HomeMy WebLinkAbout06/25/2025 - Stormwater Management Report - - 364 JOHNSON STREET Stonnwater Management Report-364 Johnson Sheet
STORMWATER MANAG EM E NT REPORT
Watershed Protection District Special Permit
Project Address: 364 Johnson Street
North Andover, MA
Parcel 1131.1 038.0-0015-0000,0
Applicant.- Gregory & Melissa Buitkus
Prepared by.: John J. McDonnell, MSCE, PE, PLS
Massachusetts PE Registration No.: 33601
Date of Report: June 1253 2025
Paee 1 of IS
Stormwater Management Report..364 Johnson Street
TABLE OF CONTENTS
1• roJect Overview..►.►!■a.■•.■..f•■...e.■■ a■ara.►1■•..■.■...■....►...►..............►a.►.......a.►........................►...■.....
II. Design Parameters......!.■aa►at•af../aA..a.alaa.f/f■►i.,!•f■f1}L}a..e,a1■ a.a•.i■1iaa.i.aAe.aRAf.a1■a..■.■we%w■aRs■aa..r■►aaa.■\,.,
III. Design Storm Rainfall Data...............f..r.r.....■■.....11a....%.►.1■..1...saa■a...r.a..a..............................►.
A. I oo--year Roof Subcatchment .......................................f a}....................r................................6
B. 1 oo-rear Storm Future Expansion Subcatchrnent.....f.........a.a........a..r..................................7
Iv. Stormwat.^'r Management System.....r............a.a...aa.sa...as..sa...a.......a.r..s..................►...►.....fa.a}■aV
C. Overview a..........►.r....♦.r..■..s.►.►ra.r...........r►\.r.raa..It ar...aa■s}wsary.►saw►\►asaa■a.\aa►.a►a.saa.a.aaa■►..ar►s►....►rsa8
s Soil Conditions................ *o**0 0**4
►.
1) Test Pit Investigation:.............■....►.a..e......a.rr....as....r■......................................................8
2) Soil Profile Description.*a1..s•■■.....■........a■a■.►.........a..............■........■arr.■►..w..r.....r.r...■......a 0 a 8
3) Subsurface Conditions...................a...........■►..■►a.....................■..a..1.1...............................9
E. Pre-treatment System stem ar...............s..........►...............■.►..r....a.r.......►..■....■........................■......9
4) System Configuration.............................................■.f.w..■...■\..►r.e►.,.1...aa...it.l...li1...f..ia■R..a
5) Design Specifications t.t......et........a.a/.....a....a......■.....■■........■..■ r...■.aa....•...,a..■s■saaaf/a/a►•\.
6) f►attar Quality Performance....a.........a r..a.a...............a...r...........................►..........1.a s 1 1*0 a f../
7) Maintenance .a.....1.......►!f►}f a 1 f 1.!%f Is a■a 1►r 1►!►►a f a a..a 1 r►i..y...f../a....i/►.■.r*f.a■►..f a r a 4 a.1►.i R i......►r■•■•■■■10
F. Infiltration Chamber..►..►..r..r..........■....►...........►....►..........►■■■....a.■■..■.... ■.......■.......ts.►■1aa.■■a■■a 10
G. Site Conditions& Installation..x...a■..a■........a....r....a..........►....►......►.....■............&................12
8) Groundwater and Elevation Management.r..•r■.•.r•.r.■.■•a.■•.■••.fl1x■..}R..f.1al71alaa.i a.a.a\a.aa\saga 12
9] System Design Criteri'aft►fa3.a r+a%i r a e a f a l s.l}f■i.a la11 1it as/a afa la.■a■at..aar\a►.aar./sa.t■.It w.a s*.f w a.•■.■a r►.r►a.aa.12
He P erfonuanc e Analysis sis..■......a.........•.......■....a..........►..►.......e..►.........►.....1.■■f}/!fa/►■ak Laial.ai.4a4la i Ly
1 o f Peak Flow Reduction....................................................................................................
eduetion...........t.......f......../ss...aaa.►............a....■•.■►►►.r.■.....■■a..■....►........■......■12
1 1) Volume Management..■..}.....f.......■..a.......►,..af.1..1..t■.......■..a........►.................■...............13
1.2) Dr[.ado V n Analysis (Time to Empty) a■a.as►..aaaa.f.a►r..�a■+1af►aa■■aala 13
V . oP E.L- TI ON AND MAINTENANCE PLAN►..■..f......■.►.......■...■.■r...■■....................laa.aaaaa.aa■
I. System Components and�.espo�lslb�l�t eS./.r\,a......ft.a...t..fa.....a..............■...a.........a./............14
1 3) Homeowner Re sp o n si bi it1es•■f\a. a■a\►ara..■..........►r..►a►a,...■!a/rr■rs%%•ays.as►ala.aaaaaar..ar..aa.►taa►r• 4
J. Maintenance Schedule and Procedures ....tr.a.lta■1.a■aa.a..:.r..ra.aR....l.,.►,►.....s►.aa.aas..■ka.■fafar.►►••►..1 4
14) Routine Maintenance (Homeowner): ....,■....r......►.../...i f........■■......w........................■■....14
15) Professional Maintenance: ►\..a.*■1a■►..asf■...a/.}f.{iafailia.a►a.►a i•woos s.,o...■■a a.i.a to asset 4
'age 2 of 15
Stormwater Management Report•-364 Johnson Street
K. Inspection and Monitoring Requirements.a a.a a......a.a a a a.■a a r.a.+a►s•a a•a.a a.r a.a a a.a r a r a r.a a.•►►►■■a a s a.►r a■14
16) Inspection Elements. a....►.►••...•a■..a►..+r.....a•sa.a•.■............►r...►.....r►•.r.r...►..rr..■errr.a.►..r...s■t..r 14
L. Maintenance Agreement and Easements ........................................................................14
17) Maintenance Responsibility r.a..............r...►.........a...................►.►.►..•.............................14
M. Annual Reporting�e�r���e�en �flfef!►flifilfsii■IfRi!!1lslffaKa ifisla•al•f■lari.a.!►s..►+.rs.R..■...■sif..a...a.sti��
18)
Documentation.....■a.a.....a....a...►..a....•...s......■......►.....■......a...a...sa.►.......►►......................►..15
V1. Compliance & Benefits►a...a a a............r.r+.•.....►..a........a►.►►r►.....+..............r............r.......►.a..►.....■ 5
V11• Recommendation..a■..•►a....a.a..a■aa...a■..■.r...•....■..r■....•rr■r....■.■s...as■s...a►i►aras...aar..r.........r...a...r.....15
Page 3 of 15
Stormwater Management Report-364 Johnson Street
I Project C7verview
The project planned for 364 John Street in North Andover, Massachusetts
involves of the construction of a two-story addition to an existing two-story
single-family home (the "Project")
This, report presents the stormwater management analysis for a proposed
addition which will have an additional 376 square feet of roof. In order to
comply with the requirements of the bylaw, the Project will include the
installation of a stormwater infiltration system to facilitate the infiltration of
the runoff from the new roof area.
The infiltration system has been conservatively designed to accommodate
both the area of roof above the currently planned addition and potential
future paved surface on the site, which total approximately 900 square feet
for an existing driveway access off Abbott Street, that may be paved in the
future.
Page 4 of 15
Stommater Management Report-364 Johnson Street
i i. Design Parameters
Table 1 . Design Parameters for current roof addition, future paved area,
total managed area, design storm, and surface type.
Parameter Value
Current Roof 376 sq ft (Subcatchment 1 S)
Addition
Future Paved 900 sq ft (Subcatchment 3S)
Area
Total Managed 1 ,276 sq ft (0.029 acres)
Area
Design Storm 11 00-year, 24-hour event (7.97 inches rainfall per
NOAA Atlas 14)
Surface Type 100% impervious (CN = 98)
Page 5 of 15
Stormwater Management Report-364 Johnson Street
L D e s ......1 Storm U ff n m r Data
The s:ystem has been designed using the 100:-year, 24-hour event rain fall
data fro .9711)
A. 100-yea�� �^�, � � ICI
r
Surnmary for Subcatcl-in-aerit i s.*1 Root
Runoff 007 cfs '12.03 hns-, VC)1LM-1tE-= 0.0065 znf, C�ej--)th= 7 TA,"
Routed to Pands 2P - Infultraticirl (-Ml-u--lmber
Runciff by GCS TR-20 1-riethod, UH=SC-S, Weighted-CN, Tirrte� Sj:)an= 0.00-261,013 hl,s, O -i
PF—C)epth_Enq1ish FIDS 24-,hi,S1 1 010-yr Rainfall=7,C 7"9
A rea (sf) C N
3743 91 S. R f
.... .................
376 "100.000/,'0" IrnperviOUs, Area
Tc Lerigth Slope. Velocity -*,apacity DescTiption
fus
Ex.0 22 0.07 Direct Entry. Ricig 11 eto Giutter
Subcatchment is: Roof'
fri y1cl ir cq,,;rci
10 7 E 0�07 c fis
�YV
PF� De)th 91 11SI'l 0.07- _E —P S 24 t
0,0 15 PICA
Rlitic�'ff
R,611cd V 1.�I t I!1 01
� A�l ea-37
;Ill t
2"
N
J,
101
emU;1"',Ll�
0"Aw 1
FEW,w I I 91(i l`��" l�lJ.... r'��... io VWmVN'°°'INS.. I_" �I � u V t,,.;yi ,�„6, O� y;v. w
Vg
0 7' 9
Time Ihs>urs)
Figure 1. In a I 00-year, 24 hour storm event, the peak runoff rate for proposed roof 'Is 0.07 cfs.
Page 6 of 15
StoiniNvater Management Repoil,-364 Johnson Street
1"I Z5 U
y-r
00-year Storm F m'LltUre
SL,AMMaty flor Subcatchrrient 3S: FuturIe Parking Expansiovt
R 1-t noff 0.17 cf,--. (ifi) 12.0.4 1-irs, Volt..jrne= 0-0 1, ct,f, D e r-,)t h= 7,7-?j
Routed to Pond 2�P - 11-IfUltratint-1
RUIlOff by S,(:;S TR-20 rnethod, VVeighted-C"N, Tinie SPcin= 000-255,00 1-irs, cit= 0.01 1-Irs
PF—Depth_Engfish—PL)IS 244-ir S1 'I 010-yr R;.-0nfa11=7.197"
Area (sf) C-;P14 Des
19010 C)H-
F-11
19010 411PIel-ViODUS Are-a
I c Lengtl-i slope Velocity Cca pacity Descrip-tion
_Lf-r-lin) (fi�et) (ft/s e c (Cfs)
5.0 Direct Entry,
Subcatchmerit 3S.: Future Parking Expanslorl
H y cl r o(,,,.l ir apt
i,
co,I a:. 7 cfSj
0.1'7--'
Mrs
.1
R U I o�f f o I t1114i-0. -13 of
Ru IcAf,De th, 7.73"
Mll
�. u a r
0,04
0 0 3
0.0
IM, Ald
C� 9 12 13 14 15 1 c-5
Time (hours)
A
Figure 2. In a 1 00-year, 24 h�o,ur storm eIvent, the peak runoff rate forthe
a
future expans,ion area is 0.17 cfs.
uombin�ed Inflow into the system has a peak runoff rate of 0.,24 cfs.
Page 7 of 15
Storniwater Management Report-364 Johnson Street
I'V. Storn��"iwa"!,'e i-I 110 a t'--i a g e I'll E'1:1�0`11"1"0' 1 ylstiern
C. 0 v le ry i e lo)r
The proposed system utilizes a subsurface infiltration chamber (Cultec R-
i
180HD) as the primary means of storage and infiltration.
a
The propo�sed system also Utilizes a mini dry well - l) as
the primary, means of pretreatment, as well as the component of the system
that will provide for equal distribution to the three chambers of'the
infiltration system,,
The System Flow Path is, the Following.
e Roof --* Gutters ---> Downspouts --+ Pretreatment Infiltration --4
Groundwater
D. S lIol I lo° i
1 ) Test Pit Investigation:
• Performed
bya John McDonnell MSCE, P.E.,
0 Date: June 7, 2025
• Test Pit: TH-1
• Surface Elevation.- 255.8 feet
2) Soil Profile Description:
0 0 19 m 10". Horizon A, Fine Sandy Loam (FSL), 10YR 3,/4 (dark
yellowish brown)
0 loll: - 23": Horizon Bw, Fine Sandy Loam (FSQ, 10YR 6/8 (brownish
yellow)
a 239V . 74": Horizon C, Sandy Loam (SL), 2.5Y 5/6 (light olive brown)
Page 8 of 15
Stornmater Management Report-364 Johnson Street
3) Subsurface Conditions
0 Mottling observed at 48" depth (Elevation 251 .8 feet)
0 Water weeping at 71" depth (Elevation 249.9 feet)
0 Sail texture,,, Predominantly sandy loam throughout profile
0 Infiltration capacity:
Good infiltration potential based on soil texture
E. Pre-treatment System
41) System Configuration
A Shea Concrete Mini Dry Well (160-gal{on capacity) provides pretreatment
upstream of the Cultec 'Infiltration system.
51) Design Specifications
Capacity: 160-gallon precast concrete chamber
Access: Cast iron grate with 24" round frame for maintenance
Filtration: Filter fabric and crushed granular media
• Outlet,: 4" diameter connection to distribution system
6) Water Quality Performance
The system achieves 96% Total Suspended Solids (TSS) removal in the
main Infiltration chamber, exceeding the 80% regulatory requirement. Per
the TSS Removal Calculation Worksheet from the Massachusetts
Stormwater Handbook, the mini dry well provides initial treatment (80%
TSS removal) through settling and filtration, with the Cultec infiltration
system providing additional treatment (80% of remaining load).
Page 9 of 15
Stotinwater Management Report-364 Johnson Street
INSTRLJCTICMS.
'I.lo KIP Column,click 01)BILW Cell to Activate Droi)DovA)l0enu
2 $elect BNIP from Drop Down fvlenu
3,After Btfll?is selected,TSS Removal ON Oth9V COILHIMS W'P,tAlt(NDOCi.111�1 collipleted,
Location: xin$t,Norlh Andover,MA 0 1845
C D E F
TSS Removal Starting T38 Amount Remaining
-BMP' Rate" Load* Removed (C*D) Load
Dry Well 0.80 1.00, 0.80 0.20
0 0 Dry Well 0.80 0.20 0.16 0.04
(D
0 0.00 0.04 0.00 0.04
MM
U)
0.00 0.04 0.00 0.04
0.00 0.04 0.00 O04
S lie pini, Needs tc)
b a C o m p le t le d f j:),r roc 1-1,
of TSS Removal == C")u t I le t 0 r B T'41 P T ra 1 I'l
Project IC4 Johnson SL Adfton ................
Prepared By.- John M'cDonnall 'Ecluz)1%;re-mainfilq 1Q0 frOn,Pr root IP(E)
Date.- 611812025 vvhwh enters the-RIP
Non-autornated TSS Calculation Stieet
MU St be!USed It Proprietary SNIP Proposed
1.Froni MassOEP Stonwater Handbook Vol, I t"fass Ne).11,of Enviro'l live n"al pfote�:tlflo
7) Maintenance
The 24" access cover allows for periodic inspection ana cielanout of the
%1
mini' dry well chamber to maintain system performance.
F In''ilti&a�'I:ioiri,
Table 2. Sx,
ystem components and specifications of proposed subsurface
infiltration chamber
System Specifficaflon
Component
Configuration 3 chambers 'in stone field
NO
Dimensions 9.,33' x 12.001 x 2.83' deep
Storage 166.7 cubic feet (0.004 acre-feet)
Page 10 of 15
Stormwater Management Report-364,John,son Street
Capacity
Infiltration Rate 12 inches/hour (derived from field percolation test
yielding 24 inches/hour with factor of safety of 2.0
applied)
Emergency Emergency overflow pip�es installed per manufacturer
Overflow specificat. i ions. System design prevents surface
discharge during 1 00-year, 24-hour storm events
through adequate storage capacity and infiltration rates.
InfUltratlon Chamber - Charniber Wizard Stone Field
Cl-tamber Model = CuAtee R-1 8,OHD (For restidential use only)
Effective Size= 3,r3.6.-V'W x 20-O"H =-- 3A4 sf x 63.33'L = 21.8, cf
Overall Size= 36s'.01"'W x 201.5"H x 7.33'L with 1.00' (Dverlap
Row Length AdjLJSt1-T1e1-1t= +'1,00" X 3.44 sf x .3 rows,
36.0" Wide + 6.0" Spacing =42.0" C-C Row Spacinc g
1 Cli amber-s/Row x 6-3,3' Long +,1.00' Row AdjUSAMellt = T33' Row Lerigth -4-12,10"' Fret St(.-)ne x 2
use Lerigtl'i
3 Rows x 36.0"Wide + (3.0" pac Siticl x 2 + 12.0" id ne.Se Sto x 2 = 12.00' Base,Width
6.0" St tie, Btase + 20.5" Car Heigl-it 3.0" Stone Cover= 2.71' Field Height
3, Cham bers x 2 1-8 cf +1.00' Row AdjUStment x 3.44, Ff x 3 Rows 75.6) cf 0-101 hz.im ber StcIrz.10,e
303.2 cf Field - 75.61 Cf Chambei's= 2127.6 cf Stone x 40. ,o' VoicJs 9. . cf Stone Stot'Lage
Chaiiiber Storage + Stot-te Stc)rage cf O004 af
Over-all Storage Efficiency = 56.W%
Overall CSystem Size 11i).33"x 12.0 'x 2.71'
,3 C'Oluunbers
11,2 cy Field
8A cy Stotie
11110
00
I M
111MIN
Figure 3. Modeled Infiltration mber System, Embedded in Stone Field'
Page I I of 15
Stormwater Management Report-364 Johnson Street
G. Site Conditions & Installation
8) Groundwater and Elevation Management:
0 Seasonal high, groundwater: Estimated, at elevation 251.8 feet
(based on mottling observed in Test Pit TH-1)
• Stone field bottom elevation: Set at elevation 254.0 feet to ensure
minimum 2-foot clearance above groundwater
• Actual groundwater seplarafiona. 2.2 feet (exceeds DEP minimum
requirement)
• Ronal turf elevation: 257.16 feet above system installation
• Sife regrading: Area will be regraded post-construction to achieve
proper drainage patterns
9) System Design Criteria:
• Groundwater protection:'System design maintains adequate
separation from seasonal high groundwater to prevent contamination
and ensure proper 'infiltration
• Drainage design: System design maintains adequate slope for
proper drainage and conveyance to treatment components
H. Performance Analysis
The HydroCAD analysis demonstrates excellent system performance-,
10} Peak Flow Reduction
Table! 4. Pre- and post-treatment peak flow ('in efs)
Flow Parameter Value
Pre-treatment Peak Inflow 0.24 cfs,
Post-treatment Peak 0.03 cfs
Outflow
Flaw Attenuation 87.5%
Page 12 of 15
Stormwater Management Report-364 Johnson Street
11) Volume Managlea"ient
Table 5. Volume parameters related t ischarge to watershed
Volume Parameter Value
Total runoff volume (100-year 0.029 acre-feet
storm)
Runoff infiltration All runoff infiltrated through subsurface
system
Surface discharge to watershed None
Pond 2P,* Infultration Chamber
Hydrograph
_J............................
3 1 n(I OW
4 cf
Outflow
L I
D i E,ca r(t eej�
'029, M nflov�_Area:�O,; �1,1 MEN PrImmy M
0.24" w,..- tit,
1, J_
6=0 0 i
tbir
S a e
40
V,O
'J
R,E
LL
0.
g,
0.08-
01.03 ds
...........
0,03 CfS
0.04-
0,0!0
0-
0 2 4 6 8 10 12 14 16 18 20 22 224 6 28 30 32 34 36 38 40 42 4�4, 46 48
Time (hours)
Figure 4. Infiltration Chamber Hydrograph sho�ws all runoff'Infiltrated through subsurface
system
12), Drawdown Atialysis (Time to Empty)
0 2-year storm: 6.5 minutes
0 1 Ovoyea r sto rM 1." 11 .7 rn 1 n utes,
0 25-year storm: 15.4 minutes
0 1 010-year storm-, minutes
Pale 13 of IS
Storrilwater Management Report-364 Johnson Street
OPERATIONI j8�ND PL-ANJ
IurJp� „gum �m lv
L Syste n"-Ii Coni,�I,,,.),or"Iuierits al,'I'idoJw
13) Homeowner Responsibilities:
0 Routine inspection r nd downspouts
0 Seasonal cleaning of debris from system inlets
a An n ual inspection of p retreatment, chamber
0 Prompt repair of any system deficiencies
,.J. Mainte nan c MM Nma rw �
e Sche dule and
'14) Routit-lie MaIritenance (Horneowner):
• Quarterly,: Visual 'inspection of surface conditions
• Bi-annually: Gutter and downspout cleaning
• Annually,: Pretreatment chamber i nspection and clean ing
0
• As needed-, Debris, removal and minor repairs
15) Professional MaIntienwIlice:
a
• Every 3-6 years. Comprehensive system evaluation
• As needed,: Infiltration rate testing and system rehabilitation
K. Inspection at-Ixl Mioriltrin o i R . III(=k 1,0111f
g 1 %eq.,jire lctS
16) Inspection Elements:
Roof drainage system condition
Pretreatment chamber sediment levels
Evidence of system backup or overf'low
Infiltration petformil Inc e observations,
L.. I\Aali��'��Iitenance Agreeffient and
'0171) Maintenance Resporisilbility
• Property owner responsible for system maintenance,
• Access maintained for inspection and cleaning
Documentation of maintenance activities
Professional assistance as needed
Page 14 of 15
Stormwater Management Report-364 Johnson Street
Riepor 'ig ReqL"Ji'"en'ients
18) Doicbmet"itation
* Annual maintenance log!
0 Inspection findings and recommendations
* Any repairs or modifications made
* System perf'ormance observations
wil% "M
cor'lirl 0 a n ice, & E131enli'll,wifits
1411,1110 %MJ
1'* Watershed Priotectl*ons, The system Iiminates all: surface runoff,
providing 100%1 volume control and significant peak flow reduction.
2. Conservative Desl"gn's. The system is sized for 340%, more
i -mpervious area than, the current rolof addi'tionY ensuring adequate
capacity for future development. Infiltration rate based on site-specific
OR a 1. A
testing with a conservativ T
ety T I actlor.,
3. Groundwater Recharge,,, Allstormwater is returned to the
groundwater system through infiltrationl maintaining natural
hydrology.
V11. Recori""ii-l"Iiieiida-tion
The proposed infiltration system exceeds typical storrinwater management
requirements by providing complete volume control and substantial peak
flow, attenuation for both current and anticipated future development. The
system design ensures no adverse impact to the wateirsh!ed and supports
the Town's stormwater management objectives.
Analysis prepared using HydroCADO software following SCS TR-20 methodology
1A, OF
Prepared By: John J McDonnell, MSCE, PE, PLC
I JOHN J.,
MCDONNELL
CIVIL
NO.41157
QIST
fill
ONIA",
Page 15 of 15