HomeMy WebLinkAboutStormwater Management Report - - 364 JOHNSON STREET Storm apt er Management Report-364 Johnson Street
STORMWATER MANAGEMENT REPORT
Watershed Protection District Special Permit
Project Address: 3,64 Johnson Street North Andover, MA
Parcel IDI-, 038.0-0015-0000.0
Applicant: Gregory & Melissa Buitkus
Prepared by: John J. McDonnell, P,E,, PLS
Massachusetts Registration No.: 336,01'
Data: 0 2025
T
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S&mrmovvaterMaosgeoment Report-364 Johnson Street
K. inspection and Monitoring Requirements......................................................................... I2
16) Inspection���mm���m:_—._.~.......—_—..~^.....~.........-._.__-._--....—_ 12
L^ Maintenance Agreement and Easements.......................................................................... 12
17) Maintenance Responsibility ......................... 12
M. Annual Reporting Requirements....... _^__',,~^,~........____,,~^.^.,,,~,,,.,~,__,,,, 12
18) Documentation.............................................................................................................. 12
V[ Compliance &Beoefi1s~^,~.,,^.^,,~_____~^^~.,^^~~,~~,.,_---_....-.^.~.~^^..^~^~^—^'^~~ 12
Vl& ....................................................~........................................................... 83
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Stormwater Management Report-364 Johnson Street
ii. Design Parameters
Table 1. Design parameters for current roof addition, total managed area, des'n storm, and
19
surface type.
Parameter Value
Current Roof Addition 376 sq ft (Sub,catchmen.�._. ...__..t 1S)
Total Managed Area 376 sq ft
Design Storm 1 00-year, 24-hou'r event (7.97 inches rainfall per NOAA Atlas, 14)
Surface Type 100% impervious (CN = 98)
.......... ............ .......... .........................
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Storm rater Management Report-316,4 Johnson Street
IV. Stormwater Management System
B. Overview
The proposed system utilizes a subsurface infiltration, chamber (Cultec R-1801HD) as the primary
means of storage and infiltration.
The proposed system utilizes a mini dry well (Shea Mini-Dry Well) as the primary means of
pretreatm,ent.
The System Flow Path is the Following.-
0 Roof--* Gutters --* Downspouts Pretreatment Infiltration Groundwater
C. Soil Conditiolls
1) Test Plit Investigation:
0 Performed by.-I John McDonnell P.E., C.S.E
a Date: June 7, 2025
0 Test P*lt: 'TH-1
a Surface Elevation: 255.8 feet
2) S,oi rofile Description:
0 0" - 10": Horizon A, Fine Sandy Loam (FSL , I 01YR 3/4 (dark yellowish brown)
a 10" - 23": Horizon Burr, Fine Sandy Loam (FSL), 10YR 6/8 (brownish yellow)
0 2311 m 74": Horizon C, Sandy Loam (SL), 2.5 `5/6 (light olive brown)
3) Subsurface Conditions
a Motthrig observed at 418"1 depth (Elevation 251.8 feet),
a Water weeping at 71" depth (Elevation 2,49.9 feet)
0 Somil texture: Predominantly sandy loam throughout profile
0 Infiltration capacity: Good infiltration potential based on soil texture
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System Spwectficatio
Component
�� ��...�....... �...,,,mw.,.,,.,�.,,..,�a...�.w..w®.w�...�...,�.,,.�..�,..,w.,.w...,..„.....,.w,_,.,m,.m,�,..,.�.,,.,.,,,�,..,.., .....�.....� ...�..,.,.,�.......�...,....�.,.,,.W�,.,„�.W...,m„ ................«....,.M..,.,,.,.....,�,,,.,..,,,,..,.,,. .,� �����,�..�w.....�,......w..,�.,�w,.,,..m,....,, ..,....,,.,,,........w.�....,.�,.,.. ...,,m,,,..,,,,....,,...,..�.,,...,,,M,.,.,,,.,.mm...�...�.,,.,,,...,.�.m,,m,.........mmmm..........�... .,.,,. ����....,.. �����.���..,�..,..w..,�,.....,.w.....,,.»..,...,,,m..
Confi �uratioln 3 chambers in stone field
Dimensions µ m 9. ,�m� . 1�2.0 . ,2.83deep
_
w
Storage capacity 166.7 cubic feet (0.004 ;acre-feet)
...,.,.__._.._,.,,.,,,.. ..... ............�.....,..,,,�.......�.. _.._........._.._ .._m.,.,,.,.,........,.,..,...... .� — -------...�.__._-------------
Infiltration Rate 12 inches/hour (derived from,, field percolation .._ . yielding
l ---
inches/hour with factor of safety of'2.0 applied)
_. ._ ... __ ... _ _a _, m .m mm-...._ ,
Emergency Emergency overflow pipes installed per manufacturer spl ciIfi'c,ations
Overflow System design prevents surface discharge during 1 -year, 4-hour,
storm events through adequate storage capacity and infiltration rates.
Pond 2 ,* Infultration Chia -Chamber Wizard Stone 'l
Chamber Model=Cu to R- 0HD(For r s° n'tial use only
Effective Size= 33.6,"' x 201_0"' =>3.44 sf x 6.33L=21.8 f
Overall Baas=36.0"W x 20. "H x 7-33 .w" th 1- "Overlap
Row Length Adjustaient= + . "x 3_44 sf x 3,rows,
6. "'Wilde+ .. "'Spacing 42. ""C-C w Spicing
Chamiber r x 6..33,"Long+ -00'Row Adjustment=7-33Row Length, +12. ""End Stone x 2 9-33
Base Length
Rows,x 3 _ ":Wide +6. ""Spacing x 2-i�- *1 2_ "Side Stoma x 2 = 12.00"Base Width
6. "l Stone Base,-*-20.E" Chamber Heigh - .0""Stoma Cover=2.7 1' Field Height
Chambers x 21.8 cf --t-1.00" Row Adjustment x TM 4 sf x 3 Rows 75.6 cf Chamber Storage
303,.2 cf Field-75.6 cf Chambers'22 w6 cf Stone x 4 .0%Voids 91.0 cf Stone Storage
Chamber Storage+Stoma Storage= 166.7cf 0.004 auf
Overall Storage Efficiency=55.10%
Overall System Size 91.33x .00"x 2.7
Chambers
1.2 cy Field
.4 cy Stone
liiiiiiiiiiiillllllllllllllll
d
Figure 3. Modeled Infiltration Chamber System Embedded in ,stone Field
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Stormwater Management Re port-36,4 Johnson Street
Pond 2P: Infullitration Chamber
Hydrolgraph
0.07 cfs EM inflow
—— — I -— ---- EJ oufflow
M Discarded
'U da
ow-A 9
1" /211 Primary
0.0175 ev
0.0 7- ------
0.065. A 0,0-af—
Ile
01.06.
0.055
0,05. I O Ell M c OM c i
40 0.045.
0 0.03 ifs
0.04 .........
0.035
0.03.
0.025-
0.02-
0.0 15.
01 0.00-efs
0
0 -4 8 10 '12 14, 16 '18 20 22 24 '26 28'' 30 32 34 36 38 40 42 44 46 48
Time (hours)
Figure 4. Infiltration Chamber Hydrograph shows all runoff infiltrated through subsurface
system
12)Drawdown Analysis (Time to Empty)
0 2-year storm: 6.5 minutes
0 1 0-year storm: 11.7 minutes
a 25-year storm: 15.4 minutes
0 1 00-year storm.: 21.9 minutes
V. OPERATION AND MAINTENANCNE PLAN
H. Slystern Components and Responsibilities
13),Ho�m,e own e,r Res pons ibi I' es:
a Routine inspection of roof gutters and downspouts
• Seasonal cleaning of debris from system inlets
• Annual inspection of pretreatment chamber
• Prompt repair of any system deficiencies
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Stormwater Management Report-364 Johnson Street
I Groundwater Recharge: All stormwater is returned to the groundwater system through
infiltration, maintaining natural hydrology.
VIL Recommendation
The proposed infiltration system exceeds typical stormwater management requiremen,ts 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
watershed and supports the Town's stormwater management objectives.
Analysis prepared using Hy dr C ADI software, following SCS TR-20 methodology
Prepared By.- John J McDonnell,PE,, PLS
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