HomeMy WebLinkAboutWPO201400030 Calculations 2014-04-15°
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U Lic. No. 035791 ,ti
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OUTFACE INTO ROUTE 29's ROADSIDE DITCH &
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OUTFACE PIPES, WHERE THE RUNOFF DRAINS TO
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SHEET NO.
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(DA #1 B, 1C & 2) IS APPROXIMATELY 1% OF THE
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JOB NO.
122076
J rA SCALE
NOTE:
THE PROPOSED DEVELOPMENTS & SWM FACILITIES
1 " =500'
OUTFACE INTO ROUTE 29's ROADSIDE DITCH &
OUTFACE PIPES, WHERE THE RUNOFF DRAINS TO
SHEET NO.
HERRING BRANCH &THE PROJECTS WATERSHED -
(DA #1 B, 1C & 2) IS APPROXIMATELY 1% OF THE
.� OF 1
OVERALL CONTRIBUTING WATERSHED.
BRIARWOOD
CHANNEL ADEQUACY REPORT
Completed on
November 4th, 2013
Revised on June 9th & July 21st, 2014
(July 21SY, 2014 Revisions noted in yellow)
PREPARED BY:
COLLINS
200 GARRETT STREET, SUITE K
CHARLOTTESVILLE, VA 22902
434.293.3719 PH O�W EALT�
434.293.2813 FX O,i,
www.collins-engineering.com ° 41157
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TONAL ENG
The Briarwood Channel Adequacy Report & Calculations
Overview
The following channel adequacy report and calculations were analyzed by dividing the
watershed into three major sections. Drainage areas #1B, 1 C and 2 all drain to route 29's
grass lined roadside ditch, which then outfall into two structures running beneath route
29. This development is uniquely located such that it is situated at the very downstream
portion of its watershed. This is evident in its close proximity to Rivanna River.
Summaries of these three sections, and the overall watershed, can be found in the
construction plans and the attached sheet entitled Channel Adequacy Exhibit. Because the
post-development flows are less than or equal to the pre-development flows, and the
project's outfall points are located where the development's drainage area is
approximately 1% of the overall contributing watershed, an analysis of route 29's
receiving roadside ditch and stormwater management outfall points were completed. The
following report will detail the flows resulting from the proposed development and will
prove the adequacy of the downstream receiving channels.
Drainage Area, D.A. #1B:
This section consists of drainage flowing to the proposed stormwater management
(SWM) facility#1 for detention. This facility is a pre-manufactured underground
detention system supplemented with separate water quality facilities. The runoff flowing
to this system has the following characteristics in the post-development state:
D.A.= 3.29 ac.
CN= 73.8 (58'.0 in the Pre-Development Scenario)
Type II distribution
P= 3.7 inches (2-year event)
Tc= 0.10 hours
Drainage Area, D.A. #1C:
This watershed drains to the existing route 29 roadside ditch and is largely undisturbed
until the proposed gas station is developed (WPO 201400059). When this watershed is
developed, as indicated on the proposed gas station WPO plans, a proposed underground
detention system will be installed releasing runoff at rates less than the existing
conditions analyzed below. This will therefore make this report more conservative and
the gas station plans compliant with channel adequacy requirements. This watershed
contains the following characteristics:
D.A.= 1.80 ac.
CN= 66.9 (62.0 in the Pre-Development Scenario)
Type II distribution
P= 3.7 inches (2-year event)
Tc= 0.12 hours
Drainage Area, D.A. #2:
Drainage area#2 drains to proposed SWM facility #3, which is an extended detention
facility. This basin provides both water quality and detention for its runoff. This
watershed contains the following characteristics:
D.A.= 3.84 ac.
CN= 68.4 (>5.6 in 1110 Pic-Uc1 c'lohrnc'itt S( 4'110110)
Type II distribution
P= 3.7 inches (2-year event)
Tc= 0.11 hours
The following image shows the pre-development onsite ground cover in the vicinity of
drainage areas #1B, 1C and 2 which were analyzed in the following SCS TR-55
calculations as being 50% forest and 50% grass in good condition. The image also lists
the project's main hydrologic soil groups. Approximately 90% of the drainage areas are
composed of soil types 34D and 14D, glenelg loam and chester loam, respectfully. These
two soils have a hydrologic soil group type B.
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Summary of Calculations
Drainage areas #1B and 2 were each individually routed through their respective SWM
facilities prior to being released into route 29's roadside ditch. The peak 2- and 10-year
final build out flows for drainage area#1B are 1.73 cfs and 6.86 cfs, respectfully. The
peak 2- and 10-year flows for drainage area#2 are 0.44 cfs and 4.18 cfs, respectfully.
The calculations showing this can be viewed in the following section entitled Stormwater
Management Facilities'Routings.
Drainage areas #1B and 1C drain to the existing 24" corrugated metal pipe (CMP) culvert
beneath route 29. These flows are therefore cumulative and were summed to assume one
synchronized storm event during the analysis of MS-19 cross section#1. This is a worst
case scenario because it assumes both peak flows from DA#1B and 1C occur
simultaneously, despite the fact the time of peak flow being released from DA#1B and
1C vary. The aforementioned MS-19 cross section #1 was analyzed downstream of this
pipe for compliance and details can be found in the following report. This portion of the
reach(cross section#1) is the channel between the existing CMP's outlet and the stream,
and is proposed to be improved with the Briarwood Road plans. The proposed
improvements specify this channel be riprap lined.
SWM facility#3 is isolated from DA#1B and 1C and outfalls immediately upstream of
an existing DI-7, where it is released into an existing 18" concrete pipe beneath route 29.
The cross section immediately downstream of this 18"pipe was analyzed for channel
adequacy as well and details are provided within this report. Please see MS-19 cross
section#3 for additional information.
Downstream of MS-19 cross sections #1 and 3, on the east side of route 29, additional
cross sections were analyzed and incorporate the runoff from upstream, offsite drainage
areas. During all of the analyses, the receiving channels were found to be adequate after
taking into consideration the post-development state.
MS-19 Cross Section#1: (Revised to be a proposed riprap lined channel)
(Outlet immediately downstream of route 29's existing 24" CMP and SWM Facility #1)
'
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The channel was analyzed with an approximate slope of 15% (more conservative than
prior 10% analysis) and the calculated velocity and depth listed below was determined
from the Manning's equation.
*Manning's `n' value= 0.028
Max. Calculated Depth= 0.30'
Max. Calculated Velocity= 5.72 ft/s
**Permissible Velocity= 6.0 ft/s
*Manning's `n'values are in accordance with Table 5-8 of the VESCH
(Earth bottom, rubble sides per 7/22/14 conversation with County Engineering)
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 1
Input:
Slope 0.150
Flow (given) 4.020
line x y n
0 0.000 0.500 0.028 (first n value not used)
1 4.000 0.000 0.028
2 8.000 0.500 0.028
Output:
Depth 0.296
(y) ( 0.296)
Channel bed segment output:
line Q V A P
1 2.01 5.72 0.35 2.39
2 2.01 5.72 0.35 2.39
Tue Jul 22 09:31:50 EDT 2014
11a•///Cl/1Tc arc/Graham Alacletnn/Rrianx,nnd/C,,,e04/(1Qartinno/7(1Mn 04')(11 tvt17/171)111d 0.55.d7 A M1
MS-19 Cross Section#3: (Revised to be a proposed riprap lined channel)
(Outlet immediately downstream of route 29's existing 18" concrete pipe and SWM
Facility #3)
/ i ':it ..1 'lit, , :I ''f
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r =Alt 1,0..:
t / i a
,,,s rip/rap channel.
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The channel was analyzed with an approximate slope of 20% (more conservative than
prior 10% analysis) and the calculated velocity and depth listed below was determined
from the Manning's equation.
*Manning's `n' value= 0.028
Max. Calculated Depth= 0.23'
Max. Calculated Velocity= 5.60 ft/s
**Permissible Velocity= 6.0 ft/s
*Manning's `n' values are in accordance with Table 5-8 of the VESCH.
(Earth bottom, rubble sides per 7/22/14 conversation with County Engineering)
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 3
Input:
Slope 0.200
Flow (given) 1.820
line x y n
0 0.000 0.500 0.028 (first n value not used)
1 3.000 0.000 0.028
2 6.000 0.500 0.028
Output:
Depth 0.233
(y) ( 0.233)
Channel bed segment output:
line Q V A P
1 0.91 5.60 0.16 1.42
2 0.91 5.60 0.16 1.42
Tue Jul 22 09:36:24 EDT 2014
ila•///(`I/T Tc arc/C1 raham/llac 4tnn/Rrian vnn 11/(`rncco/7(1Caatinno/71I7■Tn 0/7(12 tvtl7/71/7(11 d 0.SS•dR AMl
MS-19 Cross Section#4:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel-Loam and Cobbles/Stone mixture)
(T} Y
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r Yi tt
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The channel was analyzed with an approximate slope of 1% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.07
Max. Calculated Depth= 2.90'
Max. Calculated Velocity= 4.31 ft/s
**Permissible Velocity= 5.0 ft/s
*Manning's `n' values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 4
Input:
Slope 0.010
Flow (given) 159.130
line x y n
0 0.000 3.000 0.070 (first n value not used)
1 2.000 0.000 0.070
2 12.000 0.000 0.070
3 20.000 3.000 0.070
Output:
Depth 2.896
(y) ( 2.896)
Channel bed segment output:
line Q V A P
1 5.13 1.83 2.80 3.48
2 124.92 4.31 28.96 10.00
3 29.08 2.60 11.18 8.25
Tue Jul 22 09:38:50 EDT 2014
i1a•///(`I/TTePre/C.raham/Ilr.e4tnraRrianxrnnrl/(`rneco/'Jf1Cprtinno/7(1Nn 047(1d tvtf'7/')')/')(l1d Q• 5•452 41\41
MS-19 Cross Section#5:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel-Loam and Cobbles/Stone mixture)
w „art , .� r,
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K X h
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t" +f> i{.pi .'
N� k )0. , # .
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r1st :
The channel was analyzed with an approximate slope of 1.5% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.07
Max. Calculated Depth= 2.60'
Max. Calculated Velocity= 4.91 ft/s
**Permissible Velocity= 5.0 ft/s
*Manning's `n' values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 5
Input:
Slope 0.015
Flow (given) 159.130
line x y n
0 0.000 3.000 0.070 (first n value not used)
1 0.500 0.000 0.070
2 12.000 0.000 0.070
3 16.000 3.000 0.070
Output:
Depth 2.596
(y) ( 2.596)
Channel bed segment output:
line Q V A P
1 0.52 0.93 0.56 2.63
2 146.63 4.91 29.86 11.50
3 11.98 2.67 4.49 4.33
Tue Jul 22 09:39:23 EDT 2014
=Ala•///C I/1TePrc/fsham/T1Pclttnn/Rriarwunn 11/('rncc0/7(1Sartinno/7111MLs 0/7115 tvtf7/77/7(lld 0.65•AR A M1
MS-19 Cross Section#6:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel-Loam and Cobbles/Stone mixture)
•
.
sA
.lr
tit .
The channel was analyzed with an approximate slope of 1.5% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.07
Max. Calculated Depth= 2.14'
Max. Calculated Velocity= 4.32 ft/s
**Permissible Velocity= 5.0 ft/s
*Manning's `n'values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 6
Input:
Slope 0.015
Flow (given) 159.130
line x y n
0 0.000 3.000 0.070 (first n value not used)
1 2.000 0.500 0.070
2 2.500 0.000 0.070
3 18.000 0.000 0.070
4 18.500 0.500 0.070
5 25.000 3.000 0.070
Output:
Depth 2.144
(y) ( 2.144)
Channel bed segment output:
line Q V A P
1 1.80 1.67 1.08 2.11
2 2.99 3.16 0.95 0.71
3 143.68 4.32 33.24 15.50
4 2.99 3.16 0.95 0.71
5 7.66 2.18 3.51 4.58
Tue Jul 22 09:39:55 EDT 2014
=1 •///f I/TTcPre/(s ham/TLpclr tnn/Rriarn:rnnil/(`rneco/7(1Cartinno/711T\Tn 0/7(1F.tvtf7/77/1(11d 0•cc•z1R AI'T1
MS-19 Cross Section#7:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel-Loam and Cobbles/Stone mixture)
A .
s„,. ,
__: ., , .,_ „_:,..... ., , _.
. ..., ,..i..........„,......., _ ,..,......,-,,,_ �, ,,.,
*E. Vim: " ;i -
* * /"yam''' :
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+. i �, T _ •
4"-.
4.4
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°°
, ,.
a
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., , ,, ,r.,. _ ,-.
The channel was analyzed with an approximate slope of 1% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.07
Max. Calculated Depth= 2.46'
Max. Calculated Velocity= 3.59 ft/s
**Permissible Velocity= 5.0 ft/s
*Manning's `n' values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 7
Input:
Slope 0.010
Flow (given) 159.130
line x y n
0 0.000 3.000 0.070 (first n value not used)
1 3.000 0.000 0.070
2 11.000 0.500 0.070
3 23.000 0.500 0.070
4 30.000 2.750 0.070
Output:
Depth 2.455
(y) ( 2.455)
Channel bed segment output:
line Q V A P
1 5.82 1.93 3.01 3.47
2 63.38 3.59 17.64 8.02
3 77.89 3.32 23.46 12.00
4 12.04 2.02 5.95 6.39
Tue Jul22 10:41:29 EDT 2014
1p•///(`I/TTer>re/C;raham/rlaeletnn/(`rnec047(1Qartinno 47(/Mn 0/7(17 tvt17P)7/')(l1d 1(1•d')•1Q 1 M1
MS-19 Cross Section#8:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel-Loam and Cobbles/Stone mixture)
•
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a•z♦ .. .`•z..
ry. •
z> .a .
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J` s
iii 4 1, a1
The channel was analyzed with an approximate slope of 2% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.07
Max. Calculated Depth= 1.98'
Max. Calculated Velocity= 4.73 ft/s
**Permissible Velocity= 5.0 ft/s
*Manning's `n'values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 8
Input:
Slope 0.020
Flow (given) 159.130
line x y n
0 0.000 3.000 0.070 (first n value not used)
1 4.000 0.500 0.070
2 16.000 0.500 0.070
3 17.000 0.000 0.070
4 25.000 0.000 0.070
5 28.000 3.000 0.070
Output:
Depth 1.977
(y) ( 1.977)
Channel bed segment output:
line Q V A P
1 3.83 2.20 1.74 2.79
2 68.98 3.89 17.72 12.00
3 6.93 4.01 1.73 1.12
4 74.77 4.73 15.81 8.00
5 4.62 2.36 1.95 2.80
Tue Jul 22 09:41:55 EDT 2014
1P•/1/C I/ITeare/fIraham/flaclrtnrJRriaruxrnn 11/(`rneco/7(1QArtinnoG7(1RTn 0/7(152 htf7/')')/7O1d Q•G5•d0 A Al
MS-19 Cross Section#9:
(Minor reduction in flow, 0.03cfs, from DA 1B routing did not impact values below)
(Channel- Firm Loam)
=f ,
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•;` / f
n '''
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rte\
The channel was analyzed with an approximate slope of 0.5% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.06
Max. Calculated Depth= 3.31'
Max. Calculated Velocity= 3.48 ft/s
**Permissible Velocity= 3.5 ft/s
*Manning's `n'values are in accordance with Tables 5-16 through 5-21 of the VESCH.
Please see attached derivations.
**Permissible Velocities are in accordance with Table 5-22 of the VESCH
Complex Channnel- Cross Section No. 9
Input:
Slope 0.005
Flow (given) 159.130
line x y n
0 0.000 4.000 0.060 (first n value not used)
1 3.000 1.000 0.060
2 17.000 0.000 0.060
3 23.000 4.000 0.060
Output:
Depth 3.313
(y) ( 3.313)
Channel bed segment output:
line Q V A P
1 4.10 1.53 2.67 3.27
2 137.18 3.48 39.38 14.04
3 17.85 2.17 8.23 5.97
Tue Jul 22 09:44:23 EDT 2014
ila•///(`I/T Terwc/(sham/T1relrtnrJ Rriar unnil/Crnec04111Qartinno/7(N\Tn 0/711Q tvt17/77/701 d Q•GS•dQ A M1
MS-19 Cross Section#10:
(Proposed channel rom SWM acility to existing DI-grass legume mixture)
ri
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alow
doirtoki.411 .,
r
7, .47r s , s
t , ' :.:, ''''''.-; v, a
The channel was analyzed with an approximate slope of 0.5% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.024
Max. Calculated Depth= 0.51'
Max. Calculated Velocity= 2.80 ft/s
**Permissible Velocity= 4.0 ft/s
*Manning's `n'values are in accordance with Table 5-3 of the VESCH.
**Permissible Velocities are in accordance with Table 5-14 of the VESCH
MS-19 Cross Section#12:
(Existing 18"concrete pipe calculations based off Manning's equation)
***Manning's `n' value= 0.013
Max. Calculated Depth= 0.56'
Max. Calculated Velocity= 12.72 ft/s
****Permissible Velocity= 15.0 ft/s
***Manning's `n' values are in accordance with Table 5-12 of the VESCH.
****Permissible Velocities are in accordance with Albemarle County Design Standards
Manual
Complex Channnel- Cross Section No. 10
Input:
Slope 0.005
Flow (given) 7.770
line x y n
0 0.000 1.000 0.024 (first n value not used)
1 5.000 0.000 0.024
2 9.000 0.000 0.024
3 13.000 1.000 0.024
Output:
Depth 0.511
(y) ( 0.511)
Channel bed segment output:
line Q V A P
1 1.14 1.74 0.65 2.61
2 5.73 2.80 2.05 4.00
3 0.90 1.73 0.52 2.11
Wed Jun 04 13:01:02 EDT 2014
11..///Cl/(T¢Prc/G sham/llaclrtnn/Rrianumnn i1/CrnceOZ,MCartin110/7f11Vno/7(11 f1tvtf7 ill/)flldQ•SS•dc A M1
MS-19 Cross Section#11:
(Minor increase in flow, 0.06cfs, from DA 1B 10 yr routing did not impact values below)
(Proposed water quality swale/channel from SWM facility to existing 24" CMP)
‘" ff ' �,.
+'•4. ,'w .
i '
'F 4. s +
p yF '
`,#j -/7,, ,1''_ 4. 7.,,4 '"_�.►r—"`fir' x
,01 +�/ ,/,..—Ct �/t w `4, „I4 i. 7,""'V , i .0
The channel was analyzed with an approximate slope of 0.5% and the calculated velocity
and depth listed below was determined from the Manning's equation.
*Manning's `n' value= 0.024
Max. Calculated Depth= 0.70'
Max. Calculated Velocity= 3.44 ft/s
**Permissible Velocity= 4.0 ft/s
*Manning's `n'values are in accordance with Table 5-3 of the VESCH.
**Permissible Velocities are in accordance with Table 5-14 of the VESCH
MS-19 Cross Section#13:
(Minor increase in flow, 0.06cfs, from DA 1B 10 yr routing did not impact values below)
(Existing 24" CMP calculations based off Manning's equation)
***Manning's `n' value= 0.024
Max. Calculated Depth= 0.61'
Max. Calculated Velocity= 13.81 ft/s
****Permissible Velocity= 15.0 ft/s
***Manning's `n'values are in accordance with Table 5-12 of the VESCH.
****Permissible Velocities are in accordance with Albemarle County Design Standards
Manual
Complex Channnel- Cross Section No. 11
Input:
Slope 0.005
Flow (given) 12.640
line x y n
0 0.000 1.000 0.024 (first n value not used)
1 3.000 0.000 0.024
2 7.000 0.000 0.024
3 10.000 1.000 0.024
Output:
Depth 0.697
(y) ( 0.697)
Channel bed segment output:
line Q V A P
1 1.52 2.09 0.73 2.20
2 9.59 3.44 2.79 4.00
3 1.52 2.09 0.73 2.20
Tue Jul 22 09:48:00 EDT 2014
11a•MCI/TTeAre/(;raham/flPebtnn/Rrianxrnnrl/Crneeo/7flcartinno/7(1Nn o/7(111 tvtf7 ill/')(lld Q•55.4Q A Ml
Stormwater Management Facilities' Routings
(Note: SWM routing calculations for DA #1B were updated)
Briarwood Underground Detention No. 1-Post Development
BasinFlow printout
INPUT:
Basin: Briarwood underground Detention System DA 1B- Post Development
0 Contour Areas
Elevation(ft) Area(sf) Computed vol . (cy)
3 Storage Pipes
Storage pipe 0
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 175.000
invert (ft) 402.390
angle 0.287
volume (cy) 153.989
Storage pipe 1
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 175.000
invert (ft) 402.310
angle 0.287
volume (cy) 153.989
Storage pipe 2
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 181.000
invert (ft) 402.300
angle 0.287
volume (cy) 159.269
Start_Elevation(ft) 402.30 Vol . (cy) 0.00
4 Outlet Structures
Outlet structure 0
Orifice
name: Low-Flow Orifice
area (sf) 0.049
diameter or depth (in) 3.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 402.300
multiple 3
discharge into riser
Outlet structure 1
Culvert
name: Barrel
multiple 1
discharge out of riser
D (in) 24.000
h (in) 0.000
Length (ft) 58.400
Slope 0.005
Manning's n 0.010
Inlet coeff. Ke 0. 500
Equation constant set 3
Invert (ft) 402.300
Outlet structure 2
Page 1
Briarwood underground Detention No. 1-Post Development
Orifice
name: Overflow Orfices
area (sf) 0.136
diameter or depth (in) 5.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 405.650
multiple 4
discharge into riser
Outlet structure 3
Orifice
name: Emergency Spillway Simulation
area (sf) 0.385
diameter or depth (in) 8.400
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 407.550
multiple 1
discharge into riser
2 Inflow Hydrographs
Hydrograph 0
SCS
name: 2- Yr. Storm- SCS Method
Area (acres) 3.290
CN 73.800
Type 2
rainfall , P (in) 3.700
time of conc. (hrs) 0.1000
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 5.707
peak time (hrs) 11.917
volume (cy) 604.153
Hydrograph 1
SCS
name: 10- Yr. Storm- SCS Method
Area (acres) 3.290
CN 73.800
Type 2
rainfall , P (in) 5.600
time of conc. (hrs) 0.1000
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 11.827
peak time (hrs) 11.917
volume (cy) 1252.168
OUTPUT:
Routing Method: storage-indication
Hydrograph 0
Routing Summary of Peaks: 2- Yr. Storm- SCS Method
inflow (cfs) 5.680 at 11.92 (hrs)
discharge (cfs) 1.145 at 12.12 (hrs)
water level (ft) 405.037 at 12.14 (hrs)
Page 2
Briarwood underground Detention No. 1-Post Development
storage (cy) 181.146
Hydrograph 1
Routing Summary of Peaks: 10- Yr. Storm- SCS Method
inflow (cfs) 11.772 at 11.92 (hrs)
discharge (cfs) 4.254 at 12.08 (hrs)
water level (ft) 406.953 at 12.08 (hrs)
storage (cy) 379.824
Thu Jul 17 10:18:34 EDT 2014
Page 3
Briarwood underground Detention No. 1-Final Buildout
BasinFlow printout
INPUT:
Basin: Briarwood underground Detention System DA 1B- Final Build Out
0 Contour Areas
Elevation(ft) Area(sf) Computed Vol . (cy)
3 Storage Pipes
Storage pipe 0
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 175.000
invert (ft) 402.390
angle 0.287
volume (cy) 153.989
Storage pipe 1
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 175.000
invert (ft) 402.310
angle 0.287
volume (cy) 153.989
Storage pipe 2
name: Effective Pipe volume
diameter (in) 66.000
length (ft) 181.000
invert (ft) 402.300
angle 0.287
volume (cy) 159.269
Start_Elevation(ft) 402.30 Vol . (cy) 0.00
4 Outlet Structures
Outlet structure 0
Orifice
name: Low-Flow Orifice
area (sf) 0.049
diameter or depth (in) 3.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 402.300
multiple 3
discharge into riser
Outlet structure 1
Culvert
name: Barrel
multiple 1
discharge out of riser
D (in) 24.000
h (in) 0.000
Length (ft) 58.400
Slope 0.005
Manning's n 0.010
Inlet coeff. Ke 0. 500
Equation constant set 3
Invert (ft) 402.300
Outlet structure 2
Page 1
Briarwood underground Detention No. 1-Final Buildout
Orifice
name: Overflow Orfices
area (sf) 0.136
diameter or depth (in) 5.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 405.650
multiple 4
discharge into riser
Outlet structure 3
Orifice
name: Emergency Spillway Simulations
area (sf) 0.385
diameter or depth (in) 8.400
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 407. 550
multiple 1
discharge into riser
2 Inflow Hydrographs
Hydrograph 0
SCS
name: 2- Yr. Storm- SCS Method
Area (acres) 3.290
CN 81.400
Type 2
rainfall , P (in) 3.700
time of conc. (hrs) 0.1000
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 7.942
peak time (hrs) 11.917
volume (cy) 840.859
Hydrograph 1
SCS
name: 10- Yr. Storm- SCS Method
Area (acres) 3.290
CN 81.400
Type 2
rainfall , P (in) 5.600
time of conc. (hrs) 0.1000
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 14.866
peak time (hrs) 11.917
volume (cy) 1573.826
OUTPUT:
Routing Method: storage-indication
Hydrograph 0
Routing Summary of Peaks: 2- Yr. Storm- SCS Method
inflow (cfs) 7.905 at 11.92 (hrs)
discharge (cfs) 1.730 at 12.12 (hrs)
water level (ft) 405.842 at 12.12 (hrs)
Page 2
Briarwood underground Detention No. 1-Final Buildout
storage (cy) 267.526
Hydrograph 1
Routing summary of Peaks: 10- Yr. storm- sCS Method
inflow (cfs) 14.796 at 11.92 (hrs)
discharge (cfs) 6.857 at 12.06 (hrs)
water level (ft) 408.246 at 12.06 (hrs)
storage (cy) 462.949
Thu Jul 17 10:24:05 EDT 2014
Page 3
Briarwood Extended Detention Basin- DA 2
BasinFlow printout
INPUT:
Basin: Briarwood Extended Detention Basin- DA 2
5 Contour Areas
Elevation(ft) Area(sf) Computed Vol . (cy)
424.30 217.00 0.0
426.00 3899.00 105.7
428.00 5953.00 467.9
430.00 8356.00 995.4
432.00 10755.00 1701.3
Start_Elevation(ft) 424.30 Vol . (cy) 0.00
4 Outlet Structures
Outlet structure 0
Orifice
name: 30hr Drawdown Orifice
area (sf) 0.049
diameter or depth (in) 3.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 424.300
multiple 1
discharge into riser
Outlet structure 1
Orifice
name: Midflow Orifices
area (sf) 0.196
diameter or depth (in) 6.000
width for rect. (in) 0.000
coefficient 0.600
invert (ft) 426.710
multiple 4
discharge into riser
Outlet structure 2
Culvert
name: Barrel
multiple 1
discharge out of riser
D (in) 24.000
h (in) 0.000
Length (ft) 60.000
Slope 0.005
Manning's n 0.013
Inlet coeff. Ke 0. 500
Equation constant set 3
Invert (ft) 424.240
Outlet structure 3
weir
name: Riser Standpipe
diameter (in) 30.000
side angle 0.000
coefficient 3.300
invert (ft) 428.960
multiple 1
discharge into riser
Page 1
Briarwood Extended Detention Basin- DA 2
3 Inflow Hydrographs
Hydrograph 0
SCS
name: 2-Year, 24-hr Peak SCS Storm Event
Area (acres) 3.840
CN 68.400
Type 2
rainfall , P (in) 3.700
time of conc. (hrs) 0.1100
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 4.980
peak time (hrs) 11.923
volume (cy) 537.488
Hydrograph 1
SCS
name: 10-Year, 24-hr Peak SCS Storm Event
Area (acres) 3.840
CN 68.400
Type 2
rainfall , P (in) 5.600
time of conc. (hrs) 0.1100
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 11.242
peak time (hrs) 11.923
volume (cy) 1213.361
Hydrograph 2
SCS
name: 100-Year, 24-hr Peak SCS Storm Event
Area (acres) 3.840
CN 68.400
Type 2
rainfall , P (in) 9.100
time of conc. (hrs) 0.1100
time increment (hrs) 0.0200
time limit (hrs) 30.000
fudge factor 1.00
routed true
peak flow (cfs) 24.968
peak time (hrs) 11.923
volume (cy) 2694.911
OUTPUT:
Routing Method: storage-indication
Hydrograph 0
Routing Summary of Peaks: 2-Year, 24-hr Peak SCS Storm Event
inflow (cfs) 4.979 at 11.92 (hrs)
discharge (cfs) 0.438 at 12.28 (hrs)
water level (ft) 426.779 at 12.28 (hrs)
storage (cy) 228.866
Hydrograph 1
Routing Summary of Peaks: 10-Year, 24-hr Peak SCS Storm Event
inflow (cfs) 11.241 at 11.92 (hrs)
Page 2
Briarwood Extended Detention Basin- DA 2
discharge (cfs) 4.181 at 12.08 (hrs)
water level (ft) 427.938 at 12.08 (hrs)
storage (cy) 454.286
Hydrograph 2
Routing Summary of Peaks: 100-Year, 24-hr Peak SCS Storm Event
inflow (cfs) 24.966 at 11.92 (hrs)
discharge (cfs) 16.459 at 12.04 (hrs)
water level (ft) 429.487 at 12.04 (hrs)
storage (cy) 842.890
Thu May 29 10:56:07 EDT 2014
Page 3
SCS Calculations
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 2:Runoff Curve Number and Runoff
Project: Briarwood Designed By: FGM,PE Date: 7/17/2014
Location: Briarwood Drive&Rte.29 Checked By: FGM,PE Date: 7/17/2014
Check One: Present X Developed X
1.Runoff curve Number(CN)
Cover description
Soil name and CN(weighted)=
Drainage Area (Cover type,treatment,and hydrologic condition; Area Product of Calculated
hydrologic group CN total product/
Description (Appendix A) percent impervious;unconnected/connected (Acres) CN x Area total area '5'Value
impervious area ratio)
Impervious Areas 98 0.00 0.0
D.A#1B B Woods in Good Condition(approx.50%) 55 1.13 62.2 58.0 7.24
(Pre-Dev.)
Lawns in Good Condition (approx.50%) 61 1.13 68.9
D.A.#1C Approved Bypassed Imp.Areas-Rte.29&Briarwood Dr. 98 0.28 27.4
B Woods in Good Condition(approx.50%) 55 1.28 70.1 62.0 6.14
(Pre-Dev.) Lawns in Good Condition (approx.50%) 61 1.28 77.8
D.A#16 Proposed&Existing Road/Sidewalk Imp.Areas 98 1.14 111.5
B Future Impervious Areas 98 0.00 0.0 73.8 3.55
(Post-Dev.)
Lawns in Good Condition 61 2.15 131.3
D.A#1C Approved Bypassed Imp.Areas-Rte.29&Briarwood Dr. 98 0.40 39.2
B Woods in Good Condition(approx.50%) 55 0.70 38.5 66.9 4.95
(Post-Dev.) Lawns in Good Condition (approx.50%) 61 0.70 42.7
D.A.#18 Proposed&Existing Road/Sidewalk Imp.Areas 98 1.14 111.5
(Final Build Out) Future Impervious Areas 98 0.68 66.4 81.4 2.28
Lawns in Good Condition 61 1.47 90.0
D.A.#1C
(Final Build Out) Not part of this set of plans
Revisions noted in yellow are per comments dated 7/16/14:Decreased future impervious area(and increased lawn area)by 500sf.
2.Runoff
2-Year Storm 10-Year Storm Drainage Area Description
Frequency-years 2 10 n/a
Rainfall,P(24 hour)-inches 3.7 5.6 n/a
Runoff,Q-inches _ 0.53 1.51 D.A#1B(Pre-Dev.)
Runoff,Q-inches _ 0.71 1.82 D.A.#1C(Pre-Dev.)
Runoff,Q-inches 1.37 2.83 D.A#1B(Post-Dev.)
Runoff,Q-inches 0.96 2.22 D.A#1C(Post-Dev.)
Runoff,Q-inches 1.90 3.56 D.A.#1B(Final Build Out)
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 3:Time of Concentration(T)or Travel Time(T,)
Project: Briarwood Designed By:FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Rte.29 Checked By:FGM,PE Date: 6/9/2014
Check One: Present X Developed X
Check One: T, X T, Through subarea n/a
D.A#1B D.A.#1C D.A#1B D.A#1C D.A.#1B
Segment ID: (Pre-Dev.) (Pre-Dev.) (Post-Dev.) (Post-Dev.) (Final Build Out)
Sheet Flow:(Applicable to T,only)
1 Surface description(Table 3-1) Dense Grass Dense Grass Dense Grass
2 Manning's roughness coeff.,n(Table 3-1 0.24 0.24 0.24
3 Flow length,L(total L<100)(ft) 100 100 100
4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 3.7
5 Land slope,s(ft/ft) 0.14 0.11 0.11
6 Compute T,=[0.007(n*L)°'e]/P205 s°'4 0.10 I 0.11 I I 0.11 I I I
Shallow Concentrated Flow:
7 Surface description(paved or unpaved) Unpaved Unpaved Unpaved
8 Flow Length,L(ft) 115 250 125
9 Watercourse slope,s(ft/ft) 0.30 0.17 0.16
10 Average velocity,V(Figure 3-1)(ft/s) 9 6.8 6.5
11 T,=L/3600*V 0.00 I 0.01 I I 0.01
Channel Flow:
12 Cross sectional flow area,a(ft2)
13 Wetted perimeter,Pw,(ft)
14 Hydraulic radius,r=a/Pw,(ft)
15 Channel Slope,s(ft/ft)
16 Manning's Roughness Coeff,n
17 V=[1.49r213s5]/n
18 Flow length,L(ft)
19 T,=L/3600*V I I I I I I
20 Watershed or subarea T,or T, (Min.SCS Tc) (Min.SCS Tc)
(Add T,in steps 6,11 and 19) 0.10 I 0.12 I 0.10 I 0.12 I 0.10 I I
U.S.Department of Agriculture FL-ENG-21C
Natural Resources Conservation Service 06/04
TR 55 Worksheet 4:Graphical Peak Discharge Method
Project: Briarwood Designed By: FGM,PE Date: 7/17/2014
Location: Briarwood Drive&Rte.29 Checked By: FGM,PE Date: 7/17/2014
Check One: Present X Developed X
Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area
1.Data Description Description Description Description Description Description Description
D.A#1B D.A.#1C D.A#1B D.A#1C D.A.#1B
(Pre-Dev.) (Pre-Dev.) (Post-Dev.) (Post-Dev.) (Final Build Out)
Drainage Area(Am)in miles '= 0.0035 _ 0.0044 0.0051 0.0028 0.0051 _
Runoff curve number CN= _ 58.0 _ 62.0 73.8 66.9 81.4 _
Time of concentration(Tc(= 0.10 0.12 0.10 0.12 0.10
Rainfall distribution type= - II - II II II II
Pond and swamp areas spread 0 0 0 0 0
throughout the watershed=
2.Frequency-years 2 10 2 10 2 10 2 10 2 10
3.Rainfall,P(24 hour)-inches 3.7 5.6 3.7 5.6 3.7 5.6 3.7 5.6 3.7 5.6
4.Initial Abstraction,la-inches 1.448 1.448 1.228 1.228 0.710 0.710 0.990 0.990 0.457 0.457
5.Compute la/P 0.39 0.26 0.33 0.22 0.19 0.13 0.27 0.18 0.12 0.08
6.Unit peak discharge,Qu-csm/in 825 975 850 925 975 1000 850 925 975 1000
7.Runoff,Qfrom Worksheet 2-inches 0.53 1.51 0.71 1.82 1.37 2.83 0.96 2.22 1.90 3.56
8.Pond and Swamp adjustment factor,Fp 1 1 1 1 1 1 1 1 1 1
9.Peak Discharge,Qp-cfs Routed Through Routed Through
where Qp=Qu Am Q Fp 1.56 5.21 2.67 7.44 SWM Facility 2.29 5.78 SWM Facility
Revisions noted above in yellow are per comments dated 7/16/14:Decreased future impervious area(and increased lawn area)by 500sf.
WATERSHED SUMMARY
2 year Storm Event
Pre-Development Area Flow Post-Development Area Flow Final Build Out Area Flow
D.A#113(Pre-Dev.) 2.26 at 1.56 cfs ID.A#1B(Post-Dev.) 3.29 ac. 1.15 cfs ID.A.#1B(Final Build Out) 3.29 ac. 1.73 cfs
D.A.#1C(Pre-Den.) 2.83 at 2.67 cfs D.A#1C(Post-Dev.) 1.80 ac. 2.29 cfs D.A#1C(Post-Dev.) 1.80 ac. 2.29 cfs
Total= 5.09 4.22 Total= 5.09 3.44 Total= 5.09 4.02
10 year Storm Event
Pre-Development Area Flow Post-Development Area Flow Final Build Out Area Flow
D.A#1B(Pre-Dev.) 2.26 ac 5.21 cfs ID.A#1B(Post-Den.) 3.29 ac. 4.25 cfs ID.A.#113(Final Build Out) 3.29 ac. 6.86 cfs
D.A.#1C(Pre-Dev.) 2.83 at 7.44 cfs D.A#1C(Post-Den.) 1.80 ac. 5.78 cfs D.A#1C(Post-Dev.) 1.80 ac. 5.78 cfs
Total= 5.09 12.65 Total= 5.09 10.03 Total= 5.09 12.64
Revisions noted above in yellow are per comments dated 7/16/14:Routing calculations modified per lowering of weir plate to 407.55',increasing effective/simulated orifice
opening to 8.4"and showing a revised CN value of 81.4 per the decreased future impervious area.
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 2:Runoff Curve Number and Runoff
Project: Briarwood Commercial Development Designed By: FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Rte.29 Checked By:FGM,PE Date: 6/9/2014
Check One: Present X Developed X
1.Runoff curve Number(CN)
Cover description
Drainage Soil name and CN(weighted)=
(Cover type,treatment,and hydrologic condition; Area Product of CN Calculated
Area hydrologic group CN total product/
percent impervious;unconnected/connected (Acres) x Area '5'Value
Description (Appendix A) total area
impervious area ratio)
DA#2 Impervious Areas 98 0.06 5.5
(Present) B Woods in Good Condition(approx.50%) 55 3.78 208.1 55.6 7.98
Lawns in Good Condition (approx.50%) 61 0.00 0.0
DA#2 Impervious Areas 98 0.77 75.3
(Developed) B Woods in Good Condition 55 0.00 0.0 68.4 4.62
Lawns in Good Condition 61 3.07 187.4
2.Runoff
2-Year Storm 10-Year Storm Drainage Area Description
Frequency-years 2 10 n/a
Rainfall,P(24 hour)-inches 3.7 5.6 n/a
Runoff,Q-inches
Runoff,Q-inches
Runoff,Q-inches
Runoff,Q-inches
Runoff,Q-inches 0.44 1.34 DA#2(Present)
Runoff,Q-inches 1.04 2.35 DA#2(Developed)
Runoff,Q-inches
Runoff,Q-inches
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 3:Time of Concentration(T)or Travel Time(T,)
Project: Briarwood Commercial Development Designed By:FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Rte.29 Checked By:FGM,PE Date: 6/9/2014
Check One: Present X Developed X
Check One: T, X T, Through subarea n/a
DA#2 DA#2
Segment ID: (Present) (Developed)
Sheet Flow:(Applicable to T,only)
1 Surface description(Table 3-1) Dense Grass Dense Grass
2 Manning's roughness coeff.,n(Table 3-1 0.24 0.24
3 Flow length,L(total L<100)(ft) 100 100
4 Two-year 24-hour rainfall,P,(in.) 3.7 3.7
5 Land slope,s(ft/ft) 0.12 0.12
6 Compute T,=[0.007(n*L)08]/P2°5 s' I I I I 0.11 I 0.11
Shallow Concentrated Flow:
7 Surface description(paved or unpaved) Unpaved Unpaved
8 Flow Length,L(ft) 300 75
9 Watercourse slope,s(ft/ft) 0.060 0.09
10 Average velocity,V(Figure 3-1)(ft/s) 4.0 4.8
11 T,=L/3600*V I I I I 0.02 I 0.00 I I __,____
Channel Flow:
12 Cross sectional flow area,a(ft')
13 Wetted perimeter,P„,(ft)
14 Hydraulic radius,r=a/P„,(ft)
15 Channel Slope,s(ft/ft)
16 Manning's Roughness Coeff,n
17 V=[1.49r2"s°s]/n
18 Flow length,L(ft)
19 T,=L/3600*V I I I I I I I
20 Watershed or subarea T,or T,
(Add T,in steps 6,11 and 19) I I I I 0.13 I 0.11
NOTE:Minimum SCS time of concentration is 0.10 hours.
U.S.Department of Agriculture FL-ENG-21C
Natural Resources Conservation Service 06/04
TR 55 Worksheet 4:Graphical Peak Discharge Method
Project: Briarwood Commercial Development Designed By: FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Rte.29 Checked By: FGM,PE Date: 6/9/2014
Check One: Present X Developed X
Drainage Drainage Area Drainage Drainage Area Drainage Drainage Area Drainage Drainage Area
1.Data Area Description Area Description Area Description Area Description
DA#2 DA#2
(Present) (Developed)
Drainage Area(Am)in miles 2= 0.0060 0.0060
Runoff curve number CN= 55.6 68.4
Time of concentration(Tc)= 0.13 0.11
Rainfall distribution type=
Pond and swamp areas spread 0 0
throughout the watershed=
2.Frequency-years 2 10 2 10
3.Rainfall,P(24 hour)-inches 3.7 5.6 3.7 5.6
4.Initial Abstraction,la-inches 1.595 1.595 0.924 0.924
5.Compute la/P 0.43 0.28 0.25 0.17
6.Unit peak discharge,Qu-csm/in 675 875 925 950
7.Runoff,Q from Worksheet 2-inches 0.44 1.34 1.04 2.35
8.Pond and Swamp adjustment factor,Fp 1 1 1 1
9.Peak Discharge,Qp-cfs Routed Through
where Qp=Qu Am Q Fp 1.78 7.03 SWM Facility
NOTE:Qu of 1000 csm/in is the most conservative value for the type II rainfall distribution
Watershed Summary
2 year Storm Event
IDA#2(Present) 1.78 cfs > DA#2(Developed) 0.44 cfs
10 year Storm Event
IDA#2(Present) 7.03 cfs > DA#2(Developed) 4.18 cfs I
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 2:Runoff Curve Number and Runoff
Project: Briarwood Designed By: FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Route 29 Checked By:FGM,PE Date: 6/9/2014
Check One: Present X Developed X
1.Runoff curve Number(CN)
i
Cover description
Soil name and CN(weighted)=
Drainage Area (Cover type,treatment,and hydrologic condition; Area Product of CN Calculated
hydrologic group CN total product/
Description percent impervious;unconnected/connected (Acres) x Area '5'Value
(Appendix A) total area
impervious area ratio)
Offsite Overall Remote&Undeveloped Wooded Areas 55 991 54477.5
DA B Residential Subdivisions 75 42 3150.0 57 7.50
(Present) Commercial Development 92 40 3634.0
Overland Flow Impervious Areas 98 0.14 13.5
to Existing B Woods in Good condition 55 0.16 8.8 64 5.61
Inlet Grass in Good condition 61 1.06 64.8
2.Runoff
2-Year Storm 10-Year Storm Drainage Area Description
Frequency-years 2 10 n/a
Rainfall,P(24 hour)-inches 3.7 5.6 n/a
Runoff,Q-inches 0.50 1.45 Offsite Overall DA(Present)
Runoff,Q-inches 0.81 1.99 Overland Flow to Existing Inlet
U.S.Department of Agriculture FL-ENG-21A
Natural Resources Conservation Service 06/04
TR 55 Worksheet 3:Time of Concentration(T,)or Travel Time(Ti)
Project: Briarwood Designed By:FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Route 29 Checked By:FGM,PE Date: 6/9/2014
Check One: Present X Developed X
Check One: T, X T, Through subarea n/a
Tc Path ff1 Tc Path 442 Overland Flow to
Segment ID: Existing Inlet
Sheet Flow:(Applicable to T,only)
1 Surface description(Table 3-1) Dense Grass Dense Woods Dense Grass
2 Manning's roughness coeff.,n(Table 3-1 0.24 0.8 0.24
3 Flow length,L(total L<100)(ft) 100 100 100
4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 3.7
5 Land slope,s(ft/ft) 0.04 0.02 0.07
6 Compute TT=[0.007(n*L)08]/P2 5 s°° 0.168 I 0.580 I 0.134 I I I I I
Shallow Concentrated Flow:
7 Surface description(paved or unpaved) Unpaved Unpaved Unpaved
8 Flow Length,L(ft) 800 720 230
9 Watercourse slope,s(ft/ft) 0.063 0.053 0.100
10 Average velocity,V(Figure 3-1)(ft/s) 4.1 3.7 5.1
11 Tt=L/3600*V 0.054 I 0.054 I 0.013
Channel Flow:
12 Cross sectional flow area,a(ft') B n c o a
13 Wetted perimeter,Pw(ft) ' w m w �+
14 Hydraulic radius,r=a/Pw(ft) :.E. E v Y E 0 3 2, 0 3 m o
15 Channel Slope,s(ft/ft) ; ; N
16 Manning's Roughness Coeff,n •E To E m m
17V=[1.49r2/3ss]/n N ; E N E
18 Flow length,L(ft) 1O 0 0 0
19 T5=L/3600*V 0.704 I 0.763 I I I I I I
20 Watershed or subarea 1,or Tr
(Add T,in steps 6,11 and 19) 0.93 I 1.40 I 0.15 I I I I I
U.S.Department of Agriculture FL-ENG-21C
Natural Resources Conservation Service 06/04
TR 55 Worksheet 4:Graphical Peak Discharge Method
Project: Briarwood _ _ Designed By: FGM,PE Date: 6/9/2014
Location: Briarwood Drive&Route 29 Checked By: FGM,PE Date: 6/9/2014
Check One: Present X Developed X
Drainage Area Drainage Drainage Area Drainage Drainage Drainage Drainage Drainage Area
1.Data Description Area Description Area Area Area Area Description
Offsite Overall DA Overland Flow
_ (Present) to Existing Inlet
Drainage Area(Am)in miles 2= 1.6750 0.0021
Runoff curve number CN= 57 64
Time of concentration(Tc)= 1.40 _ 0.15
Rainfall distribution type= II II
Pond and swamp areas spread 0 0
throughout the watershed=
2.Frequency-years 2 2 10
3.Rainfall,P(24 hour)-inches 3.7 3.7 5.6
4.Initial Abstraction,la-inches 1.500 1.123_ 1.123
5.Compute la/P 0.41 0.30 0.20
6.Unit peak discharge,Qu-csm/in 185 800 850
7.Runoff,Qfrom Worksheet 2-inches 0.50 0.81 1.99
8.Pond and Swamp adjustment factor,Fp 1 1 _ 1
9.Peak Discharge,Qp-cfs
where Qp=Qu Am Q Fp 154.67 1.38 3.59
30-hour Drawdown Orifice Calculations
30 Nots, cA`c uuArzotA. - Coq t`a. of
a„ „ S.A: a%sas ierA
840 3
CQ�F e,CaPA t MOO'SFSE/) SIMN•E J' r 4ae -A1111tECf
OTV: axlnj{ V IS RsaVlsso fopzrt 30,hr. SDP•h. NJ/J Cr (ZJNGF'F cSC'TWC-kNI
Low fiOw aikZ:.r pr,0 'f-t c M•s o-FIX*4 0121 cEs
Ml()TIM CRXFjCE. INN 1IT
•_..._...-ft .ej !4Z 9(tym ed) OeNarTICgsd
y0.14'oty (f,MXN, ax4.4c \ci Fl7G1't t;
J
axW 3o opaw N/ J
LcR: row oasfzcc
Ai Cu hr -W4 W�� x a r "o = �6 ab
Env, co.caes G z_ a 1- -e& - Wa6.11 ' *Az•z X�- 6
Mid^'Ft OR Fake sGT Foto,/ w ov P r E<�V ^y-a 6.�11 �{�av x a ' " 3
■
, 5 zzxoG of 30 Vc � w.Yry�m. 4,'
001,k a eiu. rvr ac../
ti wt
wNe' • G: A.46. V. X 350°
ash >�•
Q - 0.0069 ",c.{La' wHEge a, 1<ra
> ° 4Q 64
0.0 5i
rk iv. 02= E.9uR-s 3" To ��ravru -�ee� Rss�c ,:� t MO \A",
Supplemental Manning's `n' Derivations
(Note: Revisions are noted in red)
A Co55 - c'TTC a (ZEpiaa w/ RCkloodAL of C:JA 4"1 SWM TACaiaz`1)
f- 6po5s S t7xoN i,3 �' ownisgEo'\ or k.Xxc 6 1$.,crag Q=f , • 13 Er3,C%,K a,j�tiY 1(ax4
o.w1 k \
6 4' 1r i.01 43/3
�a
C! .% .c*.
C r' °�- QA 3'aS 4 1c + a * OJ 1:gM.. ivATCAShtv,J \7A
A ' + ,Q,V+ 0.44 + \54.6'1
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CROSS 5“1-10,4C 44 43
5,12. Cpur,1-1 er1G.WCE(4 6. 9 c:"." " A 5 -Airs .> # •-G 4.,04. 6teodie"R- w' - i '-
r 4,6LKG r ti 1'10.1E c cAt r` = o,oAit PE2
C(tp,5 SC-ccTacNS U 4 -8_
= 0.03 cNAN*.'aL z ru rivcrr{
r\ 0.01 fAsfv,c, ctiAPAO.S t Ce(i '4CINN CF0JSO SStt , "PO
Y�3= 0.005 C ASsoNAt_ AL-IS&MAtXNC S-ECt 4 ScAuSlaC CtcA ciaAL 2F? sti.a F4o`ry FAQM. szxx-
C>y = Q,o 3 P4l'2CC-zA4)(.e g FFc-t or C3'r,,STR
uct=0∎6 fRo SrnrJ c Bc 007-N6-
n = p,C) rawcsr 0,6CAVEcx cFrEeN TRSM CAASSi tAA j TR C c SzE '4661(WeJ4Gaewr.) \ICsciA•tzt,
5
0.000 Nc61x„s.ESt.E EFFECT Fµom. jar✓NO / cc MVAx+Gf`
fl O.O'1
Cpc65 SCC*asi 419
O.oa. t�lRNnkl 7r+ �ARStI SLOE'S
ha= Q.o�, ScvERC pEGRCE ox 44.0 Gu.1.Aa�"y, 'pa, w Ei4N)CA; SY:}G
h3` O.SJOS OccASiAI ROtaNP
�an14' SCCrlowS rAv5-1/46 ote.*,uAL 5fl1FS -iN c-oz/ FAOm 51, Yn SS01;'
hk 0.010 PAINoA. EFFECT OF Sr-owe'
Y\S = 9.005 Le1wS! l<.C,EtE; OF gfrEc't Ffr0M r.RINSS F TREE' 5tCDL'7r., s/04Ek6 own.! UEGC1 of'40"
rG O,00 1\1L-20.2 z* t E [I^`"#;'rf Fk1st 4SZ1,‘1agT'y/cIr6(2. G` ME'fvrOrR
C, A '
0.0
C a�55 Styr 3 a r� �O
6.n4S 6.11,E chkivp -L. xSTs-N16,_ SPA) 1 ;tAZ, Cor.K� 0 0a � Q VEs4tt TAB 53
NV,c1 Ito t�►c C,QoSS �EcTA0r,) 10 as Ec1�AL /(.tP.oM OA Xy,01, ccs's) PwD QVKKLANAb FrL 3 s�c`' ,0R 1171cr"
(ROSS 5Ecsao -\�
wioPQS D wpatlz QVM:111 SwAt GRAsS Lx..r: TO r St;4. " C . NQ-t, 64, f02TI-E=S S�CtzoN
c.OMt S F( r✓+ OA 15 CFtNAL '6uzi..o 041-) oR iFd'c� �tls P -tLtx V CSCH TAP.,t
CRASS cr.scA 349.
cor rck�•�E Sc pf�44 a ov e RL-ate flout, Mr•> >JG'% ',A' V PL-�E 0.013 \ z.
kaG 18 �zot
\I E5CH 1-Nor 5-la. 61t0= 'L9'1 cfs Ice Ns•SSttc w/ CR s 5CCirc4J t4iC�,
CROSS Sc- X13 a
C-,2-T alJG 94" c At 114 MArf main s VALUE 0,0D4 'TAL
ao = 1Q,�$ fi3/1, dys,/-zsTvsn w/crzcss Sceezor li