Number(CN) = 80 (Lawn, or Open Space, good
condition) (See attached copy of Table 2-2a from the N.R.C.S. TR55 manual for
soil group D)
Given a proposed Cover Curve Number(CN) = 98 (Impervious areas) (See attached
copy of Table 2-2a from the N.R.C.S. TR55 manual for soil group D)
10/10/02 Project CLP0205
Page 2
Using attached Table 2-1 from N.R.C.S. TR55 calculate existing runoff depth for
100-year 24-hour rainfall of 6.5 inches= 4.23 inches
Using attached Table 2-1 from N.R.C.S. TR55 calculate proposed runoff depth for
100-year 24-hour rainfall of 6.5 inches = 6.26 inches
Calculate the increased runoff depth resulting site development: 6.26 inches-
4.23 inches= 2.03 inches
Calculate the increased runoff volume resulting from site development: (1,400
square feet)(2.03 inches)/(12 inches/foot) = 254 cubic feet
Thus, to meet the 100-year rainfall requirement 254 cubic feet of storage must be
provided in proposed trench.
Calculate Provided Storage Volume
Given a trench cross-section of 3.00 feet wide, 2.00 feet high and utilizing 11
infiltrator units at a length of 6.25 feet each, all as detailed on the attached pages.
Calculate the total system volume proposed: (3.00 feet)(2.00 feet)(11 units)(6.25
feet) = 412 cubic feet
Given an infiltrator void volume of 16.3 cubic feet per unit(See attached
manufacturer's sheet)
Calculate the total stone volume proposed: 412 cubic feet- (11 units)(16.3 cubic
feet) = 232 cubic feet
Given an approximated stone void ratio (Vv/Vt) = 0.33
Calculate the total storage volume provided: (11 units)(16.3 cubic feet) + (232
cubic feet)(0.33) = 255 cubic feet
Calculate the total length of trench provided: (11 units)(6.25 feet) = 69 feet
Thus, as designed the proposed infiltrator trench will store the net increase in site
stormwater runoff volume incurred by the proposed house addition.
Given the entire above do not hesitate to contact me should you have questions or comments
regarding this matter.
Very truly yours,
10M A
SOUCY
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John Jr., P. :v�+
Principal
Milestone• 52 Washington Street, Newburyport,MA 01950 • Civil/Site and Environmental Engineering
Table 2w :--Runoff curve Ttumbors for Urbnn.arens}
Cave numbers for
is tiv t°des ptl hydrolog'ie mil:gia
.Aver e pe ront
ever cypc and hydrologic c onditi �ap� �u�: �� .:.: �� � C:..:. p
Fatly dnvtoped urban arras fv-gvtatioyt eat bbMedi �RDPD: CDN�CTIb►�
Open space(lawns, parks, golf coupes,cemeteries, EK1�JT11.��, CbNDiI�L�bFJ
etc.)",
Poor condition(grws aver.< ;5t1 x) _...,:........: : 86
Fair eTndition(mss cover 1 to 75%),........ 49...: 69 73$
Gootlwnditjon(gross cover.> 77.5%).. ........... 39 61 74 .. 1
Impel v rrrus areas:
Faxed parking lotz, roofs, driveways, etc..
(exc udirg rightaaf ivy). ,.. ........ ........ 98 98 98 -98
Streets anti roads:
Bared:garbs and storm se,%�6rs(excluding
igkst vv'ay)..
......,,, ,.>. ,...., 9€3 98 98
Paved.Wen ditches(including rigbt-o-way) , 83
Gravel(including r ht=oi-way) , i
Dirt OnehAhg tight-of way} ......... ..... . -72 822 87,..
Western desert tftn areas:
Natoral desert landsimping(pervious area only)4... 63 _41
Arti#tcW desert jandscapng(impervious weed
b«crier, des-Art shml7 u th I= tv 2-inch sand
or gravel nwIch-and basin border), 96 96 96 .
Urban distr'ieis.
Corrtttterdal anA business.:................:...
85 .:: 92 94 9.5
Indwstrial...... ...... ........ 72
lfl 88 91 93
Residential districts}by average let size;
118 acre or less(town hewer ,,,.
V4 Ure
.30 81
80. 85
..
1 a(re., .... :�D 5i 7�_ 134
2 Acre* -,.......:
...............,.:......... .. . r2 16 65 ii iii
Deretoping urban aaas
Newly graded are: (pervious areas only..
no
.. . . ... .
Idly:land*(CWs arre deterrty'.d_ wing cover types
situ to those in tabled :..
'Av a runufTei-ditioii;ar lx > : . ... .... .... _......
..._.._.............. ::... . . .._... .
2I'he tavern per ne impvc c ions area shown aK used ker develop the tern . yCe GN .ether 3 tlrttptluna are fulleiSr�; itu»r iu 2
am tllrecsly#.*ww4,wd to the dminop tiy"etn,ImpervIO is a elill hav*a�. 1; .a is#'p ry ad ass itr .winsidored etiuh aloft:t .a n
:;paeo in Roo hvf3r+ale ndicion l�' for alter'i o, binst r t:c ndtt ra iii of _d ustiig r ,
d'a xhc»n ate eiitnt tti°tit of stare t' utate "7' 2te t�tiiSp4L `l`rir vt er'eamhtrit3tcu +f tri apue gwt tyica _
4COFn Ate CN`:c for oaturgi de.�i•t land-leaping y
pa y. pttcg hrid be cumpaitod nog li 2-3 ar:,�#based itc�1#iiyititi arm pare : #E' 1
9di anti the Wn iotw um- Gil.The pervious area t"`N#.are ax�ittrted,s al it nt to desert#h''�ili in pow- �rlreil jmlitiw
4c9miwite Cut's to we ror the de-Agn sxf temporary y mc:iKtai4s dsirin �. �ti . �_ ;
�tvt3 strcact#iiri�auSilif#�e i' tl�iitrel iisles�, Cgtti�:.t zcr�.A
h3��a1 on this dear of develupwot timperviowt 4trea petuntage)and the CN s for the twwly Xraded pervious aiea$.
texture is givers in appendix A for determining. the Hydrologic condition
HSO classification for disturbed soils.
ydrolo*:rendition Wicates the Weems of cover
typl..� twat pt on ix3:tiltration and runoff and is
Cover type generally estimated from density of plant and residue
cover on rnple areas. Good hydrologic condition
Fable 2,1 W&e must cover tees, sueh as indicates'that.the soil usually has a low runoff
vegetation, bare soil, and Impervious surfaces. There potential for that-speate hydrologic sail group, cover
are a number of methods for determ Ming cover taw- tgvpes d tr ."MeAi SDrft6 factors to eonoder in
The raost conunon are field reconnaissance, aerial e ti in °thre'.kffect..of cover owinfiltration.and
photographs, and land use maps. runoff at6(6)canoppy or density of laves, crops,car
other vegetative areas;(b)anxount of year-round
cover; (c)<"ount of gibs or close-seeded legumes in
Treatment rota ons;°(d)percent of residue cover; and (e)degree
of surface roughness.
rrewm_erd is a coiner type modifier(used only in
table 24b)to describe the management of cultivated C t -C\()o = �.2� I K1
agricultural lands. It includes roecha!p cal p>raetic ,
such as contouring and terracing,and mana, ment ►�CZc��T�D oS�
practuces, such as crap rotatiom and reduced or no -TIbW = (p. p:1f4mvs,
tillage,
Fable 2-1.-Runoff depth for:selected CN's and ira atall wnountes
T Ituriol dcpfh for curve
liainfiail 40 46 50 80
55 .. �:.:::
7fl re .......:.......90 95
......»,.�_...»........�,�.... »3333 .»..».,,.. .--'..
1.0 0,00 O.Oo Q, } 0.400 0.00 4).€7+0 �4� 003 A08: 0.17 0.32 Q..5C) €).i9
. . _...: _a_ $
L2 ,00 .€0 W:- _00 R03....:_:�:;,�}7..:._. ......,.15 2 f �4._. . .99
1:4 .00 .00 ,00 . -,00 .1� _ 3 : : .61 ��� 1.),8
1.6 .00 4Q 60 3 3 3 3. :( : 4I 4 ..... .. .34 62 .'76 1.11:: 1 .
.......
2.0 .00 17t7 QO'33 3 3 V
14 4 y3$: 5 .89 1:09 °
.08 X43 146:3 . .. _f+ii€ �' 1.18 1.53
2.5 411} 00 17 1•I) ....._
3.0 _0O .02 .19 .33 :6.1 ,i 1 <' .96 1, 1.59 .1.98 446.
,tom : .35 A .75 1 f11 1130 1x63 2.02 2A5 + 8� 3.
4.0 ,06 .18 03 : .:: :.59 .76 1,(l� i, _:::_�;67. 2.04 2.46
:2.92 . 1- 4-3. .:.. 3.7,
4,5
14 ). 74,._ 1,0� 1. 1:67 2 � 2.91 340 �. 426
5,0 ,44 .69 ,98 1.30 1,F'w... ._.....� ,.46............z� SZ7 a:$$.. .. 4_422.. . ...-4.%..
6.Q .50 130 1:14 L52 1.92 U5- 2.81 328 3.7$ 4.34 4.83 5A1 5.76-
TO :94 124 1 ....2.1�... ..�� ���........:...� ....-.':.4.15 4.69 53x*` i 5.82 (W: 6,7
8-0 uz 1.74 2s 2.78 8-U 3.89 4 f; 5' ... ..6:21 .._ 0.87.-..:: UO 7.76
9.0 1.71 2,29 2M 8,49 4.10 4.72 15,33 :::_ 5.9& 6-57 7.18 7.79 t3,4O 8.76
10.0 2M 189 3.56 423 4.90 & 622. .:.:.6.$$. _33 33.`1352 8.16 838 9.14 9.76
11.0 2.78 3.52 4.26 5,00 6.72 6.48 7.1$:.. :.-.7.81 8.48 9.13 9.77 10.39 10.76
.4) 3.38 4.19 5,11i) 6.719 6.56 7. 8 ij5:.:.:.. 8+743 9345 10.11 10.76 11.39 11,76
119 4.00 4.89 5.76 f,4;1 7.42 8 2 :::..:,....8:98 ....::O 71 .. 1t 42 11.10 . 11.76 12.119 12.76
1=1,4 4.65 6,62 6.55 7.44 8.30 9.12 9M 10.M 11.39 12.08 12.7 1510 6.33 6.333 6336 7.36 8.29 9.19 1x.94 10,85 11.63 12.37 13.47 13.74 14:39 14:
'1ntesgra3at the vu sbown w olaWn r�rsuff�lu�th3 for N 3 or rainfsitl a iaanta tsar sltuwn
(210='VI-TR-55, Seemd Eel., June 19N)
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Engincerin;and
Plannilia consultants
November 16, 1993
Ms. Kathleen Colwell
Town Planner
120 Main Street
North Andover, MA 0184
Re: Modification of Special Permit
Lot B-1 14arbleridge Road
Dear Katheen:
On behalf of my client, Flintlock Inc., I am requesting that the driveway providing access to
the dwelling on lot B -1 be allowed to be paved. During the public hearings, we had
submitted evidence that using pavement instead of gravel in the driveway construction would
not have an effect on the quantity or quality of runoff from the site, Based on this evidence,
it is our opinion that such a change would be considered a minor and consistent with the
design concepts of the original proposal, The implement of pavement would not require any
specific modification of any other part of the design,
Thank you for your consideration of this matter. Should you require additional information,
please do not hesitate to call.
Sincerely,
Michael J. Ra u
Project Manager .
62 lrontvale Avenue .
Suite I
stone6111,31A 02180
(617)438-,)'121
Fax(617)438-9654
Flintlock Inc.
P.O. 8®X 531
NORTH ANDOVER, MA 01845
November 2, 1993
Kathleen Colwell, Town Planner
Town of North Andover
120 Main Street
North Andover, MA 01345
Re: Lot B-1 Marbleridge Road
Dear Mrs. Colwell:
According to the condition of the special permit on
Lot B-1 Marbleridge Road, we have determined that the water
table at the house location is at 40 inches below existing grade.
If you have any questions, please contact me at 688-6558.
Thank you.
Sincerely,
David A. Kindred
President