HomeMy WebLinkAboutStormwater Report - 815 CHESTNUT STREET 7/14/1994 HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES
PROPOSED BUILDING ADDITION
July 14, 1994
As Prepared By
PORT ENGINEERING ASSOCIATES, INC
ONE HARRIS STREET
NEWBURYR ` 4F ss9. 01950
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PORT
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ENGINEERING
Civil Engineers& PAUL D. TURBIDE, PE/PLS
Land Survevurs PRESIDENT
One Harris Street
Newburvpurt,MA
01950
(508)-165-8594
HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES - FLAGSHIP DRIVE, NO® ANDOVER
INTRODUCTION
Port Engineering Associates, Inc. was retained by Watts
Industries to provide engineering consulting services in
conjunction with a project located on Flagship Drive in
North Andover, Ma. The project proposes the construction
of a new building addition to the existing Watts Indus-
tries R & D facility on Chestnut Street which will have
additional access from Flagship Drive.
The scope of services involved the completion of hydro-
logic storm runoff computations for the pre-development
and post-development sites, and the preliminary design of
a closed storm drainage system to be discharged directly
to the existing Flagship Drive municipal drainage system
with proper runoff mitigation being provided by a new on
site runoff detention pond to be developed near the
Flagship Drive entrance. The results of this study are
to be reviewed by the Town of North Andover municipal
boards as part of the North Andover Site Plan Review
Process.
In an effort to determine the changes to the drainage
patterns of surface water to the basin outlets for the
site, runoff computations have been made for the entire
site as it exists under present conditions, and similar
computations have been made for the site as it would
exist after construction is completed. The drainage
computations for the site were computed for storms fre-
quencies of 2, 10, and 100 year recurrence interval and
Type III 24 hr rainfall for the New England coastal area
as specified by the USDA-SCS. For the 100 year storm
calculations, a 24 hr rainfall of 7. 0 inches was used to
be in compliance with DEP regulations 310 CMR.
Runoff computations which were produced for inclusion in
this report were based upon methods developed by the U.S.
Dept. of Agriculture, Soil Conservation Services (S.C.S. )
in their publication, Technical Release # 20 (TR-20)
PORT "COMPUTER PROGRAM FOR PROJECT FORMULATION HYDROLOGY", 2nd
Edition (draft) , May 1983 .
INGINFIRINGFlood routing and hydrograph generation were developed
using a comprehensive computer hydrology program entitled
Civil Engineers& "HYDROCAD" , developed by Applied Microcomputer Systems
Land Surveyors Page Hill Road, Chocorua, New Hampshire 03817, which is
also based on these same SCS TR-20 methods.
One Harris Street
Newburyport,MA
01950
(508)465-8594
1
HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES - FLAGSHIP DRIVE, NO® ANDOVER
EXISTING DRAINAGE PATTERNS
The total site is divided into two drainage basins. One
drainage area (Subcatchment 1) encompasses the area of
proposed driveway and parking lot that will exit onto
Flagship Drive. The other drainage area (Subcatchment 3)
encompasses all of the existing improvements on the site
including the existing building roofs, the existing
driveways and parking lots, and the existing detention
pond. All soils at the site have hydrological soil
coefficients of "C".
Flagship Drive Basin (Subcatchment 1)
Preconstruction subcatchment 1 was modeled as 1.88 acres
of good grass cover, and 0. 05 acres of pavement with a
Time of Concentration of 4 . 6 minutes. As shown on the
enclosed sketches, preconstruction Subcatchment 1 has a
design point near existing drain manhole 5 located in
Flagship Drive.
Existing Detention Pond Area (Subcatchment 3)
As shown on the enclosed sketches, preconstruction condi-
tions were modeled as Subcatchment 3 and Pond 3 (the
existing on site detention pond) which mitigates runoff
from Subcatchment 3 including all of the improvements
that exist at this time including roofs, parking lots and
driveways. Subcatchment 3 was modeled as 2. 10 acres of
good grass, and 1.90 acres of pavement and roof.
PROPOSED DRAINAGE PATTERNS
Flagship Drive Basin (Subcatchment 2)
For Post-Development site conditions, runoff from the
existing parking lot to the rear of the existing building
located in Subcatchment 3 will be diverted from the
existing detention pond (3) to the proposed detention
PORT pond (1) located adjacent to the Flagship Drive entrance.
From this point, Pond 1 discharges into drain manhole 5.
Post construction Subcatchment 2 was modeled as 2. 5 acres
INGINIIHING
of good grass and 1.75 acres of pavement with a Time of
Concentration of 2.3 minutes. Pond 1 was designed using
Civil Engineers& three outlet control structures that will flow into
Land Surveyors proposed drain manhole 4 : a 7 11pipe at elev 264.0 ' , a 8"
One Harris Street pipe at elev 267.41 , and a 10" pipe at elev 270.01 .
Newburyport, MA
01950
(508)467-8591
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EXISTING DETENTION BASIN �
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HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES - FLAGSHIP DRIVE® NO® ANDOVER
Existing Detention Pond Area (Subcatchment 4)
As shown on the enclosed sketches, post-construction
conditions were modeled as Subcatchment 4 and Pond 4 .
Pond 4 is the existing detention basin with the existing
parking lot behind the building re-diverted to the pro-
posed detention basin at Flagship Drive.
Subcatchment 4 was modeled as 2 . 10 acres of good grass,
and 1. 16 acres of roof and pavement. The following table
is a summary of hydrologic runoff calculations:
The following tables summarize hydrologic runoff calcula-
tions:
CONDITION PEAK STORM FLOW (CFS)
100 YR 10 YR 2YR
PRECONSTRUCTION 9.7 5.4 2. 3
(SUBCATCHMENT 1)
POSTCONSTRUCTION 8. 5 4.0 1.7
(POND 1)
PRECONSTRUCTION 3. 0 3 .0 3 .0
(POND 3)
POSTCONSTRUCTION 3. 0 3 .0 2.7
(POND 4)
For more detailed drainage computation information, a
full copy of the runoff computations is Attached as
Appendix A.
PODT
Elk
it
ENGINEERING
Civil Engineers&
Land Surveyors
One Barris Street
Newburvport,MA
01950
(508)465-859-1
3
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� ,e04rou MAP
POND 1
OWL
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u CHMENT
POST CONSTRUCTION
FLAGSHIP DRIVE ARE
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MSTINC DETENTION BASIN � °�
HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES - FLAGSHIP DRIVE® NO® ANDOVER
STORM DRAINAGE SYSTEM DESIGN
In sizing the closed storm drain system for the site, the
surface inflow from each subcatchment contributary area
was computed using the Rational Method.
The pipes were designed to accommodate the cumulative
increment of the catch basin inlets, and have been sized
to accommodate the 10 year storm incident (i = 5.2 inches
per hour) .
All pipes are proposed to be high density polyethylene
plastic (HDPE) , except for the pipeline between proposed
drain manhole 4 and existing drain manhole 5. Because of
its location beneath Flagship Drive, this line is pro-
posed to be a 2411 reinforced concrete pipe. As per Town
standards, the minimum pipe size used is 12 t' , except for
outlet control structures. The minimum design velocity
has been kept at 2 feet per second for self pipe clean-
ing, and the maximum design velocity is 10 feet per
second. The results of the pipe sizing calculations are
shown in Appendix B.
DRAINAGE SUMMARY
Based upon the storm runoff computations (Appendix A) the
added pavement and roof surfaces will not significantly
alter the peak discharge rate of the site to Flagship
Drive drainage structures nor would the existing or
proposed ponding areas at any of the drainage system
basin inlets be overtaxed for the 100 year storm inci-
dent.
RUNOFF MITIGATION MEASURES
It is impossible to avoid changes in chemical constitu-
P 1) T of surface runoff during the construction phase of
oft I any project. Erosion and siltation of surface waters is
an unavoidable aspect of any construction project. For
INGINERNG the Watts Industries project, siltation is expected to be
a problem only during the construction period as the
surface water intrusions will diminish greatly as the
Civil Engineers& areas proposed for development will be totally stabilized
Land Surveyors by pavement or building construction and re-vegetation of
the site. In an effort to control the effects of con-
One Harris Sheet struction erosion and siltation, the following measures
Newburvport,MA
oi950 are suggested:
(508).165-859,1
4
HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES ® FLAGSHIP DRIVE, NO® ANDOVER
SILTATION CONTROL MEASURES
1. All excavation shall be kept to the minimum that is
required for the completion of the proposed work and
it shall be scheduled as efficiently as possible so
as to minimize the time which exposed areas remain
without vegetative cover.
All debris , fill and excavated material shall be
stockpiled beyond the limits of any vegetated wetland
and at a location to prevent surface runoff sediment
from entering wetland resource areas. At no time
shall any debris or other material be buried or
disposed of within any area marked on the plans as
wetland, other than that fill which is allowed by any
valid order of conditions for the project that may be
issued by the Conservation Commission or as outlined
in final plans.
2. After excavated materials are stockpiled, they shall
be surrounded by siltation control fencing to trap
silts before they can leave the stockpile.
3. Any cross drains shall have hay bale silt filters
staked across the entrance and exit of the pipe.
4 . Any proposed drainage swales, either temporary or
permanent, to be constructed at the site shall be
provided with hay bale filters staked across the
swale at regular intervals of 50 ft. along the swale.
5. Prior to any earth moving activities, all proposed
work which takes place within 100 feet bordering any
on or off site vegetated wetland areas shall be
buffered from the wetland resource with a double
row siltation filter consisting of a double row of
staked hay bales, placed end to end, or a single row
of geotextile fabric siltation fence along with a
single row of hay bales. The barriers shall be
P IDT placed along the entire interface between the
OR I proposed work and the resource area. The erosion
control measures shall be viewed by the local
conservation commission prior to the commencement of
INGINIIHING
Civil Engineers&
Land Surveyors
One Harris Street
Newburyport, MA
01950
(508)465-8594
5
HYDROLOGIC STORM RUNOFF COMPUTATIONS
AND STORM DRAINAGE SYSTEM DESIGN
WATTS INDUSTRIES - FLAGSHIP DRIVE® NO® ANDOVER
SILTATION CONTROL MEASURES
(continued)
6. All hay bale or geotextile fabric silt filters shall
be staked in place prior to the commencement of any
work in the area protected by the filters, and they
shall remain in place and shall be maintained and
replaced as required until a stabilizing cover of
vegetation has been established, or a determination
has been made by the local conservation commission
that the control measures are no longer necessary.
7. Equipment, material, and fuel storage and refueling
operations shall be situated in an upland area at a
horizontal distance greater that 100 feet from the
established boundaries of any vegetated wetlands.
8. After all new vegetation has been successfully
established and all site improvements have been
approved and accepted by the local Conservation
Commission, remove the siltation barriers and any
accumulated silt material for disposal at a location
to be approved by the conservation commission.
9. Proposed Fill Specifications
Any borrow fill used at the site shall be clean
granular material with no more than 20 % passing a No
200 mesh sieve, and shall be free from organic
matter, large stones, masonry, stumps, frozen clumps
of earth, wood, tree branches, and construction
waste material. All fill shall be properly placed
and mechanically or hydraulically compacted in 6"
lifts or allowed to settle for a period of 6 months.
The major contributor to post-construction siltation will
be 'the dirt and sand fraction of street and parking lot
litter and oils and grease that will be washed off the
paved site areas by rainfall runoff. The majority of the
it i PO silt sediment and parking lot litter will be removed by
the sumps in the catch basin structures, thus, leaving
�NGI�EEGI�G only the soluble dust fraction of the litter and the oil
and grease as a potential degrader of the surface water.
Any remaining pollution from suspended solids and oil and
Civil Engineers& grease would be attenuated by the vegetation that will
Land Surveyors develop in the runoff mitigation detention basins.
One Harris Street
Newburyport,MA
01950
(508)465-8594
6
APPENDIX A
HYDROLOGIC RUNOFF COMPUTATIONS
PDT
ofti
INGINIEHING
Civil Engineers&
Lund Surveyors
One Harris Street
Newburvport,MA
01950
(508)-165-8594
Data for P1700 WATTS 100 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
WATERSHED ROUTING
pjQ�Co�tST�uGT10�l 1D®57~Co1�ST�U WKI
1 2
1
0 SUBCATCHMENT F—] REACH APOND LINK
Data for P1700 WATTS 100 YEAR STORM TOTAL BUILDOUT #2
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 APplied Microcomputer Systems
WATERSHED ROUTING
3 4
3 /4\
0 SUBCATCHMENT ❑ REACH APOND LINK
SECTION I
PRE-DEVELOPMENT STORM RUNOFF
POIDIII
ft
INGIREHING
Civil Engineers&
Land Surveyors
One Harris Street
Newhuryport,MA
01950
(508)465-8594
PRE-DEVELOPMENT STORM RUNOFF
2 YEAR STORM FREQUENCY
PDT
ORI
tKINEEGING
Civil Engineers&
Land Surveyors
One Harris Street
Newburvport,MA
01950
(508) 165-8594
Data for P1700 WATTS 2 YEAR STORM 7 Jul 94
Prepared by PORT ENGINEERING ASSOC. INC.
HydroCAD 3 t0 000482 (c) 1986 1993 Applied Microcomputer Systems
SUBCATCHMENT 1 PRECONSTRUCTION
ACRES CN
1.88 74 GOOD GRASS C SCS TR-20 METHOD
.05 98 PAVEMENT TYPE III 24-HOUR
1.93 75 RAINFALL= 3.1 IN
PEAK= 2.3 CFS @ 12.06 HRS
VOLUME= .12 AF
Method Comment Tr (min)
SHALLOW CONCENTRATED/UPLAND FLOW PRECONSTRUCTION 4.6
Short Grass Pasture Kv=7 L=5001 s=.066 1/1 V=1.8 fps
SUBCATCHMENT 1 RUNOFF
PRECONSTRUCTION
2 . 2
2 . 0 AREA= 1 . 93 AC
1 . 8 Tc= 4 . 6 MIN
CN= 75
r,
1 . 6
o 1 . 4 SCS TR-20 METHOD
1 . 2 TYPE III 24-HOUR
RAINFALL= 3 . 1 IN
3 1 . 8
PEAK= 2 . 3 CFS
LL 6 @ 12 . 06 HRS
4 UOLUME= . 12 AF
. 2
8 . am Ln m LO m m Lo m
R1 cv M rY) d- d- Ln
TIME (hours )
Data for P1700 WATTS 2 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 3 EXISTING CONDITIONS
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.90 98 PAVT AND ROOF TYPE III 24-HOUR
4.00 85 RAINFALL= 3.1 IN
PEAK= 7.0 CFS @ 12.11 HRS
VOLUME= .41 AF
Method Comment Tc (min)
DIRECT ENTRY FROM 27 MAR 90 CALCULATIONS 9.0
SUBCATCHMENT 3 RUNOFF
EXISTING CONDITIONS
7 . 0
6 . 5 AREA= 4 AC
6 . 0 Tc- 9 MIN
5 . 5
5 . 0 CN= 85
4 . 5 SCS TR-20 METHOD
4 . 0 TYPE III 24-HOUR
3 . 5 -.
3 3 . 0 RAINFALL= 3 . 1 IN
0 2 . 5
2 . 0 PEAK-- 7 . 0 CFS
1 . 5 @ 12 . 11 HRS
1 . 0 VOLUME= . 41 AF
. 5
e . Bm Ln m n M n CS) Ln m
f V N �''1 m v T Ln
TIME (hours )
PRE-DEVELOPMENT STORM RUNOFF
10 YEAR STORM FREQUENCY
Po
ENGI�EEGI�G
Civil Engineers&
Land Surveyors
One Harris Street
Newburyport,MA
01950
(508) I65-8591
Data for P1700 WATTS 10 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HYdroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer SYStems
SUBCATCHMENT 1 PRECONSTRUCTION
ACRES CN
1.88 74 GOOD GRASS C SCS TR-20 METHOD
.05 98 PAVEMENT TYPE III 24-HOUR
1.93 75 RAINFALL= 4.8 IN
PEAK= 5.4 CFS a 12.05 HRS
VOLUME= .27 AF
Method Comment Tc (min)
SHALLOW CONCENTRATED/UPLAND FLOW PRECONSTRUCTION 4.6
Short Grass Pasture Kv=7 L=5001 s=.066 1/1 V=1.8 fps
SUBCATCHMENT 1 RUNOFF
PRECONSTRUCTION
5 . 0
AREA- 1 . 93 AC
4 . 5 Tc- 4 . 6 MIN
4 . 0 CN= 75
3 . 5
to
(4- 3 . 0 SCS TR-20 METHOD
TYPE III 24-HOUR
2 . 5 RAINFALL- 4 . 8 IN
a 2 . 0
1 . 5 PEAK= 5 . 4 CFS
1 . 0 @ 12 . 05 HRS
UOLUME= . 27 AF
5
0 . am Ln ® D m LO m Ln m
m m IT d- Ln
TIME (hour5 )
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Apptied Microcomputer Systems
SUBCATCHMENT 3 EXISTING CONDITIONS
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.90 98 PAVT AND ROOF TYPE III 24-HOUR
4.00 85 RAINFALL= 4.8 IN
PEAK= 13.2 CFS a 12.11 HRS
VOLUME= .76 AF
Method Comment Tc (min)
DIRECT ENTRY FROM 27 MAR 90 CALCULATIONS 9.0
SUBCATCHMENT 3 RUNOFF
EXISTING CONDITIONS
13
12 AREA= 4 AC
11 Tc= 9 MIN
10 CN- 85
r, 9
to 4 8 SCS TR-20 METHOD
TYPE III 24—HOUR
6 RAINFALL— 4 . 8 IN
0 5
4 PEAK- 13 . 2 CFS
3 0 12 . 11 HRS
2 UOLUME- . 76 AF
1
C
CD IS) LO CS3 LO cs) LO m
TIME (hours )
PRE-DEVELOPMENT STORM RUNOFF
100 YEAR STORM FREQUENCY
PORT
INGINIIHING
Civil Engineers&
Land Surveyors
One Harris Street
Newburyport,MA
01950
(508)465-8594
Data for P1700 WATTS 100 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Ac�lied MicrocomDuter SYstems
SUBCATCHMENT 1 PRECONSTRUCTION
ACRES CN
1.88 74 GOOD GRASS C SCS TR-20 METHOD
.05 98 PAVEMENT TYPE III 24-HOUR
1.93 75 RAINFALL= 7.0 IN
PEAK= 9.7 CFS a 12.05 HRS
VOLUME= .48 AF
Method Comment Tc (min)
SHALLOW CONCENTRATED/UPLAND FLOW PRECONSTRUCTION 4.6
Short Grass Pasture Kv=7 L=5001 s=.066 1/1 V=1.8 fps
SUBCATCHMENT 1 RUNOFF
PRECONSTRUCTION
9 . 5
g : � AREA= 1 . 93 AC
8 . 0 - c- 4 . 6 MIN
7 . 0 CN= 75
6 . 5
u 5. 5 SCS TR-20 METHOD
, ' -5 -HOUR TYPE III 24-HOUR
0 RAINFALL= 7 . 0 IN
o 3 . 5
3 . 0 PEAK- 9 . 7 CFS
2 . 0 @ 12 . 05 HRS
1 . � UOLUME= . 46 AF
. 5
0 . 0m Ln CS) n m n ® U-) m
T (V CV m m IT d- In
TIME (hours )
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 3 EXISTING CONDITIONS
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.90 98 PAVT AND ROOF TYPE III 24-HOUR
4.00 85 RAINFALL= 7.0 IN
PEAK= 21.4 CFS a 12.10 HRS
VOLUME= 1.23 AF
Method Comment Tc (min)
DIRECT ENTRY FROM 27 MAR 90 CALCULATIONS 9.0
SUBCATCHMENT 3 RUNOFF
EXISTING CONDITIONS
20
18 AREA= 4 AC
Tc— 9 MIN
16 CN= 85
,--� 14
to
12 SCS TR-20 METHOD
10 TYPE III 24—HOUR
RAINFALL= 7 . 0 IN
0 8
6 PEAK- 21 . 4 CFS
4 @ 12 . 1 HRS
UOLUME— 1 . 23 OF
am in m m
cv cv m d- d- to
TIME (hours )
SECTION II
POST-DEVELOPMENT STORM RUNOFF
PORT
tKINEEGING
Civil Engineers&
Land Surveyors
One Harris Street
Newburvport, !CIA
01950
(508),165-859,1
POST-DEVELOPMENT STORM RUNOFF
2 YEAR STORM FREQUENCY
PORT
ENGINEERING
Civil Engineers&
Land Surveyors
One Harris Street
Yewburyport,MA
01950
(508)465-8594
Data for P1700 WATTS 2 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3 10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 2 POST CONSTRUCTION
ACRES CN
1.75 98 PAVEMENT & ROOF SCS TR-20 METHOD
2.50 74 GOOD GRASS C TYPE III 24-HOUR
4.25 84 RAINFALL= 3.1 IN
PEAK= 8.8 CFS a 12.02 HRS
VOLUME= .41 AF
Method Comment Tc (min)
SHALLOW CONCENTRATED/UPLAND FLOW POSTCONSTRUCTION: GRASS 1.7
Short Grass Pasture Kv=7 L=2001 s=.075 1/1 V=1.92 fps
CIRCULAR CHANNEL POST CONSTRUCTION .6
12" Diameter a=.79 sq-ft Pw=3.11 r=.251
s=.05 '/' n=.015 V=8.79 fps L=300' Capacity=6.9 cfs
Total Length= 500 ft Total Tc= 2.3
SUBCATCHMENT 2 RUNOFF
POST CONSTRUCTION
8 . 5
8 . 0 AREA- 4 . 25 AC
7 . 5
7 . 0 Tc= 2 . 3 MIN
6 . 5 CN- 84
r, 6 . 0
5 . 0 SCS TR-20 METHOD
L) 4 . 5 TYPE III 24-HOUR
4 . 0 RAINFALL- 3 . 1 IN
3 . 5
0 3 . 0
2 . 5 PEAK- 8 . 8 CFS
2 . 0 @ 12 . 02 HRS
1 . 5 UOLUME= . 41 OF
1 . e
. 5
® . am Lo m m
TIME (hours )
Data for P1700 WATTS 2 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 1 FLAGSHIP DRIVE
STARTING ELEV= 264.0 FT
FLOOD ELEV= 273.0 FT 2 x FINER ROUTING
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK ELEVATION= 266.8 FT
264.0 670 0 0 PEAK STORAGE = 7469 CF
265.0 1460 1065 1065 Qin = 8.8 CFS is 12.02 HRS
272.0 5500 24360 25425 Qout= 1.7 CFS 8 12.45 HRS
273.0 5700 5600 31025 ATTEN=. 81 % LAG= 26.0 MIN
IN/OUT= .41 / .40 AF
INVERT (FT) OUTLET DEVICES
264.0 7" CULVERT
n=.015 L=40' S=.021/' Ke=.5 Cc=.9 Cd=.6
272.0 401 BROAD-CRESTED RECTANGULAR WEIR
Q=C L H^1.5 C=2, 0, 0, 0, 0, 0, 0, 0
267.4 8" CULVERT
n=.011 L=401 S=.011/' Ke=.5 Cc=.9 Cd=.6
270.0 10" CULVERT
n=.011 L=40' S=.021/' Ke=.5 Cc=.9 Cd=.6
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
264.0 0.0 0.0 .1 .3 .4 .6 .7 .8 .9 1.0
265.0 1.1 1.1 1.2 1.2 1.2 1.3 1.3 1.3 1.4 1.4
266.0 1.4 1.5 1.5 1.5 1.6 1.6 1.6 1.7 1.7 1.7
267.0 1.7 1.8 1.8 1.8 1.8 1.9 2.0 2.2 2.4 2.6
268.0 2.9 3.0 3.2 3.3 3.5 3.6 3.7 3.8 3.9 4.0
269.0 4.1 4.2 4.2 4.3 4.4 4.5 4.6 4.7 4.7 4.8
270.0 4.9 5.0 5.2 5.4 5.7 6.0 6.4 6.7 7.1 7.3
271.0 7.5 7.8 8.0 8.2 8.4 8.6 8.8 8.9 9.1 9.3
272.0 9.4 12.1 16.9 23.0 30.3 38.5 47.5 57.3 67.8 79.0
273.0 90.9
Data for P1700 WATTS 2 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 1 INFLOW & OUTFLOW
FLAGSHIP DRIUE
8 . 5
8 . 0 - STOR- IND METHOD
7 . 5
7 . 0 PEAK ELEU= 266 . 8 FT
6 . 5 PEAK STOR= 7469 CF
6 . 0
i 5 . 5
t+- 5 . 0 - Q i n= 8 . 8 C F S
u 4 . 5 Qout= 1 . 7 CFS
4 . 0 LAG- 26 MIN
3 . 5
0 3 . 0
2 . 5
2 . 0
1 . 5
5
e . 0m Ln csD LO IS3 LO CS3 LO m
c� N rn m IT cr- Ln
TIME (hours )
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 4 POST CONSTRUCTION
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.16 98 ROOF AND PAVT TYPE III 24-HOUR
3.26 83 RAINFALL= 7.0 IN
PEAK= 20.0 CFS a 12.04 HRS
VOLUME= .97 AF
Method Comment Tc (min)
DIRECT ENTRY 4.0
SUBCATCHMENT 4 RUNOFF
POST CONSTRUCTION
20
AREA= 3 . 26 AC
17 - Tc— 4 MIN
14 CN= 83
3
to 2
(-l- SCS TR-20 METHOD
TYPE III 24-HOUR
RAINFALL= 7 . 0 IN
a
-� PEAK- 20 . 0 CFS
4 @ 12 . 04 HRS
VOLUME= . 97 OF
1
Om m m
TIME Chour57
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 EXISTING POND PRECONSTRUCTION
STARTING ELEV= 278.3 FT
FLOOD ELEV= 282.5 FT 2 x FINER ROUTING
ELEVATION CUM.STOR STOR-IND METHOD
(FT) (AF) PEAK ELEVATION= 281.5 FT
278.3 0.00 PEAK STORAGE = .61 AF
280.0 .30 Gin = 21.4 CFS a 12.10 HRS
282.0 .70 Gout= 3.0 CFS a 11.88 HRS
282.5 1.20 ATTEN= 86 % LAG= 0.0 MIN
IN/OUT= 1.23 / .89 AF
INVERT (FT) OUTLET DEVICES
0.0 CATCHBASIN GRATE ELEV(FT) DISCH(CFS)
278.3 0.0
278.5 2.0
278.8 3.0
282.5 3.0
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
278.3 ( 0.0 1.0 2.0 2.3 2.7 3.0 3.0 3.0 3.0 3.0
279.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
280.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
281.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
282.3 3.0 3.0 3.0
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 INFLOW & OUTFLOW
EXISTING POND PRECONSTRUCTION
23 - STOR- IND METHOD
18 - PEAK ELEU- 281 . 5 FT
16 - PEAK STOR- . 61 AF
14 -
u12 - Qln-- 21 . 4 CFS
Qout-- 3 . 0 CFS
LAG- 0 MIN
0 8 -
4 - ....................................................... ...........................................................................................................................
2 - ..........
CD Ln CSD L0 CS3 LO 0 in CD
N m m "T Ln
TIME (hours )
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 4 EXISTING POND POST CONSTRUCTION
STARTING ELEV= 278.3 FT
FLOOD ELEV= 282.5 FT 2 x FINER ROUTING
ELEVATION CUM.STOR STOR-IND METHOD
(FT) (AF) PEAK ELEVATION= 280.7 FT
278.3 0.00 PEAK STORAGE = .44 AF
280.0 .30 Oin = 20.0 CFS a 12.04 HRS
282.0 .70 Cout= 3.0 CFS is 11.88 HRS
282.5 1.20 ATTEN= 85 % LAG= 0.0 MIN
IN/OUT= .97 / .88 AF
INVERT (FT) OUTLET DEVICES
0.0 CATCHBASIN GRATE ELEV(FT) DISCH(CFS)
278.3 0.0
278.5 2.0
278.8 3.0
282.5 3.0
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
278.3 ( 0.0 1.0 2.0 2.3 2.7 3.0 3.0 3.0 3.0 3.0
279.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
280.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
281.3 ( 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
282.3 3.0 3.0 3.0
Data for P1700 WATTS 100 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer systems
POND 4 INFLOW & OUTFLOW
EXISTING POND POST CONSTRUCTION
20
19 -
18 - STOR- IND METHOD
17 -
16 - PEAK ELEU- 280 . 7 FT
' 5 - PEAK STOR- . 44 AF
' 4 -
' 3 -
' 2 -
c+- Qln-- 20 . 0 CFS
U
Qout- 3 . 0 CFS
LAG- 0 MIN
0
4 -
3 - ..............................................................................................................................I.....................................................
2 -
1
a
CD Ln CD Ln CD Ln ED Ln
N N m m v "T U)
TIME (hours )
i
POST-DEVELOPMENT STORM RUNOFF
10 YEAR STORM FREQUENCY
PORT
INGINIIHING
Civil Engineers&
Land Surveyors
One Harris Street
Newburvport,MA
01950
(508)465-8594
Data for P1700 WATTS 10 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 2 POST CONSTRUCTION
ACRES CN
1.75 98 PAVEMENT & ROOF SCS TR-20 METHOD
2.50 74 GOOD GRASS C TYPE III 24-HOUR
4.25 84 RAINFALL= 4.8 IN
PEAK= 16.9 CFS a 12.02 HRS
VOLUME= .79 AF
Method Comment Tc (min)
SHALLOW CONCENTRATED/UPLAND FLOW POSTCONSTRUCTION: GRASS 1.7
Short Grass Pasture Kv=7 L=2001 s=.075 1/1 V=1.92 fps
CIRCULAR CHANNEL POST CONSTRUCTION .6
12" Diameter a=.79 sq-ft Pw=3.1' r=.251
s=.05 1/1 n=.015 V=8.79 fps L=3001 Capacity=6.9 cfs
Total Length= 500 ft Total Tc= 2.3
SUBCATCHMENT 2 RUNOFF
POST CONSTRUCTION
16
14 AREA= 4 . 25 AC
13 Tc- 2 . 0 MIN
12 CN- 84
11
4- 18 SCS TR-20 METHOD
U TYPE III 24-HOUR
RAINFALL- 4 . 8 IN
0 6
-� 5 PEAK- 16 . 9 CFS
�. 4
3 @ 12 . 02 HRS
UOLUME- . 79 AF
2
1
am CS) LO CS] LO m
TIME (hours )
Data for P1700 WATTS 10 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 1 FLAGSHIP DRIVE
STARTING ELEV= 264.0 FT
FLOOD ELEV= 273.0 FT 2 x FINER ROUTING
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK ELEVATION= 269.0 FT
264.0 670 0 0 PEAK STORAGE = 14881 CF
265.0 1460 1065 1065 Qin = 16.9 CFS is 12.02 HRS
272.0 5500 24360 25425 Qout= 4.0 CFS @ 12.39 HRS
273.0 5700 5600 31025 ATTEN=. 76 % LAG= 22.1 MIN
IN/OUT= .79 / .67 AF
_INVERT (FT) OUTLET DEVICES
264.0 7" CULVERT
n=.015 L=401 S=.021/1 Ke=.5 Cc=.9 Cd=.6
272.0 40, BROAD-CRESTED RECTANGULAR WEIR
Q=C L H^1.5 C=2, 0, 0, 0, 0, 0, 0, 0
267.4 8" CULVERT
n=.011 L=401 S=.011/1 Ke=.5 Cc=.9 Cd=.6
270.0 10" CULVERT
n=.011 L=401 S=.021/' Ke=.5 Cc=.9 Cd=.6
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
264.0 0.0 0.0 .1 .3 .4 .6 .7 .8 .9 1.0
265.0 1.1 1.1 1.2 1.2 1.2 1.3 1.3 1.3 1.4 1.4
266.0 1.4 1.5 1.5 1.5 1.6 1.6 1.6 1.7 1.7 1.7
267.0 1.7 1.8 1.8 1.8 1.8 1.9 2.0 2.2 2.4 2.6
268.0 2.9 3.0 3.2 3.3 3.5 3.6 3.7 3.8 3.9 4.0
269.0 4.1 4.2 4.2 4.3 4.4 4.5 4.6 4.7 4.7 4.8
270.0 ( 4.9 5.0 5.2 5.4 5.7 6.0 6.4 6.7 7.1 7.3
271.0 7.5 7.8 8.0 8.2 8.4 8.6 8.8 8.9 9.1 9.3
272.0 9.4 12.1 16.9 23.0 30.3 38.5 47.5 57.3 67.8 79.0
273.0 90.9
Data for P1700 WATTS 10 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 1 INFLOW & OUTFLOW
FLAGSHIP DRIUE
16
14 - STOR- IND METHOD
PEAK ELEU= 269 FT
13 -
12 PEAK STOR- 14881 CF
11
u
`- 10 Q i n= 1 6 . 9 CFS
9 -
8 Qout= 4 . 0 CFS
LAG- 22 . 1 MIN
0 6
5
4
3 -
2
�m Ln CSD LO 0 n CS3 Ln m
TIME (hours )
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microc2MMter Systems
SUBCATCHMENT 4 POST CONSTRUCTION
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.16 98 ROOF AND PAVT TYPE III 24-HOUR
3.26 83 RAINFALL= 4.8 IN
PEAK= 12.1 CFS a1 12.04 HRS
VOLUME= .59 AF
Method Comment Tc (min)
DIRECT ENTRY 4.0
SUBCATCHMENT 4 RUNOFF
POST CONSTRUCTION
12
11 AREA= 3 . 26 AC
10 Tc= 4 MIN
9 CN- 83
0 SCS TR-20 METHOD
6 TYPE III 24-HOUR
3 5 RAINFALL-- 4 . 8 IN
4 PEAK- 12 . 1 CFS
3 @ 12 . 04 HRS
2 VOLUME= . 59 OF
1
am Ln m m Ln m Ln m
N (V m v d Ln
TIME (hours )
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 EXISTING POND PRECONSTRUCTION
STARTING ELEV= 278.3 FT
FLOOD ELEV= 282.5 FT 2 x FINER ROUTING
ELEVATION CUM.STOR STOR-IND METHOD
(FT) (AF) PEAK ELEVATION= 280.0 FT
278.3 0.00 PEAK STORAGE = .30 AF
280.0 .30 Oin = 13.2 CFS @ 12.11 HRS
282.0 .70 pout= 3.0 CFS is 12.04 HRS
282.5 1.20 ATTEN= 77 % LAG= 0.0 MIN
IN/OUT= .76 / .75 AF
INVERT (FT) OUTLET DEVICES
0.0 CATCHBASIN GRATE ELEV(FT) DISCH(CFS)
278.3 0.0
278.5 2.0
278.8 3.0
282.5 3.0
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
278.3 0.0 1.0 2.0 2.3 2.7 3.0 3.0 3.0 3.0 3.0
279.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
280.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
281.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
282.3 3.0 3.0 3.0
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 INFLOW & OUTFLOW
EXISTING POND PRECONSTRUCTION
13
12 STOR- IND METHOD
11 PEAK ELEU- 280 FT
10 PEAK STOR= . 30 AF
9
LO 4 O Gin= 13 . 2 CFS
u
Gout= 3 . 0 CFS
6 LAG= 0 MIN
o 5
� 4
3 ;. ........_.._......................_..........._.......__........._....._.......................
2
aCD m m
tW N m m d- IT Ln
TIME Chour57
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 4 EXISTING POND POST CONSTRUCTION
STARTING ELEV= 278.3 FT
FLOOD ELEV= 282.5 FT 2 x FINER ROUTING
ELEVATION CUM.STOR STOR-IND METHOD
(FT) (AF) PEAK ELEVATION= 279.5 FT
278.3 0.00 PEAK STORAGE = .20 AF
280.0 .30 Qin = 12.1 CFS a 12.04 HRS
282.0 .70 Qout= 3.0 CFS @ 12.04 HRS
282.5 1.20 ATTEN= 75 % LAG= 0.0 MIN
IN/OUT= .59 / .58 AF
INVERT (FT) OUTLET DEVICES
0.0 CATCHBASIN GRATE ELEV(FT) DISCH(CFS)
278.3 0.0
278.5 2.0
278.8 3.0
282.5 3.0
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
278.3 0.0 1.0 2.0 2.3 2.7 3.0 3.0 3.0 3.0 3.0
279.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
280.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
281.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
282.3 3.0 3.0 3.0
Data for P1700 WATTS 10 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 4 INFLOW & OUTFLOW
EXISTING POND POST CONSTRUCTION
12
11 STOR- IND METHOD
10 PEAK ELEU= 279 . 5 FT
9 PEAK STOR-- . 20 AF
n 8
� 7 Gin= 12 . 1 CFS
u
6 Gout= 3 . 0 CFS
LAG- 0 MIN
0 4
3 .............. .......................................
2
1
0m ............ Ln m U-) m Ln M Ln m
m m v v m
TIME (hours )
POST-DEVELOPMENT STORM RUNOFF
300 YEAR STORM FREQUENCY
PORT
ENGINEEGING
:ivil Engineers&
Land Surveyors
hie Harris Street
Vewburvport,MA
01950
(508)465-8594
Data for P1700 WATTS 100 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 2 POST CONSTRUCTION
ACRES CN
1.75 98 PAVEMENT & ROOF SCS TR-20 METHOD
2.50 74 GOOD GRASS C TYPE III 24-HOUR
4.25 84 RAINFALL= 7.0 IN
PEAK= 27.7 CFS a 12.01 HRS
VOLUME= 1.28 AF
Method Comment Tc (min)
SHALLOW CONCENTRATED/UPLAND FLOW POSTCONSTRUCTION: GRASS 1.7
Short Grass Pasture Kv=7 L=200' s=.075 1/1 V=1.92 fps
CIRCULAR CHANNEL POST CONSTRUCTION .6
12" Diameter a=.79 sq-ft Pw=3.11 r=.251
s=.05 '/' n=.015 V=8.79 fps L=300' Capacity=6.9 cfs
Total Length= 500 ft Total Tc= 2.3
SUBCATCHMENT 2 RUNOFF
POST CONSTRUCTION
26
24 AREA- 4 . 25 AC
22 Tc= 2 . 3 MIN
20 CN= 84
,-�
18 -
C�- 16 SCS TR-20 METHOD
U 14 TYPE III 24-HOUR
12 RAINFALL= 7 . 0 IN
0 10
-� 8 PEAK= 27 . 7 CFS
6 @ 12 . 01 HRS
4 UOLUME- 1 . 28 AF
2
TIME (hours )
Data for P1700 WATTS 100 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 ApRtied Microcomputer Systems
POND 1 FLAGSHIP DRIVE
STARTING ELEV= 264.0 FT
FLOOD ELEV= 273.0 FT 2 x FINER ROUTING
ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD
(FT) (SF) (CF) (CF) PEAK ELEVATION= 271.4 FT
264.0 670 0 0 PEAK STORAGE = 23510 CF
265.0 1460 1065 1065 Qin = 27.7 CFS is 12.01 HRS
272.0 5500 24360 25425 Qout= 8.5 CFS @ 12.29 HRS
273.0 5700 5600 31025 ATTEN= 69 % LAG= 16.8 MIN
IN/OUT= 1.28 / 1.09 AF
INVERT (FT) OUTLET DEVICES
264.0 7" CULVERT
n=.015 L=401 S=.021/1 Ke=.5 Cc=.9 Cd=.6
272.0 401 BROAD-CRESTED RECTANGULAR WEIR
Q=C L H^1.5 C=2, 0, 0, 0, 0, 0, 0, 0
267.4 8° CULVERT
n=.011 L=401 S=.011/' Ke=.5 Cc=.9 Cd=.6
270.0 10" CULVERT
n=.011 L=401 S=.021/' Ke=.5 Cc=.9 Cd=.6
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
264.0 0.0 0.0 .1 .3 .4 .6 .7 .8 .9 1.0
265.0 1.1 1.1 1.2 1.2 1.2 1.3 1.3 1.3 1.4 1.4
266.0 1.4 1.5 1.5 1.5 1.6 1.6 1.6 1.7 1.7 1.7
267.0 1.7 1.8 1.8 1.8 1.8 1.9 2.0 2.2 2.4 2.6
268.0 2.9 3.0 3.2 3.3 3.5 3.6 3.7 3.8 3.9 4.0
269.0 4.1 4.2 4.2 4.3 4.4 4.5 4.6 4.7 4.7 4.8
270.0 4.9 5.0 5.2 5.4 5.7 6.0 6.4 6.7 7.1 7.3
271.0 7.5 7.8 8.0 8.2 8.4 8.6 8.8 8.9 9.1 9.3
272.0 9.4 12.1 16.9 23.0 30.3 38.5 47.5 57.3 67.8 79.0
273.0 90.9
Data for P1700 WATTS 100 YEAR STORM
Prepared by PORT ENGINEERING ASSOC. INC. 7 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 1 INFLOW & OUTFLOW
FLAGSHIP DRIUE
26
24 STOR- IND METHOD
22 PEAK ELEU= 271 . 4 FT
20 PEAK STOR= 25510 CF
18
+ 16 Qin= 27 . 7 CFS
u 14 Qout= 8 . 5 CFS
3 12 LAG= 16 . 8 MIN
0 10
� S ;
6
4 ,_
2 '` _.. ........_...... ...............
csD Ln CS) LO csl LO CD Lo CD
TIME (hours )
Data for P1700 WATTS 2 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
SUBCATCHMENT 4 POST CONSTRUCTION
ACRES CN
2.10 74 GRASS GOOD C SCS TR-20 METHOD
1.16 98 ROOF AND PAVT TYPE III 24-HOUR
3.26 83 RAINFALL= 3.1 IN
PEAK= 6.2 CFS a 12.04 HRS
VOLUME= .30 AF
Method Comment Tc (min)
DIRECT ENTRY 4.0
SUBCATCHMENT 4 RUNOFF
POST CONSTRUCTION
6 . 0
5 . 5 AREA- 3 . 26 AC
5 . 0 Tc- 4 MIN
4 . 5 CN-- 83
4 . 0
3 . 5 SCS TR-20 METHOD
,u 3 0 TYPE III 24-HOUR
2 . 5 RAINFALL- 3 . 1 IN
2 . 0 PEAK= 6 . 2 CFS
1 . 5 @ 12 . 04 HRS
1 . 0 UOLUME-- . 30 AF
5
8 . Bm Ln m LO m n m Ltd m
TIME (hours )
Data for P1700 WATTS 2 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 EXISTING POND PRECONSTRUCTION
STARTING ELEV= 278.3 FT
FLOOD ELEV= 282.5 FT 2 x FINER ROUTING
ELEVATION CUM.STOR STOR-IND METHOD
(FT) (AF) PEAK ELEVATION= 278.9 FT
278.3 0.00 PEAK STORAGE = .11 AF
280.0 .30 Qin = 7.0 CFS a 12.11 HRS
282.0 .70 Qout= 3.0 CFS a 12.20 HRS
282.5 1.20 ATTEN= 57 % LAG= 5.4 MIN
IN/OUT= .41 / .40 AF
INVERT (FT) OUTLET DEVICES
0.0 CATCHBASIN GRATE ELEV(FT) DISCH(CFS)
278.3 0.0
278.5 2.0
278.8 3.0
282.5 3.0
TOTAL DISCHARGE vs ELEVATION
FEET 0.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
278.3 0.0 1.0 2.0 2.3 2.7 3.0 3.0 3.0 3.0 3.0
279.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
280.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
281.3 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
282.3 3.0 3.0 3.0
Data for P1700 WATTS 2 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 3 INFLOW & OUTFLOW
EXISTING POND PRECONSTRUCTION
7 . 0
6 . 5 STOR- IND METHOD
6 . 0 PEAK ELEU= 278 . 9 FT
5 . 5 - PEAK STOR= . 11 AF
5 . 0
LO
4 . 5
4 0 Q i n= 7 . 0 CFS
3 5 Qout= 3 . 0 CFS
3 . 0 LAG= 5 . 4 MIN
0 2 . 5
1 . 5
5 ..........
to m m in m m
TIME (hour5 )
Data for P1700 WATTS 2 YEAR STORM EAST AREA
Prepared by PORT ENGINEERING ASSOC. INC. 8 Jul 94
HydroCAD 3.10 000482 (c) 1986-1993 Applied Microcomputer Systems
POND 4 INFLOW & OUTFLOW
EXISTING POND POST CONSTRUCTION
6 . 0
5 . 5 STOR- IND METHOD
5 , 0 PEAK ELEU= 275 . 7 FT
4 . 5 PEAK STOR- . 07 AF
LO 4 . ®
S 5 Q i n= 6 . 2 CFS
U 3 . 0 Qout- 2 . 7 CFS
LAG= 11 . 2 MIN
2 . 5 -
° 2 . 0
1 . 5 -
1 . 0
. 5
0 . em...................Ln m
T n1 cv m m d- d- LSD
TIME (hours )
APPENDIX B
STORM DRAINAGE SYSTEM DESIGN
PoDrr
ILI
iNGINEEGING
,ivil Engineers&
Land Surveyors
)ne Harris Street
Vewburyport,MA
01950
(508)465-8594
STORM DRAINAGE PIPE CULVERT CAPACITY ANALYSIS
(FROM MANNING'S FORMULA)
PODT
iti
c�lGI�IEEGI�IG
;ivil Engineers&
Land Surveyors
hie Harris Street
lewburvport,MA
01950
(508)465-8594
�EL ?7?0•
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NV.27(200'
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