20140994 Ver 1_Stormwater Info_20140919

40 9 94',
-STOR,MWATE,R [MPkTANALYSIS, FIaNALDESIGN. OF',,
S'TO R�M�WATE R' �MA�NAG,E�M E NT ��FAC <I LI�TI,E`S: I=�I
'DESIGN O F- CU LVER °CROSS1�N G_5r
o- -WESTON TOW,N40MES
_lVl I,H- 14000
CARY NORTH' CARO`L'ANA'.
} s s£ DATE:_SEPTEMB,ER 2014
_ -�� - ; _ _ ° " . ; , _ �' ' �_. . •- � ";� - � - - PREPARED-FOR:
MCI HOMES OF RALEIGH, LLC_ z , _
- -1511, SUNDAY= DRIVE;, SUITE' 100 _
RA'LEIGH ;'NORTW CAROLINA�27607 ��
''McADAMS-"
Raleigh /Durham • 2905 Meridian Parkway si Durham, NC 27713
Charlotte ® 1,1,301, .Carmel Commor ,-131 4i SuiteJ11 ■ Charlotte, NC 28226
McAdamsCo.com
Designing Tomorrow's I kis"tructurem &tommunitiesi - °

The.John R McAdams
Company, Inc
Raleigh / Durham, NC
2905'Mendian`Parkway
Durham, North Carolina 27713
(919) 361 -5000
Charlotte, NC
11301 Carmel Commons Blvd,
Suite 111
Charlotte North Carolina 28226
(704)527 -0800
McADAMS
MEMORANDUM
ANDUM
Date: .Tune 26, 2014
To: Mr. Jeremy Finch, PE
From: George Buchholz, PJ 1M, �PWS and Stewart Pickens
Re: Weston Parkway Townhomes— Phase I
Seasonal High Water Table Determination
MIH -14000
A field investigation was conducted on June 9, 2014 at the location of a
proposed stormwater management pond and stormwater wetland associated
with the Weston Parkway Townhomes- Phase 1 project, located off of Weston
Parkway 0.01 miles west of Sheldon Drive in Cary, North Carolina (Wake
County PIN Number: 0755502824), within the western section of the Wake
County. A soil boring was established within the proposed stormwater
management pond and stormwater wetland to determine the approximate
seasonal high water table depth from the soil surface. Below is a brief
summary of the soil type and the approximate seasonal high water table depth.
Proposed Stormwater Management Pond:
Soil Type.
Pinkston sandy loam: This soils 1s on side slopes in the uplands. Infiltration is
good, and surface runoff is very rapid. Because of the steepness of the slopes
and the shallowness of the subsoil, this soil should,not be cleared.
General `Soil Borina'Observations:
In general, the profile of the soil borings graded from yellowish brown with
no mottles, to brownish yellow consisting of a minimal amount of yellow
mottles.
'Soil Boring Results:
The soil boring was established at an approximate existing elevation of 354
feet. It is anticipated that the approximate seasonal high water table depth
from the soil surface is greater than 48 inches; or length of soil auger.
Below is a photograph of the soil boring.
McAdamsCocorn Designing Tomorrow's Infrastructure & Commurfities

J McADAMS
Mr. Jeremy Finch, PE
Weston Parkway Townhomes; SHWT
June 26, 2014
Page 2 of 3
Photo 1. Soil boring for the stormwater management pond is located at an
approximate existing elevation of 354 feet. It is anticipated that the
approximate seasonal high water table depth from the soil surface is greater
than 48 inches below the soil surface.
Proposed Stormwater Wetland:
Soil Type:
Pinkston sandy loam: This soils is on side slopes in the uplands. Infiltration is
good, and surface runoff is very rapid. Because of the steepness of the slopes
and the shallowness of the subsoil, this soil should not be cleared.
General Soil Boring Observations:
In general, the profile of the soil borings graded from very pale brown with
yellow mottling, to brownish yellow soils consisting very pale brown mottles;
ending with brownish yellow soils consisting of minimal light gray mottles.
MIH -14000

'J McADAMS
Mr. Jeremy Finch, PE
Weston Parkway Townhomes; SHWT
June 26, 2014
Page 3 of 3
Soil Boring Results:
The soil boring was established at an approximate existing elevation of 370
feet. It is anticipated that the approximate seasonal high water table depth
from the soil surface is greater than 48 inches; or length of soil auger.
Below is a photograph of the soil boring.
Photo 2. Soil boring for the stormwater wetland is located at an approximate
existing elevation of 370 feet. It is anticipated that the approximate seasonal
high water table depth from the soil surface is greater than 48 inches below
the soil surface.
MIH -14000

WESTON TOWNHOMES
CARY, NORTH CAROLINA
STORMWATER IMPACT ANALYSIS, FINAL DESIGN OF
STO'RMWATER MANAGEMENT FACILITIES, & FINAL
DESIGN OF CULVERT CROSSINGS
PRoi -Ec T NUMBER:
DESIGNED BY:
DATE:
DEVISED:
a[
MIH- 14000
JON ALDRIDGE, PE
JOSH SHINN, EI
JUNE 2014
SEPTEMBER 2014
CADAMS
2905 MERIDIAN PARKWAY
DURHAM, NORTH CAROLINA 27713
NC LIC. # C -0293

WE'STON TOWNHOMES
Stormwater Impact Analysis, Final Design of Stormwater ManagementFacilities, & Final
Design of Culvert Crossings
Proiect Descrintion and Summa
The project will be located on approximately 25 -acres of land and is located off of
'Weston Parkway within the Weston PDD in the 'Town of Cary. The proposed
development will consist of approximately 100 residential townhome units and the
associated infrastructure:
The, proposed development is, located within the Neuse River Basin and will be subject to
,the stormwater management requirements set forth in the Town of Cary Land
Development Ordinance (LDO). Stormwater management on this site shall address two
primary issues: (1) peak discharge rates and' (2) water quality management.
4. 7.3.3 Peak Runoff Control
There shall be no net increase in peak stormwater run -off flow leaving a development from
pre- development conditions for the one (1) -year design storm New developments are
required to minimize damage to subject streams caused by storm flows
(A) Calculation of'Peak Flow
Acceptable methodologies for computing pre- and post - development conditions for the
one (1) =year design storm Include
The Rational Method (used whenthe drainage area is two hundred (200) acres or
less)
2 The Peak Discharge Method as described in ,USDA Technical "Release Number
55 (TR -55) (drainage area is 2, 000 acres orless)
3 The Putnam Method (drainage area is greater than 2, 000 acres)
USGS Regression Equations, where applicable
The same method must be used `for both the pre- and post- development conditions
(B) Exceptions to Peak Flow Control
Developments with less than ten (10) percent net increase in peak flow of the one (1)-
year design storm are not required to ,control peak, flow from the site However, if the
net increase in peak flow from the new development is greater than ten (10) percent,
the entire net increase from pre - development one (1) -year design storm ,peak flow
must be controlled
(C) Downstream Impact-Analysis
A Downstream Impact Analysis, shall be ,supplied for all new proposed developments
that require site/ subdivision plan approval Site %,subdivision plans which are not
subject to the stormwater management regulations are exempt from the Downstream
Impact Analysis requirements
Each development plan shall
1 Calculate the pre- and post- development discharges for each discharge point
from the site

If the post- development calculated discharge is equal to or less than a ,ten (10)
percent increase for the two (2), five (5) and ten (10) -year peak discharges ,at
each discharge point, then no further analysis is needed
If the post - development peak discharge at any discharge point Is greater than
forty (40) cubic feet per second (cfs) then funkier analysis is needed and shall be
treated as in ,Section 7 3 3(C)(2) below In lieu of the ten (10) percent increase in
off -site run -off the engineer shall limit run -off to the extent that downstream
conveyance systems can accommodate the run -off increase without causing any
rp operty damage _
2 If the post - development discharge for the two (2), five (5) and ten (10) -year
discharges at any discharge point rs greater than ten (1b) percent of the pre -
development discharge, then additional analysis is needed for that discharge
point
Identify the point downstream where the impacts become less than a ten (10)
percent increase
Analyze the impacts of the increase on the stormwater conveyance system(s)
(pipes, 'culverts, ditches, swa'les, etc) between the discharge point and the point
where the impact becomes less than ten (10) percent
Identify_ negative impacts on all improvements (businesses, homes, lawns,
streets, pipes, ditches, swales, etc) through the use of inlet and outlet control
calculations and backwater analyses for culverts, channel capacity' calculations
for swales and ditches
Construct on -site detention, off -site improvements, or make a payment -in -lieu for
inadequate downstream conveyance systems to fully mitigate all Impacts created
by the proposed development Requests fortpayment -m -lieu must be approved by
Town Council
Payment-In-lieu shall be based on the sealed, approved estimate of one hundred
(100) percent of the costs to construct the appropnate mitigation facility Those
costs shall include design, land costs, construction, and a ,f/fty (50)- year�cycle of
maintenance The chosen facility has to be a facility that is capable of obtaining
all permits required,by all appropriate state and federal agencies
3 If on -site detention is the chosen mitigation, limit the peak discharge at all
discharge points to what would be expected from an R -40 zoning condition for the
two (2), five (5) and ten (10) -year storm events, not to exceed a ten (10) percent
increase over,the pre - development conditions
2. 7.3.2 Nutrient Reduction Requirements
(D) Nitrogen and Phosphorous Export Standards
Any,activity that Is required to submit a nitrogen control plan in the Neuse River
Basin must achieve a nitrogen export of less than or equal to three and six- tenths
(3 6) pounds per acre per year Any activity that is required to submit a nitrogen
and phosphorus control plan in the Cape Fear Raver Basin must achieve an
export rate of less than or equal to two and two- tenths (2 2) pounds per acre per
year of nitrogen and eighty -two hundredths ,(0,82) pounds per acre per year of
phosphorus in the Upper New Hope and four and four - tenths (4 4) pounds per
acre per year of nitrogen and seventy -eight hundredths (0 78) pounds per acre
2

per year in the Lower New Hope If the development contributes greater than
,three.and six- tenths (3 6) pounds per acre per year of nitrogen in the Neuse River
Basin, greater than two and two - tenths (2 2) pounds per acre per year of nitrogen
and /or eighty -two hundredths (0 82) pounds per acre per year of phosphorus in
the Upper New Hope, or greater than four and four - tenths (4 4) pounds per acre
per,year of nitrogen and /or seventy -eight hundredths (0 78) pounds per acre per
year of phosphorus in the Lower New Hope, then the table below explains the
options available depending whether the development is residential or non-
residential
2 Notwithstanding the foregoing, in the Cape Fear River Basin, redevelopment that
would replace or expand existing structures or improvements and would result in
a net increase in built -upon area shall have the option of either meeting the
loading standards identified in section 7 3 2 (D)(1) or meeting a loading rate that
achieves the following nutrient loads compared to the existing development in
the Upper New Hope'Watershed,, thirty -five (05) percent reduction in nitrogen ,and
five (5) percent reduction in phosphorus, and in the Lower New Hope Watershed,
no increase for nitrogen or phosphorus
3 Development subject to this section 7 3 shall attain a maximum nitrogen loading
rate on -site of six (6) pounds per acre per year for single family, detached and
_duplex residential development and ten (10) pounds per acre per year for
other development, including mulb- family residential, commercial and Industrial
and shall meet any requirements for engineered stormwater controls otherwise
imposed by the LDO An applicant may achieve the additional reductions in
,nitrogen and phosphorus loading required by this section by making offset
payments to the North Carolina Ecosystem Enhancement Program contingent
upon the acceptance of payments by that program An applicant may propose
other offset measures; ,including' providing his or her own offsite offset or utilizing
a private seller All offset measures permitted by this ordinance shall meet the
requirements of 15A NCAC 02B 0273 (2) through (4) and 15A NCAC 02B 0240
TABLE 7.3 -1: NITROGEN /PHOSPHORUS EXPORT REDUCTION OPTIONS
Residential /Multifamily Residential
Commercial /Industrial /Institutional /Local
Government
'If the computed export is less than 6 0 Ibs /ac /yr,
If'the computed export is less than 10 0 Ibs /ac /yr,
.then the owner may either
then the owner may either
Install BMPs to remove enough nitrogen to bring
Install BMPs to remove enough nitrogen to bring
,the development down to 3 6 Ibs /ac /yr in the
thedevelopment down to 3 6' Ibs /ac /yr in the
" Neuse River Basin Install BMPs to bring the
Neuse River Basin Install BMPs to bring the
nitrogen down to 2 2 Ibs /ac /yr and phosphorus
nitrogen down to 2 2 Ibs /ac /yr and "phosphorus to
to 0 82 Ibs /ac /yr in the Upper New Hope and the
0 82 Ibs /ac /yr in the Upper New Hope and the
nitrogen down to 4 4�lbs /ac/yr °and the
nitrogen down to 4 4ilbs /ac /yr and the phosphorus
phosphorus to 0 78'Ibs /ac /yr Lower New Hope
to 0 78'lbs /ac /yr Lower New,Hope in the Cape
in the Cape Fear River Basin
Fear River Basin
Pay a one -time offset payment to bring the
Pay a one -time offset payment to bring the
nitrogen down to the 3 6 Ibs /ac /yr in the Neuse
nitrogen down to the 3 6 Ibs /ac /yr in the Neuse
River Basin Pay a one -time offset payment to
River Basin ;Pay a one -time offset payment to

bring the nitrogen down to 2 2 Ibs /ac /yr and
phosphorus to,0' 82 Ibs /ac /yr in the Upper New
Hope and the nitrogen down to 4.4 Ibs /ac /yr and
the phosphorus to 0 78 Ibs /ac /yr Lower New
Hope in the Cape Fear River Basin
bring the nitrogen down to 2 2 Ibs /ac /yr and
phosphorus to 0 82 Ibs /ac /yr in the- Upper'New
Hope and the nitrogen down to 4 4 Ibs /ac /yr and
the phosphorus to 0 78' Ibs /ac /yr Lower New Hope
in the Cape Fear River Basin
Do a combination of BMPs and offset payment
Do ,a combination of BMPs and offset payment to
to achieve a 3 6 Ibs /ac /yr export in -the Neuse,
,achieve a 3 6 Ibs /ac /yr export,in the Neuse, 2 2
2 2 Ibs /ac /yrnitrogen and 0 82 Ibs /ac /yr
Ibs /ac /yr nitrogen and 0 82 Ibs /ac /yr phosphorus in
phosphorus iri the Upper New Hope and 4=4
the Upper New Hope,and 4 4,Ibs /ac /yr nitrogen
Ibs /ac /yr nitrogen and 0 78 Ibs /ac /yr phosphorus
and 0 78 Ibs /ac /yr phosphorus in the Lower New
in the Lower New Hope
Hope
If,the computed nitrogen export is greater than
If the;computed nitrogen export is greater,than
6 0 Ibs /ac /yr, the owner must use on -site BMPs
10 0 Ibs /ac /yr, the owner must, use on -site BMPs
to bring the development's export down to 6 0
to bring the development's export down to 10 0
Ibs /ac /yr Then, the owner'may'use one.of the
Ibs /ac /yr,' Then, the owner may use one of the
three options above to achieve the reduction
three options above to,achieve the reduction
between 6 0 and 3 6 Ib /ac /yr in the Neuse River
between 10 0 and 3 6 Ib /ac%yr in the'Neuse River
Basin, 2 2 Ibs /ac /yr in the Upper New Hope or
Basin, 2.2 Ibs /ac /yr in the Upper New Hope or 4 4
4 4 Ibs /ac /yr'in the Lower New Hope of the
Ibs /ac /yr in the Lower New Hope of'the Cape Fear
Cape Fear River Basin
River Basin
Once it has been determined that an offset payment Is forthcoming, the owner,
shall-furnish the Town, with evidence that the ,payment for the reductions In
nitrogen and /or phosphorus has been made prior to the Town's Issuance of a
grading, permit
4 The nitrogen and phosphorus export standards in this ordinance are supplemental
to, not replacements for, stormwater standards otherwise required by federal,
state or local law, Including without limitation any npanan buffer requirements
,applicable to the,location of the development This Includes, without limitation, the
riparian buffer protection requirements of 15A NCAC 28 0267 and 0268
3. 4.4.6 Watershed Protection Overlay
(D) OvervieW of High Density and Low Density Development Options
There are two (2) development options In the Watershed Protection Overlay, a Low
Density Option and a High Density Option, each with different provisions related to
either the Swift Creek Watershed or the Jordan Lake Watershed as well as to sub-
areas within either watershed
1 Impervious Surfaces
The maximum allowable amount of impervious surface within a
proposed development Is limited based upon the Low or High Density Option, and
differs from Watershed ,to watershed as depicted in Table, 4 4 -5
2 Calculation of jmpervious Surfaces
Calculation of impervious surface area shall Include the pavement area of all
existing and proposed Internal u1 h and private streets, one -half (112) of the
width of roadways on the perimeter of the project, driveways, rooftops, parking
lots, patios, and all other Impervious surfaces For the purpose of calculating the
impervious surface of roadways on the perimeter of a project, the ultimate
pavement cross section of the roadway based on the Comprehensive
4

Transportation Plan and any sidewalk(s) or greenway(s) along the perimeter
roadway will be included in the calculation. For purposes of calculating the
percentage of impervious area coverage, the total project area shall be regarded
as the actual area of the rp opert y plus the area within theriahts -of -way of the
internal and perimeter streets included in the calculation of impervious area.
3. Residential Density
in addition to limitations on the amount of impervious surface, the Low and High
Density Development Options limit the gross residential densities of projects
based upon the watershed where they are proposed, with higher densities
allowed under the High Density Option as depicted in Table 4.4 -5.
4. Runoff Control
Engineered stormwater controls intended to contain the runoff from the first one
(1) inch of rainfall are required in any development utilizing the High Density
Option in either watershed.
(F) Limitations on Impervious Surface Area and Density
2. High Density Option
High Density Option development proposals may be approved, provided that
the development applications are consistent with the following standards:
TABLE 4.4 -5: MAXIMUM IMPERVIOUS SURFACE LIMITS: HIGH DENSITY OPTION
Suburban -New
Urban -New
Existing Urban
Residential
Non - Residential
Residential
Non - Residential
Residential and
Non -
Residential
Swift Creek Watershed
Maximum
Two and one-
The impervious
Six (6.0) dwelling
The impervious
The impervious
Impervious
half
area allowed
units per acre
area allowed
area allowed
Surface Limits
(2.5)dwelling
under the
east of Holly
under the
under the
unitsper acre
underlying
Springs Rd.,
underlying
underlying
not to exceed
general
greater than six
general
general
thirty (30)
use zoning
(6.0) units per
use zoning
use zoning
percentimpervio
districts, not to
acre west of
districts, not to
districts, not to
us surface area.
exceed thirty (30)
Holly Springs
exceed seventy
exceed seventy
percent.
Rd., not to
(70) percent.
(70) percent.
exceed seventy
(70)
percentimperviou
s surface area.
Sewer
Required
impoundment
Required to contain and treat the runoff from the first one (1) inch of rainfall and to achieve

and
a minimum of eighty -five (85) percent average annual removal for Total Suspended Solids
Maintenance
(TSS) Public or private maintenance [Other BMPs besides' impoundments maybe
available, consult the Division of Water Quality's State Design Manual for Best Management
'Practices Related to Stonrwater'Control
Jordan Lake Watershed
Where new development exceeds the Low Density Option'Standards above, engineered stormwater controls
shall be used to control and treat runoff from the first inch of rainfall and to achieve a minimum of eighty-five
(85) percent average annual removal for'Total Suspended Solids (TSS) Development shall not exceed
seventy (70) percent impervious surface area
Jordan Lake Watershed Critical Area
Where proposed development exceeds the Low Density Option Standards above, engineered stormwater
controls are required to control and treat runoff from the first inch of rainfall and to achieve a minimum of
eighty -five (85) percent average annual removal for Total Suspended Solids (TSS) Development shall not
exceed fifty (50) percent impervious surface area
This report contains calculations detailing the expected stormwater impacts -as a result of
a portion of the proposed development, along with final design calculations for the
stormwater management facilities that will be used to alleviate those impacts and meet
the requirements of the Town of Cary. Please refer to the appropriate sections of this
report for additional information.
Calculation Methodoloey
© Rainfall data for the Cary, NC region is derived from NOAA Atlas 14. This data
was used to generate a depth - duration- frequency (DDF) table describing rainfall
depth versus time for varying return periods. These rainfall depths were then
input into the meteorological model within Pond'Pack V8i for peak flow, rate
calculations. Please reference the rainfall data section within this report for
additional information.
The on -site topography used in the analysis ist from a field survey performed by
The John R. McAdams Company, Inc. The offsite topography used in the analysis
is from `Town of Cary GIS data. Please refer to the pre- and ,post- development
watershed maps for additional information.
Using maps contained within the Wake County Soil Survey, the on- and off -site
soils were determined to be from hydrologic soil groups (HSG) `13% `C', and `D'
soils. Since the method chosen t& compute both pre- and post - development peak
flow rates and runoff, volumes is dependent upon the soil type,* care was taken
when selecting the appropriate Soil Conservation Service Curve Number (SCS
CN).
Within each sub - basin, an approximate °proportion of each soil group was
determined using NRCS Soil Survey Maps. Once an approximate proportion was
determined, a composite `SCS' CN was computed for each cover condition.
a A composite SCS Curve Number was calculated for both the pre- and post -
development condition using SCS curve numbers and land cover conditions.

Land cover conditions for the pre- development condition were taken from a field
survey by The John R. McAdams Company, -Inc. Land cover conditions for the
post - development condition were taken from the proposed development plan.
Please refer to the pre- and post - development watershed maps for additional
information.
• The times of concentration are calculated using the SCS TR -55 Segmental
Approach. The Tc flow paths are divided into three segments: overland flow,
concentrated flow, and channel flow. The travel time is then computed for each
segment, from which the, overall time of concentration is determined by taking the
sum of each segmental time.
• Reach lengths are modeled, as appropriate, for several sub - basins within the
PondPack model assuming a time translation only, which is based on the
computed travel time through each appropriate; downstream channel segment.
Please refer to pre= and post - development hydrologic inputs for additional
information.
• The post - development time of concentration to the proposed stormwater
management facility is assumed to be 5' minutes. This provides ,a conservative
estimate of facility size for design purposes.
• PondPack Version V8i, by Bentley Systems, Inc., was used in determining the
pre- & post- development peak flow rates for the 1 -, `2 -, 5 -, 10 -, and 100 -year
storm events, as well as routing calculations for the proposed stormwater
management facility.
• Nitrogen calculations were prepared for the project using Neuse watershed
calculation methods.
• A riprap� basin is provided at the principal, spillway outlets to prevent erosion and
scour in these areas. The basin will be constructed using rip rap, underlain with a
Woven geotexti'le filter fabric. The filter fabric is used to minimize the loss of soil -
particles beneath the basin.
• To guard against dam failure- due to the buoyant forces caused by the riser - barrel
outlet structures, anti - flotation calculations were performed for each facility.
These calculations consisted of determining the amount of concrete that is
required to anchor the outlet structure down and prevent it from floating. In
addition, the pre -cast riser sections are to be tied together to prevent separation
caused by buoyant forces.
Culvert Calculation MethodoloQy
The entrance culvert crossing was designed in HY -8 using 25 year peak flow rates
taken from Junction #2 of the PbndPack model. In order to accurately depict the
tailwater conditions for both,25 year and 100 year storms, an "as- built" model of
the existing two 60" pipes ctossirig under Weston,Parkway was performed in Hy-
8 and the calculated headwater was used as the tailwater conditions for the
designed crossing. For'this crossing an embedment depth of 12" was assumed and
resulted in two 54" Concrete pipes passing the 25 year storm at 1.2 Hw /D. Peak
flow rates from the 100, year storm were also ,routed to ensure the proposed road
would not be overtopped.
The rear culvert crossing -was also designed in HY -8 using 25 year peak flow rates
taken from Junction 45 of the PondPack model. This culvert was designed to be

laid on grade with a 20% embedment depth. Results of the model showed one 24"
concrete pipe met the 1.2 Hw /D along with road overtopping requirements.
• Outlet protection for each of the culvert crossing was designed in HY -8, using the
l0 `year peak flow rates from each of the respective Junctions from PondPack.
Streambed level tip -rap basins were the preferred exit scour treatment.
Discussion of Results
Peak Runoff Control Requirements
The proposed project will result in a significant increase in peak.flow rates. To mitigate
this impact, the proposed facility has been sized such that post - development peak flow
rate
s are no greater than pre - development levels in the 1 -, 2 -, 5 -, and 10 -year storm
events.
Pollutant and Nutrient Control Requirements
This report contains pre -- and post - development nitrogen calculations for the development
with offset estimated payment calculations.
Conclusion
If the development on this tract is built as proposed within this report, then the
requirements set forth in Section, 7.3 and 4.4.6 of the Town of'�Cary Land Development
Ordinance will be met with the proposed stormwater management facilities: However,
modifications to the proposed development may require that this analysis be revised.
Some modifications that would require this analysis,to be revised include:
1. The proposed site impervious surface exceeds the amount accounted for in this
report.
2. The post- development watershed breaks change significantly from those used to
prepare this report.
The above modifications may result in the assumptions within this report becoming
invalid. The computations within this report will need to be revisited if any of the above
conditions become apparent as development of the proposed site moves forward.

1
SUMMARY OF RESULTS
2
MISCELANEOUS SITE INFORMATION
3
WATERSHED SOILS INFORMATION
4
PRECIPITATION DATA
PRE - DEVELOPMENT HYDROLOGIC
5
CALCULATIONS
POST - DEVELOPMENT HYDROLOGIC
6
CALCULATIONS
DESIGN OF STORMWATER
7
MANAGEMENT FACILITY #1
DESIGN OF STORMWATER
8
MANAGEMENT FACILITY #2
9
NUTRIENT LOADING CALCULATIONS
10
CULVERT DESIGN CALCULATIONS

SUMMARY OF RESULTS
WESTON TOWNHOMES_
MIH -14000

WESTON TOWNHOMES SUMMARY'OF RESULTS C GEORGE; El, PLS
MlH -14000 1 9/10/2014
POINT OF ANALYSIS41
Return Period
Pre -Dev
[cfs]
Post -Dev
[cfs]
% Increase
%]
1 -Year
94
94
0%
2 -Year
142
140
-1%
5 -Year
207
204
_1%
10 -Year
1 261
260
1 0%
JUNCTION #2
Return Period
Pre-Dev
[cfs]
Post -Dev
[cfs]
% Increase
[ %]
1 -Year,
56
57
2%
2 -Year
81
81
0%
5 -Year
112
_ 112
0%
10 -Year
139
138
-1%
JUNCTION #3
Return Period
Pre-Div
[cfs]
Post -Dev
[cfs]
% Increase
[ %]
1 -Year'
38
38
0%
2 -Year
55 _
55
0%
5 -Year
76
76
0%
10 -Year
1 93
93
1 0%
JUNCTION44
Return Period
Pre-Dev
[cfs]
'Post -Dev
[cfs]
% Increase
[ %]
1 -Year
29
28
-30/.
2 -Year
46
44
4%
5 -Year
70
67
4%
10 -Year
91
86
1 -5%
JUNCTION #5
Return Period'
Pre-Dev
[cfs]
Post -Dev
[cfs]
% Increase
[ %]
1 -Year
3
3
0%
2 -Year
4
5
25%
5 -Year
7
8
14%
10 -Year 1
9
10
I 1 %
JUNCTION #6
Return ^Period
Pre-Dev
[cfs]
Post -Dev
[cfs]
% Increase
[ %]
1 -Year
19
19
0%
2 -Year
29
29
0%
5 -Year
43
43
0%
10 -Year
55
55
1 0%

WESTON TOWNHOMES SUMMARY OF RESULTS C GEORGE „EI, PLS
MIH -14000 9/10/2014
Design Drainage Area =
7,07
ac
Design Impervious Area =
401
ac
Impervious =
568%
34824
Top of Dam =
35050
ft
NWSE =
34600
ft.
Average Depth =
329
ft
Surface Area at NWSE =
10,118
sf
Required Surface,Area at NWSE _-
9,805
sf
Siphon Diameter =
2000
in
Siphon, Elevation =
34600
ft
Secondary Onfice =
(2) - 2 -5' Weir
3620
Secondary Onfice Elevation,=
34820
ft
Risef -Size =
5'x 5'
Riser Crest =
34900
ft
Barrel Diameter =
36
in
# of Barrels =
1
Invert In =
34350
ft
Invert Out =
34300
ft
Length =
43
ft,
Slope =
00116
ft/ft
STORMWAIER_ Mt1NAGTMENTgFACH—A-T—VA"EAM—Wal
JILL, r
Return Period
Inflow
[cfs]
Outflow
[cfs]
Max. WSE
[ft]
Freeboard
[ft]
I -Year
1951
_ 035
34824
226
2 -Year
2542
1 37
34839
211
5 -Year
3208
575
34873
177
10 -Year
36'94
875
348,92
158
25 -Year
4264
1920
34920
130
100-Year
'50 19
3620
34944
1 06

WESTON TOWNHOMES SUMMARYOF RESULTS C .GEORGE „EI, PLS
MIH -14000 1 9/10/2014
STORMWATER-. MANAGEMENT�FACII :PIi]'=- `.�2'�SUMMARYk _
Design Drainage Area =
245
ac
Design Impervious Area=
159
ac
% Impervious =
647%,
# of Barrels =
Top of Dam =
368`00
ft
NWSE =
363 50
ft
WQ Volume Elevation=
364'33
ft
Siphon Diameter =
1 250
in
Siphon Elevation =
36350
ft
Secondary Onfice Diameter =
20
in
Secondary Orifice Elevation =
36450
ft
Riser Size =
4'x 4'
Outflow
f cfs]
Riser Crest =
36660
ft
Barrel Diameter =
24
in
# of Barrels =
l
979
Invert in =
36250
ft
InverhOut =
36200
ft
Length,=
39
ft
Slope =
0 0128
ft/ft'
Return Period
Inflow
[cfs]
Outflow
f cfs]
Max. WSE
[ft]
Freeboard
[ft]
I Year
7 71
01-2
36506
294
2 -Year
979
0 16
36549
2`51
5-Year
1205
0'19
366 10
1 90
10 =Year
1368
027
1 36660
140
25 -Year
15'58
193
36671
1 29
100 -Year
1808
5 13
36682
1 18

MISCELLANEOUS SITE INFORMATION
WESTON TOWNHOMES
MIH- 14000

;V ,
Al �
54 � a 1L .
t
w
N
A
0 150 300
1 inch = 300 feet
J_
SITE
WESTON TOWNHOMES
SITE AERIAL MAP
6 fleet PROJECT #: MIH -14000
CARY, NORTH CAROLINA
0
so
7;
"
=+�tidf ii
� ;911Information and Anafysiy, N
�C
! I
lufl
McADaMs

I
T
.0.
�h`CC�
F Pr, 07, q
1�101
t�, 214 1 rill- Ik I
i (IM? � J 5
o4
0
-W
RN,
fillip V\ -t7 �P,'
fit, �'
1���1"L . � ; �cr:� �l
-- Wif 4� 4;
7
w loffis
t
ON TOVVNHC
1 'r^M^ RA AM
4 ®r-1.
0,
im I . id
o:;--- — � VON.
4f
44
par.
NI Lim, N s 7 tiles

NEUSE RIVER BASIN
Name of Stream Subbasin Stream Index Number Map Number Class
Chavis Branch
Cherry Branch
Cherrytree Branch
Chunky Pipe Creek
Clarks Branch (Ketchum Pond)
Clayhill Branch
Clayroot Swamp
Clubfoot Creek
Coffee Creek
Coffee Creek
Coles Branch
Contentnea Cr (Buckhorn Reservoir)
Contentnea Creek
Contentnea Creek
Contentnea Creek (Wiggins Mill Reservoir)
Cooper Branch
Coot Creek
Core Creek
Core Sound
Courts Creek (Coaches Creek)
Cow Branch
Cow Branch
Cow Gallus Creek
Cox Creek
Coxes Creek
'rabtree Creek
Crabtree Creek
Crabtree Creek (Crabtree Lake)
Creeping Swamp
Crooked Creek
Crooked Run
Crooked Run
Cub Creek
Cullie Creek
Cypress Branch
Cypress Creek
Cypress Creek
Daileys Creek
Dam Creek
Daniels Branch
Dawson Creek
Dawson Creek
Deep Bend
Deep Bottom Branch
Deep Branch
Deep Branch
Deep Creek
Deep Gully
Deep Gut
Deep Oak Gut
Deep Run
;eep Run
NEU02
27- 34 -8 -1
NEU10
27 -119
NEUll
27- 101- 5 -1 -0.3
NEU01
27 -9 -1
NEU05
27 -80 -4
NEU11
27- 101 -28
NEU09
27 -97 -5
NEU10
27 -123
NEU10
27- 135 -13
NEU10
27- 141 -3 -2
NEU02
27 -33 -3
NEU07
27- 86 -(1)
NEU07
27- 86 -(4.5)
NEU07
27- 86 -(7)
NEU07
27- 86 -(5.8)
NEU02
27 -43 -13
NEU13
27- 152 -10
NEU08
27 -90
NEU14
27 -149
NEU10
27 -127
NEU03
27- 43 -15 -14
NEU07
27- 86 -14 -6
NEU13
27- 150- 26 -2 -2
NEU13
27- 150 -28 -5
NEU05
27 -70
NEU01
27 -2 -6 -1
NEU02
27- 33 -(10)
NEU02
27- 33 -(3.5)
NEU09
27- 97 -5 -3
NEU01
27 -2 -18
NEU11
27- 101 -18
NEU10
27 -108 -1
NEU01
27 -2 -20
NEU10
27- 128 -6 -1
NEU11
27- 101 -5 -4
NEU11
27 -101 -8
NEU10
27- 107 -10
NEU05
27 -71 -1
NEU10
27 -110
NEU10
27- 112 -6 -1
NEU10
27- 125 -(1)
NEU10
27- 125 -(6)
NEU14
27 -148 -4
NEUll
27- 101 -15 -5
NEU08
27- 98 -2.1
NEU10
27 -115 -2
NEU01
27 -3 -4
NEU11
27- 101 -32
NEU10
27 -137 -3
NEU13
27- 150- 26 -2 -1
NEU05
27 -80 -1
NEU10
27 -106 -6
D24SW9
C;NSW
H31NE5
SA;HQW,NSW
G28SW4
C;Sw,NSW
C23SE8
WS- IV;NSW
G28NE4
C;Sw,NSW
G30SWB
C;Sw,NSW
F30NW1
C;Sw,NSW
H31SE3
SA;HQW,NSW
H32NE5
SA;HQW,NSW
G32SW3
SA;HQW,NSW
D23SE5
C;NSW
E26NE4
WS -V;NSW
E26NE5
WS- IV;NSW
E27NW5
C;Sw,NSW
E27NW1
WS- IV;NSW,CA
E25SW5
C;NSW
G32NE3
SA;HQW,NSW
G29NW6
C;Sw,NSW
H33NE8
SA;ORW,NSW
H32NW4
SA;HQW,NSW
E24SE6
C;NSW
F27NE2
C;Sw,NSW
G32NE8
SA;HQW,NSW
G32NE4
SA;HQW,NSW
G27NE1
C;NSW
C22SW9
WS- II;HQW,NSW
D24SW1
C;NSW
D23SE5
B;NSW
F30NW5
C;Sw,NSW
C23SW5
WS- IV;NSW
G29SE7
C;Sw,NSW
H31NW1
SC;Sw,NSW
C23SW6
WS- IV;NSW
H32NW6
SA;HQW,NSW
G28SE4
C;Sw,NSW
H29NW1
C;Sw,NSW
G31SW3
SC;Sw,NSW
G27NE5
WS- IV;NSW
H31NW2
SC;Sw,NSW
H31NW5
SC;Sw,NSW
G31SE9
SC;NSW
G31SE9
SA;HQW,NSW
H33NE1
SA;HQW,NSW
G29NW9
C;Sw,NSW
G30NWB
C;Sw,NSW
H31SE1
SC;Sw,NSW
B23SW3
WS- III;ORW,NSW
G30SW5
C;Sw,NSW
H33NW1
SA;HQW,NSW
G32NE8
SA;HQW,NSW
G28NW7
C;Sw,NSW
G31NW8
SC;Sw,NSW
Page 5 of 23 2013 -12 -19 11:14:52

WATERSHED SOILS INFORMATION
WESTON TOWNHOMES
NUH -14000

WESTON TOWNHOMES WATERSHED SOIL INFORM_A_TION C GEORGE, EI
MIH -14000 6/26/2014
Watershed soili from the Wake County Soil Survey
Symbol
Name _ _
Soil Classification
CrB2, CrC2
Creedmoor sandy loam
C
CtB, CtC
Creedmoor,silt,loam
C
MeA _ _
Mantachie sandy loam
C
m 2'
Mayodan gravelly sandy loam
B
M C2
Mayodan silt loam
B
PkF
Pmston sandy loam
B
WsC2
White Store sandy loam_
_ D
WtB,
White,Store silt-loam
D
References:
Web Soil Survey: Wake County, North Carolina ,
United States Departmentof Agriculture Soil Conservatlon,Service,(m cooperation
with North Carolina - Agriculture Experiment Station)
SCS TR -55
United States Department of Agriculture Soil Conservation Service 1986
COVER CONDITION, SCS CN - HSG B
Impervious
98
Open
61
Wooded
55
Pond
100
COVER CONDITION SCS CN - HSG,C
Impervious
98
_ Open
74
Wooded
70
Pond
100
COVER CONDITION SCS CN - HSG D
Impervious 98
Open 80 '
Wooded .77

�a
k
**r
iyl
. 7 41
M#
Ic
s
i
s
Y
PkF
etc
4 h
i \
SITE
(#3
Y 0
r
/OOCt
� y
P$(
wA a
x o e
Ct(
L-jr
N
WESTON TOWNHOMES !!j
NRCS SOIL SURVEY
0 200 400 800 PROJECT #: MIH -14000
Feet
1 inch 400 feet CARY, NORTH CAROLINA MCA-DAMS

McADAMS
MEMORANDUM
Date: June,,26, 2014
CA4 a ''e
eryr
Ing
-�7 �s•f
� a
�lWee� '4'040
To: Mr. Jeremy Finch, PE
From: George Buchholz, REM, PWS and Stewart Pickens
Re: Weston Parkway Townhomes— Phase I
Seasonal High Water Table Determination
MIH -14000
am w }.
7M Tq
�t -..r
H,
A field investigation was conducted on June 9, 2014 at the location of a
proposed stormwater management pond and stormwater wetland associated
with the Weston Parkway Townhomes- Phase 1 project, located off of Weston
Parkway 0.01 miles west of Sheldon Drive in Cary, North Carolina (Wake
County PIN Number: 0755502824), within the western section of the Wake
County. A soil boring was established within the proposed stormwater
management pond and stormwater wetland to determine the approximate
seasonal high water table depth from the soil surface. Below is a brief
summary of the soil type and the approximate seasonal h'igh`water table depth.
Proposed Stormwater Management Pond:
Soil Type:
Pinkston sandy loam: This soils is on side slopes in the uplands'. Infiltration is
good, and surface runoff is very rapid. Becau "se ,of the ,,steepness of the slopes
and the shallowness of 'the subsoil, this soil should not be cleared.
General Soil Boring Observations:
In general, the profile of the soil borings graded from yellowish brown with
no mottles, to brownish yellow consisting of a minimal amount of yellow
mottles.
The John R. McAdams Soil Boring Results:
Company, Inc. The soil boring was established at an approximate existing elevation of 354
feet. It is anticipated that the approximate seasonal high water table depth
Raleigh / Durham, NC from the soil surface is greater than 48 inches; or length of soil auger.
2905 Meridian Parkway
Durham, North Carolina 27713 Below is a photograph of the soil boring.
(919)361 =5000
Charlotte, NC
1,1301'Carmel Commons Blvd,
Vorth Carolma,28226
_/ -0800
MoademsCo.wm Designing Tomorrow's Infrastructure & Communities

'J McADAMS
Mr. Jeremy Finch, PE
Weston Parkway Townhomes; SHWT
June 26, 2014
Page 2 of 3
Photo 1. Soil boring for the stormwater management pond is located at an
approximate existing elevation of 354 feet. It is anticipated that the
approximate seasonal high water table depth from the soil surface is greater
than 48 inches below the soil surface.
Proposed Stormwater Wetland:
Soil Type:
Pinkston sandy loam: This soils is on side slopes in the uplands. Infiltration is
good, and surface runoff is very rapid. Because of the steepness of the slopes
and the shallowness of the subsoil, this soil should not be cleared.
General Soil Borinp, Observations:
In general, the profile of the soil borings graded from very pale brown with
yellow mottling, to brownish yellow soils consisting very pale brown mottles;
ending with brownish yellow soils consisting of minimal light gray mottles.
MIH -14000

'J McAD-AMS
Photo 2. Soil boring for the stormwater wetland is located at an approximate
existing elevation of 370 feet. It is anticipated that the approximate seasonal
high water table depth from the soil surface is greater than 48 inches below
the soil surface.
MIH -14000

PRECIPITATION DATA
WESTON TOWNHOMES
MIH -14000

Storm Data Detailed Report: Cary, HC
ElemenWetads
ID
60
Notes
Label
Cary, NC
1 Yr 24 Hr
Label
i Yr 24 Hr
Increment
5.000 min
Return Event
1 years
End Time
1,440.000 min
Start Time
0 000 min
Storm Event Depth Type
Cumulative
1Yr24Hr
Time
Depth Depth
Depth
Depth
'Depth
(min)
(in) (in)
(in)
(in)
(in)
0.000
00
0.0
00
0:0
0'.0
25.000
0:0
00
0:0
010
0.0
50.000
010
0.0
M
0:0
0:0
75.000
00
0.1
0.1
0.1
0.1
100.000
0:1
0.1
0.1
01
0.1
125.000
0.1
0.1
0.1
0.1
0.1
150.000
0.1
0.1
0.1
0.1
01
175.000
0.1
0.1
01
0.1
01
200.000
01
0.1
0.1
0:1
0.1
225 000
0.1
0.1
01
0.2
0.2
250.000
0.2
0.2
0.2
0.2
0.2
275.000
0.2
0.2
0.2
0.2
0.2
300 000
0.2
0.2
0.2
0.2
0.2
325.000
,0.2
0.2
0.2
0:2
02
350,000
02
0.2
0.2
0 .'2
0.2
375.000
0.2
0.2
0.3
0.3
0.3
400:000
t03
03
0.3
0.3
0.3
425.000
0.3
03
03
03
0.3
450.000
0.3
0.3
023
03
0.3
475.000
0.3
04
0.4
0.4
0.4
500.000
0.4
0.4
0.4
04
0.4
525.000
0.4
0.4
0.4
0.4
0.4
550.000
04
04
05
0.5
0.5
575.000
0.5
0.5
0.5
0.5
0:5
600.000
65
0.5
0.5
06
0.6
625 000
0.6
0.6
0.6
0.6
0.6
650 000
0.6
06
0.6
0.7
07
675:000
0.7
0.7
0.7
0.7
0 "8
700.000
0.9
0.9
1.0
12
1.6
725.000
1.8
1:8
1.9
2.0
2,.0
750,000
'2 1
21
2:1
22
2.2
775 000
2.2
2.2
2.2
2.2
2.2
800.000
2.2
2.2
2:3
2.3
2.3
825.000
2.3
2.3
2.3
2.3
2.3
850.000
2.3
2.3
2.3
2.4
24
875.000
2.4
2.4
2.4
2.4
2.4
'900.000
2.4
2.4
2.4
2.4
2.4
Weston Townhomes
C George, El
6/20/2014

Storm Data Detailed Report: Cary, NC
1Yr24Hr
Time
Depth
Depth
Depth
Depth
Depth
(min)
(in)
(in)
(in)
(in)
(in)
925.000
25
2.5
25
2.5
25
950.000
2.5
2.5
25
2.5
2 5
975.000
2.5
2.5
25
25
25
1,000.000
2.5
25
2.5
25
2.6
1,025.000
2.6
26
2.6
26
2.6
1,050.000
2.6
26
26
2.6
2.6
1,075.000
26
26
26
2.6
2.6
1,100 000
26
2.6
2.6
2.6
2.6
1,125.000
2.6
2.6
2.6
27
2.7
1,150.000
2.7
27
2.7
2.7
2.7
1,175.000
2.7
27
2.7
2.7
2.7
1,200.000
2.7
2.7
27
2.7
2.7
1,' 225.000
2.7
2.7
27
2.7
27
1,50.000
27
2.7
2.7
27
2.7
1,275 000
27
2.7
2.7
2.7
2.7
1,300.000
2.8
28
2.8
2.8
2.8
1,325.000
2.8
28
28
28
28
1,350.000
2.8
28
2.8
28
2.8
1,375 000
2.8
28
2.8
2.8
2.8
1,400.000
2.8
2.8
2.8
28
2.8
1,425 000
28
2.8
2.8
2.8
(N /A)
2 Yr 24 Hr
Label
2 Yr
24 Hr
Increment
5.000 min
Return Event
2 years
End Time
1,440.000 min
Stan: Time
0.000 min
Storm Event Depth Type
Cumulative
2Y,r24Hr
Time
Depth
Depth
Depth
Depth
Depth
(min)
(in)
(in)
(In)
(in)
(in)
0.000
00
0.0
0.0
0.0
0.0
25 000
0.0
0.0
0.0
0.0
0.0
50.000
00
0.0
0.0
0.1
0.1
75.000
0 1
0.1
0.1
0.1
0.1
100.000
0.1
0.1
01
01
0.1
125.000
0.1
0.1
0.1
0 1
0.1
150.000
01
0.1
0.1
0.1
01
175.000
0.1
0.1
0.1
0.2
0.2
200.000
02
02
0.2
0.2
02
225.000
0.2
0.2
0.2
0.2
0.2
250.000
0.2
0.2
0.2
0.2
0.2
275.000
0.2
0.2
0.2
0.2
0:2
300.000
0.2
0.2'
0.2
0.2
0.3
325.000
0:3
0.- 3
0.3
0:3
03
350.000
0.3
0.
0.3
0.3
0.3
375.000
0.3
0.3
0.3
0.3
0.3
Weston Townhomes
C George, El
6/20/2014

Storm Data Detailed Report: Cary, NC
2 Yr 24,Hr
Time
Depth Depth
Depth
Depth
Depth
(min)
(in) (in)
(in)
(in)
(in)
400 000
0.3
03
03
0.4'
0.4
425.000
04
0.4
0.4
0.4
0.4
450.000
0.4
04
04
0.4
0.4
475 000
0.4
0.4
0.4
0.4
0.5
500.000
05
05
05
0.5
0.5
525.000
0.5
05
05
0.5
0.5
550.000
05
05
06
0.6'
0.6
575.000
06
06
0.6
06
0.6
600.000
06
0.7
0.7
0.7
0.7
625.000
0.7
0.7
07
07
07
650.000
08
0.8
08
_ 0.8
08
675.000
0:8'
0.9
09
0 °9
1.0
700.000
1 1
1 1
1 2
1.4
19
725.000
2.1
2.2
2.3
2:4
2.4
750000
25
25
26
2.6
26
775.000
2:6
27
2.7
2:7
27
800.000
2.7
2.7
2.7
i 2.7
2.7
825.000
2.7
2.8
2.8
18
28
850.000
28
28
2.8
2.8
2.9
875.000
2.9
2.9
2.9
29
29
900 000
2.9
2.9
29
29
29
925 000
3.0
30
10
3.0
10
950.000
30
3.0
10
3.0
10
975.000
3.0
30
10
30
3.0
1,000.000
3.0
3.1
3.1
3.1
3.1
1,025.000
3.1
3.1
3.1
3.1
3.1
1,050.000
31
3 1
3.1
3.1
3.1
1,075.000
3.1
3.1
'3.1
3.2
32
1,100.000
3.2
3.2
32
32
3.2
1,125.000
3.2
3.2
3.2
3.2
3.2
1,150.000
3.2
32
3.2
3.2
3.2
1,175.000
3.2
32
3.2
3.2
3.2
1,200 000
32
32
3.2
3.3
33
1,225.000
33
33
33
3.3
3.3
1,250 000
3.3
3.3
33
3.3
3.3
1,275.000
3.3
3.3
33
33
3.3
1,300.000
3.3
33
3.3
3.3
3.3
1,325.000
3.3
3.3
3'3
'3.4
3.4
1,350.000
3.4
3.4
14
3.4
3.4
1,375:000
3.4
3.4
3.4
3.4
3.4
1,400.000
3.4
14
3.4
3.4
3.4
1,425 000
3:4
3.4
3.4
3.4
(N /A)
5 Yr 24 Hr
Label
5 Yr 24 Hr
Increment
5.000 min
Return Event
5 years
End Time
1,440:000 min
Weston Townhomes
C George, El
6/20/2014

Storm Data Detailed Report: Cary, NC
5 Yr 24 Hr
Start Time
0.000, min
Storm Event Depth'Type
Cumulative
5Yr24Hr
Time
Depth Depth
Depth
Depth
Depth
(min)
(in) (in)
(in)
(in)
(in)
0.000
0.0
00
0.0
0.0
0.0
25.000
0.0'
0.0
0.0
00
0.0
50.000
0.1
0.1
0.1
01
0.1
75.000
0.1
0.1
0.1
0.1
01
100.000
0.1
01
01
0.1
0.1
125.000
0.1
0 1
0.1
01
0.- 2
150.000
02
02
0.2
0.2
0.
175.000
0.2
0.2
02
0.2
02
200.000
02
02
0.2
0.2
0.2
225.000
0.2
0.2
.0.2
03
0.3
250.000
0:3
03
03
0.3
0 3
'275.000
0.3
0.3
0.3
0.3
0 -3
300.000
0.3
03
03
0.3
03
325.000
0.3
0.3
0.3
0.4
0.4
350 000
0.4
04
04
0.4
0.4
375.000
0.4
0.4
0.4
0.4
04
400:000
0.4
0.4
0.5
0:5
05
425.000
05
0.5
0.5
0.5
05
450.000
0.5,
05
Ors
05
0.5
475.000
0.6
0.6
06
0.6
0.6
500.000
0.6
0.6
0.6
0.6
0.6
525.000
06
06
0.6
0.7
0.7
550.000
0.7
07
07
07
0.7
575.000
0.8
0.8
0.8
08
0.8
600 000
0.8
0.8
0.9
0.9
09
625.000
09
09
09
09
0.9
650:000
1.0
10
10
10
1.0
675.000
1 1
1 1
1 1
1.2
1.3
700.000
1.4
1.5
1.6
1.8
24
725.000
2.6
2.7
28
29
3 0
750.000
3.1
3.2
3.2
32
32
775.000
3.3
3.3
33
33
3:3
800.000
3.4
3.4
3.4
34
3.4
825.000
34
3.4
35
3.5
3.5
850.000
3 5
3.5
3.5
3.5
36
875 000
3.6
36
3.6
3.6
3.6
900 000
3.6
3.6
3.7
37
3.7
925 000
3.7
3.7
3.7
3.7
3.7
950.000
3.7
3.7
3.7
3.7
37
975.000
3.8
3.8,
3.8
38
3.8
1,000.000
3.8
3.8
38
3.8
18
1,025.000
3.8
3.8
3.8
3.9
3.9
1,050.000
3.9
3.9
3.9
3.9
3.9
1,075.000
3.9
3.9
3.9
3.9
3.9
Weston Townhomes
C George, El
6/20/2014

0
Storm Data Detailed' Report: Cary, NC
'S Yr 24 Hr
Time
Depth
Depth
Depth
Depth
Depth
(min)
(in)
(in)
(in)
(in)
(In)
1,100:000
39
39
19
4.0
4.0
1,125,000
4.0
4.0
4.0
40
4.0
1,150.000
4.0
4.0
4.0
4.0
4.0
1,175.000
40
40
40
40
40
1,200.000
4.0
4.0
4.1
4.1
4.1
1,225 000
4.1
4.1
4.1
4.1
4.1
1,250.000
41
41
4.1
4.1
4.1
1,275 000
41
41
4.1
41
41
1,300 000
4.1
4.1
42
4.2
4.2
1,325 000
4.2
4.2
42
4.2
42
1,350 000
4.2
4.2
4.2
42
42
1,375.000
42
42
4.2
42
42
1,400.000
4.2
4.3
4.3
43
43
1,425.000
4.3
43
4.3
4.3
(N /A)
10Yr24Hr
0.3
0.3
0.3
275.000
0.3
Label
10 Yr 24 Hr Increment
5.000 min
Return Event
10 years End Time
1,44M00 min
Start Time
0.000 min Storm Event-Pepth Type
Cumulative
10Yr24Hr
Time
Depth
Depth Depth
Depth
Depth
(min)
(in)
(in) (in)�
(in)
(in)
0:000
0.0
0.0
0.0
0.0
00
25:000
0.0
00
0.0
010
0.1
50:000
0.1
01
0.1
0.1
0.1
75.000
-0.1
0.1
0.1
0.1
0.1
100.000
0.1
0.1
0.1
0.1
0.1
125.000
0.1
0.1
0.2
02
0.2
150.000
02
02
0.2
02
02
175.000
0.2
0.2
0.2
0.2
0.2
200:000
0.2
0.2
0.2
0.2
0.3
225.000
0.3
0.3
03
0.3
0.3
250 000
0.3
0.3
0.3
0.3
0.3
275.000
0.3
03
03
0.3
03
300 000
0.3
0:3
0.4
0.4
04
325.000
0.4
0.4
0.4
0.4
0.4
350.000
0.4
0.4
0.4
04
0.4
375.000
0.4
0.4
0.5
05
0.5
400.000
0.5
0.5
0.5
0.5
0.5
425.000
0.5
0.5
06
0.6
0.6
450.000
0.6
0.6
0.6
0.6
06
475.000
06
0.6
0.6
0.7
0.7
500 000
0.7
07
0.7
0.7
0.7
525:000
0.7
0.7
0.7
0.8
0.8
550.000
0.8
0.8
0.8
0.8
0.9
Weston Townhomes
C George, El
6120/20,14,

Label
Storm Data Detailed Report:
Cary, NC
Return Event
100 years End Time
1,440 000 min
10Yr24Hr
Start Time
0.000 min Storm Event Depth Type
Cumulative
Time
Depth
Depth Depth
Depth
Depth
(min)
(in)
(in) (in)
(in)
(in) (in) (in)
(in)
575 000
0.9
0:9
0.9
0.9
0.9
600.000
1.0
1.0
1.0
10
1.0
625.000
1.0
1 1
1.1
1.1
1.1
650.000
1.1
1 1
1.1
1.2
1.2
675 000
13
1.3
13
1.4
15
700.000
1.6
1.7
1.8
2 1
2.7
725.000
3.0
3.1
3.3
34
3.5
750 000
3.6
3.7
37
37
3.8
775.000
3.8
18
3.8
39
3.9
800.000
3.9
3.9
3.9
39
4.0
825.000
4.0
4.0
40
4.0'
4.0
850.000
4.1
41
4.1
4.1
4.1
875.000
41
42
4.2
4'2
4.2
900 000
4.2
42
4.2
42
4.3
925.000
4.3
43
43
4.3
43
950.000
43
4.3
4.3
4.3
4.4
975 000
44
44
44
4.4
44
1,000 000
4.4
44
44
4.4
44
1,025.000
45
45
4.5
4:5
45
1,050.000
4.5
4.5
45
4.5
4.5
1,075,000
4.6
4.6
4.6,
4.6
4.6
1,100.000
4.6
4.6
4:6
'4.6
4.6
1,125:000
46
4.6
4.6
4.6
4.6
1,150.000
4.6'
4.6
47
4.7
4:7
1,175.000
4.7
4.7
4.7
4.7
4.7
1,200.000
47
4.7
47
47
4.7
1,225 000
4.7
4.7
4.7
47
4.7
1,250.000
48
48
4.8
4.8
48
1,275.000
4.8
4.8
4.8
4.8
48
1,300 000
4.8
4.8
4.8
4.8
4.8
1,325.000
4.8
4.8
49
49
4.9
1,350 000
4.9
4.9
4.9
4.9
4.9
1,375 000
49
49
49
+9
4.9
1,400.000
4.9
4.9
4.9
4.9
4,9
1,425.000
50
50
5.0
5.0
(N /A)
100 Yr 24 Hr
Label
100 Yr 24 Hr Increment
5.000 min
Return Event
100 years End Time
1,440 000 min
Start Time
0.000 min Storm Event Depth Type
Cumulative
100Yr24Hr
Time
Depth Depth Depth
Depth
Depth
(min)
(in) (in) (in)
(in)
(in)
0.000
0.0 0.0 0.0
0.0
0.0
25.000
00 00 0.1
0.1
0.1
Weston Townhomes
C George, El
6/20/2014

Storm Data Detailed Report: Cary, NC
100 Yr 24 Hr
Time
Depth
Depth
Depth
Depth
Depth
(min)
(In)
(In)
(in)
(In)
(In)
50.000
0.1
0.1
0.1
0.1
0.1
75.000
0.1
0.1
0.1
0.1
01
100.000
0.1
0.2
02
0.2
0.2
125.000
0.2
0.2
02
0.2
0.2
150.000
0.2
0.2
0.2
0.2
0.3
175.000
0.3
03
03
0.3
0.3
200:000
0.3
03
0.3
0.3
0.3
225.000
0.3
03
0.3
0.4
04
250:000
0.4
04
04
0.4
04
275.000
04
04
0.4
04
0.4
300:000
0.4
0.4
0.5
05
0.5
325 000
05
0 -5
0.5
0.5
05
350 000
0.5
05
0.5
0.5
06
375.000
0.6
6.6
0.6
0.6
0.6
400.000
07
0.7
0.7
0.7
07
425:000
07
0.8
0.8
0.8
6.8
450.000,
0.8
0.8
0.8
0.9
0.9
475.000
0.9
0.9
0.9
09
1.0
500.000
1.0
1.0
1.0
1.0
1.0
525 000
1.0
1.1
1.1
1. 1,
1 1
550 000
1.1
1:2
1.2
1.2
1.3
575.000
1.3
1.3
1.3
1.4
1.4
600.000
1.4
1.4
1.5
15
1.5
625.000
1.5
1.6
1.6
1.6
1.7
650.000
1.7
1.7
1.8
1.8
19
675.000
1.9
2.0
2.1
2.1
2.3
700.000
2.5
2.7
2.8
3.2
39
725.000
4.3
45
4.7
4.9
5.0
750 000
5:2
53
5.3
5.4
5.5
'775.000
5,5
5.6
5 6
57
5.7
800.000
5.7
5.7
58
58
5.8
825.000
5.9
5.9
5.9
5.9
6.0
850.000
6.0
6.0
60
61
61
875.000
6.1
6.1
62
62
6.2
900.000
63
6.3
63
6.3
6.3
925.000
6.3
6.3
6.4
6.4
6.4
950.000
6.4
6.4
64
6 5
65
975.000
6.5
6.5
65
6.5
6.6
1,000.000
6.6
6.6
6.6
66
6.6
1,025.000
6.6
67
6.7
6.7
67
1,050.000
6.7
6.7
6.8
68
6.8
1,075.000
6.8
6.8
6.8
6.8
6.8
1;100.000
6.8
6.9
6.9
6.9
6.9
1,125:000
.6.9
6.9
6:9
6.9
64
1,150.000
6.9
6.9
6.9
6.9
7.0
1,175.000
7.0
7.0
7.0
7.0
7.0
1,200:000
7.0
7.0
7.0
7.0
7.0
Weston Townhomes
C George, El
6/20/2014

Storm Data Detailed Report: Cary, NC
100 Yr 24 Hr
Time
Depth
Depth
Depth
Depth
Depth
(min)
(in)
(in)
(in)
(in)
(in)
1,225.000
7.0
7.0
7.0
7.1
7.1
1,250.000
7.1
7.1
7.1
7.1
7.1
1,275.000
7.1
7.1
7.1
7.1
7.1
1,300.000
7.1
7.2
7.2
7.2
7.2
1,325.000
7.2
7.2
7.2
7.2
7.2
1,350.000
7.2
7.2
7.2
7.2
7.2
1,375.000
7.3
7.3
7.3
7.3
7.3
1,400.000
7.3
7.3
7.3
7.3
7.3
1,425.000
7.3
7.3
7.3
7.4
(N /A)
7.5
6.9
6.3
5.6
5.0
4.4
y 3.8
CL
3.1
2.5
1.9
1.3
0.6
0.0
we
200.000 400.000 600.000 800.000 1,000.000 1,200.000 1,400.000
Time (min)
100 Yr 24 Hr - 10 Yr 24 Hr - 5 Yr 24 Hr - 2 Yr 24 Hr
1 Yr 24 Hr
Weston Townhomes C. George, El
6/20/2014

PRE-DEVELOPMENT HYDROLOGIC
CALCULATIONS -
WESTON TOWNHOMES
MIH -14000

W o
0L N
J
O
O
Z �
y
O
0 �
W �
W
W
ci
G7
W
O
x
00
' O
O
O
7
,w x
3�
O
,--
00
O
N
[l)
h
O
tn
AO
kn
M
�O
00
N
—
—
N
N
—
--
N
F
z�
U
naonnoo
nn.OV�
onnn
d
L
00
00
n
r4
01
kn
N
Vl
O
00
O
-n
M
r
,--+
00
00
M
R
IaOi
IS
F
M
N
O
00
00
O,
O
M
O
O
O
I
R
M
00
o0
M
M
V.
E.
O
O
Cl
O
O
O
Cl
O
O
O
O
O
R
C
0
0
0
0
0
0
'D
O
O
O
O
O
N
00
0O
.
C
O
O
O
O
O
O
O
O
O
O
O
O
O
,d
'L
iV
y
r-
O
n
0000
00
-
O
O
O
ON
v
N
Q
d
p
3
v)
O
C7\
00
O
d
o0
O
N�o
O
O
O
n
n
M
n
O
O
O
--
N
M
h
7
O
•�
T
O—
O
n
0
0
0
N
w
v1
a,
T
00
00
n
n
O
O
N
R
O
0
0--
—
O
h
M
OS
v)
w
CT
n
C,
O
N
O)
oo
O)
M
W)
O
M
p
M
00
—
—
00
M
w
0
0
0
0
0
0
0
0
0
0
0
0
0
0
C
0.
0
0
0
C.
0
0
0
O
0
O
0
O
0
O
0
0
0
0
0
0
0
h
Y
C
O
O
O
O
O
O
L
ci
.1'a
'E
n
M
00
N
O)
00
M
W)
O
p
M
M
00
.-
M
'.0
M
00
00
00
O
N
O
00
d
M
0
0
0
M
.y
C
A
y
O)
O
)O
N
0
0
0
v)
O
O
O
n
0
0
0
0
0
0
0
0
0
0
0
0
0
0-
7
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
L
O
O
O
O
O
O
O
O
O
O
O
O
O
O
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
a
�
u
�
F
Gn

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin IA 6/25/2014
Assume:
_ HSG _
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A'= 0%
HSG 'B' = 75%
HSGC' = 25%
HSG'D'= 0%
Cover Condition
SCS CN
Comments
Im erv�ous
_ 98 _
-
O en
64
Assume good condition
Wooded
59
Assume good condition
A. Onsite Impervious Breakdown
Contributing Area'
Area Isf]
Area jacresl
Building
0
000'
Parkm gads
0
000
_ _Sidewalk
_ 0_ _ _ _
000,
Otlier
0
000
T,otdls
0
000
B. Watershed Breakdown
Contributing Area
SC&CN
Area 1sf1
Area facresl
Comments
Onsi eraperviotis
98
0
000
__ O_nsrte open _ _ _ _
64
546
0`01
Assume good condition
Onsite•wooded
59
14,830
0'34
Assume good condition
Onsite and
100
1 0
000
-
Offsrte im dr-06ds _
98
39,392
090
Offsite o en
64
38,692
0,89
Assume good,condition
_ Offsjte wooded
59
31,938
073,
Assume good condition
Offsite and _
100
0
000
-
Total area =
Composite SCS CN =
% Impervious —
2 88 acres
00045 sq mi
73
314%

WESTON TOWNHOMES PRE= DEVELOPMENT °HYDROLOGY C GEORGE El
M1H- 140000 Subbasin 1A' 025/2014
C. Time o_f „Concentration Information
Length ,=
225
me�of concentrdtton is calctila`ted -using the SCS Segmental Approach (TR -55)
Segment 1: Overland,Flow
Bot Elev =
'323
L=ength,=
100
ft
Top,Elev,=
370
No
But Elev—
360
Segment'Ttme'=
Height =
10
ft
Slope =
0.1000
ft/ft
Maftnmg's m=
640
wooded,,light §underbrush
Ps(2.year /24' -hour) =
343
mches,(Cary, NC)
SegmentiTune,=
10'90
minutes
Segment 3 - Channel Flow
Length =
58
ft
Top Ll_ev =
323
Bot,E1ev =
3,19
Height =
4'
ft
Slope =
00690
ft/ft
Mannmg'sin =
0 045
natural channel
•Flow Area—
400
sf (assume?2"x 2” channel)
Wetted Perimeter =
600,
If (assume 2'x 2' channel)
Channel Velocity =
6,64
ft%sec
Segment Tiine =
015
minutes
Segnzent2: ConcentratediFlow,
Length ,=
225
Top �Elev =
360
Bot Elev =
'323
Height--
37
Slope =
101644
Paved? =
No
Velocity =
654
Segment'Ttme'=
0.57
Timetof Concentration = d,l 61 minutes
SCS LagXime = 697 minutes (SCS Lag =`0 6* .T6)
Time Increment = 202 minutes (= 0 29 *SCS Lag)
ft
ft
ft/ft
,ft/sec
minutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 1B 6/25/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A'=
0%
HSG'B "=
62%
HSG'C'­
38%
HSG 'D "=
0%
Cover Condition
SCS CN
Comments
Impervious
98
000
Open
66
Assume good condition
Wooded
61-
Assume good condition
A. Onsrte,Impervious Breakdown `
Contributing Area
Area [sI]
Area lacresi
.Buddm
0- _
000
Parkin Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributin ,Area
SCS CN
Area 1sfl
Area acres
Comments
Onsite impervious
98
0
0'00
Onsite open
66
23,389
054
Assume, good condition
Onsite wooded
61
232,894
535
Assume ood condition
Onsite pond
'' 100
0
000
Offsiteim ervious
98
0
000
Offsrte open
66 _ _
77
0100
Assume good condition
Offsite wooded
61
0
000
Assume good conditwn
Offsite pond
100
0
000
-
Total area =
Composite SCS CN =
% Impervious=
5 89 acres
00092 sq mi
61
00%

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 1B 6/25/2014
C. Time of Concentration Information
Length =
402
-ne of concentration is calculated using the SGS Segmental
Approach (TR =55)
Segment k Overland Flow
342
Height =
Length-=
100
ft
Top Elev =
3995
Velocity =
Bot'Elev =
394
1.15
Height =
5 5
ft
Slope =
010550
ft/ft
Manning's n =
040
wooded „light underbrush
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time =
13.84
minutes
Segment 3: Channel Flow
Length =
916
ft
Top Elev =
342
Bot Elev =
319
Height =
23
ft
Slope =
00251
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2'x 2' channel)
Wetted`Penmeter =
6.00
If (assume'2' x T channel)
Channel Velocity =
400
ft/'sec
Segment Time =
3.81
minutes
Segment 2 Concentrated Flow
Length =
402
Top Elev—
394
Bot Elev =
342
Height =
52
Slope =
01294
Paved o =
No
Velocity =
580
Segment Time =
1.15
Time of Concentration= 1881 minutes
SCS Lag Time = 11 -28 minutes (SCS Lag = 0 6* Tc)
Time Increment = 327 minutes = 0 29 *SCS La
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES RRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbastn IC 6/25/2014
.,S--c' 5 T E CI BER
Assume.
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A'=
0%
HSG 'B' =
33%
HSG 'C' =
38%
HSG'D' =
29%
Cover Condition
SCS CN
Comments
Impervious
98
_ _ 000
Open _
71
Assume good,condition
Woodedi
67
Assume good condition
JIM ! 1 ' ! .vF
A. Onsite Impervious Breakdown
Contributing Area
Area lsfJ
Area acres
Building
0 _ _ _
_ _ 000
,Parking/Roads- _ _
0
OM
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Area Isil
Area acres
omments
Onsite impervious
98
0
000
Onsrteo-en -
71
17,033
0`39
MA�ssume good condition
Onsite wooded'
67'
78,416
1 80
ood condition
Onsite pond
100
0
0,00
Offsite impervious
98-- _
91,741
211
Offsjte open
71
56,237
129
Assume good condition
Offsite wooded
67
207,721
477
Assume; good condition
Oti'site pond _ _
100
0
000
-
Total,area =
Composite SCS CN =
% Impervious =
1036 acres
,0 0162' sq mi
74'
203%

WESTON TOWNHOMES PRE - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000' Subbastn IC 6/25/2014
C. Time of Concentrationjnformation
-ime of concentration is,calculated�using the,SC&Segmental Approach (TR -55)
Segment,]: Overland `Flow
Length =
671
Length =
100
ft
Top Elev =
404
67
Bot Elev =
400
Paved 9 =
Height =
4
ft
Slope =
00400
ft/ft
Manning's n =
040
wooded, light underbrush
P (2- year/24 -hour) =
343
inches (Cary, NC)
Segment Time =
1572
minutes
Segment'3. Channel.Flow
Length =
639
ft
Top Elev =
333
Bot Elev =
319
Height =
14
ft
Slope =
00219
ft/ft
Manning's n =
0'045
natural channel
Flow Area =
400
sf (assume 2'x 2' channel)
Wetted Perimeter =
600
if (assume 2'x 2' channel)
Channel "Velocity =
374
ft/sec
SegmenfTime =
285
minutes
Segment 2: Concentrated Flow
Length =
671
Top Elev =
400
Bot Elev =
333
Height =
67
Slope =
00999
Paved 9 =
No
Velocity =
5 10
Segment Time =
2.19
Time,of Concentration = 20'76 minutes
SCS Lag Time = 1246 minutes (SCS Lag = 0 6• Tc)
Time Increment = 361 minutes (= 0'29•SCS,Lag)
ft
ft
ft/ft
ft/sec
rmnutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 SubGastn 2A 6!25%2014
Assume.
HSG'
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A'= 0%
HSG 'B' = 86%
HSG 'C' = 0%
HSG"D'= 14%
Cover Condition
_SCS'CN
Comments
Impervious
98,
000
Open
64
Assume g6dd condition
Wooded
58
Assume good condition
A Onsite`Impervious Breakdown
Contributor Area
Area [sf[
Area Jacresl
Building
0
000
Parking/Roads
0
000
Sidewalk _
0
000 _
Other
0
000 _
Totals
0
000
B. Watershed Breakdown
Contributing,Ares
SCS CN
Area lsfl
Area acres
Comments
Onsite impervious
98
0
000
Onsite open
64
104
000
Assume good condition
Onsite wooded
58
7,218
017
Assume g6odcondition
Onsite pond
100
0
000
Offsite impervious
98
175,240
402
Offsne open
64
116,583
2,68
Assume good condition
Offsae wooded
58
80,199
1 84
Assume good condition
Offstte pond
100
0
000
Total area =
871 acres
00136 sq,mi
Composite SCS CN =
78
% Impervious =
462%

W ESTON^ TO WNHOMES
MIA- 140000
PRE- DEVELOPMENT HYDROLOGY
Subbasin 2A
C., Time of Concentration Information
,ime of concentration is calculated using the SCS Segmental, Approach (TR -55)
Segment 1 Overland Flaw
Length =
Length =
100
ft
Top Elev =
380
Bot Elev =
Bot Elev =
368
Height
Height =
12
ft
Slope =
0 1200
, ft/ft
Manning's n =
040
wooded, light underbrush
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time =
1013
minutes
Segment 3• Pipe Flow
Length =
Length =
174
ft
Top Elev =
360
Bot Elev =
Bot Elev =
34-37
Height =
Height=
1582
ft
Slope =
00909
ft/ft
Manning's n =
0 024
CMP
Flow Area—
3 14
sf (24 ")
Wetted Perimeter =
628
if (24 ")
Channel Velocity =
1179
ft/sec
Segment Time =
015
minutes
C GEORGE, El
6/25/2014,
Segment 2 Concentrated Flow
Length =
252
ft
Top Elev =
368
Bot Elev =
35952
Height
848
ft
Slope =
00337
ft/ft
Paved 7 =
No
Velocity =
296
ft/sec
Segment Time =
142
minutes
Segment 4 Channel Flow
Length =
218
ft
Top Elev =
344
Bot Elev =
325
Height =
187
ft
Slope =
00858
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume Tx 2' channel)
Wetted Perimeter =
600
If (assume 2' x 2' channel)
Channel Velocity =
740
ft/sec
Segment Time =
0.49
minutes
Time of, Concentration = 12,29 minutes
SCS Lag Time = 737 minutes (SCS Lag = 0 6s Tc)
Time Increment = 2 14 minutes (= 0 29'SCS Lag)

WESTON'TOWNHOMES PRE - DEVELOPMENT HYDROLOGY C' GEORGE, El
MIH- 140000 Subbasin 2B 6/25/2014
Assume:
HSG
Impervious
Open
Wooded
A
_ 98_
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG 'A' = 0%
HSG 'B' = 60%
HSG'C'= 0%
HSG 'D' = 40%
Cover Condition
SCS CN
C_ omments
Impervious
98
000
Open
69
Assume good condition
Wooded
64
Assume good condition
II. PRE -'D_V ,E C P,MEN- _
A. Onsite Impervious Breakdown
Contributing Area
Area jig
Area acres
Building
0
000
Parking/Roads
0
000
Sidewalk
0
__000
Other
0
000
Totals
0
0,00
B. Watershed Breakdown
Contributing Area
SCS CN
Area Isg
Area lacresl
Comments
Onsite im ervious
98
0
'000
-
Onsite open
60
6,855
016
Assume ood`condition
,Onsite,wooded
64'
14,274
033
Assume good,condition
Onsite pond
100
0
'000
-
Offsrte impervious
98 1
206,132
473
-
Offsrte open
69
113 1,201
3,01 _
Assume good condition,
Offsite',wooded
64
79,549
183
Assume, good condition
Offsrte pond
100
0
0100
-
TotaLarea-
Composite SCS CN =
% Impervious =
10'06 acres
00157 sq rm
81
471%

WESTON TOWNHOMES' PRE - DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 140000 Subbasin 2B 6/25/2014
C. Time of Concentration Information
Length =
82
' ne of concentration is calculated using the SCS Segmental
Approach (TR -55)
Segment L `Overland Flow
350
Height =
Length =
100
ft
Top,Elev =
368
Velocity =
Bot Elev =
356
031
Height =
12
ft
Slope =
01260
ft/ft
Maritimes n =
040
wooded, light underbrush
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time =
1013
minutes
Segment 3: Channe6Flow
Length =
891
ft
Top Elev =
350
Bot Elev =
325
Height =
25
ft
Slope =
00281
ft/ft
Mannmg's n =
0 045
natural channel
Flow Area'=
400
sf (assume 21 x 2' channel)
Wetted,Perimeter =
600
If (assume 2'x 2'channel)
Channel Velocity =
423
Mee
Segment Time =
3.51
minutes
Segment 2 Concentrated F, low
Length =
82
Top Elev =
356
Bot Elev =
350
Height =
6
Slope =
0'0732
Paved 9=
No
Velocity =
436
Segment Time =
031
Time of Concentration = 1395 minutes
SCS Lag Time = 837 minutes (SCS Lag = 0 6* Tc)
Time Increment = 243 mmutes = 0 29 *SCS La
ft
ft
ft/ft
fVsec
minutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C ,GEORGE, EI
MI14- 140000 Subbasin 2C 6%25/2014
KS—GSI-0MVEINUMBE RS .s
Assume.
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55�
C
98_
74
70,
D
98 -
80
77
HSG 'A' =
0%
HSG'B'=
79%
HSG'C'=
21%
HSG'D'=
0%
Cover Condition
SC&CN
Comments
Impervious
98, _
000
Open
'64
Assume good condition
Wooded
58
Assume good condition
A. Onsite Impervious Breakdown
Contributing Area
Area,(sq
Area acres
Building
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
Q
000
B. Watershed Breakdown
Contributing Area
SCS CN
Areas
Area acres
Comments
Onsite impervious
98
0
000
Onsite o en
64
5,197
012
Assume good condition
Onsite wooded
58
247,442
568
Assume ood.condition
Onsite and
100
0
000
Offsrte,im ervious
98
0
000
-
Offsde�o en
64
741
002,
Assume good condition
Offsite wooded
58
4,592
Oil
Assume good,condition
Off ne pond
100
0
000
-
Total area =
Composite SCS CN =
% Impervious =
592 acres
00093 sq mi
58
00%

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE „EI
MIH- 140000 Subbasin 2C 6%25/2014
C. Time of Concentration Information
980
ft
me of concentration is calculated using the SCS Segmental
Approach (TR -55)
Segment I Overland Flow
Bot Elev =
325
Length =
100
ft
v
Top Elev =
40,7
0.0276
Bot EleV=
405
0 045
Height=
2
ft
Slope =
00200
ft/ft
Mannmg'sm =
040
wooded, light underbrush
P (2- year /24 -hour) =
343
inches (Cary„NC
Segment Time =
2074
minutes
Segment 3• Channel Flow
Length =
980
ft
Top Elev =
352
Bot Elev =
Bot Elev =
325
53
Height=
27
ft
Slope=
0.0276
ft/ft
Manning's n =
0 045
natural,channel
Flow Area=
400
sf (assume 2'x 2' channel)
Wetted Perimeter=
600
If (assume 2'x T channel)
Channel Velocity =
419
ft/sec
Segment Time =
389
minutes
Segment 2. Concentrated Flow
Length =
353
Top Elev =
405
Bot Elev =
352
Height =
53
Slope =
0 1501
Paved 9 =
No
Velocity =
625
Segment Time =
094
Time of Concentration = 25 58 minutes
SCS Lag Time = 1535 minutes (SCS Lag,= 0 6* Tc)
Time Increment = 445 minutes (= 0 29 *SCS Lag)
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Sub'basin 3 6/25/2014
Assume.
HSG
Impervious
Open
Wooded
_ A,
e
98
39
30
B
98
61
55
C
98
74
70
D
98,
80
77
HSG 'A' =
0%
HSG'B'=
62%
HSG "C' =
24%
HSG'D'=
14%
_C&—ci Conditjoii
'SCS,CN
Comments
Impervious
98
000
Open
67
Assume good condition
_ Wooded
62
Assume good condition
H:1'RE"DEVELt�P ENT
A. Onsite Impervious Breakdown
Contributing Area
Area (st]
Area lacresl
Building
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
reas
Area acres
Comments
_Onsiteim ervious
98
0
000
Onsite open
67
0
r6150,81713
000
Assume good condition
Onsite wooded
62
3,8
032
Assume -ood condition
Onsite and
100
0
000
Offs ife'im ervious
98
1494
-
Offsite,o en
67
606,552
1392
Assume, good condition
Offsite wooded
62
333,870
766
Assume, ood, condition
Offsite; and
100 1
26,335
060
Total area =
Composite SCS CN =
% Impervious =
37 45 acres
0'0585 sq mi
79
399%

WESTON TOWNHOMES PRE_ - DEVELOPMENT HYDROLOGY C GEORGE,.EI
MIH- 140000 Subbasin 3 6/25/2014
C. Timeaof Concentration Information
—,me of concentration;is calculated usmg.the SCS Segmental Approach (TR -55)
Segment I Overland Flow
Segment 2 Concentrated Flow
,Length =
100
ft
Length =
276
ft
Top Elev =
438
Top Elev =
434
Bot Elev =
434
Bot,Elev =
414
Height =
4'
ft
Height =
20
ft
Slope =
00400
ft/ft
Slope =
00725
ft/ft
Manning's n =
040
wooded light underbrush
Paved 9=
No
P (2- year/24- hour)'=
343
mches,(Cary NC)
Velocity =
434
ft/sec
Segment Time =
1572
minutes
Segment -Time =
106
minutes
Segment 3 Channel Flow
Segment 4 Pipe Flow
Length =
468
ft
'Length =
266
ft,
Top,Elev =
414
Top Elev—
394
Bot Elev =
394
Bot Elev =
384
Height =
20
ft
Height =
10
ft
Slope =
00427
ft/ft
Slope =
00376
ft/ft
Manning'§ n =
0 045
natural channel
Manning's n =
0 013
Assumed RCP
Flow Area =
400
sf (assume 2' x 2' channel)
Flow Area =
3 14
sf (24 ")
Wetted Perimeter =
600
If (assume 2'x 2' channel)
Wetted Perimeter =
628
If (24 ")
Channel Velocity =
522
ft/sec
Channel Velocity =
1400
ft/sec
Segment Trine =
149
minutes
Segment Time =
0.32
nunutes
Segmenta5 Pond
Segmenta6• Pipe Flow
Length=
384
ft
'Lenngth,=
266
ft
Top Elev =
384
Top Elev =
374
Bot Elev =
374
Bot Elev =
362
Height =
10
ft
Height =
12
ft
Slope =
00260
ft/ft
Slope =
00451
ft/ft
Channel Velocity =
000
ft/sec
Manning's n =
0 013
Assumed RCP
Segment Time =
0.00
minutes
Flow,Area =
3 14
sf (24 ")
Wetted Perimeter =
628
lf'(24" )'
Channel Velocity =
1534
ft/sec
SegmentTime =
029
minutes
Segment 3 - Channel Flow
Length =
313
ft
Top Elev =
362
Bot,Elev =
354
Height =
8
ft
`Slope =
00256
ft/ft
Manning's n =
0 045
natural channel
Flow,Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
600
if (assume 2'x T channel)
Channel Velocity =
404
ft/sec
Segment Time =
129
minutes
Time of.Concentration = 20 17 minutes
SCS Lag Time = 12 1'6 minutes (SCS Lag'— 0 6* Tc)
Time Increment = 3 51 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES PRE - DEVELOPMENT HYDROLOGY C GEOR6E, EI
MIH- 140000 SubbasTn 4A 6/25/2014
I.:SCS'C YEs OU BE
Assume.
HSG
Impervious
Open
Wooded
A
98_
39
30
R
98
61
55
C'
98
74
70
D
98
80
77
HSG'A'= 0%
HSG'B'= 46%
HSG'C'= 54%
HSG 'D' = 0%
Cover Condition
SCS CN
Comments
Impervious
9&
000
Open
68
Assume ood condition
Wooded
63
Assume good'condition
A. Onsite Impervious Breakdown
Contributin ,Area
Area,jsf]
Area Jacresl
Buddirig
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Area [sil
Area lacresl
Comments,
Onsite impervious
98
0
000
Onsite open
68
0
000
Assume good condition
Onsite wooded
63
169,323
3 89
Assume good condition
Onsite pond
100
0
000
-
Offsite impervious
98
1,744
004
'Offsite open
68
4,310
_ 0 10
Assume good condmon
Offsae wooded
63
2,546
0 06
Assume good condition
Offsite pond .
100
0
000
Total area=
Composite SCS'CN =
% Impervious =
408 acres
00064 sq mi
64
10%

W,ESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 4A 6/25/2014
C. Time of Concentration Information
Length =
185
me of concentration is, calculated using the SCS`Segmental Approach (TR -55)
Segment 1. Overland Flow
Bot Elev =
369
Length =
100
ft
Top Elev =
411
No
Bot Elev =
405
Segment Time =
Height =
6
ft
Slope =
00600
ft/ft
Manning's n =
040
wooded, light underbrush
P (2- year/24 -hour) =
343
inches (Cary, NC)
Segment Time =
1337
minutes
Segment 3. Channel Flow
Length =
609
ft
Top Elev =
369
Bot Elev = -
343
Height =
26
ft
Slope =
0,0427
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2' x'2' channel)
Wetted Perimeter =-
660
If (assume 2'x 2' channel)
Channel Velocity =
5`22
ft/sec
Segment Time =
194
minutes
Segment 2• Concentrated Flow
Length =
185
Top Elev =
405
Bot Elev =
369
Height =
36
Slope =
0 1946
Paved 9=
No
Velocity =
7 12
Segment Time =
0 41
Time of Concentration = 1574 minutes
SCS Lag Time = 945 minutes (SCS Lag = 0 6* Tc)
Time Increment = 274 minutes (= 0 29 *SCS Lag)
7
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 SuAastn 4B 6/25/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
`98
61
55
C
98
74
__70
D
'98
80
77
HSG 'A' = '0%
HSG 'B'­ 92%
HSG'C'= 8%
HSG ,'D' = 0%
Cover Condition
SCS CN_
Comments
Impervious
98'
_ 000
Open
62
_
Assume ood;condition
Wooded
56
Assume good'condition
,II; -PRE DE".1?EILOPMENT � -
A. Onsite Impervious Breakdown
Contributin Area
Area (sfJ
Area acres
Building
0
_ 000
Parking/Roads
_ _ 0
_ 000
Sidewalk
0
060
Other
0
060
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN_
Area Isfl
Area acres
Comments
Onsite impervious
98
0
000
Onsite open
62
0
000
Assume good condition
Onsite wooded
56
81,945
188
Assume, good condition
Onsite pond
100
0
000
Offsite impervious
98
_ 0
000
Offsite open
62
0
000
Assume good condition
Offsite wooded
56
0
000
Assume good condition
Offsite pond
100
0
000
-
Total,area =
Composite SCS'CN­
Impervious =
1 88 acres
00029 sq mi
56
00%

WESTON TOWNHOMES PRE - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 4B 6/25/2014
C. Time of Concentration Information
nme�of concentration is calculated using the,SCS Segmental Approach (TR -55)
Segment 1 Overland Flow
652
ft
Length =
100
ft
Top Elev =
409
32
Bot Elev =
404_
ft
Height=
5
ft
Slope=
00500
ft/ft
Manning's n =
040
wooded, light underbrush
P (2- year /24 -hour) =
3,43
inches:(Cary, NC)
Segment Time =
1438
minutes
Segment 3 Channel Flow
Length =
652
ft
Top Elev =
372
Bot Elev =
Bot Elev =
343
32
Height =
29
ft
Slope =
00445
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
6 00
If (assume 2'x 2' channel)
Channel Velocity =
5'33
ft/sec
Segment Time =
204
minutes
Segmenta2 Concentratedflow
Length =
150
Top,Elev =
404
Bot Elev =
372
Height =
32
Slope =
0,2133'
Paved 9 =
No
Velocity =
745
Segment Time =
034
Timeof Concentration = 1675 minutes
SCSTag Time = W05 minutes (SCS,Lag =10 6* Tc)
Time'Increment = 2,91 minutes (= 0 29 *SCS Lag)
ft
ft
ft/ft
ft/sec
minutes

WESTONITOWNHOMES PRE- DEVELOPMENT'HYDROLO_ GY C', GEORGE, E1
MIH,- 140000 Subbastm4C 6/25/2014
L :- S�CUR.: �iitiINI�ERS -
Assume.
HSG
Impervious,
Open
Wooded
A - -
98, _
39 _
30
- — — -B _
98,
161 _
55
�— C' -
-- 98,
`74'
70
D
98
;80
77
HSG ;'A' = 0%
HSWB' = 56%
HSUV = 44%
HSG V— 0%
Cover,Condjtiod_ _ _
SCS CN
Comments
Impervious
98
_
Open
67
Assume`, ood,condrti6n
Wooded _
62
Ass6fh6lgo6ida66ndition
MU M o
A. Onsite Impervious Breakdown
Contributor g Area
Area [sn'
Area acres
Building
0
_ 0°00
--Parking/Roads,
0
000
Sidewalk__
0 _ _
'000
_ Other _.
01
0100
Totals
,0
0100
X. Watershed Breakdown
Codtribuhn Area
SCS'CN
Area acres
Comments
Onsrte im ervious
98
101%
0`00
_ Onsrte,'o en
67 _ _
015 _ _
Assume ood condition
Onsit6 wooded _
_ _ _ _ 62
3y84
Assume ood condition
_ _Onsite and
100'
Fe
0 100
_
Offsitefim ervious'
98,
1 62
Mite o en
67' _
1 71
_ Assume, ood condition
Offsite�wooded
62
119
Assume; ood condition
Offsite' and
100
000
-
TotaLarea =
851 acres
-00133 sq mi
Composite,SCS,CN =
70
' %,I'mperviousl=
101%

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH= 140000 Subbastn 4C 6/25/2014
C: Time'of Concentration Information
246
Top Elev =
me,6f concentrathonvs,calculated usmgsthe SCS SegthentabApp
oack (TR -55)
Segment 1 Overland,Flow
Height =
46
Length =
100
ft
Top Efev =
409
698
Bot Elev =
402
Height =
7
ft
Slope =
00700
ft/ft
Manning's n =
040
wooded light underbrush
P (2- year /24- hour) =
343
inches (Cary, NC)
Segment Time =
1157
minutes
Segment,3• Channel Flow
Length =
562
ft
Top Elev =
356
Bot'Elev =
343
Height =
13
ft
Slope =
00231
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
600
IP(assume 2' x 2' channel)
Channel Velocity =
384
ft/sec
Segment Time'=
244
minutes
Segment 2 Concentrated Flow
Length =
246
Top Elev =
402
Bot Elev =
356,
Height =
46
Slope =
0 1870
Paved v =
No
Velocity =
698
Segment'Ttme =
059
Time of Concentration = 15 59 minutes
SCS Lag Time = 935 minutes (SCS Lag = 0 6* Tc)
Time Increment= 2 71 minutes = 0 29 *SCS La
ft
ft
ft/ft
ft/sec
nunutes

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 140000 Subbastn 4D 6/25/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG 'A' = 0%
HSG 'B' = 24%
HSG 'C' = 30%
HSG'D'= 46%
Cover Condition
SCS CN
Comments
Impervious
98
000
Open
74
Assume good condition
Wooded
70
Assume good condition
A. Onsite Impervious Breakdown
Contributing Area
Area Est]
Area jacresl
Building
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Areas
Area acres
Comments
Onsite impervious
98
0
000
Onsite open
74
0
000
Assume good condition
Onsite wooded
70
1,512
0 03
Assume ood condition
Onsite and
100
0
000
"Offsite impervious
98
68,700 0
1 58
Offsite open
74
77,012
1 77 _
Assume good,conditibn
Offsite wooded
70
216,652
497
Assume good condition,
Offsite pond
100
0
000
Total area =
Composite SCS CN =
% Impervious =
835 acres
00131 sq mi
76
189%

WESTON TOWNHOMES PRE-DEVELOPMENT HYDROLOGY C GEORGE.,EI
MIH- 140000 Subbasin 4D 6/25/2014
C. Time of Concentration Information
Length =
208
,me of concentration,rs,calculated using 1he,SC -S Segmento Approach (TR -SS)
Segment I Overland Flow
'Bot Elev =
348
Length =
1'00
ft
Top Elev =
404
No
Bof Elev—
396
Segment Time =
Height-
8
ft
Slope =
0080 - 0
ft/ft
Mammng's n
04,0
wooded light underbrush
P (2- year /24- hour) =
143
inches (Cary; NC)
Segment Time—
1191
minutes
Segment 3 Channel Flow,
Length =
234
ft
Top Elev =
348
Bot Elev =
343
Height =
5
ft
Slope =
00214
ft/ft
Mannmg's,n =
0 045
natural channel
Flow,Area =
400
sf (assume,2 "x 2' channel)
Wetted, Perimeter =
600
ff (assume 2'x 2' channel)
Channel Velocity =
3 69
fcsec
Segment Time =
1.06
minutes
Segment 2• Concentrated Flow
Length =
208
Top Elev =
396
'Bot Elev =
348
Height-=
48
Slope =
02308
Paved 9'_
No
Velocity =
775
Segment Time =
045
Time of Concentration = 1342 minutes
SCS,Lag Time = 805 minutes (SCS Lag = 0 6* Tc)
Time Increment = 233 minutes (= 0 29 *SCS La
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES PRE- DE-VELOPMENT- HYDROLOGY C GEORGE „EI
MIH 4140000 Su "'Bbasttt 5 6/25/201'4
Assume.
HSG _
Impervious
Open
Wooded_
A
,98
39'
30,
B
'98
61
_ _55
C
98
74
70_
D
98
80
77
HSG 'A' = 0%
HSG 'B',= 70%
HSG'C "= 30%
HSG'D''= I0,%
Cdv&,Condition
SCS CN
�Comment_s
Impervious'
98
_
Open
65 s _
_ Assume ood condition
Wooded
60
- Assume,good condition
SIT P ;D GEI ©$MENT- -- '
A: Onsitedmpervious Breakdown
Contributing Area
_SCS CN
es
Buildiri
Comments+
_
Parkm oad's
0, -
=Areas,
_
_Sidewalk
en _ _
65
Other
000-
Assume good condition-
Totals
r
10,701 _
B. Watershed Breakdown
,Contributin Area _
_SCS CN
Area WI
Areal acres
Comments+
'Onsrte impervious
98
0, -
---000, , _ j
-
en _ _
65
10
000-
Assume good condition-
Onsite wooded
60
10,701 _
025
Assume_ ood condition _
Onsite pond
100
0
000,
Offsite impervious
98 _
_ 41,012-
094,
Offsite o eii,
65 _
.102,845 -
236
Assume goodiconaition
Off ite wooded
66'
24,857
_0 57
Assume good,condrtion _
Offsrte pond
100 _
0
.0 -00 _ 1
+ T -
Tota_I area =
412 acres
0'0064 sq mn
Composite SCS CN—
71'
Impervious,=
229%

WESTON TOWNHOMES PRE-DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 5 6/25/2014
C. Time,of Concentration Information
- -me of concentration is'calculated using the SCS Segmental Approach (TR -55)
Segment 1. Overland Flow
Segment 1: Concentrated,Flow
Length =
100
ft
Length— 618
ft
Top,Elev =
420
Top Elev = 418
Bot Elev =
418
Bot Elev = 372
Height =
2
ft
Height = 46
ft
Slope =
00200
ft/ft
Slope = 00744
ft/ft
Manning's n,=
024
dense grasses
Paved ? = No
P (27year /24 -hour) =
343
inches (Cary, NC)
Velocity = 440
ft/sec
Segment Time =
13.78
minutes
Segment Time = 2.34
minutes
'Time of Concentration = 1612 minutes
SCS Lag Time = 9 67 minutes (SCS Lag ='0 6 *`Tc)
Time Increment;= 281 minutes (= 029 *SCS Lag)

WESTON TOWNHOMES PRE - DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 140000 Subbastn 6 6/25/2014
� L� C�'SaC�.JRYE�71'�1tfp ■BiicS� � �
Assume.
HSG
Impervious
Open,
Wooded
A
98
39
30
B
98
61
_ 55
C
98
74
70
D
98
80
77
HSG'A'= 0%
HSG 'B' = 26%
HSG'C' = 72%
HSG'D' = 2%
Cover Condition
SCS,CN
Comments
Impervious _
98
000
Open
71
Assume good condition
Wooded
66
Assume good condition
LTfjI - DE_YELOEMEN7 - �- - -
A. Onsite Impervious Breakdown
Contributing Area
Area lsi]
Area [acres]_
Building
0
000
Parking/Roads
0
6,00
Sidewalk
10
0100
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Area acres
Comments
Onsite impervious
98
000
Onsite open
71
M255959
000
Assume good condition
Onsite wooded
66
0 +00
Assume good condition
Onsite and
100
000
_
Off ne impervious
98
5 88
Offsrte open
71
467,799
1074
Assume, ood condition
Offsite wooded
66
676,753
'1-5--54
Assume good condition
Offsite, and
100
10,438'
4
Total area =
Composite SCS CN =
% Impervious =
3239 acres
00506 sq mi
74
18 1%

WESTON TOWNHOMES PRE- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 6, 6/25/2014
C. Time of Concentration Information
213
Top Elev =
Time of concentration is calculated using the SCS, Segmental Approach (TR -55)
Segment,l: Overland Flow
433
Height =
Length
100
ft
Top Elev =
441 5
Velocity—
Bot'Elev =
440
121
Height =
1 5
ft
Slope =
00150
ft/ft
Mannmg's n =
040
wooded, light underbrush
P (2- year/24 -hour) =
3,43
inch&(Cary, NC)
Segment Time =
23.27
minutes
Segment 3: Channel Flow
Wetted Perimeter =
628
Length =
1130
ft
Top Elev =
433
Bot Elev =
384
Height =
49
ft
Slope =
00434
ft/ft
Manning's m=
0 045
natural channel
Flow Area =
400
sf (assume 2'x 2' channel)
Wetted Perimeter =
600
if (assume 2' x 2' channel)
Channel Velocity =
526
11/sec
Segment Time =
3.58
minutes
Segment 5: Channel Flow
Length =
80
ft
Top Elev =
374
Bot Elev =
371
Height =
3
ft
Slope=
00375
11/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2'x T channel)
Wetted Perimeter =
600
If (assume 2'x 2' channel)
Channel Velocity =
489
ft/sec
Segment Time =
027
minutes
Segment 3• Concentrated,Flow
Length =
213
Top Elev =
440
Bot Elev =
433
Height =
7
Slope =
00329
Paved 9 =
No
Velocity—
292
Segment Time =
121
Segment 4: Pipe Flow
Length =
291
Top Elev—
384
Bot Elev =
374
Height =
10
Slope =
00344
Manning's n =
0 013
Flow Area =
3 14
Wetted Perimeter =
628
Channel Velocity =
1338
Segment Time =
036
Time of Concentration = 28'70 minutes
SCS'Lag Time = 1722 minutes (SCS,Lag = 0 6* Tc)
Time,lncrement = 499 minutes' (= 0 29 *SCS La
ft
11/11
ft/sec
minutes
ft
fi
11/ft-
Assumed RCP
sf (24 ")
If (24" )
ft/sec
minutes

WESTON TOWNHOMES HYDROLOGIC CALCULATIONS C GEORGE, El, PLS
MIH -14000 Pre- Development Reach Data 6/25/2014
III ,CHANNEL REACH DATA
Reach #102 - POA 2 to POA 1
Channel Flow
Length =
Top Elev =
'Bot Elev =
Height=
Slope =
Manning's n
Flow Area =
Wetted Perimeter =
Channel Velocity =
Segment Time =
Total.TravelTime =
Reach #203 - POA 3 to POA 2
Channel Flow
Length
Top Bev =
Bot Elev =
Height =
Slope =
Manning's n =
Flow Area =
Wetted Perimeter =
Channel Velocity =
Segment Time =
Total Travel Time =
Reach #104 - POA 4 to POA 1
Channel Flow
Length =
Top Elev =
Bot Elev =
Height =
Slope =
Manning's n =
Flow Area =
Wetted,Penmeter =
Channel' Vel ocity-
Segment Time =
Total Travel Time =
243
ft
325
319
6
ft
00247
ft/ft
0 045
Natural Channel
2000
sf (Assume 5' x4' Channel)
1300
ft (Assume 5' x 4' Channel)
693
ft/sec
058
minutes
058 minutes
1041
A
354
325
29
ft
00279
ft/ft
0 045
Natural Channel
400
sf (Assume 2'x 2' Channel)
&00
ft,(Assume 2'x 2' Channel)
422
ft/sec
411
minutes
411 minutes
989
ft
343
319
24
ft
00243
ft/ft
0 045
Natural,Channel
400
sf (Assume Tx 2' Channel)
600
ft (Assume Tx 2' Channel)
394
ft/sec
419
minutes
419 nunutes

WESTON TOWNHOMES
1001
HYDROLOGIC CALCULATIONS C GEORGE, El, PLS
MIH -14000
371
Pre- Development Reach Data 6/25/2014
Bot Elev =
343
Reach 4405 - POA'5,to,POA 4
28
Channel Flow
Slope =
00280
Length =
653
ft
Top Elev =
372
400
Bot Elev =
343
600
Height =
29
ft
Slope =
00444
ft/ft
Mammng'sm =
0 045
Natural Channel
Flow,Area =
4 +00
sf (Assume 2;x 2' Channel)
Wetted Perimeter-=
600
ft (Assume 2'x 2' Channef)
Channel Velocity =
533
ft/sec
Segment Time =
204
minutes
Total Travel Time =
204
minutes
Reach #406 - POA 61to POA 4
Channel Flow
Length =
1001
ft
Top Elev =
371
Bot Elev =
343
Height =
28
Ift
Slope =
00280
ft/ft
Mammng's'n =
0 045
Natural Channel
Flow Area =
400
sf (AssumeZ xs2' Channel)
Wetted Perimeter =
600
ft (Assume 2'x 2' Channel)
Channel Velocity =
423
ft/sec
Segment Time =
395
minutes
Total Travel Time =
395
nunutes
0

Scenario: Pre - Development
Weston Townhomes C
MIH14000 ppc George, El
6/25/2014

I MCADAMS
Subsection: ,Master Network Summary
Catchments Summary
Label Scenario
Return Hydrograph Time to Peak Peak Flow
Event Volume (min) (ft3 /s)
(years). (ac -ft)
SUB 1A P
Pre- 1 Yr 24 Hr 1
1 0
0.179 7
727.000 2
2.55
SUB 1'A P
Pre- 2 Yr 24 Hr 2
2 0
0.268 7
726.000 3
3.98
SUB 1A P
Pre- 5 Yr 24 Hr 5
5 0
0.412 7
726.000 5
588
SUB IA P
Pre- 10 Yr 24 Hr 1
10 0
0.536 7
726.000 7
7.42
SUB 4B P
Pre- 1 Yr 24 Hr 1
1 0
0 028 7
754.000 0
0.14
SUB 4B P
Pre- 2 Yr,24 Hr 2
2 0
0 056 7
735:000 0
0.35
SUB 4B P
Pre - 5 Yr 24 Hr' 5
5 0
0 11'0 7
73 -1000 0
0.93
SUB 4B P
Pre- 10 Yr 24 Hr 1
10 0
0°162 7
731 000 1
1.51
SUB 5 P
Pre- 1 Yr 24 Hr 1
1 0
0.235 7
730 000 2
274
SUB 5 P
Pre- 2 Yr 24 Hr 2
2 0
0.355' 7
729.000 4
4.42
SUB 5 P
Pre- 5 Yr 24 Hr 5
5 0
0.554 7
729.000 6
6.72
,SUB 5 P
Pre- 10 Yr 24 Hr 1
10 0
0.726 7
729:000 8
862
SUB' 1B P
Pre- 1 Yr 24 Hr 1
1 0
0.157 7
735.000 1
1:01
SUB 1B P
Pre- 2-Ye 24 Hr 2
2 0
0 275 7
733.000 2
2 36
SUB 1B P
Pre- 5 Yr 24 Hr 5
5 0
0.485 7
732.000 4
4.71
SUB 1B P
Pre- 10 Yr 24 Hr -
-10 0
0.678 7
732.000 6
6.79
SUB 4A P
Pre- 1 Yr 24 Hr 1
1 0
0.131 7
732.000 1
1.08
SUB 4A P
Pre- 2 Yr 24 Hr 2
2 0
0:220 7
730.000 2
228
SUB 4A P
Pre- 5 Yr 2+H 5
5 0
0.377 7
730:000 4
4.18
SUB 4A P
Pre- 10 Yr 24 Hr 1
10 0
0 519 7
730.000 5
581
SUB 1C P
Pre- 1 Yr 24 Hr 1
1 0
0 697 7
733 000 7
753
SUB 1C P
Pre- 2 Yr 24 Hr 2
2 1
1 026 7
733 000 1
1-150
SUB 1C P
Pre- 5 Yr 24 Hr 5
5 1
1.559 7
731.000 1
16:87
SUB 1C P
Pre- 10 Yr 24 Hr 1
10 2
2.014 7
73100& 2
21.35
SUBIA P
Pre- 1 Yr 24 Hr 1
1 0
0.743 7
727.000 1
11.14
SUB 2A P
Pre- 2 Yr 24 Hr 2
2 1
1.054 7
726.000 1
15.96
SUB 2A P
Pre- 5 Yr 24 Hr S
S 1
1.545 7
726.000 2
21.99
SUB 2A P
Pre- 10 Yr 24 Hr 1
10 1
1.956 7
726:000 2
26.78
SUB 2B P
Pre- 1 Yr 24 Hr 1
1 1
1 015 7
727 000 1
14.76
SUB 2B P
Pre- 2 Yr 24 Hr 2
2 1
1.402 7
727.000 2
20.38
SUB 2B P
Pre- 5'Yr 24 Hr 1
15 2
2.004 7
727.000 2
27.15
SUB 2B P
Pre- 10 Yr 24,Hr 1
10 2
2.501 7
727 000 3
3251
SUB 2C P
Pre- 1 Yr 24 Hr 1
1 0
0.113 7
757.000 0
0.56
SUB 2C P
Pre- 2 Yr 24 Hr 2
2 0
0.212 7
741.000 1
128
SUB 2C P
Pre- 5 Yr 24 Hr 5
5 0
0.398 7
740.000 2
2.91
SUB 2C P
Pre- 10 Yr 24 Hr 1
1'0 0
0:572 7
737.000 4
4:53
SUB 3 P
Pre- 1 Yr °2+Hr 1
1, 3
3.273 7
732,000 3
38.43
SUB 3 P
Pre- 2 Yr 24 Hr 2
2, 4
4.624 7
732.000 5
54.86
3UB 3 P
Pre- 5 Yr 24 Hr 5
5 6
6.752 7
731.000 7
75.79
3UB 3 P
Pre- 10 Yr 24 Hr 1
10 8
8.531 7
731.000 9
92.87
3UB 4D P
Pre- 1 Yr 24 Hr 1
1 0
0.622 7
728.000 8
8.75
3UB 4D P
Pre- 2 Yr 24 He 2
2 0
0.902 7
728.000, 1
12.93
;UB 4D P
Pre- 5 Yr 24 Hr 5
5 1
1.350 7
727.000 1
1829
;UB 4D P
Pre- 10 Yr 24 Hr 1
10 1
1 729 7
727:000 2
22.64
;UB 4C P
Pre- 1 Yr 24 Hr 1
1 0
0:433 7
730.000 4
4.94
;UB 4C P
Pre- 2 Yr 24 Hr 2
2 0
0.669 7
730.000 8
8.27
;UB,4C P
Pre- 5 Yr 24 Hr 5
5 1
1.062, 7
729.000 1
12.91
�UB 4C P
Pre- 10 Yr 24,Hr 1
10 1
1.405 7
729.000 1
16.78'
IUB ,'6 P
Pre- 1 Yr 24 Hr 1
1 2
2.120 7
739.000' 1
18:71
Weston Townhomes
10I1-1140oo ppc
C George, El
6/25/2014

9 MCADAMS
Subsection: Master Network Summary
Catchments Summary
Label' Scenario
SUB 6 1 Pre- 5 Yr 24 Hr
SUB 6 t Pre- 10 Yr 24 Hr
Return Hydrograph
Event Volume
(years) (ac -ft)
5I 47,84
10; 6.194
Time to,Peak
(min)
738 000
738 000
Peak Flow
(ft3 /S)
42.97
5481
Node Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (min) (ft3 /s)
( vears) (ar -ft)
POA #1
Pre- 1 Yr 24 Hr
1
9729
734 000
93.89
POA #1
Pre- 2 Yr 24 Hr
2
14.176
734 000
14166
POA #1
Pre- 5 Yr 24 Hr
5
21.358
734.000
206.62
POA #1
Pre- 10 Yr 24 Hr
10
27.481
734 000
26099
JUNC #2
Pre- 1 Yr 24 Hr
1
5 138
733.000
56-37
JUNC #2
Pre- 2 Yr 24 Hr
2
7.285,
733 000
80.74
JUNC #2
Pre- 5 Yr'24 Hr
5
10.687
733 000
112.43
JUNC #2
Pre- 10 Yr 24 Hr
10
13 547
733 000
138.65
JUNC #4
Pre- 1 Yr 24 Hr
1
3.565
735 000
2887
,JUNC #4
Pre- 2 Yr 24 Hr
2
5.333
735.000
45.98
JUNC #4
Pre- 5 Yr 24 Hr
5
8 229
734.000
70.23
JUNC #4
Pre- 10 Yr 24 Hr
10
10 724
733 000
9097
,JUNC #3
Pre- i Yr 24 Hr
1
3273
732.000
38.43
JUNC #3
Pre- 2'Y,r 24 Hr
2
4.624
732.000
5486
JUNC #3
Pre- 5 °Yr 24 Hr
5
6.752
731 000
7579
JUNC #3
Pre- 10 Yr 24 Hr
10
8 531
731.000
9287
JUNC #5
Pre- 1 Yr 24 Hr
1
0 235
730.000
2.74
JUNC #5
Pre- 2 Yr 24 Hr
2
03 55
7,29:000
442
JUNC #5
Pre- 5 Yr, 24 Hr
5
0 554'
729.000
672
JUNC #5
Pre- 10 Yr 24 Hr
10
0.726
729 000
8.62
JUNC #6
Pre- 1 Yr 24 Hr
1
2 120
739.000
18.71
JUNC #6
Pre- 2 Yr 24 Hr
2
3.136
738.000
28.85
JUNC #6
Pre- 5 Yr 24 Hr,
5
4.7841
738.000
4297
JUNC #6
Pre- 10 Ye'24 Hr 1
101
6.1941
7380001
54.81
Weston Townhomes C George „EI
MIH14000 ppc 6/25/2014

!!JI MCADAMS
Subsection: Master Network Summary
Catchments Summary
Label Scenario Return Hydrograph Mme to Peak Peak Flow
Event Volume (min) MIN
(years) (ac -ft)
SUB 1A
Pre- 100 Yr 24 He
100
1.009
726.000
11.93
SUB 1B
Pre- 100 Yr 24 He
100
1.473
730.000
13.79
SUB 1C
Pre- 100 Yr 24 Hr
100
3.744
731 000
34.64
SUB 2A
Pre- 100 Yr 24 He
100
3.486
726;000
40.20
SUB 2B
Pre- 100 Yr 24 H�
100
4.325
727.000
47.12
SUB 2C
Pre- 100 Yr '24 He
100
1.313
737.000
10.33
SUB 3
Pre- 100 Yr 24 He
100
.15 139
731.000
14137
SUB 4A
Pre- 100 Yr 24 He
100
1 094
728.000
11 15
SUB 4B
Pre- 100 Yr 24 He
100
0 385
730.000
364
SUB 4C
Pre- 100 Yr 24 He
100
2.741,
728.000
28.62
SUB 4D
Pre- 100 Yr 24 Hr
100
3.156
727.000
35 10
SUB 5
Pre- 100 Yr 24 He
100
1.389
729.000
14.32
SUB 6
Pre-' 100 Yr 24 He
1 1001
11.570
1 738.000
90.99
NodekSummary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (min) (ft3 /s)
(years) (ac -ft)
JUNC #2
Pre- 100 Yr 24 He
100
24.245
732.000
214.42
JUNC #3
Pre- 100 Yr 24 He
100
15139
731.000
141.37
JUNC #4
Pre- 100 Yr 24 He
100
20.320
732.000
156.08
JUNC 45
Pre- 100 Yr 24 He
100
1.389
729.000
14.32
JUNC #6
Pre- 100 Yr 24' Hr
100
11.570
738.000
'90.99
POA #1
Pre- 100 Yr 24' Hr
100
50.765
733.000
424.69
Weston Townhomes C Geogge„ EI
MIH14000 ppc 6/26/2014

POST = DEVELOPMENT HYDROLOGIC
CALCULATIONS
WESTON TOWNHOMES
MIH -14000

� O
C7 O
0
0
a
�a
ti
O
LI
0
w
Q
a
Q
o
z a
3 z
w � a
x
� po
N
I
Q��V)
_
.-.
00
e0+f
N
�
S
tT
NIA
— V'f
l�
ODI„M„
V1
M
�pIN
C4
z
i
N
V'f
O
00
00
[�
ID
O
00
V1 I
t-
t`io00�
oo
n
_-:
00
C
�ot-
a0
Ic4nnGoe
v1
�o
ON
V k
-
I M
t-
en
VOietm
Din
00
O
N
M
•••
C
,
t�
N
00
4
i M
_
I
?o
l-
N
OI
v1 n
'
'n
v�10
0
O
Olin
O
M
Of
�F
N
O
0100
O�oOI
O�O��
O
O
er
O
o0
AIM
�
!O
8f0
S
S
S�OO�OiS
O�O�S
S
S
8jN
�
fp°C;CCCCiCCCCCC!CCCC�C
o
u
j)j'p
�p
rl
p
fl
C
p
O
C
O
C
t.
I v
p
O
0000.
00
f O
�O
p
O
C
Q
Q
3
w
G
b
0
S
N
O
B
O
i
T
8
n
M
O
C
C
C
C
N
M
O
i
^
I C
I
C
I
C�
I
0M C
e
O
O
O
S
N
�O
S
00
V1
00100
CT! 00
a
C
O
G
cV
M
10
th
N
O
O
OIN
1 1
0,—
O
I
Ip ,pi
O SIS
N1S'O,O
pp
5100 OO O cV O S'S
�W,'"�
pp, C C
C
C
C
C
C C C C C O C C C O
C
'C [� �DppIM
�D
t`
N1�0 OVf vl p O O p
M— O — O O M S
0
0 N O 0 0 N. O O O; O
Q O O
M,
00
I
00
M
S
M( O
t�
C—
(VEC
Cf
C�C,C
O O C C C O CIC
I
n
M
8��/1O
OCC1CC,CCIjOGC
":
f
O
C
1
I
OHO O
;
N.SjNIS
N
v1
S
'
OZ'S
O
I�
;iR
I
t
i
N
N
N
`^
�
w
v
G
v

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin IA 9/10/2014
d S @S,IIRVE,NUMBERS
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
7,7
HSG'''A' =
0%
HSG'B' =
75%
HSG'C'=
25%
HSG'D'=
0%
Cover-Condition
SCS-CN
Comments
Impervious
98
-
Open
64
Assume. good condition
Wooded
59
Assume good condition
A. Onsite Impervious Breakdown
Contributing, Area
Area Isfj
Area4 acres
Building
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS -CN
Area lsfl
Area lacresl
Comments
Onsite impervious
98
0
0.00
Onsite open
64
278
0.01
Assume good,condifion
Onsite wooded
59
7,553
017
Assume goo&condition
Onsite pond
100
0
000
-
Offslte mi ervious
98
39,782
091
Mite open
64
29,085
067
Assume good condition
Offsite wooded
59
31,938
073
Assume good condition
Offsite pond
100
0
000
-
Total area =
Composite SCS CN =
% Impervious =
249 acres
108;636' sq ft
75
366%

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, ,El
MM- 140000 Subbastn IA 9/10/2014
C. Time of Concentration Information
Length =
225
ne of concentration m calculated using the SCS
Segmental Approach (TR -55) ,
Segment 1: Overland Flow
323
Height =
Length =
100
ft
Top Elev =
370
Velocity=
Bot Elev =
360
0.57
Height =
10
ft
Slope =
01000
ft/ft
'Mammng's n =
r0 40
wooded, light underbrush
'P (2- year /24 -hour) =
343
mches,(Cary, NC)
Segment Time =
70.90
minutes
Segment 3: ChanneGFlow
Length =
58
ft
Top Elev =
-323
Bot Elev =
319`
Height =
4
ft
Slope =
0,0690
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
600
if (assume 2'x 2' channel)
Channel Velocity =
664
ft/sec
Segment Time =
0.15
minutes
Segment 2: Concentrated'Flow
Length =
225
Top Elev =
360
Bot Elev =
323
Height =
37
Slope =
01644
Paved 9 =
No
Velocity=
654
Segment Time =
0.57
Time of Concentration = 1161 minutes
SCS Lag Time= 697 minutes (SCS Lag = 0 6* Tc)
Time Increment = 202 minutes (= 0 29 *SCS'Lag)
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES POST - DEVELOPMENT H"ROLOGY C GEORGE,.EI
M1H- 1,40000 Subbasin 1B 9/10/2014
cSC3 M1RVE; [1�IMBERS
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
_ B
98
61
55
C _
98
74
70
D
98
80
77
HSG 'A' =
0 %
HSG'B' =
65%
HSG "C' =
35%
HSG''D' =
0%
Cover "Condition
SCS CN
Comments
Impervious
98
011
Open
66
Assume good condition
Wooded
60
Assume good condition
A. Onsite Impervious,Breakdown
Contributing Area
Area (sf]
Area acres
Buildm
4,912
011
Parkin oads
15,070
0 35
Sidewalk
5,062
012
Other
0
0 00
Totals
25,044
0 57
B. Watershed;Breakdown
Contributing Area
SCSCN
Area Jsfj
Area acres
Comments
Onsite-impervious
98
25,044
057
-
Onsite open
66
47;391
109
Assume ood condition
Onsite wooded
60
68,117
156
Assume good condition
Onsite pond
100
0
000
-
Offsite impervious
98
5;879
013
-
Mite open
66
2;547
006 _
Assume ood,condition
Offsite wooded
60
0
000
Assume ood condition
Offsite pond
100
0
0100
-
Total area=
Composite SCS CND=
% Impervious =
C. Time,of Concentration Information
Time of concentration is assumed to be 5- minutes
3 42 acres
148;978 sq ft
70
208%
Time of Concentration = 5'00 minutes
SCS,Lag Time = 300 minutes (SCS Lag = 0 6* Tc)
Time Increment = 087 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES
MIH- 140000
Assume:
POST_ - DEVELOPMENT HYDROLOGY C GEORGE, El
Subbasin 1B- To SWMF 1 9/10/2014
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
_ _C
98
74
70
D
98
80
77
HSG 'A' =
0%
HSG'B' =
43%
HSG 'C' =
57%
HSG'D'=
0%
Cover Condition
SCS CN
Comments
hn ervious
98
-
en
68
Assume good condition
Wooded
64
Assume goo&condition
A. Onsite Impervious Breakdown
Contributing Area
Area [sf]
Area acres
Building
80,747
F85
Parking/Roads
53,337
122
rSidewalk
(8,406
042
Driveway
22,353
051
Totals
174,843
4',01
B. Watershed Breakdown
Contributing Area
SCS CN
Area lsfl
Area acres
Comments
Onsite impervious
98
174,843
401
-
,Onsite open
68
123,057
283
Assume good condition
Onsite wooded
64
0
000
Assume' ood condition
Onsite pond
100,
10,1'56
0,23
-
Offsite`im ervious
98_
0
000
-
Offsite open
68
0
000
Assume good condition
Offsite wooded
64
0
000
Assume good condition
Offsite pond
100
0
000
-
Total area =
Composite'SCS CN =
% Impervious`=
C. Time of Concentration Information
Time of concentration is assumed to be 5 minutes
707 acres
308,056 sq ft
86
568%
Time of Concentration = 500 minutes
SCS Lag Time = 300 minutes (SCS Lag = 0 6* Tc)
Time Increment = 087 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin IC 9/10/2014
Assume.
HSG
Impervious
Open
Wooded
A
_ 98
39
30,
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A' = 0%
HSG'B' = 33%
HSG'C' = 38%
HSG'D' = 29%
Cover Condition
S_ CS CN
Comments
Impervious
98
-
en
71
Assume good condition
Wooded
67
Assume good condition
II. PROS F DEVEIOPMEfi1T
A. Onsite Impervious Breakdown
Contributing Area,
Area [sf]
Area acres
Buildin
0
0 00
Parton oads
0
0 00
_
918
0 02
_Sidewalk
Other
0
0 00
Totals
918
0 02
B. Watershed'Breakdowu
Contributing Area
SCS'CN
Area acres
Comments
Onsite impervious
98
002
_
Onsite open
71
M75,481
044
Assume good condition
Onsite wooded
67
1 73
Assume ood condition
Onsite and
100
0 00
Offsite im ervious
98
211
-
Offsite open
71
56,237
129
Assume ood condition
Offsrte wooded
67
207,721
477
Assume good condition
Offsite _ nd
`100
0
&00
-
Total,area =
Composite SCS CN =
% Impervious =
10'36 acres
451,148 sq ft
74
205%

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 140000 Subbastn IC 9/10/2014
C. Time of Concentration Information
Time of concentration is calculated using the SCS - Segmental Approach (TR -55)
Segment 1: Overland''Mw
639
ft
Segment 2: Concentrated Flow
333
Length =
100
ft
Length = 671
ft
Top Elev =
404
Slope =
Top Elev = 400
ft/ft
Bot Elev =
400
naturalchannel
Bot Elev = 333
400
Height =
4
ft
Height = 67
ft
Slope =
0,0400
ft/ft
Slope = 00999
ft/ft
Manning's n =
040
woods, light underbrush
Paved 9= No
P (2= year/24- hour')`=
343
inches (Cary, NC)
Velocity = 5 10
ft/sec
Segment Time =
15.72
minutes
Segment Time = 2.19
minutes
Segment 3: Channel Flow
Length =
639
ft
Top Elev =
333
Bot Elev =
319
Height =
14
ft
Slope =
0021'9
ft/ft
Manning's n =
0 045
naturalchannel
Flow Area =
400
sf (assume -2"x,2' channel)
Wetted Penmeter =
600
If (assume 2'x 2' channel)
Channel Velocity =
374
ft/sec
Segment Time =
2.85
minutes
Time'of Concentration = 20'76 minutes
SCS Lag Time = 1246 minutes (SCS Lag =,0 6* Tc)
Time Increment = 3 61 minutes ( = +0 29 *SCS Lag)

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, EI
M1H7140000 Subbasin ID 9/,10/2014
Assume:
H_ SG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A',=
0%
HSG'B'=
87%
HSG'C''=
13%
HSG 'D' =
0%
Cover Condition
SCS,CN Comments
Impervious
98 -
en
63 Assumne, oo&condition
Wooded
57 Assume,good condition_
II:�POSTDEVrELOPM��X- r `' � :
A. Onsite Impervious Breakdown
Contributing Area
Area [if]
Area acres
Building
0
000
Parking/Roads
0
000
Sidewalk
361
001
Other
0
000
Totals
361
001
B. Watershed Breakdown
Contributing Area
SCS'CN
Areas
Area jacresl
Comments
Onsiterim ervious
98
361
001
-
_ Onsite open
63
16,366
038
Assume good condition
Onsite wooded
57
11,333
026
Assume, good condition
Onsite pond
100
0
000
Offsite impervious _
98 _ —
0
000
-
Offsite open
63
-791 _
002
Assume, good condition
Offsite wooded
57
0
0'00
Assume good condition
Offsite pond
100
0
600
-
Total area =
Composite SCS'CN =
% Impervious =
C. Time of Concentration Information
Time of concentration,massumed to,be,S,minutes
0'66 acres
28,851 sq ft
61
13%
Time�of Concentration = 500 minutes
SCS Lag Time = 300 mmnutes,(SCS lag = 0 6* Tc)
Time Increment = 087 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES POST- DEVELOPMENT'HYDROLOGY C GEORGE, EI
MI13- 140000 Subbastn lA 9/10/2014
Assume.
HSG
Impervious
Open
Wooded
A
98
39-
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG'A'= 0%
HSG B'= 86%
HSG'C'= 0%
HSG U= 14%
Cover Condition
SCS CN
Comments
Impervious
98
000
Open
64
Assume good condition
Wooded
58
Assume good condition
IIP.OSTDEVE OPMENT`
A. Onsite Impervious Breakdown
Contributing Area
Area IsQ
Area acres
Biulding
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other_
0
000
Totals
0
000
B.. Watershed,Breakdown
Contributing Area
SCS CN
Area lsfl
Area facresl
Comments
Onsite impervious
98
0
000
Onsite open
64
134
000
Assume good condition
Onsite wooded
58
7,188
0 17
Assume, ood condition
Onsite pond
100
0
000
-
Offsite impervious
98
175;240
402
Offsite open
64
116,583
2168'
Assume - ood condition
Mite wooded
58
80,199
184
Assume good condition
Offsite pond
100
0'
`0'00
Total area = 871 acres
379,344 sq ft
Composite SCS CN = 78
% Impervious = 462%

WESTON TOWNHOMES POST- DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 140000 Subbasin 2A 9/10/2014
C. Time of Concentration, Information
Time of concentration is calculated using the SCS Segmental Approach,(TR -55)
Segment 1: Merland Flow
Segment 2: Concentrated Flow
Length =
100
ft
Length =
252
It
Top Elev =
380
Top Elev =
368
Bot Elev =
368
Bot Elev =-
35952
Height=
12
Il
Height=
848
ft
Slope =
01200
ft/ft
Slope =
00337
ft/ft
Mannmg's g =
040
woods, light underbrush
Paved 9=
No
P (2- year /24 =hour) =
343
inches (Cary, NC)
Velocity =
296
ft/sec
Segment Time =
10.13
minutes
Segment Time =
1.42
minutes
Segment 3: -Pipe Flow
Segment 4. Channel Flow
Length =
174.
ft
Length =
218
ft
'Top Elev =
360
Top Elev =
344
Bot Elev =
343'7
Bot Elev =
325
Height =
1582
ft
Height =
18 °7
It
Slope =
00909
ft/ft
Slope =
00858
ft/ft
Mannmg'sn =
0 024
CMP
Manning's n =
0 045
natural channel
Flow Area =
3 14
sf(24')
Flow Area =
400
sf (assume 2'x T channel)
Wetted Penmeter =
628
If (24 ")
Wetted Penmetcr =
600
if (assume 2' x 2' channel)
Channel Velocity—
1-179
'ft/sec
Channel Velocity =
740
ft/sec
Segment Time =
0.25'
minutes
Segment Time =
0.49
minutes
Time,of Concentration = 1229 minutes
SCS Lag,Time = 737 minutes (SCS Lag = 0 6* Tc)
Time Increment = ,2 14 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES POST_- DEVELOPMENT"HYDROLOGY C GEORGE, EI
MIH- 140000 Subbastn 2B 9/10/2014
Assume:
,HSG
Impervious'_
'Open
Wooded'
A
98
39
30
B
98
61
55
C
98
74
_ 70
D
98,
80
77
HSG "A' = 0%
HSG'B' = 60%
HSG'C' = 0%
HSG'D'= 40%
Cover Condition
SCS CN_
Comments
Iin ervious
'98
_ -
en
69
Assume gbodxondition
Wooded
64
Assume good,condrtion
II. POST °DE PME- 4,
A. Onsite Impervious Breakdown
,Contributing Area
Area Isf]
Area acres
Building
0
000
Parking/Roads
0
0'00
Sidewalk
523
001
Other
0
000
Totals
523
001
B. Watershed'Breakdown
Contributing Area
SCS CN
Area's
Area acres
Comments
Onsite impervious _ _
98
523
001
-
Onsite open
69
6,738
015
Assume g22d condition
Onsite wooded
64
13,868
032
Assume good condition
`Onsite pond
100
01
000
Offsue im er6ous
98
207;284
476
Mite open
69
130,661
300
Assume good condition
Offsite wooded
64
78,968
181
Assume good condition
Offsite pond
100
0
000
Total area =
Composite SCS CN =
% Impervious =
10'06 acres
438,042 sq ft
82
474%

WESTON TOWNHOMES
MIH- 140000
POST - DEVELOPMENT HYDROLOGY
Subbastn 2B
C. Time of Concentration Information
lime of concentration is cdlculated using the SCS Segmental,Approach (TR -55)
Segment 1: Overland Flow
Length =
82
Length =
100
ft
Top Elev =
368
6
Bot Elev =
356
Paved ? =
Height =
12
ft
Slope =
01200
11/11
Mammng's n =
040
woods, light underbrush
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time=
10.13
minutes
Segment 3: Channel Flow
Length=
891
ft
Top Elev—
350
Bot Elev =
325
Height =
25
ft
Slope =
00281
ft/ft
Mammng's n =
0 045
natural channel
Flow,Area =
400
sf (assume 2'x 2' channel)
Wetted Perimeter =
600
if, (assume 2' x 2',channel)
Channel Velocity =
423
ft/sea
Segment Time =
3.51
minutes
Segment 2: Concentrated Flow
Length =
82
Top Elev =
356
Bot Elev =
350
Height =
6
Slope =
00732
Paved ? =
No
Velocity =
436
Segment Time =
0.31
Time of Concentration = 1395 minutes
SCS Lag Time = 837 minutes (SCS Lag = 0 6s Tc)
Time Increment = 243 minutes = 0 20SCS4Ia
C GEORGE, EI
9/10/2014
ft
ft
11/11
II/sec
minutes

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 2C 9/10/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
-39
30
B
98
61 _
55
C
98
74
70
D
98
80
77
HSG'A'= 0%
HSG B' = 99%
14SG'C'= 1%
HSG D'= 0%
Cover Condition
SCS CN
_ Comments
Impervious
98
0`25
Open
61
Assume good condition
Wooded
55
Assume good condition
II, PO, S1' DEVEI;OP.MENT�
A. Onsite Impervious Breakdown
Contributing Area
Area jsQ
Area acres
Building
11,058
0`25
Parking/Roads
0
000
Sidewalk
924
002
Other
0
000
Totals
11,982
_228
B. Watershed Breakdown
Contributing Area
SCS CN
Area lsfl
Area acres
_Comments
Onsite impervious
98
11,982
0.28
Onsite open
61
18,530
043
Assume good condition
Onsite wooded
55_
94,622
217
Assume good condition
Onsite pond
100
0
000
Offsite im ervions,
98
0
000 _
Offsite open
61
1 741
11 0`02
Assume good condition
Offslte wooded
55
3,377
008
Assume good condition
Offsnte pond
100
0
000
Total area = 297 acres
129,252 sq ft
Composite SCS CN = 60
% Impervious— 93%

WESTON TOWNHOMES POST- DEVELOPMENT HYDROLOGY C GEORGE, EI
MIH- 1,40000 Subbasin 2C 9/10/2014
C. Time of Concentration Information
Tame ,ofconcentrahomis,calculated using the SCS Segmental Approach,(TR -55)
3
Segment l: Overland Flow
Length =
Top Elev =
Bot Elev =
Height =
Slope =
Manomg'sn =
P (2- year /24 -hour) =
Segment Time =
100
ft
370
352
18
ft
01800
ft/ft
040
woods,,light-underbrush
343
inches (Cary, NC)
8.61
minutes
Segment 3:'Channel'Flow
Length =
Top Elev =
Bot,Elev =
Height =
Slope =
Mannmg's'm=
Flow Area =
Wetted Perimeter =
Channel Velocity=
Segment Time =
Time of Concentration = 1251 mmutes
SCS Lag Time = 750 minutes (SCS Lag = 0 6* Tc)
Time Increment = 2 18 minutes (= 0 29 *SCS Lag)
980
ft
352
325
27
ft
00276
ft/ft
0,045
natural channel'
400
sf (assume Tx 2" channel)
600
if (assume 2'x 2' channel)
419
ft/sec
3.89
minutes

WESTON TO_ W NH_ OMES POST- DEVELOPMENT'HYDROLOGY C GEORGE, El
MIH- 140000 Subbastn.3 9/10/2014
y SCS 11
_
Assume:
HSG
Impervious
Open
Wooded
` A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG 'A' =
0%
HSG'B'—
62%
HSG'C'=
24%
HSG 'D' =
14,%
Cover Condition;
SCS CN
Comments
impervious
98
-
en
67
Assume good condition
Wooded
62
Assume good condition
,10XV69MM I NT
A. Onsite Impervious Breakdown
Contributing Area
Area [st]
Area jacresl
Building
0
000
Parking/Roads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Area IsA
Area acres
Comments
Onsite impervious
98
0
000
Onsite open
67
455
001
Assume good condition
Onsite wooded_
62
0
000
Assume good condition
Onsite pond
100
0
000
Offstte impervious
98 _
650,873
1494
Mite open
67
606,622
1393
Assume good condition
Offstte wooded
62
335,073
769
Assume good condition
Offstte pond
100
26,335
060
Total area =
Composite SCS CN =
% Impervious =
3718 acres
1,619,358 sq ft
79
402%

WESTON TOWNHOMES POST- DEVELOBMENT HYDROLOGY 'C .GEORGE „EI
MIH- 140000 Subbastn 3 9/10/2014
C. Time of Concentration, Information
m"e;of concentraabn wcalculated'usmg.the SCS Segmental Approach (TR -55)
Segment 1: Overland Flow
313
ft
Length =
100
ft
Top Elev =
438
20
Bot Elev =
434
ft
Height =
4
ft
Slope =
00400
ft/ft
Mammng's`n =
040
woods, light underbrush
P.(2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time =
1572
minutes
Segment 3:,Channel Flow
1.29
minutes
Length =
468
ft
Top Elev =
414
Channel Velocity =
Bot Elev =
394
0.32
Height =
20
ft
Slope =
00-427
Rift
Manning's n =
0 045
natural channel
F1ow.Area =
400
sf (assume 2'x 2' channel)
Wetted " Penmeter =
600
If (assume 2'x 2' channel)
Channel Velocity =
-5,22
ft/sec
Segment'Time =
1.49
minutes,
Segment 5: Pond
Length =
384
ft
Top Elev =
384
Bot'Elev =
374
Height =
10
ft
Slope =
00260
ft/ft
Channel Velocity =
000
ft/sec
Segment Time =
0.00
minutes
Segment 3: Channel Flow
Length =
313
ft
Top Elev =
362
Bot Elev =
Bot Elev =
354
20
Height =
8
ft
Slope =
00256
ft/ft
Manning's n­
0 045
natural channel
Flow Area=
400
sf (assume 2' x 2' channel)
Wetted Penmeter =
600
if (assume 2'x 2 "channel)
Channel Velocity =
404
ft/sec
Segment Time =
1.29
minutes
Segment "2: Concentrated Flow
Length =
276
Top Elev =
434
Bot Elev =
414
Height =
20
Slope =
0 0725
Paved 9=
Tfo
Velocity =
434
Segment Time =
1.06
Segment 4: Pipe Flow
Length =
266
TopiElev =
394
Bot,Elev =
384
Height,=
10
'Slope =
0 03,7,6
Manning's n =
0 013
Flow Area =
3 14
Wetted Penmeter =
628
Channel Velocity =
1400
Segment Time=
0.32
Segment 6: Pipe Flow
Length =
266
Top Elev =
374
Bot Elev'=
362
Height =
12
Slope =
00451
Manrung's n =
0 013
Flow Area =
3 14
Wetted:Penmeter=
628
Channel Velocity =
1 °5 34
Segment Time =
0.29
Time of,Concentration = 20 17 minutes
SCS Lag Time = 12 10 mmutes,(SCS Lag = 0 6* Tc)
Time Increment = 3 51 minutes (= 0 29* CS Lag)
ft
ft
ft/ft
ft/sec
minutes
ft
ft
ft/ft
Assumed RCP
sf (24 ")
If (24 ")
ft/sec
minutes,
ft
ft
ft/ft
Assumed RCP
sf (24 ")
If (24 "),
ft/sec
minutes
N

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY 'C GEORGE, El
M19-1- 140000 Subbasin 4A 9110/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98
80
7,7
HSG "A' = 0%
HSG S'= 90%
HSG'C'= 10%
HSG U= 0%
Cover Condition
SCS CN
Comments
Impervious
98
023
Open
62
Assume good condition
Wooded
57
Assume good condition
A. Onsite Impervious Breakdown
Contributing Area
Area jsfj
Area acres
,Building
10,204_
023
ParkingfRoads
0
000
Sidewalk
598
001
Other
0
000
Totals
10,802
025
B. Watershed Breakdown
Contributor Area
'SCS CN
Area Jsfj
Area facresl
Comments
Onsite impervious
98
10,802
025
Onsite open
62
17,800
041
Assume good,condition
Onsite wooded
57
30,538
070
Assume good condition
Onste pond
100
0
000
-
OffsUe impervious
98
0
000
-
Offsite open
62
0
000
Assume, ood condition
Offsite wooded
57
0
000
Assume good condition
Offsue pond
100
0
000
Total area = 136 -acres
,59,140 sq.ft
Composite SCS CN = 66
% Impervious = 183%

WESTON TOWNHOMES POST- DEVELOPMENT HYDROLOGY C GEORGE,,EI,
MIH- 140000 Subbasin 4A 9/10/2014
C.- Time of, Concentration Information
Time of concentration is calculated, using the SCS Segmental Approach (TR -55)
Segment,l: Overland Flow
ft
Length =
64
Top Elev =
370
Bot Elev =
358
Height =
12
Slope =
0 1875
h4annmg's n.
040
V'(2-year/24, hour) =
343
Segment Time =
5.93
ft
ft/ft
woods,,hght underbrush
iiiches'(Cary, NC)
minutes
Segment 3: Channel Flow
Length =
Top Elev =
Bot Elev =
Height =
Slope =
Mannmg'sm =
Flow Area =
Wetted Perimeter =
Channel Velocity=
Segment Time =
Time,of Concentration = 738 minutes
SCS Lag Time = 443 minutes (SCS Lag = 0,6• Tc)
Tune Increment = 128 minutes (= 0 29'SCS Lag)
418
ft
358
343
15
ft
00359
ft/ft
0 045
natural channel
4 00
sf (assume 2'x - 2',channel)
600
lf,(assume 2'x ' channel)
479
ft/sec
1.46
minutes

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C, GEORGE, EI
M11-1-140000 Subbasin 4B 9/10/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70
D
98'
180
77
HSG "A' = 0%
HSG 'B'= 100%
HSG'C',= 0%
HSG 'D' = 0%
Cover Condition
SCS CN
Comments
Impervious
98
&00
O _
61
Assume good,condition
Wooded,
55
Assume good condition
H. Py03I' D>;VIIjAPMENT- -
A. Onsite Impervious Breakdown
Contributing Area
Area jst]
Area jacresl
Bialding
0
&00
ParkihgtRoads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B Watershed Breakdown
Contributing Area
SCS CN
Area lsfl
Area facresf
Comments
Onsite impervious
98
0
000
Onsite open
61'
11,030
0'25
Assume good condition
Onsite.wooded
55
28,413
0'65
Assume good condition '
Onsite pond
100
0
000
Offsite im ennous
98
0
000
Offsite open
61
0
000
Assume good condition
Offs1te wooded
55
0
000
Assume good, condition
Off ne pond
100
01
000
Total area = 091 acres
39,443 sq ft
Composite,SCS CN = 57
% Impervious = 00%

WESTON TOWNHOMES POST- DEVELOPMENT'HYDROL ^OGY C GEORGE, El
MIH- 140000 Subbastm4B 9/10/2014
C. Time of Concentration Information
Time of concentration wcalculated using the SCS Segmental Approach (TR-SS)
Segment l: Overland A~
Length =
Top Elev =
Bot Elev =
Height =
Slope =
Maritimes n =
P'(2-'year/24-hour) =
Segment371me =
95
ft
390
362
28
ft
02947
ft/ft
040
woods,, hght,underbrush
343
inches (Cary, NC)
679
minutes
Segment 3: Channel Flow
Length =
Top Elev =
Bot Elev =
Height =
Slope =
Manning's n =
Flow, Area =
Wetted Perimeter =
Channel Velocity =
Segmental-tme =
Time of Concentration = 830 minutes
SCS Lag Time = 498 minutes (SCS Lag = 0 6+ Tc)
Time Increment = 144 minutes (= 0 29•SCS Lag)
464
ft
362
343
19
ft
00409
ft/ft
0 045
natural channel
400
sf (assume 2'x 2' channel)
600
If (assume 2' x 2' channel)
5 11
ft/sec
1.51
minutes

WESTON TOWNHOMES POST-DEVELOPMENT HYDROLOGY C GEORGE, El
MIl-I- 140000 Subbastn 4C 9/10/2014
Assume.
HSG
Impervious
Open
Wooded
A_ _
98
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG 'A' = 0%
HSG'B' = 61%
HSG'C' = 39 "/0
HSG'D'= 0%
Cover Condition
SCS CN
Comments
Impervious
98
-
en
66
Assume good condition
Wooded
61
Assume good condition
II POST DEVELOPMENT - 3
A. Onsite Impervious Breakdown
Contributing Area
Area [if]
Area acres
Building
9,778
022
Parking/Roads
0
000
Sidewalk,
178`
0'00
Other
0
000
Totals
9,956
023
B. Watershed Breakdown
Contributing Area
SCS CN
Area lsfl
Area lacresl
Comments
Onsiteim ervtous
98
9,956
023
-
,Onsite open
66
26,069
060
Assume, good condition
Onsite wooded
61
93,599
215
Assume good condition
Onsite pond
100
0
000
_
Offsae impervious
98
70,773
162
-
Off ne open
66
74,502
171
Assume ood,condtfton
Offstte wooded
61
51,897
1 19
Assume good condition
Offstte pond
100
0
000
-
Total area =
Composite SCS CN =
% Impervious =
7 50 acres
326,796 sq ft
72
247%

WESTON TOWNHOMES'
MIH- 140000
POST - DEVELOPMENT HYDROLOGY
Subbastn 4C
C. 'Time of Concentration.Information
Length =
210'
ne of concentration is calculated, using the SCS Segmental
Approach (TR -55)
Segment 1: Overland Flow
359
Height =
Length=
100
ft
Top Elev =
404
Velocity-
Bot Elev =
392
0.55
Height =
12
ft
Slope =
01200
ft/ft
Manning's n =
040
woods, light underbrush,
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time—,
10.13
minutes
Segment 3: Channel Flow
Length =
622
ft
Top.Elev =
359
BovElev =
343
Height =
16
ft
Slope =
00257
ft/ft
Manning's n =
0`045
matural, channel
Flow Area =
400
sf (assume'2',x T channel)
Wetted Perimeter =
600
if (assume 2' x 2' channel)
Channel Velocity =
405
ft/sec
Segment'Time =
256
minutes
Segment 2:.Concentrated Flow
Length =
210'
Top Elev =
392
Bot Elev =
359
Height =
33
'Slope,=
01571
Paved` ? =
No
Velocity-
640
Segment Time =
0.55
Time of Concentration = 1323 minutes
SCS Lag Time= 794 mmutes'(SCS Lag = 0,6* Tc)
Time Increments= 230 nunutes; = 029 *SCS La
C GEORGE, El
9/10/2014
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Subbasin 4G To SWMF 2 9/10/2014
SL11SC,9,0M ENE UN AMBERS , _
Assume:
HSG
Impervious
Open
Wooded
A
98_
39
30
B
98
61
55
C
98
74
70
D
98
80
77
HSG':A' =
0%
HSG'B' =
46%
HSG'C' =
54 %,
HSG'D' =
0%
Cover Condition
SCS CN
Comments
- 'Impervious
98
-
en
68
Assume good condition
Wooded
63
Assume goodfcondihon
A. Onsite Impervious Breakdown
Contributing Area
SCS CN
acres
Building
Comments
8
Parkin Roads
7
M69,0881
Sidewalk
Onsite open
4
Dnvewa
074
9
Totals
63
9
B. Watershed Breakdown
"Contributiu Area
SCS CN
Area acres
Comments
Onsite impervious
98
1 59
-
Onsite open
68
074
Assume good condition
Onsite wooded
63
000
Assume good condition
Onsite pond
100
612
-
Offsite impervious
98
000
-
Offsite open
68
0
000
Assume good condition
Offsite,wooded
63
0
000
Assume good condition
,Offsite pond
100
0
060
1 -
Total area 245 acres
106,717 sq ft
Composite SCS CN = 89
% Impervious = 647%
C. Time of Concentration Information
Time of concentration is assumed to be 5 minutes
Time of Concentration = 5100 minutes
SCS-Lag Time = 300 minutes (SCS lag,= 0 6* Tc)
Time Increment = 087 minutes (= 0 29* CS Lag)
f

WESTON TOWNHOMES POST- DEVELOPMENT HYDROLOGY C ,GEORGE, EI
MIH- 140000 I Subbasin 4D 9/10/2014
Assume:
H_ SG
Impervious
Open
Wooded
A
98
39
30
B
98
61
55
C
98
74
70,
D
98
80
77
HSG 'A' = 00%
HSG,'B' = 24%
HSG'C'= 30%
HSG'D'= 46%
Cover Condition_
SC&CN
Comments
Impervious
98
000
Open
74
Assume good condition
Wooded
70
Assume good condition
II.�+P,OST= DEXEL•OPMENT�� -�,;
A. Onsite Impervious Breakdown
Contributing Area
Area' jsl]
Area' acres
Building
0
000
Parking/Roads
0
000 _
Sidewalk
0
000
Other
0
000
'Totals
0
000
B. Watershed Breakdown
Contributing Area,
SCS CN
Areas
Area acres
Comments
Onsrte impervious
98
0
000
-
Onsite open
74
1,427
003
Assume good condition
Onsite wooded
70
0
000
Assume good condition
Onsite pond
100
0
000
-
Offstte impervious
98
68,700
158
-
Offsrte open _
74
77,097
177
Assume good condition
Offsite wooded
70
216,652
497
Assume good condition
Offsite pond
100
0
000
-
Total area =
Composite SCS CN =
% Impervious =
8 35 acres
363,876 sq ft
76
189%

WESTON'TOWNHOMES' POST- DEVELOPMENT'HYDROLOGY C GEORGE,,EI
MIH- 140000 Subbastn 4D 9/10/2014
G Time of Concentration Information
Length =
208
we of concentration rs�calculated using the SCS Segmental
Approach (TR=55)
Segment l: Overland Flow
348
Height =
Length =
100
ft
Top Elev.=
404
Velocity =
Bot Elev =
396
0.45
Height =
8
ft
Slope =
00800
ft/ft
Manning'sm =
0 40
woods; light underbrush,
P (2- year /24 -hour) =
343
inches'(Cary, NC)
Segment Time =
11.91
`minutes
Segment 3: Channel Flow
Length =
234
ft
Top Elev =
348
Bot Elev =
343
Height =
5
ft
Slope =
002,14
ft/ft
Manrung's n =
0 045
natural'channel
Flow,Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
6-M
If (assume 2' x,2' channel)
Channel Velocity =
369
ft/sec
Segment Time =
1.06
minutes
Segment2: Concentrated Flow
Length =
208
Top Elev =
396
Bot Elev =
348
Height =
48
Slope =
02308
Paved P =
No
Velocity =
775
Segment Time =
0.45
Time of Concentration = 1342 minutes
SCS Lag Time = 805 minutes (SCS Lag = 0 6 *17c)
Time Increment = 233 minutes = 0 29'SCS La
ft
ft
ft/ft
ft/sec
minutes

WESTON TOWNHOMES POST - DEVELOPMENT HYDROLOGY C GEORGE, EI
MII-1- 140000 Subbastn S 9/10/2014
L SCS CQRVE,NIiMB1ERS° ��:�
Assume.
HSG
Impervious,
Open
Wooded
A _
98
39
30
B _
98
61
55
C
98
74
70
D
98
80
77
HSG'A' =
0%
HSG'B' _
'66%
HSG "C' =
34%
HSG 'D' =
0%
Cover Condition
SCS CN
Comments
hn ervious'
98
-
en
65
Assume good condition
Wooded
60
Assume good condition
A. Onsite Impervious Breakdown
Contributing Area
Area [st]
Area lacresi
Buildmg
2;917
007
Parking/Roads
0
000
Sidewalk
132
000
Other
0`
000
Totals_
3,049
007
B. Watershed Breakdown
Contributing Area
SCSCN
Area [sfl
Area acres
Comments
Onsite impervious
98_
3,049
007
-
Onsite open
65
15,998
0 3,7
Assume good condition
Onsite wooded
60
13,037
03-0
Assume good condition _
Onsite pond
100
_ 0
000
-
Offstte impervious
98
42,755
098
Offsae open
65
407,196
246
Assume good condition
Mite wooded
60
27,402
063
Assume good condition
Mite pond
100
0
0100
Total area =
Composite SCS CN =
%,Impervious =
4j81 acres,
209,437 sq ft
72
219%

WESTON TOWNHOMES POST- DEVELOPMENT HYDROLOGY C GEORGE „EI
MIH- 140000 &bbastn 5 9/10/2014
C. Time of Concentration Information
— ,me,of concentration is calculated using the SCS Segmental Approach (TR -55)
Segment ]:'Overland Flow
Segmenta2: Concentrated Flow
Length =
100
ft
Uength = 639
ft
Top Elev =
420
Top Elev = 418
Bot Elev­
418
Bot Elev = 372
Height =
2
ft
Height= 46
ft
Slope =
00200
ft/ft
Slope = 00720
ft/ft
Mammng's n =
024
dense grasses
Paved'? = No
P (2- year /24 -hour) =
343
inches (Cary, NC)
Velocity = 433
ft/sec
Segment Time =
13.78
minutes
Segment'Time = 2.46
minutes
Ti-me of Concentration = 1624 minutes
SCS Lag Time = 975 nunutes,(SCS Lag= 0 6* Tc)
Time Increment = 183 minutes (= 0 29 *SCS Lag)

WESTON TOWNHOMES' POST - DEVELOPMENT HYDROLOGY C GEORGE, El
M113- 140000 Subbasin 6 9/10/2014
Assume:
HSG
Impervious
Open
Wooded
A
98
39
30
B
`98 _
61
55
C
98
74
70
D
98
80
77
HSG "A' =
0%
HSG'''B' =
26%
HSG'C' =
72%
HSG "D' =
2%
Cover Condition
SCS`CN
Comments
Im envious _
98
-
'Open
_ 71
Assume, good condition
Wooded
66
Assumegood condition
IRN POST= DEVELOP _
A. 'Onsite Impervious Breakdown
Contributing Area
Area Isf)
Area acres
Building
0
000,
Parkm oads
0
000
Sidewalk
0
000
Other
0
000
Totals
0
000
B. Watershed Breakdown
Contributing Area
SCS CN
Areas
Area acres
Comments
Onsite impervious
98
0
000
_ -
Onsite open
71
0 _ _ _
000
Assume good condition
Onsite wooded
66
0
0 00
Assume good condition
Onsite pond
100
0
000 _
-
Offsite impervious
98
255,959
588
Offsrte o en
'71
467,799
1074
Assume good condition
Off ne,wooded
66
676,753
15 54
Assume good, condition
Offsite pond
100
10,438
0 24,
-
Total area =
Composite SCS CN =
% Impervious =
3239 acres
1,410,949 sq ft
74
18 1%

WESTON,TOWNHOMES POST- DEVELOPMENT HYDROLOGY C GEORGE, El
MIH- 140000 Sul basin 6 9/10/2014
C. Timeof Concentration'Information
'tme,of concentration is ca[cu'lated'using the,SCS Segmental Approach (TR -55)
Segment 1: Overland Flow
1130
ft
Length =
100
ft
Top Elev =
441 5
7
Bot Elev =
4,40
ft
Height =
1 5
ft
Slope =
00150
ft/ft
Manning's n =
040
woods, light underbrush
P (2- year /24 -hour) =
343
inches (Cary, NC)
Segment Time =
23.27
minutes
Segmenta3: Channel Flow
Length =
1130
ft
Top Elev =
433
Bot;Elev -=
Bot Elev =
384
7
Height =
49
ft
Slope =
00434
ft/ft
Manning's n =
0 045
natural channel
Flow Area =
400
sf (assume 2' x 2' channel)
Wetted Penmeter =
600
If (assume 2''x- 2',channel)
Channel Velocity =
526
ft/sec
Segment Time =
3.58
minutes
Segment, 5: ChannebFlow
Length =
80
ft
Top Elev =
374
Bot;Elev -=
Bot Elev =
371
7
Height =
3
ft
Slope=
00375
ft/ft
Manning's n`=
0 045
natural channel
Flow Area =
400
sf (assume 2' x 2' channel)
Wetted Perimeter =
600
If (assume Ti 2' channel)
Channel Velocity =
489
ft/sec
Segment Time =
027
minutes
Segment 3: Concentrated Flow
Length =
213
Top Elev =
440
Bot;Elev -=
-433
Height =
7
Slope =
00329
Paved 9=
No
Velocity=
2`92
Segment Time =
1.21
Segment 4: Pipe Flow
Length =
291
Top Elevl=
384
Bot'Elev,=
374
Height =
10
Slope=
00344
Manning's n =
0 013
Flow Area =
3 14
Wetted Penmeter =
628
Channel Velocity =
1338
Segment Time =
0.36
Time of Concentration = 2870 minutes
SCS Lag Time = 1722 minutes (SCS Lag = 0 6* Tc)
Time Increment = 499 minutes (= 0 29 *SCS Lag)
ft
ft
ft/ft
ft/sec
minutes
ft
ft
ft/ft
Assumed RCP
sf (24 ")
If (24 ")
ft/sec
minutes

Wl MCADAMS
Scenario: Post- 1 Yr 24 Hr
Weston Townhomes C. George, El
MIH14000.ppc 9/10/2014

JcADaMs
Subsection: Master Network Summary
Catchments Summary
Label Scenario Return Hydrograph Time to Peak Peak'Flow
Event, Volume (min) (ft3 /s)
(years) (ac -ft)
SUB IA
Post- 1 Yr 24 Hr
1
0 173
726.000
2.55
SUB IA
Post- 2 Yr 24 Hr
2
0.254
726.000
3.86
SUB 1A
Post- 5 Yr 24 Hr
5
0.384
726.000
5:55
SUB IA
Post- 10 Yr 24 Hr
10
0:495
726.000
6.90
SUB 1A
Post- 25 Yr 24 Hr
25
0 653
726.000
853
SUB 1A
Post- 100 Yr 24 Hr
100
0 915
726 000
1082
SUB 4B
Post - L Yr 24 Hr
1
0.014
751.000
0108
'SUB 4B
Post- 2 Yr 24 Hr
2
0 028
727 000
0.26
SUB 4B
Post- 5 Yr 24 Hr
5
0.055
726.000
0.65
SUB 4B
Post- 10 Yr 24 Hr
10
0.080
725 060
1.02
,SM4B
Post- 25 Yr 24 Hr
25
0.119
724:000
1.54
SUB 46
Post- 100 Yr 24 Hr
100
0.190
724.000
2.35
SUB 5
Post- 1 Yr 24 Hr
1
0.276
730.000
324
SUB 5
Post- 2 Yr 24 Hr
2
0.417
730.000
521
iSUB 5
Post- 5'Y,r 24 Hr
5
0.650
730 000
7.85
'SUB 5
Post- 1'0 Yr 24 Hr
10
0 851
729.000
,10 06
SUB 5
Post- 25 Yr 24 Hr
25
1 139
729 000
12.77
SUB 5
Post- 100 Yr 24 Hr
100
1.626
72900 0
16.70
SUB 113
Post- 1, Ye 24 Hr
1
0 177
722.000
3.16
SUB 1B
Post- 2`Yr 24 Hr
2
0.273
722:000
5 19
SUB 16
Post- 5 Yr 24 Hr
5
0 432
722.000
7.94
SUB 1B
Post- 10 Yr 24 Hr-
10
0 571
722 000
10.10
SUB 16
Post- 25 Yr'24 Hr
25
0.771
721.000
12.92
SUB 113
Post-,100 Yr 24 Hr
100
1.110
721 000
16.95
SUB 4A
Post- 1 Yr 24 Hr
1
0.052
725.000
069
SUB 4A
Post- 2 Yr 24 Hr
2
0.085
724.000
130
SUB 4A
Post- 5 Yr 24 Hr
5.
0 141
723 000
219
SUB 4A
Post- 10 Yr 24 Hr
10'
0 191
721000
2.93
SUB 4A
Post- 25 Yr 24 Hr
25
0 264
723000
3.89
SUB 4A
Post -•100 Yr 24 Hr
100
0.391
723.000
530
SUB 1C
Post- 1 Yr 24 Hr
1
0 701
733000
7.58
SUB 1C
Post- 2 Yr 24 Hr
2
1 031
7331000
11.57
SUB 1C
Post- 5 Yr 24 Hr
5
1 566
731 000
16.95
SUB 1C
Post- 10 Yr 24 Hr
10
2.022
731 000
2143
SUB 1C
Post- 25 Yr 24 Hr
25
2 670
731 000
26.87
,SUB 1C
Post -'100 Yr 24 Hr
100
3754,
7,31000
34.73
SUB 2A
Post- 1 Yr 24 Hr
1
0.743
727M0
11.14
SUB 2A
Post- 2 Yr 24 Hr
2
1.054
726 000
1596
SUB 2A
Post- 5 Yr 24 Hr
5
1 545
726.000
21.99
SUB 2A
Post- 10 Yr 24 Hr
10
1956
726.000
2678
SUB 2A
Post- 25 Yr,24 Hr
25
2:533
726.000
3240
SUB 2A
Post- 100 Yr 24 Hr
100
3.485
726.000
40.19
SUB 2B
Post- 1 Yr 24 Hr
1
1 020
727 000
14.85
SUB 2B
Post- 2 Yr 24 Hr
2
1 409
727 000
20.48
SUB 2B
Post- 5 Yr 24 Hr
5
2011
727 000
27.25
SUB 2B
Post- 10 Yr 24 Hr
10
2 509
727.000
32.62
SUB 2B
Post- 25 Yr 24 Hr
25
3.202
727 000
3878
,SUB 26
Post- 100 Yr 24 Hr
100
4.335
727.000
4722
SUB 2C
Post- 1 Yr 2+Hr
3
0:068
7,31.000
0.45
SUB 2C
Post- 2 Yr 24 Hr
2
0 123
729.000
1.21
Weston Townhomes C George, El
MIH1'4000 ppc 9/10/2014

Hit
Subsection: Master Network Summary
Catchments Summary
Label
Scenario
Return
Hydrograph
Time to Peak
Peak Flow
Event
Volume
(min)
MIN
(years)
(ac -ft)
SUB 2C
Post -5 Yr 24 Hr
5
0.223
728.000 ,
2.53
SUB 2C
Post- 10 Yr 24 Hr
10
0 "316
727.000'
3.72
SUB 2C
Post- 25 Yr 24 Hr
25
0 455
727.000
531
SUB' 2C
Post- 100 Yr 24,Hr
100
0 703
727.000
7.74
SUB3
Post- 1 Yr 24 Hr
1
3.267
7,32000
38:39
SUB 3
Post- 2 Yr 24 Hr
2
4.611
732.000
54.74
SUB 3
Post- 5 Yr 24 Hr
5
6 727
731.000
75.53
SUB`3
Post- 10 Yr 24 Hr
10
8 495
731.000
9250
SUB'3
Post- 25 Yr 24 Hr
25
10 975
731.000
11244
SUB 3
Post- 100 Yr 24 Hr
100
15 061
731.000
140.63
SUB 4D
Post- 1 Yr 24 Hr
1
0 623
728000
8:75
SUB 4D
Post- 2 Yr 24 Hr
2
0.902
728.000
1,193
SUB 4D
Post- 5 Yr 24 Hr
5
1.350
727.000
1829
SUBAD
Post- 10 Yr 24 Hr
10
1729
727.000
22.65
SUB,4D
Post- 25 Yr 24 Hr
25
2.265
727.000
27.83
SUB,4D
Post- 100 Yr 24 Hr
100
3.156
727.000
35 10
SUB °4C
Post- 1 Yr 24 Hr
1
0.433
728.000
5.67
SUB 4C
Post- 2 Yr 24 Hr
2
0 655
728 000
9.04
,SUB 4C
Post- 5 Yr 24 Hr
5
1 019
727.000
13.62
,SUB 4C
Post- 10 Yr 24 Hr
10
1.334
727 000
17.38
SUB 4C
Post- 25 Yr 24 Hr
25
1 785
727.000
21.97
SUB 4C
Post- 100 Yr 24 Hr
100
2.546
727 000
28.56
SUB 6
Post- 1 Yr 24 Hr
1
2 120
739.000
1871
SUB 6
Post- 2 Yr 24 Hr
2
3.136
738.000
28.85
SUB 6
Post- 5 Yr 24 Hr
5
4.784
738.000
42.97
SUB 6
Post- 10 Yr 24 Hr
10
6 194
738.000
5481
SUB 6
Post- 25 Yr 24 Hr
25
8.203
738.000.,
6938
SUB,6
Post- 100 Yr 24 Hr
100
11570'
738.000'
9099
SUB 1D
Post- 1 Yr 24 Hr
1
0 017
726.000
0.17
SUB 1D
Post- 2 Yr 24 Hr
2
0.030
723 000
0.41
SUB 1D
Post- 5 Yr 24 Hr
5
0.053
722.000
085
SUB 1D
Post- 10 Yr 24 Hr
10
0.074
722.000
120
SUB 1D
Post- 25 Yr 24 Hr
25
0 106
722 000
168
SUB 1D
Post- 100 Yr 24 Hr
100
0.162
721.000
240
SUB 1B to SWMF
Post- 1 Yr 24 !Hr
1
0 907
721.000
1951
SUB 1B to SWMF
Post- 2 Yr 24 Hr
2
1 208
721 000
2542
SUB 1B to SWMF
Post- 5 Yr 24 Hr
5
1 665
721.000
32.08
SUB 1B to SWMF
Post- 10 Yr 24 Hr
10
2036
721.000
3694
SUB 1B to SWMF
Post- 25 Yr 24 Hr
25,
2.547
721.000
42.64
SUB 1B to SWMF
Post- 100 Yr 24 Hr
100
3.371
721.000
5019
SUB 4C to SWMF
Post- 1 Yr 24 Hr
1
0.358
721.000
771
SUB 4C to SWMF
Post- 2 Yr 24 Hr
2
0.467
721.000
979
SUB 4C to SWMF
Post- 5 W 24.Hr
5
0.631
721.000
12.05'
SUB 4C to SWMF
Post- 10 Yr 24 Hr
10
0.763
721.000
13.68
SUB 4C to SWMF
Post- 25 Yr 24 Hr
25
0,944
721.000
15.58
SUB 4C to SWMF
Post- 100 Yr,, 24 Hr
100
1:234
721 000
18.08
Node Summary
z
Weston Townhomes C George, El
MIH14600 ppc 9/10/2014

Subsection: Master Network Summary
Node Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (min) (ft3 /s)
(years) (ac -ft)
POA #1
Post- 1 Yr 24 Hr
1
10 005
734.000'
94.49
POA #1
Post- 2-Yr 24 Hr
2
14 651
734.000
140.21
POA #1
Post- 5 Yr 24 Hr
5
22.063
734.000
20395
POA #1
Post- 10 Yr 24 Hr
10
28 331
733.000
260:33
POA #1
Post- 25 Yr 24,Hr
25
37.320
732.000
331.84
POA #1
Post- 100 Yr 24 Hr.
100
52.273
732.000
435:01
JUNC #2
Post- 1 Yr 24 Hr
1
5.109
733 000'
56.67
JUNC #2
Post- 2 Yr 24 Hr
2
7 218
733.000
8090
JUNC #2
Post- 5 Yr 24 Hr
5
10.548
732 000
112-10
JUNC #2
Post- 10 Yr 24 Hr
10
13.338
732 000
13776
JUNC #2
Post- 25 Yr 24 Hr
25
17.258
731 000
16806
JUNC #2
Post- -100 Yr 24 Hr
100
23.730
731.000
211.47
JUNC #4
Post- 1 Yr 24-Hr
1
3.633
735,000
2845
JUNC #4
Post- 2 Yr 24 Hr
2
5.370
735 000
44.48
JUNC #4
Post- 5 Yr 24 Hr
5
8.185
732.000
66.99
JUNC #4
Post- 10 Yr 24 Hr
10
10.593
732.000
86.17
JUNC #4
Post- 25 Yr 24 Hr
25
14.155
731.000
110.05 ,
JUNC #4
Post ='100 Yr 24 Hr
100
20.134
732 000
15017
JUNC #3
Post- 1 Yr 24 Hr
1
3.267
732 000
38.39
JUNC #3
Post- 2 Yr,24 Hr
2
4.611
732.000
54.74
JUNC #3
Post- 5 Yr 24 Hr
5
6.727
731.0001
75153
JUNC #3
Post- 10 Yr 24 Hr
10
8.495
731.000
92.50
JUNC #3
Post- 25 Yr 24 Hr
25
10.975
731.000
11244
JUNC #3
Post- 100 Yr 24 Hr
100
15.061
731 000
140.63
JUNC #5'
Post- 1 Yr 24 Hr
1
0.276
730.000
3.24
JUNC #5
Post- 2 Yr 24 Hr
2
0.417
730 000
5.21
JUNC #5
Post- 5 Yr 24 Hr
5
0 650
730.000
785
JUNC #5
Post- 10 Yr 24 Hr
10
0.851
729 000
1006
JUNC #5
Post- 25 Yr124 Hr
25
1.139
729 000
12.77
JUNC #5
Post- 100 Yr 24 Hr
100
1.626
729:000
16.70
JUNC #6
Post- 1 Yr 24 Hr
1
2 120
739.000
1871
JUNC #6
Post- 2 Yr 24 Hr
2
3.136
738.000
28.85
JUNC #6
Post- 5�Yr 24 Hr
5
4 784
738 000
4297
JUNC #6
Post- 10 Yr 24 Hr
10
6 194
738,000
54.81
JUNC #6
Post- 25 Yr 24 Hr
25
8.203
738.000
6938
JUNC #6
Post- 100 Yr 24 Hr
100
11 570
738 000
90 99
JUNC #7
Post- 1 Yr 24 Hr
1
0 220
1;081.000
035
JUNC #7
Post- 2 Yr 24 Hr
2
0.516
782.000
1.37
JUNC #7
Post- 5 Yr 24 Hr
5
0.965
753.000
5.75
JUNC #_7
Post- 10 Yr 24 Hr
10
1 332
751 000
875
JUNC #7
Post- 25 Yr 24� Hr
25
1:837
729.000
1920
JUNC #7
Post- 100 Yr 24 Hr
1 1001
2.656,
725.0001
36.20
Pond Summary
Label Scenario Return Hydrograph
Event Volume
(years) (ac -ft)
Time to Peak Peak Flow
(mm) (ft3 /s)
Maximum Maximum,
Water Pond Storage
Surface (ac -ft)
Elevation
(ft)
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

Subsection: Master Network Summary
Pond Summary
Label Scenario Return Hydrograph Time to Peak Peak Flow
Event Volume (min) (ft3/s)
(years) (ac -ft)
Maximum
Maximum
Water
Pond Storage
Surface
(ac -ft)
Elevation
(N /A)
(ft)
SWMF- 1 (IN)
Hr- 1 Yr 24
1
'0.907
7,21.000
19.51
(N /A)
(N /A)
SWMF 1
Post- 1 Yr 24
1
0 220
1,081.000
035
348.24
0 696
(OUT)
Hr
SWMF 1 (IN)
Yr 24
2
1.208
721.000'
25.42
(N /A)
(N /A)
Host-'2
SWMF 1
Post- 2 Yr 24
2
0.516
782 000
1-37
348.39
0.748
(OUT)
Hr
SWMF 1 (IN)
5 Yr 24
15
1.665
7,21.000
3208
(N /A)
(N /A)
Host-
SWMF 1
Post- 5 Yr 24
5
0.965
753.000
5:75
34873
0.876
(OUT)
Hr
SWMF 1 -(IN)
10 Yr 24
10
2.036
721 000
36.94
(N /A)
(N /A)
Host-
SWMF 1
Post- 10 Yr 24
10
1.332
751.000
875
348'92
0 946
(OUT)
Hr
,SWMF 1 (IN)
25 Yr 24
25
2 547
, 721.000
42.64
(N /A)
(N /A)
Host-
SWMF 1
Post- 25 Yr 24
25
1.837
729.000
19.20
349.20
1.056
(OUT)
Hr
SWMF 1 (IN)
Post- 100 Yr
100
3.371
721.000
50.19
(N /A)
(N /A)
24 Hr
SWMF 1
Post- 100 Yr
100
2 656
725.000
36.20
349.44
1.153
(OUT)
24 Hr
SWMF 2 (IN)
Post- 1 Yr 24
1
0.358
721.000
7.71
(N /A)
(N /A)
Hr
SWMF 2
Post- 1 Yr 24
1
0.119
1,082 000
0.12
36506
0.257
(OUT)
Hr
SWMF 2 (IN)
2 Yr 24
2
0.467
721.000
9.79
(N /A)
(N /A)
Host-
SWMF 2
Post- 2 Yr 24
2
0.153
1,082.000
046
36549
0336
(OUT)
Hr
SWMF 2 (IN)
Host- 5 Yr 24
5
0.631
721.000
12.05
(N /A)
(N /A)
SWMF 2
Post -:5 Yr 24
5
0.194
1,083 000
0.19
366.10
0.460
(OUT)
Hr
SWMF'2 (IN)
Host- 10 Yr 24
10
0.763
721.000
1 -3.68
(N /A)
(N /A)
SWMF 2
Post- 10'Yr, 24
10
0 225
1,078 000
027
36660,
0.567
(OUT)
Hr
SWMF 2 (IN)
Host- 25 Yr 24
25
0 944
721 000
1,558
(N /A)
(N /A)
SWMF 2
Post- 25 Yr 24
25
0:392
755 000
193
366.71
0 589
(OUT)
Hr
SWMF 2 (IN)
Post- 100 Yr
100
1.234
721.000
18.08
(N /A)
(N /A)
24 Hr
SWMF'2
'Post- 100 Yr
100
0.671
750.000
5'.13
366:82
0.614
(OUT)
24 Hr
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

STORM WA TER MANA GEMENT FA CILITY `I '
DESIGN CAL CULA TIONS
WESTON T.OWNHOMES
MIH -14000

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY ' 1' C.GEORGE, EI, PLS
MIH -14000 SSFxn Above NP 9/10/2014
STAGE - STORAGE FUNCTION - ABOVE NORMAL POOL
Ks= 12361
b = 1.1399
Storage vs. Stage
Average
Incremental
Accumulated
Estimated
70000
Contour
Contour
Contour
Contour
Stage
Contour
Stage
Area
Area
Volume
Volume
w/ S -S Fxn
(feet)
(feet)
(SF)
(SF)
(CF)
(CF)
(feet)
346.00
0.00
10,118
20000
_
346.50
0.50
12,696
11407
5704
_ 5704
0.51
347.00
1.00
13,511
13104
_
6552
12255
0.99
348.00
15,191
14351
14351
26606
1.96
349.00
_2.00
3.00
16,934
16063
16063
42669
2.96
350.00
4.00
18,746
17840
17840
60509
4.03
350.50
4.50
19,682
19214
9607
70116
4.58
Ks= 12361
b = 1.1399
Storage vs. Stage
80000
- - ._.._ __ .._�. --- --------------------- 7
70000
y = 12361X1_1399
60000
R = 0.9997
C
50000
m
40000
30000
20000
10000
0
1.00 2.00 3.00 4.00 5.00
0.00
Stage (feet)
Ks= 12361
b = 1.1399

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY '11 C.GEORGE, EI, PLS
MIH -14000 SSFxn Main Pool 9/10/2014
STAGE - STORAGE FUNCTION - MAIN POOL
Ks = 974
b = 1.5562
Average
Incremental
Accumulated
Estimated
Contour
Contour
Contour
Contour
Stage
Contour
Stage
Area
Area
Volume
Volume
w/ S -S Fxn
(feet)
(feet)
(SF)
(SF)
(CF)
(CF)
(feet)
338.00
0.00
988
340.00
2.00
1,968
1478
_ 2956
2956
2.04
342.00
4.00
3,076
2522
5044
8000
3.87 _
344.00
6.00
4,329
3703
T
7405
15405
5.89
345.50
7.50
5,336
4833
7249
22654
7.55
346.00
8.00
6,968
6152
_ _ 3076
25730
8.20
Ks = 974
b = 1.5562

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY '1" C GEORGE, EI, PL'S
MIH -14000 SSFzn Forebay 9/10/2014
FOREBAY�
Storage vs. Stage
8000
7000
Average
Incremental
Accumulated
Estimated
6000
RZ = 0 9985
Contour
Contour
Contour
Contour
Stage
Contour
Stage
Area
Area
Volume
Volume
w/ S -S,Fxn
(feet)
(feet)
(SF)
(SF)
(CF)
(CF)
(feet)
34000
0100
433
1000
0
34260
2 00
900
667
1333
1333
202
34400
400
1,499
1200
2399
3732
3.90
34550
556
2,003
1751
2627
6359
548
34600
600
2,778
2391
1195
7554
6 -12
Storage vs. Stage
8000
7000
y =4437x 1 5651
6000
RZ = 0 9985
LL 5000
_4000
M
'3000
2000
1000
0
000 200 400 600 8,00
Stage#eet)
Ks = 443.7
b = 1.5651

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY ' 1'
MIH =14000 Volume Calculation
Volume of Main Pool = 25,730
cf
Volume of Forebay = 7,554
cf
Total Volume Below NWSE = 33,284
cf
= 0.76
acre -ft
Total Volume Above NWSE = 70,116 cf
161 acre -ft
Total Volume of Facility = 103,399 cf
237 acre -ft
Per NCDWQ design,guzdelznes, the forebay volume should equal approximately 20% of the
total permanent pool volume
Total Volume Below NWSE = 33,284 cf
Volume,of Forebay = 7,554 cf
% Forebay = 22 t7%
Total Volume Below NWSE -= 33,284 cf
Surface Area at NWSE = 10,118 sf
Average Depth = 329 ft
C GEORGE, EI, PLS
9/10/201'4

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY ' 1' C GEORGE, EI, PLS
MIH -14000 Surface Area Calculation 9/,10/2014
Enter,the drainage area characteristics =>
Total drainage area to pond = 7.07 acres
Total impervious area to pond = 401 acres
Note The basin °must,be sized to treat all impervious surface runoff draining into, the pond, ,notjust the impervious
surface from on -site development
Drainage area= 7.07 acres,@ 56.8% impervious
Estimate the surface area required at pond normal pool elevation =>
Wet Detention Basins are based on an minimum, average depth of =
3.29 "feet (Calculated)
From,the DWQ BMP Handbook, the required SAIDA ratio for
90% TSS' Removal =>
3.0
3.29
3.5
Lower Boundary => 50.0 300
280
Site % impervious => 568 334
3.18
307
Upper Boundary => 60.0 350
320
Therefore, SA/DA required =
3.18
Surface area required at normal pool =
9,805
ft2
=
0 23
acres
Surface area provided at normal pool—
10,118
ft2

WESTON'TOWNHOMES STORMWATE'R MANAGEMENT FACILITY 'V
MIH -14000 WQV Calculation
DE�TERIINA,v'TIONk OF,�4R?,�ATER�QIJAL• I�'�V OLUM���', -',
WQ v = (P) (R v)(A) /12
where,
WQv = water quality volume (in acre -ft)
Rv = 0 05 ±0 009(I) where I is percent impervious cover
A =,area in acres
P = rainfall (in inches)
Input data:
14397 cf.
Total area, A =
7.07 acres
Impervious area =
4.01 acres
Percent impervious, cover, I =
56.8 %
Rainfall, P =
100 inches
Calculated values:
Rv = 056
WQv = Q33 acre -ft
1.4397 cf
�ASSOC3A"�TED�DEPTH �IN POND r�"°Y�' `��'` �
WQv=
14397 cf.
Stage I Storage Data:
Ks =
12361
b =
1.1399
Zo =
34600
Volume�m 1"' rainfall =
14397 cu ft
Calculated values:
Depth of WQv in Basin = 1 14 ft
13.72 inches
Elevation = 347.14' ft
C:GEORGE, EI, PLS
9/10/201'4

WEST,ON TOWNHOMES STORMWATER,MANAGEMENT FACILITY T
MIH -14000 WQVDrawdown Calculation
•DRAtWDOWNSIPHOi�TsDESIGN�
D onfice
# onfices
Ks
b,
Cd siphon,
'Normal Pool Elevation
Volume @ Normal Pool
Onfice Invert
WSEL @ 1" Runoff Volume
2 inch
1
12361
1 1399
060
346.00 feet
0 cf
34600 feet
34714 feet
WSEL
(feet)
Vol - Stored
(c_f)
Siphon Flow
(cfs)
Avg. Flow
(cfs)
Incr. Vol.
c
Incr. Time
(sec)
34714
14397
0108
34704
12982
0 103
0 105
1415
13423
34694
11586
0.097
0 100
1396
13949
34685
10211
0.092
0.094
1375
14562
346.75
8858
0.085
0.088
1353
1'5290
346.65
7530
0.079
0 082
1328
16179
34655
6230
0 072
'0 075
1300
1'7299
34645
4963
0 063
0 067
1267
18781
34635
3735
0 054
0.059
1228
20893
346.25
2555
0.043
0 049
1180
24312
34615
144,0
0 026
0 035
1115
32185
Drawdown Time= 2.16 days
By comparison, if calculated by�the average head over the�onfice
(assuming average head is half the total depth), the result would be-
Average driving head on onfice = 0 353 feet
Onfice composite loss coefficient 0 600
Cross - sectional area of siphon = 0.022 sf
Q = 0 0624 cfs
Drawdown Time = Volume / Flowrate / 86400 (sec /day)
Drawdown Tune= 2 67 days
C GEORGE,,EI, PLS
9/10/2014

M MCADA MS.
Subsection: Elevation -Area Volume Curve
Label: SWMF 1
Elevation Planimeter Area Al +A2 +sqr
(ft) (ft2) (ft2) (Al *A2)
(ft2)
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
Volume Volume (Total)
(ac -ft) (ac -ft)
346.00
0.0
10,118.000
0.000
0.000
0 000
`346.50
0:'0
12,696.000
34,147:937
0.131
01'31
347.00
0�0
13,511 000
39,304 162
0 150
0 281
348.00
0.0
15,191.000
43,028 395
0 329
0 610
349.00
0.0
16,934 000
48,163 840
0 369
0 979
350.00
010
18,746.000,
53,496.980
0.409
1.388'
`350.50
0.0
19;682 000
57,6363001
0 221
1 1 609
Weston TownFiomes C George, El
MIH14000 ppc 9/10/2014

Rf."Z& A ►i
Subsection: Outlet Input Data
Label: SWMF #1
Return Event: 1, years
Storm Event: 1 Yr 24 Hr
Requested Pond Water Surface Elevations
Minimum (Headwater) 346.00 ft
Increment,(Headwater) 0.10 ft
Maximum (Headwater) 350.50 ft
Outlet Connectivity
Structure Type Outlet ID Direction Outfall E1 E2
(fn lfth
Rectangular Weir
Weir - 1
Forward
Culvert
'348.20
350:50
Inlet Box
Riser
Forward
Culvert
349.00
35050
Rectangular Weir
Weir - 2
Forward
Culvert
34820
35050
Culvert- Circular
Culvert
Forward
TW
343.50
350.50
Orifice- Circular
Siphon
Forward
TW
346.00
350.50
`Tailwater Settings
Tailwater
(N /A)
(N /A)
Weston Townhomes C George, El
MIH14000,ppc 9/10/2014

M MCADAMS
Subsection! Outlet Input Data
Label: SWMF #1
Structure ID Siphon
1
Structure Type Orifice- Circular
349 00 ft
Number of Openings
1
Elevation
346.00 ft
Orifice Diameter
2 000 in
Orifice Coefficient
0.60
Structure,ID Riser
Structure Type Inlet Box
Number of Openings
1
Elevation
349 00 ft
Orfice Area
25,.0 ft2
Orifice Coefficient
0.60
Weir Length
20.00 ft
Weir Coefficient
3 00 (ft^0 5) /s
K,Reverse
050
,Manning's n
0.00
Kev, Charged Riser
0.00
Weir Submergence
False
Orifice H to crest
False
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
Weston Townhomes C George, E1
MIH14000 ppc 9/10/2014

!U] MCADAMS
Subsection: Outlet Input Data
Label. SWIMF #1
Structure ID Culvert
Structure Type Culvert- Circular
Number of Barrels
1
Diameter
36 000 In
Length
43.00 ft
Length (Computed Barrel)
43:00 ft
Slope (Computed)
0.012 ft/ft
Outlet Control Data
Manning's n
0.013
Ke
'0.50
Kb
'001
Kr
0 50
Convergence Tolerance
0.00 ft
Inlet Control Data
Equatlon'Form
Form 1
K
0.0098
M
2.0000
C
00398
Y
0.6700
T1 ratio (HW /D)
1 15
T2 ratio (HW /D)
1.30
Slope, Correction Factor
-0 50
Use unsubmerged Inlet control 0 equation below T1
elevation
Use submerged inlet,control 0 equation above T2
,elevation
In transition zone between unsubmerged and submerged
Inlet control,
Interpolate between flows at T1 & T2
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
T1 Elevation 346 96 ft T1 Flow 42.85 ft3 /s
72 jElevation 347.40 ft T2 Flow 48.97 ft3 /s
Weston Townhomes
MIH14000 ppc
a
C , George „EI
9/10/2014

Subsection: Outlet Input Data
Label: SWMF #1
Structure ID Weir- 1
Structure Type Rectangular Weir
Number of Openings
1
Elevation
348.20 ft
Weir'Length
250 ft
Weir Coefficient
3.00' (ft ^0.5) /s
Structure ID Weir - 2
Structure Type Rectangular Weir
Number of Openings,1
'Elevation
348.2011
Weir Length
2.50 ft
Weir Coefficient
3.00 (ft ^0.5) /s
Structure ID TW
Structure Type TW Setup, DS Channel
Tailwater Type
Free Outfall'
Convergence Tolerances
Maximum Iterations
30
Tailwater Tolerance
(Minimum)
0 O1 ft
Tailwater Tolerance
(Maximum)
0.50 ft
Headwater Tolerance
(Minimum)
0 Ol ft
Headwater Tolerance
(Maximum)
0 50 ft
Flow Tolerance (Minimum)
0 001 ft3 /s
Flow Tolerance (Maximum)
10.000 ft3 /s
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
Weston Townhomes C George, El
N11-114000 ppc 9/10/2014

°°JI McADAMS
Subsection: Composite Rating Curve,
Label: SWMF #1
Composite Outflow Summary
Return Event: 1 years,
Storm Event: 1 Yr 24 Hr
Water Surface Flow Tailwater Elevation Convergence Error Contributing Structures
Elevation ,(ft3 /s), (ft) (ft)
(ft)
34600
000
(N /A)
0 00
(no Q: Weir - 1,Riser,Weir -
2,Culvert,Siphon)
346.10
001
(N /A)
0 00
Siphon (no Q. Weir - 1,Riser,Weir -
2,Culvert)
346.20
0.04
(N /A)
0.00
Siphon (no Q Weir - 1,Riser;Weir-
2,Culvert)
346.30
005
(N /A)
0.00
Siphon (no Q. Weir - 1,Riser,Weir -
2,Culvert)
346.40
0 06
(N /A)
0 00
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
346.50
0.07
(N /A)
0:00
Siphon (no Q Weir - 1,Riser,Weir-
346.60
0.08
(N /A)
0.00
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
346.70
0.08
(N /A)
000
Siphon (no Q- Weir - 1,Riser,Weir -
2,Culvert)
346.80
0:09
(N /A)
060
Siphon (no,Q:'Weir - 1,Riser,Weir -
2,Culvert)
346.90
009
(N /A)
0.00
Siphon (no Q Weir - 1,Riser,Weir -
2,Culvert)
347.00
010
(N /A)
000
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
347.10
0.11
(N /A)
000
Siphon (no Q Weir - 1,Riser;Weir -
2;Culvert)
347.20
0 11
(N /A)
000
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
34730
0.12
(N /A)
0.00
Siphon (no Q Weir - 1,Riser,Weir -
2,Culvert)
34740
0.12
(N /A)
0 00
Siphon (no Q• Weir - 1,Riser,Weir,-
2 Culvert)
347 50
012
(N /A)
0.60
Siphon (no Q Weir - 1,Riser,Weir -
2,Culvert)
347.60
0.13
(N /A)
0.00
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
347.70
0.13
(N /A)
0.00
Siphon (no Q Weir - 1,Riser,Weir -
2,Culvert)
347:80
0.14
(N /A)
0.00
' Siphon (no Q: Weir - 1,Riser;Weir -
2,Culvert)
347.90
0.14
(N /A)
000
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
34800
015
(N /A)
0.00
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
34810
0.15
(N /A)
0.00
Siphon (no Q. Weir - 1,Riser,Weir,-
2,Culvert)
348.20
0.15
(N /A)
000
Siphon (no Q: Weir - 1,Riser,Weir -
2,Culvert)
348.30
0.63
(N /A)
0.00
Weir- 1,Weir - 2,Culvert,Siphon (no
Q•, Riser)
34840
1.50
(N /A)
0.00
Weir - 1,Weir - 2,Culvert,Siphon (no
Q: Riser)
348.50
2.58
(N /A)
0 00
Weir - 1,Weir - 2,Culvert,Siphon (no
Q. Riser)
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

Subsection: Composite Rating Curve
Label: SWMF , #1
Composite Outflow Summary
Water Surface Flow
Elevation MIN.
(ft)
Return Event: 1 years
Storm Event: 1 Yr 24`Hr
Tailwater Elevation Convergence Error
(ft) (ft),
34860
13.96
3.86
349.20
(N /A)
34870
349.30
5.26
(N /A)
(N /A)
34880
(N /A)
682
41.33
(N /A)
348.90
50.15
8.48
34970
(N /A)
,349.001 10.23 1 (N /A)
349.10
13.96
(N /A)
349.20
1934
(N /A)
349.30
25.83
(N /A)
'349 40
33.18
(N /A)
349.50
41.33
(N /A)
349 60
50.15
(N /A)
34970
59.42
(N /A)
349.80
66.05
(N /A)
349 90
70.80
(N /A)
350.00
7414,
(N /A)
- 350.10
76.10
(N /A)
,35020
77.09
(N /A)
350.30
77.90
(N /A),
350.40
7871
(N /A)
350.50
79.51
(N /A)
0
Weston Townhomes
MIH14000 ppc
000
000
0.00
0.00
000
0.00
000
000
0.00
000
0.00
0.00
000
0.00
000
0.00
0.00
000
000
0.00
Contributing Structures
Weir - 1,Weir - 2,Culvert,Siphon (no
Q. Riser)
Weir - 1,Weir - 2,Culvert,Siphon (no
Q• Riser)
Weir - 1,Weir - 2,Culvert,Siphon (no
Q. Riser)
Weir - 1,Weir - 2,Culvert,Siphon, (no
Q: Riser)
Weir - 1,Weir - 2,Culvert,Siphon (no
Q Riser)
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert;Siphoh
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Weir - 1,Riser,Weir, - 2,,Culvert,Siphon
Weir - 1,Riser,Weir - 2,Culvert,Siphon
Riser,Culvert,Siphon (no Q• Weir -
1,Weir - 2)
Riser,Culvert,Siphon (no Q Weir -
1,Weir - 2)
Riser,Culvert,Siphon (no Q. Weir -
1,Weir - 2)
Riser,Culvert,Siphon (no Q: Weir -
1,Weir - 2)
C ,George, El
9/,10/2014

III N1CADAN1S
Subsection: Level Pool Pond Routing Summary Return Event: 1 years
Label: SWMF 1 (IN) Storm Event: 1 Yr, 24 Hr
Infiltration
Infiltration Method
No Infiltration
(Computed)
0 907 ac -ft
Jnitial,Conditions
0 :000 ac -ft
Elevation (Water Surface,
346 00 ft
Initial)
0.220 ac -ft
Volume (Initial)
0.000 ac -ft
Flow (Initial Outlet)
0 00 ft3 /s
Flow,(Initial Infiltration)
0 :00 ft3 /s
Flow (initial, Total)
0 00 ft3 /s
Time Increment
1.000 min
Inflow /Outflow Hydrograph, Summary
Flow (Peak,In) 19:51 ft3 /s Time to Peak,(Flow, In) 721.000 min
Flow (Peak Outlet) 0.35 ft3 /s Time to Peak (Flow, Outlet) 1,081.000 min
Elevation (Water Surface, 348.24 ft
Peak)
Volume,(Peak) 0.696 ac -ft
Mass Balance,(ac -ft)
Volume (Initial)
0'000 ac -ft
Volume (Total Inflow)
0 907 ac -ft
Volume (Total Infiltration)
0 :000 ac -ft
Volume (Total Outlet
Outflow)
0.220 ac -ft
Volume (Retained)
0 :686 ac -ft
Volume (Unrouted)
0 000 ac -ft
Error (Mass Balance)
0.0%
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

U; u' 1
Subsection: Level Pool Pond Routing Summary Return Event: 2 years
Label: SWMF 1 (IN) Storm, Event: 2 Yr 24`Hr
Infiltration
Infiltration Method
No Infiltration
(Computed)
Peak)
Initial Conditions
Volume (Peak)
Elevation (Water Surface,
346 00 ft
Initial)
Volume (Initial)
Volume,(Initial)
0.000 ac -ft
Flow (Initial Outlet)
0.00 ft3 /s
Flow (Initial Infiltration)
0.00 ft3 /s
Flow (Initial, Total)
0 00 ft3 /s
Time.Increment
1.000 min
Inflow /Outflow Hydrograph Summary
Volume (Unrouted)
Flow (Peak In)
25'42 ft3 /s Time to Peak (Flow, In) 721.000 min
Flow (Peak Outlet)
137 ft3 /s Time to Peak (Flow, Outlet) 782:000 min
Elevation (WaterSurface,
348.39 ft
Peak)
Volume (Peak)
0.748 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
1.208 ac -ft
Volume (Total Infiltration)
0.000 ac -ft
Volume - ,(Total Outlet
0.516 ac -ft
Outflow)
--
Volume (Retained)
0.691 ac -ft
Volume (Unrouted)
0.000 ac -ft
Error (Mass Balance)
0.0%
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

Subsection: Level Pool Pond Routing Summary
Label: SWMF'1,(IN)
Infiltration
0.000 ac -ft
Infiltration Method
No Infiltration
(Computed)
0.000 ac -ft
Volume (Total Outlet
0 965 ac -ft
,Initial, Conditions
Elevation (Water Surface,
346 00 ft
Initial)
-0 001 ac -ft
Volume (Initial)
0 000 acA
Flow (Initial Outlet)
0 00`ft3 /s
Flow (Initial Infiltration)
0 00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
Time Increment
1.000 min
Return Event: 5 years
Storm Event: 5 Yr 24 Hr
Inflow /Out ow Hydrograph Summary
Flow (Peak In) 32 08 ft3 /s Time to Peak (Flow, In) 721.000 min
Flow (Peak Outlet) 5.75 ft3 /s Time'to Peakfflow, Outlet) 753 000 min
Elevation (Water Surface, 348.73 ft
Peak)
Volume (Peak) 0.876 ac -ft
Mass balance {(ac =ft)
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
1.665 ac -ft
Volume (Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
0 965 ac -ft
Outflow)
Volume (Retained)
0 700 ac -ft
Volume (Unrouted)
-0 001 ac -ft
Error (Mass Balance)
0.0%
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

4902� Mp���
Subsection. Level Pool Pond Routing Summary Return Event: 10 years
Label: SWMF 1 (IN) Storm Event: 10 Yr 24 Hr
Infiltration
0.000 ac -ft
Infiltration Method No Infiltration
(Computed)
Volume (Total Infiltration)
Initial Conditions
Volume (Total Outlet
Elevation (Water Surface,
346 00 ft
Initial)
Volume (Retained).
Volume (Initial]
0 000 ac -ft
,Flow, (Initial Outlet)
0 00 ft3 /s
'Flow (Initial Infiltration)
0 00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
-rime Increment
1.000 min
Inflow /Outflow Hydrograph'Summary
Flow (Peak In)
36.94 ft3 /s Time to Peak (Flow, In) 721.000 min
Flow (Peak Outlet)
8.75 ft3 /s Time to Peak (Flow, Outlet) 751.000 min
Elevation (Water Surface,
348 92 ft
Peak)
Volume (Peak)
0.946;ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac -ft
Volume,(Total Inflow)
2.636 ,ac -ft
Volume (Total Infiltration)
0.000,ac -ft
Volume (Total Outlet
1 332 ac -ft
Outflow)
Volume (Retained).
0 703 ac -ft
Volume (Unrouted)
-0 001 ac -ft
Error (Mass Balance)
00%
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

Subsection: Level Pool Pond Routing Summary
Label: SWMF 1 (IN)
Infiltration
0.000 ac,ft
Infiltration Method
No Infiltration
(Computed)
0.000 ac -ft
Volume (Total Outlet
1.837 ac -ft
Initial Conditions
Elevation (Water Surface,
0 709 ac -ft
Initial)
346.00 ft
Volume (Initial)
0 000 ac -ft
Flow "(Initial Outlet)
0 00 ft3 /s
Flow (Initial Infiltration)
0.00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
Time Increment
1 000 min
Inflow /Outflow Hydrograph Summary
Return Event: 25 years
Storm Event: 25 Yr 24 Hr
Flow (Peak In). 42 64 ft3 /s Time to Peak (Flow, In) 721.000 min
Flow (Peak Outlet) 19.20 ft3 /s Time to Peak (Flow, Outlet) 729 000 min
Elevation (Water,Surface, 349.20 ft
Peak)
Volume (Peak) 1.056 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac,ft
Volume (Total Inflow)
2.547,ac;ft
Volume (Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
1.837 ac -ft
Outflow)
Volume (Retained)
0 709 ac -ft
Volume (Unrouted)
-0.001 ac -ft
Error (Mass Balance)
0 0 %
Weston Townhomes . C George, El
MIF114000 ppc 9/10/2014

�Uj ii! • ,. W, .,
Subsection: Level Pool Pond Routing Summary Return Event: 100 years
Label: SWMF 1 (IN) Storm Event: 100 Yr 24 Hr
Infiltration
Infiltration, Method No Infiltration
(Computed)
Initial Conditions
Elevation (Water Surface,
346.00 ft
Initial)
3371 ac -ft
Volume (Initial)
0.000'ac -ft
Flow (Initial Outlet)
0.00 ft3 /S
Flow (Initial Infiltration)
0.00 ft3 /S,
Flow (Initial; Total)
0.00 ft3 /S
Time Increment
1.000 min
Inflow /Outflow Hydrograph Summary
0.0%
Flow (Peak In) 50.19 ft3 /s Time to Peak (Flow, In) 721 000'min
Flow (Peak Outlet) 36.20 ft3 /S Time to Peak (Flow, Outlet) 725 000 min
Elevation (Water Surface, 349 44 ft
Peak)
Volume (Peak) 1:153 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
3371 ac -ft
Volume (Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
2 656 ac -ft
Outflow)
-
Volume (Retained)
0.715,ac -ft
Volume, (On routed)
-0.001 ac -ft
Error (Mass Balance)
0.0%
Weston- Townhomes- C George, El
M -W4000 ppc 9/10/2014

DESIGN OF RIPRAP OUTLET PROTECTION WORKSHEET
Project
Weston Townhomes Date 24- Jun -14
Project No.
MIH -14000 Designer JAA
Outlet ID
SWMF #1
Flow, Qlo.n
9 cfs
Slope, S
1.16 %
Pipe Diameter, Do
36 inches
Pipe Diameter, Do
3 feet
Number of pipes
1
Pipe separation
0 feet
Manning's n
0.013
OEM
MOM
1 ►����� ����� N��-
MOM
I
1 1
cone nom graph above =
2
Diameter
I Thickness
Outlet pipe diameter
36 in.
Length =
18.0 ft.
Outlet flowrate
9.0 cfs
Width =
9.0 ft.
Outlet velocity
6.9 ft /sec
Stone diameter =
6 in.
Material =
Class B
Thickness =
22 in.
Zone
Material
Diameter
I Thickness
Length
Width
1
Class A
3
9
4 x D(o)
3 x D(o)
2
Class B
6
22
6 x D(o)
3 x D(o)
3
Class I
13
22
8 x D(o)
3 x D(o)
4
Class I
13
22
8 x D(o)
3 x D(o)
5
Class II
23
27
10 x D(o)
3 x D(o)
6
Class II
23
27
10 x D(o)
3 x D(o)
7
S ecial stud re uired
I . Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
2. Outlet velocity based on full -flow velocity
Rip Rap Outlet Protection Design.xlsm6 /25/2014

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY C GEORGE, El
MIH -14000 Anti- Flotation Block Calculations 6/25/2014
SE nq�5 LZ1T�TfON 1 ZFO
Input - Data —>
Inside length of riser =
Inside width ofnser=
Wall thickness of riser=
Base thicknesstof riser =
Base length ofnser=
Base width ofnser =
Inside height of Riser =
Concrete unit weight =
OD of barrel exiting manhole =
Size of dram pipe (if present) _
Trash Rack water displacement,=
ConerelePresent in Riser Structure =>
500 feet
500 feet
600 inches
6`00 inches
6 00 °feet
6 00 ^feet
5 50 feet
142 O'PCF Note: NC,Products,lists unit wt of
36 00 inches manhole concrete at 142 PCF
8 0 inches
61 74 CF J
Total amount of concrete
Base of Riser= 18,066 CF
Riser Walls = 60 500 CF
Adjust for openings
Opening for,barrel = 3 534 OF
Opening for,dram pipe 0 524 CF
Total Concrete present, adjusted for openings = 74.442 CF
Weight of concrete, present = 10571 !bs
Amount of water displaced by Riser Structure =>
Displacement by concrete =
74 442 CF
Displacement by open air in riser =
137 500 CF
Displacement by trash rack =
61 740 CF
Total water displaced by riseribarrel structure=
273'682 CF
Weight of water displaced-
17078 "Ibs
I

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY C- GEORGE, El
MIH -14000 Anti- Flotation Block Calculations 6/25/2014
Calculate amount ofconcrete to be,added,to riser =>
Safety factor to use-
Must add =
Concrete unit weight -for use =
Buoyant weight of this concrete =
Buoyant, with safety factor. applied =
Therefore, must add =
Standard based described above =
Therefore, base design must have =
Calculate size of base for riser assembly =>
Length =
Width =
Thickness =
Concrete Present =
Check validity of base as designed =>
Total Water Displaced =
Total Concrete Present =
Total Water Displaced =
Total Concrete Present =
Actual safety factor =
Results of design =>
1 15� (recommend 1 15,or higher)
9069`lbs concrete for buoyancy
142,PCF (note above observation for NCP concrete)
79'60' PCF
69 22-'PCF
131 013 CF of concrete
18 000 CF of concrete
149 017 CF of concrete
9 000 feet
9 000 feet
24 0 inches
162 000 CF OK
417 682 CF
218442 CF
26063 Ibs
31019 Ibs
119 OK
Base length =
9.00 feet
Base width =
9.00 feet
Base Thickness =
24.00 inches
CY of concrete total in base =
6 00 CY
Concrete unit weight in added base >=
142 PCF
0

STORIVIWATER MANAGEMENT FACILITY 62'
DESIGN CAL CULA TIONS
WES,TON TOWNHOMES
MIH -14000

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY 12' C. GEORGE, El, PLS
MIH -14000 SSFxn Above NP 9/10/2014
STAGE - STORAGE FUNCTION - ABOVE NORMAL POOL
Ks = 6960
b = 1.1169
Average
Incremental
Accumulated
Estimated
Contour
Contour
Contour
Contour
Stage
Contour
Stage
Area
Area
Volume
Volume
w/ S -S Fxn
(feet)
(feet)
(SF)
(SF)
(CF)
(CF)
(_feet)
363.50
0.00
6,404
364.00
0.50
6,763
6584
3292
3292
0.51
365.00
1.50
7,765
7264
7264
10556
1.45
366.00
2.50
8,824
8295
8295
18850
2.44
368.00
4.50
11,111
9968
_ 19935
38785
4.66
Ks = 6960
b = 1.1169

WESTON 'TOWNHOMES STORMWATER MANAGEMENT FACILITY '2' C GEORGE, EI, PLS
MIH -14000 Wetland Zone Calculation 9/10/2014
WETLAND',rtZONKTAB r LATIONri
�-
. ,_.
Per NCDENR "Stormwater Best Management Practices"
Zone
Depth at Normal Pool
(inches )
Depth at Temp Pool
(inches
Portion of Wetland
Surface Area
Deep Pool - Forebay
18
to
36
18
to
48
10%
Deep,Pool - Non Forebay
18
to
36
18
to
48
5%-10% _
Shallow Water
3
to
6
15
to
18
40%
Shallow Land
0
to
3
0-
to
15
30%-40%
Permanent Pool Elevation = 36350
Wetland Surface Area = 6,404
Zone
Elevation (feet
Measured Area
(Sn
Portion of Wetland
Surface Area
Deep Pool - Forebay
362 00 to 360 50
644
10 1%
Deep Pool - Non Forebay
362 00 to 360.50
477
74%
Shallow Water
363 25 to 363 00
2,346
1 366%
Shallow Land
363 50 to 363 25
2,098
1 328%

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY'2' C GEORGE, EI, PLS
MIH -14000 WQV Calculation 9/.10/2014
�DETERM�I�ATION O�F�W�A ER�QUALIT�YV�OL�UME�,�,--�_��
WQ v = (P )(R v)(A) 112
where,
WQv = water quality volume (in acre -ft)
Rv = 0 05 +0.009(I) where] is percent impervious cover
A = area in acres
P = rainfall (in inches)
Input data:
Total area, A =
245
acres
Impervious area =
1.59
acres
Percent impervious cover, I =
64.7
%
Rainfall, P =
100
inches
Calculated values:
Rv =
0.63
WQv=
013
- acre -ft
=
5626
cf
WQv
Stage %Storage Data:
Ks
b,
Zo
Volume in 1" rainfall
5626 cf.
6960
1.1169
36350
5626 cu ft
Calculated values:
Depth of WQv in Basin = 0.83 ft
9.92 inches
Elevation = 36433 ft

WESTONTOWNHOMES STORMWATER'MANAGEMFNT FACI]LITY"2'
M1H -14000 WQV Drawdown °Calculation
DRAWDOWNSYPHOlYDESIGN
D onfice=
125 inch
4 orifices =
1
Ks­
L6960
bi, =
1.1,169
Cdgsiphon­
060
Normal Pool.Elevation'=
,363.50 feet
Volume @ Normal'Pool,=
0 cf
Orifice Invert=
36150 feet
WSEL @,1" Runoff Voldrriet=
364:33 feet
C. GEORGE,,EI, PLS
9/,10/2014
WSEL
(feet)'
Vol. Stored
W)
Siphon Flow
(cfs)
Avg, Flow
(cfs)
Incr,.`Vol.
(c_f)
incr: Time
(sec)
36433
5626
0'036_
364.25
5081
0 034
0 035
546,
15501
36418
45.4°1
0'033
0 033
539
16138
364 -11
4008,
0034
0 032
533
16881
36404
;3483
0 029
0 030
526
17765,
36347
2966,
0,026
002-7
511
18842
'363.89
2458
0,;024
0.025
508
20199
3.63:82
1960
0.024
0,023
497
2'1992-
363.75
1476
0.018'
0,020
484
24536
36368
1008
0 014
0'016
468
28619
36361
563
0 009'
0'012
446
37228
Drawdown Tune= '2 52,,da s
Byroompanson, if calculated by the average hea&over'the onfice
(assuming averagethead is half,the totaledepth), the result would be
AverageAtiymg head on oiifce =
0:258 feet
Onfrce composite loss coefficient =
0.600
Cross - sectional, area of siphon =
0,009 isf
Q = 0.0208 cfs
Drawdown Tune= Volume / F1'owrate /'86400 (sec /day)
Drawdowwn Time = 3.12 days

Wl IVICADAMS
Subsection! Elevation -Area Volume Curve
Label: SWMF 2
Elevation Planimeter Area Al +A2 +sqr Volume
(ft) (ft2) (ftz) (Al *A2) (ac -ft)
(ftz)
Return Event: 1 years
Storm, Event: 1 Yr 24 Hr
Volume (Total)
(ac -ft)
363.50
00
6,404.000
0,000
0.000
0:000
364.00
00
6,881 000
19;923 217
'0.076
0 °076
365.00
00
7,878 "000
22,121 643 ,
0.169'
0'246
36600
0.0
8,932.000
251,198.462
0.193
0.438
36800
0.0
11,208.000
30,145.491
0.461
0:900
Weston Townhomes C George, El
MIH14000 ppc 9/10/2014

A.
�5
Subsection: Outlet' Input Data Return Event: 1 years
Label: SWMF #2 Storm Event, 1 Yr 24 Hr
Requested Pond Water Surface Elevations
Minimum (Headwater) 363.50 ft
Increment (Headwater) 0.10 ft
Maximum (Headwater) 368 00 ft
Outlet Connectivity
Structure Type Outlet ID Direction Outfall 'El E2
(ft) (ft)
Weston'Townhomes C George, El
MIH14000 ppc 9/10/2014
Inlet Box
Riser
Forward
Culvert
36660
368.00
Onfice- Circular
Orifice
Forward
Culvert
364.50
368.00
Culvert- Circular
Culvert
Forward
TW
36250
368:00
Onfice- Circular
Siphon
Forward "
TW
36350
368:00
Tailwater Settings
Tailwater
(N /A)
(N /A)
Weston'Townhomes C George, El
MIH14000 ppc 9/10/2014

L'11 MCADAMS
Subsection: Outlet Input Data Return Event: 1 years
Label: SWMF #2 Storm Event: 1 Yr 24 Hr
Structure ID Siphon
Structure Type Onfice - Circular
Number of Openings
1
Elevation
363.50 ft
Orifice Diameter
1.250 in
Orifice Coefficient
0.60
StructuredD Riser
Structure Type Inlet Box,
Number of Openings
1
Elevation
366.60 ft
Onfice,Area
16.0 ftz
Orifice Coefficient
0.60
Weir Length
16.00 ft
Weir Coefficient
3.00 (ft ^0 5) /s
K Reverse
050
Manning's n
0.00
Kev, Charged Riser
000
Weir Submergence
False
Onfice,H ^to crest
False
Weston7ownhomes C George, El
UH14000`ppc 9/10/2014

alff l ..
Subsection: Outlet Input Data Return Event: 1 years
Label: SWMF #2 Storm Event: 1 Yr 24 Hr
Structure ID. Culvert
Structure Type Culvert- Circular
Number of Barrels
1
Diameter
24 000 In
Length
39.00 ft
Length (Computed Barrel)
39:00 ft
Slope (Computed)
0 013 ft/ft
Outlet Control Data
Manning's n
0.013
Ke
050
Kb
0.01
Kr
0,50
Convergence Tolerance
0.00 ft
Inlet Control Data
1.15
Equation Form
Form 1
K
0.0098
M
2.0000
C
0.0398
Y
0 6700
TI ratio (HW /D)
1.15
T2 ratio (HW /D)
1.30
Slope, Correction Factor
-0.50
Use-unsubmerged Inlet control 0 equation below T1
elevation
Use submerged Inlet control 0 equation above T2
elevation
In transition zone between unsubmerged and submerged
Inletcontrol,
Interpolate between flows at T1 '& T2
T1 Elevation 364.81 ft T1 Flow 15.55 ft3 /s
T2 Elevation, 365.10 ft T2 Flow 17.77 ft3 /s
Weston Townhomes C George, El
MIH14000,ppc 9/10/2014

Subsection: Outlet Input Data
Label: SWMF #2
Structure ID Onfice
Structure Type Orifice- Circular
Number of Openings
1
Elevation
364 50 ft
Orifice Diameter
2 000 in
Orifice Coefficient
0.60
Structure ID TW
Structure Type TW Setup, DS Channel
Tailwater Type
Free Outfall
Convergence Tolerances
Maximum Iterations
30
Tailwater Tolerance
0 01 ft
(Minimum)
Tailwater Tolerance
0.50 ft
(Maximum)
Headwater Tolerance
0:01 ft
(Minimum)
Headwater Tolerance
0150 1ft
(Maximum)
Flow Tolerance (Minimum)
0 001 ft3 /s
Flow Tolerance (Maximum)
10 000 ft3 /s
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
Weston Townhomes C George, El
MIH14000 pi c 9/10/2014

ME
� 51 V- SMON M,
Subsection: 'Composite Rating Curve
Label: SWMF #2
Composite Outflow Summary
Return Event: 1 years
Storm Event: 1 Yr 24 Hr
Water Surface Flow Tadwater Elevation Convergence, Error Contributing Structures
Elevation (ft3 /s), (ft) (ft)
(ft)
36350
0.00
(N /A)
0.00'
�(no Q• Riser,Orifice,Culvert,Siphon)
363.60
0.01
(N /A)
0,00'
Siphon (no Q: Rlser,Onfice,Culvert)
36370
0.02
(N /A)
0:00
Siphon (no Q: Riser,Orifice,Culvert)
363.80
0.02
(N /A)
0.00
Siphon (no Q: Riser,Orifice,Culvert)
363.90
0.02
(N /A)'
0.00
Siphon (no Q: Riser,Orifice,Culvert)
364.00
003
(N /A)
000
Siphon (no Q: Riser,Orifice,Culvert)
364.10
0.03
(N /A)
0.00
Siphon (no Q Riser,Orifice,Culvert)
364.20
0.03
(N /A)
0.00
Siphon (no Q• Riser,Orifice,Culvert)
364.30
004
(N /A)
000
Siphon (no Q Riser,Orifice,Culvert)
36440
004
(N /A)
0,00
Siphon (no Q: Riser,Orifice,Culvert),
364.50
'0 04
(N /A)
000
Siphon (no Q• Riser,Orifice;Culvert)
364.60
0.05
(N /A)
0.00
Orifice,Culvert,Siphon (no;Q: Riser)
364.70
0.08
(N /A)
0:00
Orifice,Culvert,Siphon (no,Q. Riser)
36480
0.09
(N /A)
0'00
Orifice,Culvert,Siphon (no Q: Riser)
364.90
0.11
(N /A)
0:00
Orifice;Culvert,Siphon (no Q: Riser)
365.00
0.12
(N /A)
0.00
Orifice,Culvert,Siphon (no Q Riser)
365.10
0.13
(N /A)
0.00
Orifice,Culvert,Siphon (no Q: Riser)
36520
0 13
(N /A)
000
Orifice,Culvert,Siphon (no Q Riser)
365.30
014
(N /A)
0°00
Orifice;Culvert,Siphon (no Q: Riser)
,365.40
0.15
(N /A)
0:00
Orifice,Culvert,Siphon (no Q: Riser),
365 50
0.16
(N /A)
000
Orifice;Culvert,Siphon (no Q• Riser)
365.60
016
(N %A)
0.00
Orifice,Culvert,Siphon (no Q• Riser)
365.70
017
(N /A)
000
Onfice,Culvert,Siphon (no Q Riser)
365.80
0.18
(N /A)
0.00
Orifice,Culvert,Siphon (no Q Riser)
36590
0.18
(N /A)
0.00
Onfice,Culvert,Siphon (no Q: Riser)
366.00
619
(N /A)
000
Onfice,Culvert,Siphon (no Q. Riser)
366A0
019
(N /A)
000
Onfice,Culvert,Siphon (no Q. Riser)
36620
0.20
(N /A)
0.00
Onfice,Culvert,Siphon (no Q: Riser)
366.30
020
(N /Ap
000
Ohfice,Culvert,Sipho i (no Q: Riser)
366:40
0121
(N /A)
000
Onfice,Culvert,Siphon (no Q: Riser)
366.50
0:22
(N /A)
0.00
Onfice,Culvert,Siphon (no Q: Riser)
36660
022
(N /A)
0 00'
Orifice,Culvert,Siphon (no Q• Riser)
366`70
176
(N /A)
000
Riser;Orifice,Culvert,Siphon
366.80
452
(N /A)
0.00
Riser,Orifice,Culvert,Siphon
36690
8.13
(N /A)
0.00
Riser,Orifice,Culvert,Siphon
367.00
1238
(N /A)
0.00
Riser,Orifice,Culvert,Siphon
367.10
17.18
(N /A)
000
Riser,Orifice,Culvert;Siphon
367:20
22.49
(N /A)
000
Riser,Orifice,Culvert,Siphon
36730
28'24
(N /A) ,
0.00
Riser,6n6ce,Culvert,Siphon
367`40
29:85
(N /A)
000
Riser,Culvert,Siphon (no Q: Orifice)
367.50
30.26
(N /A)
0.00
Riser,Culvert,Siphon (no Q: Orifice)
367.60
30.67
(N /A)
0.00
Riser,Culvert,Siphon (no Q: Orifice)
36770
31.07
(N /A)
0.00
Riser,Culvert,Siphon (no Q: Orifice)
367.80
31.47
(N /A)
000
Riser,Culvert,Siphon (no Q. Orifice)
36790
31.87
(N /A)
000
Riser,Culvert,Siphon (no Q. Orifice)
368.00
32261
(N /A) 1
0.00 1
Riser,Culvert,Siphon (no Q: Orifice)
Weston TownKomes C George, El
MIH14000 ppc 9/10/2014

McADAMS.
Subsection: Level Pool Pond Routing Summary Return Event: 1 years
Label: SWMF 2 (IN) Storm Event: 1 Yr 24 Hr
Infiltration
Infiltration Method
(Computed) No Infiltration
Initial,Conditions
Elevation (Water Surface,
363.50 ft
Initial)
0.358 ac -ft
Volume,(Imtial)
0.000 ac -ft
Flow (Initial Outlet)
0'00'ft3 /s
Flow (Initial Infiltration)
0 00 ft3 /s
Flow (Initial, Total)
0 00 ft3 /s
Time Increment
1.000 min
Inflow /Outflow Hydrograph Summary
0:1 %
Flow (Peak In) 7.71 ft3 /s Time to Peak (Flow, In), 721 000 min
Flow (Peak Outlet) 0.12,ft3 /s Time to Peak #,loW, Outlet) 1,082.000 min
Elevation (Water Surface, 365.06 ft
Peak)
Volume (Peak) 0.257 ac -ft
Mass Balance,(ac =ft)
Volume, (Initial),
0.000 ac -ft
Volume (Total Inflow)
0.358 ac -ft
Volume�(Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
0.119 ac -ft
Outflow)
Volume (Retained)
0 238 ac -ft
Volume (Unrouted)
0 000 ac -ft
Error (Mass Balance)
0:1 %
Weston,Townhomes C George, El
'MIH14000 ppc 9/10/2014

Subsection: Level Pool Pond Routing Summary
Label: SWMF 2 (IN)
'Infiltration
0 OOO.ac;ft
Infiltration Method
No Infiltration'
(Computed)
0.000 ac -ft
Volume (Total Outlet
0 153 ac-ft
Initial Conditions
Elevation (Water Surface,
363 50 ft
Initial)
0 000 ac -ft
Volume (Initial)
0.000, ac -ft
Flow (Initial Outlet)
0:00 ft3 /s
Flow °(Initial Infiltration)
0',00 ft3 /s
Flow (Initial, Total)
0:00 ft3 /s
Time Increment
1.000 min
Inflow /Outflow Hydrograph Summary
Return Event: 2 years
Storm Event: 2 Yr 24 Hr
Flow "(Peak' In) 9.79 ft3 /s, Time to Peak (Flow, In) 721 000 min
Flow (Peak Outlet) 0.16.ff3 /s Time to Peak (Flow, Outlet) 1,082.000 min
Elevation (Water Surface, 365.49 ft
Peak)
Volume (Peak) 0.336 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0 OOO.ac;ft
Volume (Total Inflow)
0.467 ac -ft
Volume (Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
0 153 ac-ft
Outflow)
Volume (Retained)
0.314 ac -ft
Volume (Unrouted)
0 000 ac -ft
Error (Mass Balance)
0:01%
Weston Townhomes C George, El
MI1-11400&ppc 9/10/2014

'J McADAMS
Subsection: Level Pool Pond Routing Summary
Label: SWMF'2 �(IN)
Infiltration
0 000 ac -ft
Infiltration Method
No Infiltration
(Computed)
0.000 ac -ft,
Volume (Total Outlet
0.194 ac -ft
Initial Conditions
Elevation (Water Surface,
363 50 ft
Initial)
0.000 ac -ft
Volume (Initial)
0.000�ac -ft
Flow (Initial'Outlet)
0.00 ft3 /s
Flow (Initial Infiltration)
0 00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
Time Increment
1.000 min
Inflow /,Outflow Hydrograph Summary
Return Event: 5 years
Storm Event: 5 Yr 24 Hr
Flow (Peak In) 12 05 ft3 /s Time'to Peak (Flow, In) 721 000 min
Flow (Peak Outlet) 0.1g ,ft3 /s Time'to Peak (Flow, Outlet) 1,083 000 min
Elevation (Water Surface, 366.10 ft
Peak)
Volume (Peak) 0 460 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0 000 ac -ft
Volume (Total Inflow)
0.631 ac -ft
Volume (Total Infiltration)
0.000 ac -ft,
Volume (Total Outlet
0.194 ac -ft
Outflow)
Volume (Retained)
0:437 ac -ft
Volume (Unrouted)
0.000 ac -ft
Error (Mass Balance)
0.0%
Weston Townhomes C George, El
MIH14000 ppc '9/10/2014

�J McADAMS
Subsection: Level Pool Pond Routing Summary Return Event: 10 years
Label! SWMF 2 (IN) Storm Event: 10 Yr 24 Hr
Infiltration
Infiltration Method No Infiltration
(Computed)
Initial Conditions
Elevation (Water Surface,
363.50 ft
Initial)
0.27 ft3 /s Time to Peak (Flow, Outlet) 1,078 000 min
Volume'(Initial)
0.000 ac -ft
Flow (Initial Outlet)
0.00 ft3 /s
Flow (Initial Infiltration)
0 00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
Time. Increment
12000 min
Inflow /Outflow Hydrograph Summary
0.0%
Flow (Peak In)
13.68 ft3 /s Time to Peak (Flow, In) 721 000 min
Flow (Peak Outlet)
0.27 ft3 /s Time to Peak (Flow, Outlet) 1,078 000 min
Volume (Total Infiltration)
0 000 ac -ft
Elevation (Water Surface,
366.60 ft
Peak)
Volume (Peak)
0.567 ac -ft
Mass Balance (ac -ft)
0.000 ac -ft
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
0 763 ac -ft
Volume (Total Infiltration)
0 000 ac -ft
Volume (Total Outlet
0.225 ac -ft
Outflow)
Volume (Retained)
0 538 ac -ft
Volume (Unrouted)
0.000 ac -ft
Error (Mass Balance)
0.0%
Weston Townhome_s C George, El
MIH14000 ppc 9/10/2014

1111 -
Subsection: Level Pool Pond Routing Summary
Return Event: 25 years
Label: SWMF 2 (IN)
Storm Event: 25 Yr 24 Hr
Infiltration
Infiltration Method No Infiltration
(Computed)
Initial Conditions
Elevation (Water Surface,
363.50 ft
Initial) -
Volume (Initial)
0 000 ac -ft
Flow (Initial Outlet)
0 00 ft3 /s
Flow (Initial Infiltration)
0.00 ft3 /s
Flow (Initial, Total)
0 00 ft3 /s
Time.Increment
1 000 min
Inflow /Outflow Hydrograph Summary
Flow (Peak In)
15 58 ft3 /s Time to Peak (Flow, In)
721.000 min
Flow (Peak Outlet)
193 ft3 /s Time to Peak (Flow, Outlet)
755.000 min
Elevation (Water Surface,
366.71 ft
Peak)
Volume'(Peak)
0.589 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
0.944 ac -ft
Volume (Total Infiltration)
0.000 ac -ft
Volume (Total Outlet
0.392 ac -ft
Outflow)
Volume (Retained)
0 551 ac -ft
Volume (Unrouted)
0 000 ac -ft
Error (Mass Balance)
0.0%
Weston Townhomes' C George, El
MIH14000 ppc 9/10/2014

Subsection: Level Pool Pond Routing Summary Return Event: 100 years
Label: SWMF 2 (IN) Storm Event_: 100 Yr 24 Hr
Infiltration
Infiltration Method
No Infiltration
(Computed)
Initial Conditions
0.614 ac -ft
Elevation (Water Surface,
363.50 ft
Initial)
Volume (Initial)
0 °000 ac -ft
Flow (Initial Outlet)
0 00 ft3 /s
Flow (Initial Infiltration)
0.00 ft3 /s
Flow (Initial, Total)
0.00 ft3 /s
Time Increment
1 000 min
Inflow /Outflow Hydrograph Summary
Flow (Peak In) 18:08 ft3 /s Time to Peak (Flow, In) 721 000 min
Flow (Peak Outlet) 5 13 ft3 /s Time to Peak (Flow, Outlet) 750.000 min
Elevation (Water Surface,
366 82 ft
Peak)
Volume (Peak)
0.614 ac -ft
Mass Balance (ac -ft)
Volume (Initial)
0.000 ac -ft
Volume (Total Inflow)
1 234 ac -ft
Volume, (Total Infiltration)
0 000 ac -ft
Volume (Total,Outlet
0 671 ac -ft
Outflow)
Volume (Retained)
0 562 ac -ft
Volume,(Unrouted)
0.000 ac -ft
Error (Mass Balance)
00%
Westonjownhomes O George, El
MIH14000 ppc 9/10/2014

DESIGN OF RIPRAP OUTLET PROTECTION WORKSHEET
Project Weston Townhomes Date 24- Jun -14
Project No. MIH -14000 Designer JAA
Outlet ID SWMF #2
Flow, Q10-y,
1
cfs
Slope, S
1.28
%
Pipe Diameter, D,,
24
inches
Pipe Diameter, Do
2
feet
Number of pipes
1
Stone diameter =
Pipe separation
0
feet
Manning's n
0.013
13
1 �FAIN N —
ffzaazm
Zone from graph above =
1
Diameter
Thickness
Outlet pipe diameter
24 in.
Length =
8.0 ft.
Outlet flowrate
1.0 cfs
Width =
6.0 ft.
Outlet velocity
4.0 ft/sec
Stone diameter =
3 in.
Material =
Class A
Thickness =
9 in.
Zone
Material
Diameter
Thickness
Lenath
I Width
1
Class A
3
9
4 x D(o)
3 x D(o)
2
Class B
6
22
6 x D(o)
3 x D(o)
3
Class I
13
22
8 x D(o)
3 x D(o)
4
Class I
13
22
8 x D(o)
3 x D(o)
5
Class II
23
27
10 x D(o)
3 x D(o)
6
Class II 1
23
27
10 x D(o)
3 x D(o)
7
Special study required
1. Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
2. Outlet velocity based on full -flow velocity
Rip Rap Outlet Protection Design.xlsm6 /25/2014

WESTON TOWNHOMES STORMWATER MANAGEMENT FACILITY C GEORGE, EI
MIH -14000 Anti- Flotation Block Calculations 6/25/2014
SERAIV�L- F�OTATIONCA'LCUL,4T(ON
Input;Data =>
Inside length'of riser =
400 feet
Inside width of riser =
400 feet
Wall thickness of riser =
6'00 inches
Base thickness of user =
600 inches
Baselength of riser =
5'00 feet
Base width of riser =
500 feet
Inside height of Riser =
4 10 feet
Concrete,unit weight =
142 0 PCF
OD of barrel exiting manhole =
3600 inches
Size of drain pipe (if present) =
80 inches
Trash Rack water displacement =
61 74 CF
Concrete Present in Riser Structure =>
Total amount of concrete
Base;of Riser =
12 500 CF
Riser Walls =
36900 CF
Adjust for openings
Opening ,for barrel =
3534 CF
Opening for dram'pipe =
0 524 CF
Total Concrete present, adjusted foropeinngs =
45 342 CF
Weight of concrete present =
6439 lbs
Amount of water displaced by Riser Structure =>
Displacement by concrete=
45 342 CF
Displacement by opewair in riser =
65 600 CF
Displacement by trash rack =
61 740 CF
Total'water displaced by riser/barrel structure =
172 682 CF
Weight of water displaced =
10775 lbs
Note: NC Products lists unit wt of
manhole concrete at 142 PCF

WESTON TOWNHOMES STORM_ WATER MANAGEMENT FACILITY C, GEORGE, El
MIH -14000 Anti - Flotation Block Caictildtrons 6/25/2014
Calculate amount,ofconcret"o be added to riser =>
Safety factor to u`se =
Must add
Concrete,umt weight for use =
Buoyant weight of this concrete =
Buoyant, with safety factor applied =
Therefore, must add =
Standard based descnbed,above =
Therefore, base design must have =
Calculate size of base for riser assembly —
Length =
Width =
Thickness=
Concrete Present =
Check validity of base as designed =>
Total Water Displaced =
Total Concrete Present =
Total Water Displaced
Total Concrete Present•=
Actual `safety factor
Results of design =>
1 15 (recommend 1 15 or higher)
5953 Ibs concrete for buoyancy
142 PCF (notczbove observation for NCP concrete)
7960 PCF
69 22 PCF
86 006 CF of,concrete
12 500 CF of concrete
98 506 CF of concrete
8 000 feet
8 000 feet,
200 inches
106667 CF OK
266 849 CF
139 509 CF
16651 Ibs
19810 Ibs
/ /9 OK
Base length =
8.00 feet
Base.wtdth =
8 00 feet
Base Thickness =
20 00 inches
CY,of concrete total in base =
3.95 CY
Concrete unit weight to added base ? =_
142 PCF

N,UTRIEN'T L OADINVG" CAL,CULA TI ®N►S
WESTON TOWNHOMES
MIH -14000

Neuse NutrientReporting Form
Please�complete and submit the following „ihformation,to'the,local government permitting yourdevelopment projectto
charactenzent and assess the need'to purchase nutrient,offsets. Contactland rule, impl Lmentation'inforrriation�can,be
found online at,http / /portal- ncdenr org/ web /wq /ps /nps /n utrientoffsetmtro.
PROJECT INFORMATION
Applicant Name.
M/I Homes of 'Raleigh
Project Name:
Weston Townhomes,
Project Address (ifavadable) ,Street City/Town County,
Cary” Wake
Date;(mo /dtyr)
Project
F35 eainal degrees)
Long: (decimal'degrees)
06140M4
Location:
12561
-78 8sT3064
Is °this Redevelopments '❑ - -Yes
Development Type (P /ease�check all'that apply)
No
— -
Impervious Cover,( %)•
E]
Commercial
❑'
Mixed -Use
❑
Single Fam Residential
(Pre - Construction)
0 00
❑
Iustria
nd l
Institutional
r
[T'
Duplex Residential
❑
Multi -Fam Residential
Irriperviou&Cover ( %)-
27 82
(Post'Construchon)
WATERSHEMINFORMATION
12- 'Digit Watershed ID: (See online map l
New Development Load;Requirements.(See indiwduatrules for a full
03020201,0801
descnphon of nutneriVrequ ements )
;NutnenVStrategy
Loading Rat&Ta(rgets'Ntrogen)(N)
Offsite Thresholds
03020201
3 6 N Ib /ac/yr,
&N Ibs /ac-,Residential,
Neuse
10,N Ibs /ac Commercial
NUTRIENT
OFFSET REQUEST Must meet the,offsite thresholds, see,above
Nitrogen `Loading) Offset,Needs
(A)
(B)
(c),
'(D)
(E)
(F)
(G)
Untreated
Treated
Loading [Rate,
Reduchon;Need
Project_
Offset
State Buy Down
Loading�Rate
Loading Rate
Target(Ibs /ac/)(r)
(Ibs /ac /yr)
'Size (ac)'
Durabon'(yrs)
Amounf(Ibs)
(Ibs /ac /yr)
(Ibs /ac/yr)
B - C
D '+E" F
652
4'06
3,60
046
.25.311
'30
349,28
'Control of "Peak Stormwater Flow (1 year'24 houridesign storm)
Calculated Predeve(opmentlFlow
Calculated Post Development Flow
Flow Control Method
94 cfs
94 cfs
WQ Pond/Wetland
Authorizing ?Local Government Name-
'Staff Name:
Staff Email'
Phone:
Neuse Nutnent L.oad`Reporttrig,Form Ndvember 1, 2012

mIt
N
o; o
a
rA
z
0
z
a�
U �
a
0
W
z
F
rn
}sO
9
� Q
5
a
3i
4
4
pc
V
II
3
3
O
C
b
s
d
r
4�
O
b
w
q
E
U
_ A a a a $
in N O °^ OM m Ch
N V
r
u9
II II p II II II II II II II
o
Q m
O
> F F= a °�
Q ° Q O 5 O

E2
Ȥ
/\
� o
§ {
k =
t
� / ?
m m
% t ■ _ � o
6) $
■ _ @ 3 E $
s o
§§. 2 B Q
' 7 % % § £
�
\ /
( i U i 2
■ t \ s /
k rm d \ k
q .B
\
�
»
$ /
66
w
t m
\ /
/ �
0
w.
k
§
2
q
r
o
$
�
@
k
�B2
110
e
C'4
z
�
f
cn
?
q
tn
$
to
2 5
/ z
t
2 /
�
/ \
V
§
t
a
H
C
k
cz�
�
H
© ■
■
© ■:
■ �
� �
§ $ \
k§
E k
o.4
o
C 2
/ §
\
�
»
$ /
66
w
t m
\ /
/ �
0
w.

W �
� o
N
O
z
o.
F
U
O
w
z
F
g
Q
O
4
O
x
l3
0 o
0
0
x
3�
Q
O
O
O ^O
w
•y
U �
•�
g
w li,
O
N
O
z
O
F
h p)
C
lit
y
a
O .
o�
rol
i o o q
h y �6) :�%
N ,y
fa)
zc
F
a�
�XrA rA X
Q
w li,
O
N
O
z
F
v �
Y! y
zc
F
y
00
�--�
06
r-
N
St O
Co
bq
tx
C
O, O
ts
Uo
13
o 0
ai
� CL
4
C:1
4
4 0
ti
cd
0
O
N
� N
II 'II
i!
W �
o
F-4

W v-
H,
0
�00
� C
t j t3 ;s O
�+
�Co
z
°
U°
W
A
° e °
O y^r
V
° y
\
Qi Zi
3
o>
ti ~ O
N
\
y �
z
F
g h
r4 O it
O
i
o
o) t3 ZI qJ q6)
� �
O,
q
w
as
2 °'
O
� � •Y
44 A4 9L4 1:64 ILI
W et `q
W W W W W
H,
0
�00
� C
z
F
O y^r
V
N
as
z
F
g h
r4 O it
O
O
O
O,
w
as
2 °'
ao t
n
o, o
y
O
o
i i
i ts;
aa
Q.
y
C-)
.q
� O
N �p
II II
C
C, O
W �
a�
o
E-'

W ;c
� o
N
Oy O
rTj ,T
Q
ro
v o
�
r
o
�
U
z
�
o
v
s Lt y
►� �
Obi
ry � � O
C
M
M
z
H
�-
V
O
y o
N
H�
C
bi
oY
Go y
yam,
O
ON
d
+-• + y y
. y
A�°��°4v
C1 p
"�
Ol
C b0
�, a „i
aaaaa
y.
C
Q
ro
o
v
s Lt y
O
O
M
C
M
M
z
H
ci
M O GS
N
H�
Go y
yam,
O
ON
d
o
C1 p
"�
Ol
C b0
Id
y.
C
o
R:,
3c F
U
"
o
h
v
V
C Q
C
o� y
g
4 0
� o
�b ° R
U
� O
II ��
I�
H �
.o
o
H

23
0
/\
>
q
2
q
Q
Q
�
?,
$
a
�
/
�
\
k
0
_
§
0
\
\ §
6
G
a
2 /
� a
t m
0
� o
§ 2
t
t
� /
�
\ \
t
■ � � o
�
■
t
a ■ c k
2 f § ƒ
�
■ ■ 3 2 q
t
0
a o t= t
2$ §«{
k
k k 3§ S§
S o
\ / \
\
A
\ t / / §
� 2
%
H
R o
%
§ $
(
U
\ G 2
° 2
§ K ? k
i k
k ) § \ k
K
-
o 3t
2
o �
[-4
§ K
a A4 064 a a
W W W W#
,
� �o �
6
G
a
2 /
� a
t m
0
k
$
$
r
J
z
H
�^
CJ
-
o �
g
Q
,
F
,
,
31
�'k
/
to
�
a ■�
��
�
�,k
¥
k
0
4
/
¢
�
� ■
� � �
§
§
E�
§
( \
C 2
4 0
4
@
� \
■
%'
6
G
a
2 /
� a
t m
0

WESTON TOWNHOMES
CARY, NORTH CAROLINA
FINAL DESIGN OF CULVERT CROSSINGS
PROJECT NUMBER:
DESIGNED BY:
DATE:
MIH -14000
JON ALDRIDGE, PE
CORY GEORGE, EI
SEPTEMBER 2014
2905 MERIDIAN PARKWAY
DURHAM, NORTH CAROLINA 27713
NC LIC. # C -0293
%%- - -.,.
kk
SEAL
33»
z- 4"v A.
VIM

HY -8 Culvert Analysis, Report
Crossing Discharge Data
'Dis harge'Selection Method, Recurrence

Table 1 - Summary of Culvert'Flows at Crossing: Existing 60s
Headwater
Elevation (ft)
Discharge
Names
Total
Discharge (cfs)
Culvert 1
Discharge (cfs)
Culvert 2
Discharge (cfs)
Roadway
Discharge (cfs)
Iterations
32621
25 year
33184
16826
16357
000
10
33004
100 year
43501
21914
21587
000
6
333 00
Overtopping
50075
251 90
24885
000
Overtopping

Rating Curve Plot for Crossing: Existing 60s
330,0
329.5
329.0
0
} 320.5
cv
320.0
Y
327.5
327.0
326 -5
Total Rating Curve
Crosskg: Existing 60s
Taal Discharge (c €s)
N

Table 2 - Culvert Summary Table: Culvert 1
Discharge
Total
Culvert
Headwater
Inlet Control
Outlet
Flow
Normal'
'Critical
Outlet Depth
' Tedhiv t&
'Outlet
Names
Discharge
Discharge
Elevatiom(ft)
Depth�(ft)
Control
Type
Depth (ft)
Depth (ft)
(ft)
Depthr(ft)
Velocity
(cfs)
(cfs)
Depth (ft)
(ft/s) ,
25' ear
33184 _
168 28
32621
4 467
7 664
7-M2c
4 000
3 197
3 197
1 833
11 419
100 year
43501
21914
33004
5 928
11 492
7-M2c
4 000
3 582
3 582
2 147
13 712

Straight Culvert
Inlet Elevation (invert) ,31855 ft, Outlet'Elevation (invert) 1317 06 ft
Culvert Length 149 01 ft, Culvert,Slope 00160
NHfHMNeffNHHHifHffNNHfHHHHfHef MfHff HNf HHfffHMHfHHM

Culvert Performance Curve Plot; Culvert 1
329
® 328
m 327
w
10326
� 32�
�v
324
323
Performance Curve
Ciilv ut. C6,ert i
® 0
Inlet Control Elev Outlet Control Elev
Total Doscharge (c%s)
N

Water Surface Profile Plot for Culvert: Culvert 1
Crossing - Existing 60s.. Design Discharge - 435.0 cfs
Culvert - Culvert 1, Cuh-ert Discharge - 219.1 cfs
332
330 - + -
328
326
0
324
a�
w 322
320
318
316
50 100 1
Statbon (ft)
Site Data - Culvert 1
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 317.55 ft
Outlet Station: 149.00 ft
Outlet Elevation: 316.06 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 1
Barrel Shape: Circular
Barrel Diameter: 5.00 ft
Barrel Material: Concrete
Embedment: 12.00 in
Barrel Manning's n: 0.0120 (top and sides)
Manning's n: 0.0350 (bottom)
Culvert Type: Straight
Inlet Configuration: Thin Edge Projecting
Inlet Depression: NONE

Table,3 - Culvert, Summary Table: Culvert 2
Discharge
Total
Culvert
Headwater
Inlet Control
Outlet
Flow
Normal
C`ntical
Outlet Depth
Tailwater
Outlet
Names
Discharge
Discharge
Elevation (ft)
Depth (ft)
Control
Type
Depth (ft)
Depth (ft)
(ft)
Depth (ft)
Velocity
(cfs)
(cfs)
Depth (ft)
(ws)
25 yiiir
33184
16357
32621
4 352
7 374
7-M2c
4 000
3 153
3'153
1833,
11223'
100 year
43501
21587
33004
5'821
11202
7W2c
4 000
3 562
3 562
2 147
13 553

Straight Culvert
Inlet Elevation (invert) 318 84 ft, Outlet,Elevation (invert) 317 35,ft
Culvert Length � 149 01 ft, Culvert Slope 0'0100

Culvert Performance Curve Plot: Culvert 2
330
—329
328
327
w
'D 326
325
324
Performance Curve
CuNeit Culvert
F -AL I
Inlet Control Elev Outlet Control Elev
460 380 400
Total Discharge (c1s)

Water Surface Profile Plot for Culvert: Culvert 2
332
330
328
c 326
0
C° 324
W
W 322
320
313
316
Crossui lg - EX1Stillg 60S_ Design Discharge - 435.0 Cfs
Cuh-ert - Culvert_- Cuh-ert Discharge - 21-59 cfs
50
Station (ft)
Site Data - Culvert 2
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 317.84 ft
Outlet Station: 149.00 ft
Outlet Elevation: 316.35 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 2
Barrel Shape: Circular
Barrel Diameter: 5.00 ft
Barrel Material: Concrete
Embedment: 12.00 in
Barrel Manning's n: 0.0120 (top and sides)
Manning's n: 0.0350 (bottom)
Culvert Type: Straight
Inlet Configuration: Square Edge with Headwall
Inlet Depression: NONE
1
150

Table 4 — Downstream Channel Rating Curve (Crossing: Existing 60s)
Flow (cfs)
Water Surface
Elev (ft)
Depth (ft)
Velocity (ft/s)
Shear (psf)
Froude Number
33184
31889
183
326
057
045
435.01
31921
2 15
359
067
0.46

Tailwater Channel Data - Existing 60s
Tailwater Channel Option: Trapezoidal Channel
Bottom Width: 50.00 ft
Side Slope (H:V): 3:00 L,1)
Channel Slope: 0.0050
Channel Manning's n: 0.0450
Channel Invert Elevation: 317.06 ft
Roadway Data for Crossing: Existing 60s
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 100.00 ft
Crest Elevation: 333.00 ft
Roadway Surface: Paved
Roadway Top Width: 24.00 ft

Crossing Discharge Data
Discharge Selection Method. Recurrence

Table 5 - Summary of Culvert Flows at Crossing: Entrance Crossing
Headwater
Elevation (ft)
Discharge Names
Total Discharge
(cls)
Culvert 1
Discharge (cls)
Roadway
Discharge (cfs)
Iterations
326 66
25 year
11244
112'44
0100
1
32705
100` ear
14063
1,4663
0,00
1
334 00
Overtopping
37937
37937
0 00
Overtoppin

Rating Curve Plot for Crossing: Entrance Crossing
334
333
m
332
c�
m 331
w
330
-0329
T
328
327
Total Rating curve
Crossing Entrance Crossing
Taal Discharge (cfs)

Table 6 - Culvert Summary Table: Culvert 1
Discharge
Total
Culvert
Headwater
Inlet Control
Outlet
Flow
Normal
Critical
Outlet Depth
Tailwater
Outlet
Names
Discharge
Discharge
Elevation (ft)
Depth (ft)
Control
Type
Depth (ft)
Depth (ft)
(ft)
Depth;(ft)
Velocity
(cfs)
(cfs)
Depth (ft)
(Ts)
25 year
11244
11244
32666
2091
3 361
1 -s 1 f
1 379
1 755
3 500
5 020
4 481
100 year
14063
14063
32705
2 428
3 755
1 -s 1 f
1 590
2009
3 500
5 020
5`604

Straight Culvert
Inlet Elevation (invert).323 30 ft, Outlet Elevation (invert) '320 90,ft
Culvert,Length 101 03,ft, Culvert Slope 0 0238

Culvert Performance Curve Plot: Culvert 1
334
333
4-
(-332
0 331
}
Ei 330
L
329
328
:E 327
326
325
Performance Curve
cuhwt. cuh.-err i
w
Inlet Control, Elev Outlet Control Elev
Total Discharge (cts)

Water Surface Profile Plot for Culvert: Culvert 1
Crossing - Entrance Crossing. Design Discharge - 140.6 cfs
Culz-ert - Cuh-ert 1, Cuh-ert Discharge - 140 -6 cfs
RIM
332
330
c 328
o
326
w
324
322
320
i"
-20 0 20 40 60 80 100 120
Stab on (ft)
Site Data - Culvert 1
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 322.30 ft
Outlet Station: 101.00 ft
Outlet Elevation: 319.90 ft
Number of Barrels: 2
Culvert Data Summary - Culvert 1
Barrel Shape: Circular
Barrel Diameter: 4.50 ft
Barrel Material: Concrete
Embedment: 12.00 in
Barrel Manning's n: 0.0120 (top and sides)
Manning's n: 0.0300 (bottom)
Culvert Type: Straight
Inlet Configuration: Square Edge with Headwall
Inlet Depression: NONE

Table 7 - Downstream Channel'Rating Curve. (Crossing: Entrance ,Crossing)
Flow (cfs)
Water Surface Elev (ft)
Depth (ft)
11244
325'92
502
14063
32592
5.02

Tailwater Channel Data - Entrance Crossing
Tailwater °Channel Option: Enter Constant Tailwater Elevation
Constant Tailwater Elevation. 325.92 ft
Roadway Data for Crossing: Entrance Crossing
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 100:00 ft
Crest Elevation: 334.00 ft
Roadway Surface- Paved
Roadway Top Width: 24.00 ft

Crossing Discharge Data
Discharge Selection Method: Recurrence

Table 8 - Summary of Culvert Flows at Crossing: Western Crossing
Headwater
Elevation (ft)
Discharge Names
Total Discharge
(cfs)
Culvert 2
Discharge (cls)
Roadway
Discharge (cfs)
Iterations
371 78
25 year
1277
12 77
006
1
372 06
100 y ear
1670
1670
000
1
38600
Overtopping
4869
4869
000
Overtoppin

Rating Curve Plot for Crossing: Western Crossing
386
MI
c 382
380
w
378
376
F
37.4
372
Total Rating Curve
Crossing
_ western Crossing
Total Discharge (cis)

Table 9 Culvert Summary Table: Culvert 2
Discharge
Total
Culvert
Headwater
Inlet,Control
Outlet
Flow
Normal
Critical
Outlet Depth
Tadwater
Outlet
Names
Discharge
Discharge
Elevation (ft)
Depth (ft)
Control
Type
Depth (ft)
Depth (ft)
(ft)
Depth (ft)
Velocity
(cfs)
(cfs)
Depth (ft)
(ft/s)
'25 year
1277
1277
37178
1 280
0 0'
1S2n
0 678
1 092
0 678
0 397
10 042
100 year
16.70
1670
37206
1 563
0 0'
1S2n
0 801
1264
0 801
0 462
11 033

*Full Flow Headwater' elevation is below,inlet invert.

Straight Culvert
Inlet Elevation. (invert). 370°60 ft Outlet Elevation,(mvert) 363 05 ft
Culvert Length 107 2&ft, Culvert Slope'0 0696

Culvert Performance Curve Plot: Culvert 2
9. *Bd
384
© 382
c�
880
w
u 378
c�
X376
a�
374
372
Performance Curve
Ciih,ert Cul ert ?
F—OD FA-1
Inlet Control Oev Outlet Control Elev
Total Discharge (cts)

Water Surface Profile Plot for Culvert: Culvert 2
Crossing - Western Crossing. Design Discharge - 16.7 cfs
Cuh--ffz - Cuh-eft ?, CLlvetz Discharge - 16.7 cfs
,:
z
0 375
c�
W
370 �
365
-20 0 20 40 60 80 100 120 140
Stat on (ft)
Site Data - Culvert 2
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 370.10 ft
Outlet Station: 107.00 ft
Outlet Elevation: 362.65 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 2
Barrel Shape: Circular
Barrel Diameter: 2.00 ft
Barrel Material: Concrete
Embedment: 4.80 in
Barrel Manning's n: 0.0120 (top and sides)
Manning's n: 0.0300 (bottom)
Culvert Type: Straight
Inlet Configuration: Square Edge with Headwall
Inlet Depression: NONE

Table 10 - Downstream Channel Rating Curve (Crossing: Western Crossing)
Flow (cfs)
Water Surface
Elev'(ft)
Depth (ft)
Velocity (ft/s)
Shear (psf)
Froude Number
1277
36305
0.40
5.19
248
158
1670
36311
046
5.66
288
162

Tailwater Channel Data - Western Crossing
Tailwater Channel,Option: Trapezoidal Channel
Bottom Width: 5 00 ft
Side Slope (H:V). 3.00 (_:1)
Channel Slope 0.1000
Channel Manning's n: 0.0430
Channel Irivert Elevation- 362.65,ft
Roadway Data for Crossing: Western Crossing
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 100.00 ft
,Crest,,Elevabon: 386.00 ft
Roadway Surface: Paved
Roadway Top Width: 2400 ft

HY -8 Energy Dissipation Report
External Energy Dissipator
Parameter
Value
Units
Select ,Culvert and Flow
Crossing
Entrance Crossing
Culvert
Culvert'1
Flow
11244
cfs
Culvert Data
Culvert Width (including multiple
barrels
90
Culvert Height
5
ft
Outlet Depth
350
ft
Outlet Velocity
48
s
Froude Number
0,42
adwater Depth
502
ft
adwater Velocity
000
s
adwater Slope SO
00238
External Dissi ator Data
External Dissi pator 'Category
Streambed Level Structures
External Dissi ator, Type
Ri rap'Basin
Restrictions
Froude Number
<3
Input Data
Condition tobe used to Compute
Basin Outlet Velocity
Best Fit Curve
D50 of the Riprap Mixture
Note
Minimum HS /D50 = 2 is Obtained if
D50 = 0 153 ft
D50 of the Ri rap Mixture
0 153
ft
DMax of the,Ri ra Mixture
0 500
Results
Brink Depth
020
Bnnk'VeloG
6 933
s
Depth YE
3 542
Riprap Thickness
0 750
ft
Riprap Foreslo e
1 0000
ft
Check HS /D50
Note
OK if HS/D50 > 2 0
HS /D50
2034
HS /D50 Check
HSM50 is OK
Check HS /D50
Note
OK if 01 < D50NE <,0 7
Check 1350NY
0 043
D50NE Check
D50/YE is NOT OK
Basin Length LB
18 000
ft
Basin Width
16 500
ft
Apron Length
4 500
ft
Pool Length
13 500
ft
Pool Depth HS
03,11
/YE
1 417
adwater Depth (TW)
5 020
ft
Average Velocity with TW
0 844
s

Critical Depth (Yc)
1,080
ft
Average Velocity with Yc
5 579
fus
Downstream Riprap for High TW
Distance 1 LB
Velocity
225
s_
Size
0 116
Distance 2 LB
Velocity
3 613
s
Size
0 085
Distance 3 LB
Velocity
756
s
Size
0 050
Distance 4 LB
Velocity
135
s
Size
0030

HY -8, Energy Dissipation Report
External Energy Dissipator
Parameter
Value
Units
elect•Culvert and Flow
Crossing
Ezistm '60s
Culvert
Culvert 1
Flow
43501
cfs
Culvert Data
CulverLWidth (including multiple
barrels
50
ft
Culvert Height
50
ft
Outlet Depth
358
ft
Outlet Velocity
1371
s
Froude Number
128
adwater Depth
215
ft
adwater Velocity
359
fus
ailwater Slop ' (SO)
00100
External Dissi ator Data
External Dissi ator Category
Streambed Level Structures
External Dissi ator Type
Riprap Basin
Restrictions
Froude Number
<3
In ut °Data
Condition to be used to Compute
Basin Outlet Velocity
Best Fit Curve
D50 of the Riprap Mixture
Note
Minimum HS /1350 = 2 is Obtained if
D50 = 0 748 ft
D50 of the Riprap Mixture
0 748
ft
DMax,of the Riprap Mixture
1 420
ft
Results
Brink Depth
3582
ft
Brink Velocity
13 712
Pus
Depth YE
827
ft
Ri ra ,Thickness
2'1'30
ft
Riprap Foreslo a
28400
ft
Check HS /D50
Note
OK if HS /D50,> 2 0
HS /D50
2,002
HS /D50 Check
HS /D50 is OK
Check HS /D50
Note
OK if,01 <_D50/YE < 0 7
Check D50/YE
0 265
D50NE Check
D50/YE is OK
Basin Length LB
2 489
Basin Width
19 993
Apron Length
7 489
Pool Length
15 000
It
Pool Depth HS
1 498
ft
/YE
0 760
adwater Depth (TW)
2147
ft
AVerage'Velocity with TW 14203
fus

Critical Depth (Yc)
1 474
ft
Average Velocity with Yc
6 482
ftls
Downstream Riprap for High TW
Distance 1 LB
Velocity
11 963
s
Size)
0 933
ft
Distance 2, LB
Velocity
8 033
s
Size
0421
ft
Distance 3 LB
Velocity
5 557
s,
Size
-201
ft
Distance 4 LB
Velocity
159
s
Size
10113
Ift

HY -8 Energy Dissipation Report
External Energy Dissipator
Parameter
Value
Units
Select Culvert and Flow
Crossing
Western Crossing
Culvert
Culvert 2
Flow
1277
cfs
Culvert Data
_
Culvert Width (including multiple
barrels)_
20
ft
Culvert Height
20
Outlet Depth
068
Outlet Velocity
1004
s
Froude Number
215,
ailwater Depth
040
ailwater Velocity
519
s
ailwater Slope SO
0 0696'
External Dissi ator Data
External_Dissi ator Category
treambed,Level Structures
External Dissi ator Type
Riprap Basin
Restrictions
Froude Number
<3
Input Data
Conditionfto be used to Compute
Basin Outlet Velocity
Best Fit Curve
D50 of the Riprap Mixture
Note
Minimum HS /D50 = 2 is Obtained if
D50 = 0 321 ft
D50 of the Riprap Mixture
0 321
DMax of the Riprap Mixture
0 500
Results
Brink Depth
0 678
Brink Velocity
10,042
s
Depth YE
0 797
ft
Riprap Thickness
0 750
ft
Riprap Foreslo a
1, 0000
ft
Check.HS /D50
Note-
OK rf HS /D50 > 2 0
HS /D50
2015
HS /D50 Check
HS /D50 is OK
Check HS /050
Note
OK if 01 < D50/YE < 0 7
Check D50/YE
0 403 _
D50/YE Check
D50/YE is OK
Basin Len 'th LB
9 702
Basin Width
8 468
ft
Apron Length
234
ft
Pool Length
6 468'
ft
Pool Depth, HS
0°647
_
/YE
0 498
ailwater Depth (TW)
0 397
verage A Velocity with TW
3 470
s

Critical Depth (Yc)
10 400
verage Veloci ty with Yc
13442 VUS