20131070 Ver 2_More Info Received_20150623

David F Ramsey, P E- P S M
R &S Engineering and Construction Corporation
434 Skinner Boulevard 61 The Glens Boulevard
Dunedin, F134698 Banner Elk, NC 28604
webpage: www.ramseveni!ineerinL.com
727 409 -4639 e-mail davidf.ramsev(a),verizon.net 828 963 -5875
Professional Engineer Ohio - Florida -N Carolina -S Carolina- Georgia - Louisiana- Mississippi
Professional Surveyor Ohio - Florida -N Carolina
General Contractor Class A Florida CGC 010310 North Carolina 44555
June 10, 2015
Ms. Karen Higgins
401 and Buffer Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699 -1617
RE: Elk Creek of Banner Elk
DVWR# 12 -1070
Dear Ms. Higgins:
Please reply to North Carolina Address
[Roes
JUN 2 3 2015
DENR - WgTER 3ER OURCES
401 8 BUFFER PERMITTING
Enclosed herewith you will find the additional information as requested in an email to Angelo Accetturo dated
May 19, 2015. regarding the aforementioned project and application. Following you will find the response to
your request in the order as presented in your letter with my response in Bold.
1. The size of the wet detention pond orifice was not calculated according to our Manual as we specified
and a considerably over -sized orifice was specified. Your plan indicated that a 4" orifice would drain
the pond over a 48 hour period. That is not correct. Our quick calculation showed that a 4" orifice
would drain the pond in approximately 8 hours. Some of the reasons for the error were that the .0085
SF orifice calculated by your engineer converts to approximately 1.25" diameter orifice, not 4 inches as
was stated. Although 1.25" diameter seems to be a reasonably close to our estimated number, had we
not caught the error, the stormwater would have never been treated during the life of the project. This is
of concern. Furthermore, being one of the most critical calculations relative to the stormwater treatment
device, we would have expected it to be checked before submittal. As we said in our December 30,
2014 letter, please have your engineer refer to Section 3.5.2 "Orifice Equation" in calculating the
estimated drawdown time. In that letter, we specified that the H value should be divided by three
get an accurate assessment of the average head. His drawing needs correction to show the "driv'
head" at 2' not 3' and the average head less than that. His "Calculations" on Sheet 9 of 9 show
incorrect "Orifice Equation" formula. His "Average Head" formula shows a division by 2 although
did not use an average head but rather the maximum "driving head" in his actual calculation.
The size of the orifice is 1.5" as shown on the Sheet 8 and 9. The barrel is 4" and the orific
1/5" and will provide the draw down over a three day period.
2. We were surprised that the specific requests in our July 31, 2014 letter, December 30, 2014 letter and
at our February 3, 2015 meeting regarding the "Water Quality Notes and Calculations" (sheet 9 of 9)
have not been addressed. Again, these are:
a. There is no "filter area" in this plan.
The reference to a filter area is no longer on the plans.

Page 2:Elk Creek/June 12, 2015
b. The unidentified number (147,580) after the "V" is not the volume. It is the area in SF.
The number 147,580 is not involved in this permit application. The correct number is 134,950.90 SF
which is the square footage of the Impervious Area. The V =A *1" is volume and the results of that is
11,245.91 CF. Section 15ANCAC 02.41.1017 (13) indicates 1" of runoff over the impervious area. That
calculation is shown on the spreadsheet attachment in the drawing on Sheet 9. The area of the impervious
is 134,950 square feet which is shown on the drawings for each breakdown of the drainage areas and also
shown on the application. The equation in the manual for the volume of runoff to be treated does not
agree with the NCAC referenced code. The equation in the manual for the volume of runoff to be treated
is 341.05 cubic feet greater, however the volume provided by the pond is 16,806 cubic feet.
c. The "volume provided for retention pond is 12,298.33 CF" is an incorrect statement. The
supplement Sheet indicates that the "Volume, temporary pool" is 16,806 CF. The 12,298.33 CF
number is probably the required treatment volume.
The volume required for treatment is 12,298.33 CF but the volume provided is 16,806 cubic feet.
Language on the spreadsheet has been modified. See Sheet 9.
3. Although there were some changes made to figures on the "Supporting Calculations" sheet, it still
contains inaccuracies and is still presented in a manner that makes its review difficult. This issue was
discussed at our February meeting but was not addressed. Some of the issues on this page that were
discussed but not modified are:
a. Under "Peak Flow Calculations ", there is still the "DA -1 ..... 11 developed area" statement.
What does that statement reference?
The total project area is 11 acres but only 8.0 acres drain into the retention area. The project is in a
mountainous area and 3 acres of the property drains into a drainage stream that will not be affected by
the development. The 3 acre area that drains into the drainage stream is not included in the calculations
for the area that drains into the retention basin.
b. Also under "Peak Flow ", there is a reference to the "A" being 8.5 acres. We noted that the
previous submittal's 11 acre reference was changed in this submittal to the 8.5 acre number.
However, the calculations below that indicate an 8.0 acre drainage area. Since other
calculations in the submittal were based on 8.0 acres draining to the pond, we assume that
these other numbers were an oversight in the engineers review. Although the inconsistencies
in the project's drainage area may seem minor, it has been such a significant area of our concern
in our correspondence and discussions that we expected this to be correct in this final
submittal.
The "Peak Flow" is A being 8.0 acres. As stated previous the 11 acres is the project area but only 8.0
acres drain into the retention area and only 3.098 acres of the project is impervious.
c. We mentioned in our February meeting that the "Pollutant Removal Calcs: Bioretention" is an
inaccurate heading and should be changed. This was not done.
The words have been removed.

Page 3:Elk Creek/June 12, 2015
d. As was in the previous submittal, the misalignment of almost every column with the column
headings makes reviewing the calculations difficult. Please correct.
The Quality Notes and Calculations is preformed on a spreadsheet and inserted into the drawing.
The calculations and in the cells of the spreadsheet and the column appear to line up. The results is a
1.5 inch orifice to drain down over a three day period. The barrel is 4 inches with an orifice of 1.5
inches. The previous submitted shown the 4" barrel with an orifice in the bottom of the barrel but
the orifice was not label and the spread sheet calculation indicated a 4' barrel with a orifice but part
of the spreadsheet did not print and was on a block cell. That has been corrected.
Please review the enclosed and if you have any questions please do not hesitate to call or email.
Sri 1 11111 111 ,,'
I, c,W011
N (Z-
,'iii r� •••••.... •••'•�O ``��
David F Ramsey, PE, PSM
General Contractor

T
NCDENR
Permit No.
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
II. PROAECrUNFORMATION
Project name
Contact person
Phone number
Date
Drainage area number
III. DESIGN INFORMATION
Site Characteristics
Drainage area
Impervious area, post-development
% impervious
Design rainfall depth
Storage Volume: Non -SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5' runoff volume
Pre - development 1 -yr, 24 -hr runoff
Post - development 1 -yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr stone peak flow required?
1 -yr, 24 -hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: ) -yr, 24 -hr storm
Pre-development 1 -yr, 24 -hr peak flow
Post -development 1 -yr, 24 -hr peak flow
Pre/Post 1 -yr, 24 -hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state - required temp. pool?
Elevation of the top of the additional volume
Elk Creek at Banner Elk
David F Ramsey Professional Engineer
727 409639
3/25/2015 Revised to 3 days 06-02 -15
#1 Entire Site
348,480 fe
134,950 e
38.73 %
1.0 in
11,587 ft3
16,806 ft"
ft"
ft3
ft3
ft3
A
(Y or N)
in
(unitiess)
(unitless)
in/hr
ft3 /sec
ft'/sec
ft3 /sec
3677.50 fmsl
3675.50 fmsl
3674.70 fmsl
3676.00 fmsl
3670.00 fmsl
3669.00 fmsl
3668.00 fmsl
1.00 ft
(Y or N)
fmsl
(to be provided by DWQ)
O2C)F W A TF9OG
OK, volume provided is equal to or in excess of volume required.
D
JUN 2 3 2015
uaR WATER RESOURCES g BUFFER PERMITT NG
T
Form SW401 -Wet Detention Basin•Rev.9- 4/18/12 Parts I.8 II. Design Summary, Page 1 of 2

Permit No
" (to be provided by DWQ)
111. DESIGN INFORMATION
Surface Areas
Area, temporary pool
9,636 fe
Area REQUIRED, permanent pool
4,879 fe
SAIDA ratio
1.40 (unitless)
Area PROVIDED, permanent pool, Awmjiod
7,198 fe
OK
Area, bottom of 10ft vegetated shelf, A,0t ,en
1,773 fe
Area, sediment cleanout, top elevation (bottom of pond), Ab,_,W
950 fe
Volumes
Volume, temporary pool
16,806 ft3
OK
Volume, permanent pool, Vp „—,
22,428 ft3
Volume, forebay (sum of forebays if more than one forebay)
4,515 ft3
Forebay % of permanent pool volume
20.1% %
OK
SAIDA Table Data
Design TSS removal
85 °%
Coastal SAIDA Table Used?
N (Y or N)
Mountain/Piedmont SAIDA Table Used?
Y (Y or N)
SAIDA ratio
1.40 ( unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10 -2b)
n (Y or N)
Volume, permanent pool, Vw m-"
22,428 1`3
Area provided, permanent pool, Ap,,, j,
7,198 fe
Average depth calculated
3.10 ft
OK
Average depth used in SAIDA, dv„ (Round to nearest 0.5ft)
3.0 ft
OK
Calculation option 2 used? (See Figure 10 -2b)
n (Y or N)
Area provided, permanent pool, Ap,,,,,.,
7,198 fe
Area, bottom of 1Oft vegetated shelf, Aye,,,,,,
1,773 fe
Area, sediment cleanout, top elevation (bottom of pond), Ay�y� d
950 fe
"Depth" (distance b/w bottom of 10ft shelf and top of sediment)
1.00 ft
Average depth calculated
3.12 ft
OK
Average depth used in SAIDA, d,,,, (Round to down to nearest 0.5ft)
3.0 ft
OK
Drawdown Calculations
Drawdown through orifice?
y (Y or N)
Diameter of orifice (if circular)
4.00 in
Area of orifice (if- non -circular)
in'
Coefficient of discharge (Co)
0.40 (unitless)
Driving head (Ho)
1.00 ft
Drawdown through weir?
n (Y or N)
Weir type
( unitless)
Coefficient of discharge (Cw)
( unitless)
Length of weir (L)
ft
Driving head (H)
ft
Pre- development 1 -yr, 24 -hr peak flow
ft3/sec
Post - development 1 -yr, 24 -hr peak flow
ft'/sec
Storage volume discharge rate (through discharge orifice or weir)
if/sec
Storage volume drawdown time
3.00 days
OK, draws down in 25 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 ft
OK
Length of flowpath to width ratio
3 :1
OK
Length to width ratio
2.0 :1
OK
Trash rack for overflow & orifice?
y (Y or N)
OK
Freeboard provided
1.0 it
OK
Vegetated filter provided?
y (Y or N)
OK
Recorded drainage easement provided?
n (Y or N)
Insufficient. Recorded drainage easement required.
Capures all runoff at ultimate build -out?
y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
2' Gate Valve In Bottom of Control Structure for draw down at El of Permanent Pool
Form SW401 -Wet Detention Basin- Rev.9- 4/18/12
Parts 1.8 II. Design Summary, Page 2 of 2

SUPPORTING CALCULATIONS for Wet Detention Basins
Project Elk Creek of Banner Elk
Date: 3/23/2015 Revised 06 -12 -15
Peak Flow Calculations
Project Site
Area in Acres
11
Total Project
Peak Flow: Q =CIA Tc =S min.
required
provided
C =
0.51
arking/sidewalks w/landscaping
1 -10 =
7.5
In/hr
I -25 =
8.5
In/hr
Developed Area
Incremental
Elevation
A =
8
Acres
Q -10 =
30.60
3676.5
Q -25 =
34.680
3677.5
Totals
Q -10 =
17.1
Freeboard
Q -25=
19.4
Use Simnle Method
Site Pond DA (sq. ft.) Pond DA -ac
total 348480 8.0
WQ vol (cu.ft)
11586
Pond Sizine Calculations
site
WQ vol
WQ vol
required
provided
cu -ft
cu -ft
WP
11586.96
16806.00
Staee- Storaee Volume Calculation Table
Surface Area
Incremental
Elevation
SF
Volume CF
3675.5
7198.33
0
3676.5
8389.00
7793.665
3677.5
9636.00
9012.5
3678.5
Freeboard
0
cfs
cfs
Imperious Area (sq.ft.) Impervious Area Ac
134,950.90 3.098
Max Depth Avg Depth
ft ft
6.5 3
Cumulative
Volume CF
0
7793.665
16806.165
16806.165

C—onstruction Schedule Wet RetentionCOli11t I"'e'1-SSP GLL
Emergency Ili a 1 1. o onstruction or shall proceed nil all erosion control facilities a in lace and completed '
'ate �1 2. onstr cti n work shall proceed until all erosion control cili "ea are inspected by the engineer
t re ants n area s a 1 t
of rec rd ars approved.
C I :: to T 7® . 3 e e t ll constr c e in"t"ally along all drainage and storm r management � d
Drainage itch I 4®e Trash c I o layers. facilities.
Screw Type PlugEmbankment stablized with 4. 11 po n completion of all earth work and underground infra -structure the wet;retention area shall be cleaned
11 111
I I I
I 3677.5 MaximiumStorage Temporary Pool
'.:orall thepond. „
_ ' rash of all ads ant an all required vegetationa ts
o that e ndamagedreplaced to accordance ame
the
��c C� approved o Carolina ant ofEnvironmentalan Natural Resources (NGN its
f f Littoral shelf 1 3 7 .T
®� �e �W �� I I I II I I detailed inspection the engineer of record a report II completed n t completionletaonI�10 c��n ot» t 3675.5® 11 11 III I 1 of all (leaning an vegetation restoration.
Construction of allcilities 11 in i a,7 2015
Perm 1 1 .
w
Do 1h SIfrE ttom .
I I I I I 1L "Z
.of Permanent Pool � 111I I I II I I I
L e
_--- I VIII I I --1I I I
4.
" PVC stubbed into outlet-,
olam
LjTl
»--�� `p Stabilized Outletdwwn t t t t I I P rSedI r t Std? e 1 Min If I 1 �-�--� M I M � IE 314" cConcnft to be 30M PSI after 28 days
r on X11 a Bottom g
13 " lstln `� Discharge Pi Use 12�
i ent Storage 1. I °i
oil
Existing Inv I 3672.7
d '`✓ ®®* a
m �
WET RETENTION AREA DETAIL
"LLA
Not to Scale
•
Ht
Note
®Exasting
Ditch has a grade of 10.80/,/ 1 fill 1%
®�
� � l�PPPPlPllltt i�
low Depth 1.01 Regrade ditch to 5% 0 xisting Flow Line El 3670-43 Zf
1
11
low Rate 10-18 cfs New Grade El
( -'
ttOM Width 2'
i ;4 00 $4
CQ
Sl e Slope 2-1 Berm to
0 10 20 X sting Flow Line El
■
23 0
Ch nnel Slope 2 Protect adjacent.8 TBN 60 Pe New Grade El
Property Scale 11"Nom 10" Exasts' S ik
- 0)
El 673 r 194
CP .34 0
/ I • 027" 8
0000
00"T 193.979 413667.01
w�n
�.dge of Water
Existing,
--�
2.0% r 15
El 3663-67 03-02-15
lie
--c 4
sm
®For J 0
d Beach.,...
Tree E 668-41
El 0
Lm
F 0
0 low Characteristics 0D
soft
G El sees
.5 Bottom Wide 2' LU C
ottom Wft- Dam e tall Side Slopes 3-1 T,17-1-1-1-111
Fore
Flow Depth 0.5111
v
foil)
w n, `-1M
Boft
tt El 3673 P—M Iwo Typi al here Xisting Ditch to be
Sedimen Storage ot
(a Sh wn Regraded to 2" Wide
t
loom
W0� Bottom of 3-1 Side LUt, Slope and wth a flow■
d..
UJ
merg ny4 HWI ine not greater then 5%
�4� .�
LZI 3668" SPHI a Disch rge
.fl f 0
g
g 4 El 36 8,5
g. f µ
r/ e
•
v
A, HWT El 3674-261 1 it pond
LAJ
Sh rt
c a
a e ° ° .® �••.. a•' e • ° 4 ga. ®e . 'eg .` w R .a • �. •' •� t44^v
e
m a� w cuit top El 367 .5 CL
3 BD
d a® 1
� a �
19 i�. ottom ro�ay #2 Co
a 3673( 0
g 130 OM El 73 NNW M 5a
Q 21
1
g� • a
a
03 2� c
a
a
6
e g.
g a Q i q 00
eX C'1
>
UJ r*- —V
0 04g
g. Qi X
A 8)
4-4 9 1811 HDPE Petto Inc
.5% Gr i:. a
g
Deed Book 130 Page 120
..4 4g
°
rOP I let #1S.
V4 of
•` g � g � -
4 Grate 13678.5 . -.091

Energy Dissipator Level
Spreader
(Pion view)
gyp,
See plan for
-M__Wsize (length,
width, and
depth)
(Crass -section view) gg t
stem War
- 1lanke_ ti
I
Temporary Grow;
Construction `rt trca
Dir E crsirs and Check Dora
Overhead View
'ARack
4 -Channel '
:1 Sediment Fit
CPaSs-.^aeGtt6n
Design for Gross -lined
i itch t iiia t
2'1 --+Sediment Fit
I
3' 1
HOUL Asphalt -
porary Silt Fend
4,0
2.
__�------ _ 0% SLOPE
\--2" 1-2 ASPHALT. PAVEMENT
" NCDOT ABC(95 COMPACTION MIN.)
"-COMPACTED SUB-GRADE(95% COMPACTIOIN IN.)
Elk Crack Road Section
�
.. 2 1_2 ASPHALT. PAVEMENT
8" NCDOT A13C(95% COMPACTION MIN.)
COMPACTED SUB-ORADE(95% COMPACTION MIN.)
Inverted Crown Interior Road Section
ea SF
t
iALITl' NOTES AND CALCULATIONS:
v° s the 85 f® removal of the TSS
The retention area as shown on the detail provides
f It impervious areas t°ici area, roadway,
sidewalks s if V=A*I'
of runoff
The volume o£ water discharge a
rg 9 4 Y9
Imperviouis Area SF Volume
Its CF
Volume ces ea for Treatment is 11 45.91 CP
ff C' 134,950.90 enc s
�'eaEerette of Ramoe�
(
FirY
S 637.Ci0
Pond 16 f,00 CF`
See Supplement Sheet
Volume of Runoff
Volume Provided by P o
020
Volume of asts calculated using the SMP Manual Equation
15 ,637-00
Rv=0,4-F0„ 1a
*
=a SF Rv=
$6 8 11
i6 8 X643
't*1 01f80 ,3 8.
3677,.
1 .9 E at elevation
4 .89 1 he required storage vol oftproposed
1
1 29
� g
I�
1 C
I'It storage volts oft sed sed is
6 ,
.est.
g
The invert elevation of the outlet reser and Orifice is at elevation t
n 337
4.50 with an ave rage detention of 3 days
the flow throughthe h rise can be estimated as follows:
1,429.89
6,981S7
037
_Volume/timevtt
Ts Er Ta
412.46
0.0648 CFS 13,600.01111
Orifice li tea
tion=A 2 0.5 ewer
Olin
g Pn
Averag e tread '
Average bead
v 367°i,6 75�.
2,14 1.08
g
Total Area of the Perforations
gg sharp � e ra ed edge)
Q= ('A*(2gh) to 0.5 power Pipe slases Area
1 '� S
11
m2�7 1
1 1
.5 144
C'
2 Lower 0
(hg�
A= O.OW 0.6 9.552 SJ39784
Resents
oa
so
1f2
1 »1f
A- 0>01 S1< 1 1
,. `, ,
f s ran iter management
v embankments, litoral shelf and perimeter o the to w
The egatation to a for the a ba g
is as follows:
A.1 op of Berm and Exterior Slopes shall have Centipede Grass
B. Eitsral Shelf has a total f 6117 square feet. Need 50 plants for each 200 square feet or 1529 plants
nl ntani
t'sc a r€sisttare of Sweetfla Aco snbco tans , I11tne flag iris (tris eighties), Soft stern bulrush (Schoenoettts t e o )
g( } g g
and Primrose willow (Peltandirs virgi ' a) Spacing shall been 24" to 36" on center,
Notes All plants shall be NC Grade 1 and planted in accordance with the North Carolina Regulations
1
•
0 4�
i
w i
# lk
5rairnage Area #1 Area SF
Drainage Area #3
Area SF
Drainage Area #5
Area SF
Dranage Area #7
P4wre1 Elk Creek Dr
10,149.62
Pavia Elk Creek Dr
P
870.$6
Paving . Elk Creek 3r
$
P vi. Elk Creek Dr
a
Pawing Parking Area
15,074A9
Pawing Parking Area
2 ,SS .41
Paving Parkin Area
a $
3 257.77
Pawsr .Parkin Area
g
Sidewalk
de
1,290.60
Sidewalk8,861.59
1M
tM i i 1z !
Sidewalk
455.37
Sidewalk
Buildings_
19,5 ,00
Buildings
1,244.77
Buildings
997.53
8u14di's$s
Y
Y t
r� r ° Y: Y Y n r
Total impervious
42 632:63
Tota{ Impervious
a
i►
Tota npe rwious
Open Space
64,259.32
1 1 1 1
57,412,17
Open Space
-
Open race
Run off Coefficient
r
Run Off Coefficient
u O
0.56
Run Of f Coefficient
0.24
Runs "''f Coefficient
W Cas 1
Tota{ 110 273.73
Total
I#3 �44.80
Total
6.4$
7,856.48
Toto, ;
Drainage Area #2 Area SF 'Drainage
Area #4
Area SF
ina $ d Area #6
Drainage
Dr
Area SF
Drair e Area 8
°
Paving Elk Creek Dr
5,116.99
Paving Elk Creek Dr
au
Elk Creek Dr
Pavia E
2561.27
tr Dr
:Paw .Elk Creek
Paving Parking Area
10 61731
Paving Parkin Area
3 ,4 94.86
Paving Parking Area
PavingParkingrkin Area
i 1 r
Sidewalk
416.403
Sidewalk
2,530.00
Sidewalk
Sadew n k
Buildings
11,197.82
it
4,228.65
Buildings
„
6uildr^gs
Total Impervious
27,348.52
Total Impervious
10,25151
Total Imperviousev us
2, S 1.27
Tota; ,"rpe rva us
c
O arses
pa
48,411.33
Open Space
p0p
. 6
12 ..129 8
>
Open Space
1 _K
7,857.24
Oper, Space
:.
Run Off Coefficient
u
0.45
.
Run Off Cis@fflr•Refit
ti
Run Off Coefficient
4 .37
r �€Coefficient
Run �
Total
75,759.85
Tota{ :
22 373.37
Total,
HEM.
1 i i
Year Storm Event
Drainage 1' `i°b 10 Ties �
I.PF # Size & Type
Area
Coefficient
tasrfni6 Caches
CES
Size Repired Pipe see
P
1
253
0.490
7_
S
34,.10 »
1
13.14 ,;
18 o,
la New 18" HDPE
2.53
0.490
7.5
2.00%
10°54
1434"
181,
,"
2 Existing 24 CMP
1 74
.
0.42
7.5
»
9:819 f�
5.4$
i ✓
1
}
3 Existing 18 CMP
0.19
0,465
715
8.70 h
066
412'
18"
1 "" HOPE
4 New �
0.19
Y�
e 1
�
7. .
2.b0 r�
0,66
4 25"
18"
� i t
q
0,533
7.5
m
2.20!
91. 9z
z311t°
1�°°
fi New 1$" HDPE
2.99
0.377
7<5
0.701
&45
z5
Is."
.. 24"'
7 Existing
4.18
0.377:
7.5
0,30.1®
11.82
1802*
,
24°`
8 New 18" HOPE
4.18
0.380
7.5
0,60®6
9,88
17,55"
181,
9 New 18°` HDPE
4.69
1
75
.
eY�i� (tea
p
17,73
S8"
10 New 15°' HDPE,
0.78
0T
7.5
0.201/6
2.16
<12'
15"
,b
I
ea SF
t
iALITl' NOTES AND CALCULATIONS:
v° s the 85 f® removal of the TSS
The retention area as shown on the detail provides
f It impervious areas t°ici area, roadway,
sidewalks s if V=A*I'
of runoff
The volume o£ water discharge a
rg 9 4 Y9
Imperviouis Area SF Volume
Its CF
Volume ces ea for Treatment is 11 45.91 CP
ff C' 134,950.90 enc s
�'eaEerette of Ramoe�
(
FirY
S 637.Ci0
Pond 16 f,00 CF`
See Supplement Sheet
Volume of Runoff
Volume Provided by P o
020
Volume of asts calculated using the SMP Manual Equation
15 ,637-00
Rv=0,4-F0„ 1a
*
=a SF Rv=
$6 8 11
i6 8 X643
't*1 01f80 ,3 8.
3677,.
1 .9 E at elevation
4 .89 1 he required storage vol oftproposed
1
1 29
� g
I�
1 C
I'It storage volts oft sed sed is
6 ,
.est.
g
The invert elevation of the outlet reser and Orifice is at elevation t
n 337
4.50 with an ave rage detention of 3 days
the flow throughthe h rise can be estimated as follows:
1,429.89
6,981S7
037
_Volume/timevtt
Ts Er Ta
412.46
0.0648 CFS 13,600.01111
Orifice li tea
tion=A 2 0.5 ewer
Olin
g Pn
Averag e tread '
Average bead
v 367°i,6 75�.
2,14 1.08
g
Total Area of the Perforations
gg sharp � e ra ed edge)
Q= ('A*(2gh) to 0.5 power Pipe slases Area
1 '� S
11
m2�7 1
1 1
.5 144
C'
2 Lower 0
(hg�
A= O.OW 0.6 9.552 SJ39784
Resents
oa
so
1f2
1 »1f
A- 0>01 S1< 1 1
,. `, ,
f s ran iter management
v embankments, litoral shelf and perimeter o the to w
The egatation to a for the a ba g
is as follows:
A.1 op of Berm and Exterior Slopes shall have Centipede Grass
B. Eitsral Shelf has a total f 6117 square feet. Need 50 plants for each 200 square feet or 1529 plants
nl ntani
t'sc a r€sisttare of Sweetfla Aco snbco tans , I11tne flag iris (tris eighties), Soft stern bulrush (Schoenoettts t e o )
g( } g g
and Primrose willow (Peltandirs virgi ' a) Spacing shall been 24" to 36" on center,
Notes All plants shall be NC Grade 1 and planted in accordance with the North Carolina Regulations
1
•
0 4�
i
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5rairnage Area #1 Area SF
Drainage Area #3
Area SF
Drainage Area #5
Area SF
Dranage Area #7
P4wre1 Elk Creek Dr
10,149.62
Pavia Elk Creek Dr
P
870.$6
Paving . Elk Creek 3r
$
P vi. Elk Creek Dr
a
Pawing Parking Area
15,074A9
Pawing Parking Area
2 ,SS .41
Paving Parkin Area
a $
3 257.77
Pawsr .Parkin Area
g
Sidewalk
de
1,290.60
Sidewalk8,861.59
1M
tM i i 1z !
Sidewalk
455.37
Sidewalk
Buildings_
19,5 ,00
Buildings
1,244.77
Buildings
997.53
8u14di's$s
TotalImpervious
46014.41
Total impervious
42 632:63
Tota{ Impervious
4 710.67
Tota npe rwious
Open Space
64,259.32
Open Space
57,412,17
Open Space
3,145.81
Open race
Run off Coefficient
0.49
Run Off Coefficient
u O
0.56
Run Of f Coefficient
0.24
Runs "''f Coefficient
W Cas 1
Tota{ 110 273.73
Total
I#3 �44.80
Total
6.4$
7,856.48
Toto, ;
Drainage Area #2 Area SF 'Drainage
Area #4
Area SF
ina $ d Area #6
Drainage
Dr
Area SF
Drair e Area 8
°
Paving Elk Creek Dr
5,116.99
Paving Elk Creek Dr
au
Elk Creek Dr
Pavia E
2561.27
tr Dr
:Paw .Elk Creek
Paving Parking Area
10 61731
Paving Parkin Area
3 ,4 94.86
Paving Parking Area
PavingParkingrkin Area
Sidewalk
416.403
Sidewalk
2,530.00
Sidewalk
Sadew n k
Buildings
11,197.82
Buildings
4,228.65
Buildings
6uildr^gs
Total Impervious
27,348.52
Total Impervious
10,25151
Total Imperviousev us
2, S 1.27
Tota; ,"rpe rva us
c
O arses
pa
48,411.33
Open Space
p0p
. 6
12 ..129 8
>
Open Space
1 _K
7,857.24
Oper, Space
:.
Run Off Coefficient
u
0.45
.
Run Off Cis@fflr•Refit
ti
Run Off Coefficient
4 .37
r �€Coefficient
Run �
Total
75,759.85
Tota{ :
22 373.37
Total,
10 ........
418.52
Tota°.
Year Storm Event
Drainage 1' `i°b 10 Ties �
I.PF # Size & Type
Area
Coefficient
tasrfni6 Caches
CES
Size Repired Pipe see
P
1 Ex�ti 18 Calf,
253
0.490
7_
S
34,.10 »
9,30
13.14 ,;
18 o,
la New 18" HDPE
2.53
0.490
7.5
2.00%
10°54
1434"
181,
,"
2 Existing 24 CMP
1 74
.
0.42
7.5
»
9:819 f�
5.4$
I1.
24
3 Existing 18 CMP
0.19
0,465
715
8.70 h
066
412'
18"
1 "" HOPE
4 New �
0.19
0.465
�
7. .
2.b0 r�
0,66
4 25"
18"
P
5 New 18°° 11DPE
2.23
0,533
7.5
m
2.20!
91. 9z
z311t°
1�°°
fi New 1$" HDPE
2.99
0.377
7<5
0.701
&45
z5
Is."
.. 24"'
7 Existing
4.18
0.377:
7.5
0,30.1®
11.82
1802*
,
24°`
8 New 18" HOPE
4.18
0.380
7.5
0,60®6
9,88
17,55"
181,
9 New 18°` HDPE
4.69
28
75
.
3 I
18.57
17,73
S8"
10 New 15°' HDPE,
0.78
0T
7.5
0.201/6
2.16
<12'
15"
A Table 1{6 Year Drainage Area $ t Event
Square Feet
Cubic Feet
Drainage e Aeef Area
Q=CU C
i
�r 1
Over ln1e '
1 2:53
9.30
0.49
7.5
46,014.41
3
2 1.74
5.87
0.45
7.5
27,34&52
2,279.(
3 2-,23
9.37
0.56
7,5
42,632.63
3,552.72
4 0:51
2169253.51
0 59
74
1a
854.46
5 0 .18
0.31
0.24
7.5
4 710,57
,
392.56
6 0.24
0.49
0.27
7,5
2,56117
213144
7 0;36
0.54
0.2
7-5
0
0°00
8 019
0.53
0.37
7.5
1,429.89
119,16
Total 8.0
134,950.90
11,245.91
Overall
0.51
ea SF
t
iALITl' NOTES AND CALCULATIONS:
v° s the 85 f® removal of the TSS
The retention area as shown on the detail provides
f It impervious areas t°ici area, roadway,
sidewalks s if V=A*I'
of runoff
The volume o£ water discharge a
rg 9 4 Y9
Imperviouis Area SF Volume
Its CF
Volume ces ea for Treatment is 11 45.91 CP
ff C' 134,950.90 enc s
�'eaEerette of Ramoe�
(
FirY
S 637.Ci0
Pond 16 f,00 CF`
See Supplement Sheet
Volume of Runoff
Volume Provided by P o
020
Volume of asts calculated using the SMP Manual Equation
15 ,637-00
Rv=0,4-F0„ 1a
*
=a SF Rv=
$6 8 11
i6 8 X643
't*1 01f80 ,3 8.
3677,.
1 .9 E at elevation
4 .89 1 he required storage vol oftproposed
1
1 29
� g
I�
1 C
I'It storage volts oft sed sed is
6 ,
.est.
g
The invert elevation of the outlet reser and Orifice is at elevation t
n 337
4.50 with an ave rage detention of 3 days
the flow throughthe h rise can be estimated as follows:
1,429.89
6,981S7
037
_Volume/timevtt
Ts Er Ta
412.46
0.0648 CFS 13,600.01111
Orifice li tea
tion=A 2 0.5 ewer
Olin
g Pn
Averag e tread '
Average bead
v 367°i,6 75�.
2,14 1.08
g
Total Area of the Perforations
gg sharp � e ra ed edge)
Q= ('A*(2gh) to 0.5 power Pipe slases Area
1 '� S
11
m2�7 1
1 1
.5 144
C'
2 Lower 0
(hg�
A= O.OW 0.6 9.552 SJ39784
Resents
oa
so
1f2
1 »1f
A- 0>01 S1< 1 1
,. `, ,
f s ran iter management
v embankments, litoral shelf and perimeter o the to w
The egatation to a for the a ba g
is as follows:
A.1 op of Berm and Exterior Slopes shall have Centipede Grass
B. Eitsral Shelf has a total f 6117 square feet. Need 50 plants for each 200 square feet or 1529 plants
nl ntani
t'sc a r€sisttare of Sweetfla Aco snbco tans , I11tne flag iris (tris eighties), Soft stern bulrush (Schoenoettts t e o )
g( } g g
and Primrose willow (Peltandirs virgi ' a) Spacing shall been 24" to 36" on center,
Notes All plants shall be NC Grade 1 and planted in accordance with the North Carolina Regulations
•
0 4�
i
w i
# lk
» i
a °c
11 i M
A,
s+;
•
r" r
1 11 !
is
1M
tM i i 1z !
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