SW8021116_COMPLIANCE_20030404

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT
NO.
SW
-c
DOC TYPE
El CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
VZV COMPLIANCE EVALUATION INSPECTION
DOC DATE
n( 7�yG�
YYYYMMDD

INFILTRATION BASIN ANALYSIS
FILENAME: G:\DATAkWPDATA\WQS\INBASIN\021116-l.WK1
PROJECT NUMBER: 021116.1
DATE: 04-Apr-03
PROJECT NAME: The Gauntlet Clubhouse Tennis
Courts
DRAINAGE BASIN: Cape Fear
REVIEWER: L. Lewis
RECEIVING STREAM: Beaver Dam Creek
CLASS: SA
Index No.: CPF17 18-88-9-1-(1.5)
If ORW, is site within the 575' AEG?
SITE AREA 1.64 acres
DRAINAGE AREA: SF
IMPERVIOUS AREA CALCULATION
Rational C
BUILDINGS
PARKING/ASPHALT
CONCRETE
Tennis Courts
18720 1
TOTAL
Place a 1" here if Rational
% IMPERVIOUS, I= 61:4 #
RV= .05+.009 (I)
ELEVATION OF SEASONAL HIGH WATER TABLE
6 FEET MSL
REPORTED INFILTRATION.RATE
_;6 INCHES/HOUR
or 0.000139 FPS
SURFACE AREAS AND ELEVATIONS
Elev. (ft) Area, sq ft
Inc. Volume Acc. Volume
BOTTOM 8.25 3502
0
8.5 4814
1039.5 1039.5
TOP 8.75 6587
1425,125 2464.625
VOLUME ! DEPTH 1 DRAWDOWN CALCULATION
DESIGN STORM, INCHES
1 5
DESIGN VOLUME
227:'
CUBIC FEET
TOTAL VOLUME AVAILABLE
:,.::.:252225
CUBIC FEET
DEPTH OF RUNOFF
:>:;;<0:50.`:
FEET
TIME TO DRAWDOWN
;::_>:4'
HOURS MUST BE <120
25 YEAR 24 HOUR STORM NIA
Intensity, i = .33 inches 1 hour
Qr=CIA=
0.16 CFS
Op through the bottom of the basin=
0.49 CFS Must be > Qr
10 YEAR 10 MIN HIGH INTENSITY EVENT
Intensity, i = 6.3 inches 1 hour
Volume for 10 yr. 10 min. event =
1828.77 CF < 2522.25 CF
COMMENTS
Volume and drawdown are (not) within Design
Requirements.

INFILTRATION BASIN ANALYSIS
FILENAME: G:\DATA\WPDATA\WQS\INBASIN\021116-2.WK1
PROJECT NUMBER: 021116-2
DATE: 04-Apr-03
PROJECT NAME: The Gauntlet Clubhouse Tennis
Courts
DRAINAGE BASIN: Cape Fear
REVIEWER: L. Lewis
RECEIVING STREAM: Beaver Dam Creek
CLASS: SA
Index No.: CPF17 18-88-9-1-(1.5)
If ORW, is site within the 575' AEC?
SITE AREA 1.64 acres
DRAINAGE AREA: SF
IMPERVIOUS AREA CALCULATION
Rational C
BUILDINGS
131 1
PARKING/ASPHALT
CONCRETE
305 1
Tennis Courts
TOTAL
Place a "1" here if Rational
% IMPERVIOUS, I= 11..1 0
RV= .05+,009 (I) =
tJ 15
ELEVATION OF SEASONAL HIGH WATER TABLE
::.,::6 FEET MSL
REPORTED INFILTRATION RATE
:';;.........�.... �6 INCHESIHOUR
or 0.000139 FPS
SURFACE AREAS AND ELEVATIONS
Elev. (ft) Area, sq ft
Inc. Volume Acc. Volume
BOTTOM 8.25 94
0
8.5 415
63.625 63.625
TOP 8.75 813
153.5 217.125
VOLUME 1 DEPTH I DRAWDOWN CALCULATION
DESIGN STORM, INCHES
,:.4,>5
DESIGN VOLUME
:: : 22>'
CUBIC FEET
TOTAL VOLUME AVAILABLE
CUBIC FEET
DEPTH OF RUNOFF
:::<:>::<:'.{74$:i
FEET
TIME TO DRAWDOWN
..........:.'...4.6'-HOURS
MUST 8E <120
25 YEAR 24 HOUR STORM NIA
Intensity, i = .33 inches 1 hour
Qr=CiA=
0.01 CFS
Op through the bottom of the basin=
0.01 CFS Must be 7 Qr
10 YEAR 10 MIN HIGH INTENSITY EVENT
Intensity, i = 6.3 inches 1 hour
Volume for 10 yr. 10 min. event =
98.30 CF < 217 CF
COMMENTS
Volume and drawdown are (not) within Design Requirements.

Storm Water / Erosion Control / Soils report
.. Design Narrative and Calculations
Sub j ect:
Additional Tennis Courts
For
The Gauntlet Golf Course Clubhouse Site
Brunswick County, North Carolina
Prepared for
St. James Plantation.
P.O. Box 10879
Southport, North Carolina 28461
[phone]
RECEIVED
NOV 2 0 2002
DWQ
PROD# S'A)?02111(p
Date: November 8, 2002
IM
s S -AE
Prepared by
- -
Cape Fear Engineering, Inc.
,,'�k
151 Poole Road, Suite 100
Belville, North Carolina 28451
[phone]

DESIGN NARRATIVE
I. GENERAL:
The project site is located off of Beaver Creek drive at the Gauntlet Golf Course Clubhouse site
with in the St. James Plantation development. St. James Plantation is located along NC Hwy 211
within Brunswick County, North Carolina. The project area in question is approximately 0.8
acres. Drainage considerations are to be in accordance with DEM stonn water requirements.
2. EXISTING SITE:
Site topography in the area is relatively flat with slopes typically less than one (1) percent. The
vegetation consists primarily of grasses and minor ground cover. within the area of the
improvements. Subsurface soils are typically a mixture of sands, silty sands and organics.
3. PROPOSED IMPROVEMENTS:
Improvements proposed include the construction of a new clay tennis court with a 4' wide
concrete sidewalk and a wooden prefabricated gazebo. Two shallow infiltration swales are
proposed to be graded in this location as shown on the attached plan to trap sediment during the
construction process until vegetation has been established and to capture and treat storm water as
a permanent storm water management device.
4. DRAINAGE CALCULATION CONSIDERATIONS:
Attached to this design narrative are the drainage calculations determining the amount of storm
water to be contained and treated prior to entering any downstream surface waters. The design
utilized for this project is two infiltration swales that will capture and treat the runoff of a 24-hr
25-yr storm event. A vegetative Swale has been designed at the end of the infiltration swales as a
bypass for any storm event that would exceed the design parameters.
5. EROSION CONTROL CONSIDERATIONS:
The proposed infiltration swale will be used as a trapping device during construction and has
sufficient storage for, tile calculated amount of disturbance. Also, the perimeter will be cnclosed
in silt fence as added protection. The area of disturbance is limited to within the silt fence
boundary. Maximum graded slope is not to exceed three (3) to one (1) with vegetative
establishment a priority..
Page One
Design Narrative
St. James Plantation
The Gauntlet Clubhouse Site

6. MAINTENANCE CONSIDERATIONS:
During construction, the Contractor shall be required to inspect and repair as needed all erosion
control devices after any significant rain event. Any measure found not performing its intended
function, shall be repaired immediately. Upon completion of construction the establishment of
permanent ground cover will be a priority.
7. SOILS REPORT:
The attached soils information taken from the Brunswick County Soils Survey book along with a
site inspection was utilized to design the proposed infiltration swales. During the site visit
borings were made at the locations of the two proposed infiltration swales. Ground water was
encountered at approximately 24" below the existing top of grade which was surveyed at an
elevation of approximately 8.0 msl. The soils are identified as Leon which has a permeability
rate of 6 to 20 inches per hour. For this design 6 inches per hour has been used in the calculations
of the infiltration swales.
Page Two
Design Narrative
St. James Plantation
The Gauntlet Clubhouse Site

rt ••'�, m +�,'L' fir^ . :, I � t'. }� ' ��'";.
Wa,
ir
.%rr= a + !j� T-J;'id� �c �• � -, � S. N bi ry o
F?I
ED
o m r In
r
•'Y.'
I
�
L -�.• f
Li
ro t_ I j Z
o 121,
W
z7�
r GLU
{( � I
itl J L-V 0 Y I
1 �
m E m
m ~
° co f
J ro 1]i�, Il
7 W ° U
°
m j e
J E com.
7 am
�L! ways suiorf i

Brunswick County, North Carolina 115 T
TABLE 17.--PHYSICAL AND CHEMICAL PROPERTIES OF THE SOILS --Continued
' '
Map symbol and IDepthlClay { Moist
I I 1
r I°
I Permea- (Available{ Soil
1 1 Ireactionl
'
ISalinitylShrink-swelll
I
' Erosion '
factors (Organic
I��'-1
soil name bulk
I I
bility
water
Ica I
I
I potential'
1
matter
1 I
densit
1
acit
1 K
T
+ In I Pct 1 cm
I In hr
I In in 1
1 os cml
I
I { Pc
Jo --------------- 1 0-131 5-1511.45-1.651
113-38118-3511.40-1.601
2.0-6.0
0.6-2.0
10.10-0 1514.5-5.5
10.12-0.1514.5-5.5
1 <2
1 <2
ILow---------
]LOW ---------
10 20
10.24
1 5 1 .5-2
1 1
Johns
138-701 2-1011.60-1.751
6.0-20
10.03-0.0614.5-5.5
1 <2 ILow
---------
10.10
1 1
I I
KrB-------------- 1 0-801 0-3 11.60-1.601
6.0-20
1 <0.05 14.5-7.3
1 <2
ILow---------
10.10
1 5 1 <2
Kureb I I I
I I 1
I
I
I 1
i I
1
I
1
1
I
I
I 1
I
LA --------------- 1 0-551 --- 10.05-0 501
Lafitte 155-72130-8510 50-I D01
-
2.0-6.0
<Q.06
10.20-0.5013.6-8.4
10.15-0.2016.1-8.4
1 4-8 ILow
l 8-16
i -
---------
1High--------10
I
I----
32
1-
I --- { 30-70
1
-
Lo--------------- 1 0-801 1-6 11.40-1.651
6.0-20
10.02-0.0513.6-5:5
1 <2 IL
-----------
10.10
1 5 1 .5-4
Leon I 1 I
I
I {
I {
I
I I
1 Lu---------------1 0-181 4-1811 55-1.701
= 118-38118-3511:30-1.451
2.0-6.0
10.08-0 1214.5-5.5
10.12-0.1614.5-5.5
1 <2
1 <2 ILow---------10.32
ILow---------
01- 24 -i 5 1 2-4
1 1
Lumbee
i 138-801 1-1011.60-1.751
0.6-2.0
6.0-20
10.03-0.0614.5-5.5
I {
1 <2 ILow
I
--------- 10.10
I
I
1 1
f I
Ly------------- --1 0-161 5-2011 30-1.601
116-80I18-3511.30-1.501
2.0-6.0
10.09-0 1313.6-5.5
10.12-0.16I3.6-5.5
1 <2 ILow
------- --10.20
I 5 1 .5-5
1 l
Lynchburg
0.6-2.0
1 <2 `Low
---------
IQ 20
'
1
Ma --------------- 1 0-181 <3 11.35-1.651
118-351 2-9 11.45-1 601
6.0-20
10.03-0.0713.6-6.0
10.10-0 1513.6-6.0
1---
1 --- ILow
ILow---------
------ ---10.15
10.10
.I
1 5 1 3
I --- 1 ---
Mandarin
135-621 <3 11.35-1.451
0.6-2.0
0.6-20
10.03-00714.5-7.3
1 --- ILow
------ ---10.10
I _-- 1 ---
162-801 2-9 I1 45-1601
I I i :I
0.6-20 10.10-0
1514.5-7.3
I I
1 --- ILow
I I
--------- 10
15
I
1 --- I ---
I I
Mkm-------------- 1 0-6 110-251 ---
1
1 0.6-2:0 10.09-0
1
1515.1-7.3
10.08-0.1215.6-8.4
1 <2 ILow
1 1Low
---------
10 20
10.20
1 5 1 ---
1 1
Muckalee 6-651 5-201 ---
0.6-20
<2
1 1
---------
1
1 {
Mu --------------- 1 0-5 1 2-8 11.20-1.401
1 11.60-1
6.0-20
10.15-0.2013.6-5.5
10.05-Q
1 <2
1
ILow---- -----
ILow
10.10
10.10
1 5 I 9-20
1 I
Murville 5-801 2-8 751
I 1 I
2.0-6.0
I
0913.6-5.5
I I
<2
I 1
---------
I
I 1
j
iNeE, NhE--------- 1 0-801 --- 11.60-1.751
1 I 1
>20
I
1 <0.05 13.6-7.8
I I
1 <2 ILow
I
---------
I
10.10
I
1 5 1 ---
I I
Newhan
I I I
I
I I
{
I
!
{ I
ROB -------------- 1 0-161 2-8 11.55-1 751
6.0-20
10.06-0 1114.5-6.0
1 <2 ILow---------
10.20
1 •5 1 .5-2
Norfolk 116-63118-3511.35-1.451
63-80 --- I ---
I I I
0.6-2.0
I ---
I -
10.10-0.1514.5-5.5
--- ---
I 1
I <2 1Low
---
I
---------
------------
I
10 29
----
I
I I
I I
On ------------- --1 0-171 5-1511.45-1.651
2.0-6.0
10.11-0 1513.6-5.5
1 <2 ILow---------
10.20-1
4 1 .5-2
Onslow 117-65115-3511.30-1.501
165-801 --- I ---
I I I
0.6-2.0
I ---
I
10.12-D 1713.6-5.5
1 --- 1---
I i
1 <2 ILow
1---
{
---------
1------------
I
10 24
I----
I
1 1
I I
I I
PaA----------- �:--I 0-551 2-1211.60-1.751
155-801
6.0-20
10.05-0 1014.5-6.0
10.03-0
1 <2 ILow
1 ILow---------10.10
---------
10.10
1 5 1 .5-2
I I
Pactolus 2-12I1.60-1.751
I I I
6.0-20
I
0714.5-5.5
I I
<2
i
I
I
I I
�---------------1 0-111 5-151120-1.401
2.0,6.0
10.20-0 3013.6-5.5
1 <2
ILow---------
10.10
1 5 1 10-15
Pantego 111-15118-3511..30-1.401
0.6-2.0
10.12-0.2013.E-5.5
1 <2 ILow
---------
10.28
1 1
115-80118-4011 25-1.401
I I I
0.6-2.0
I
10.15-0.2013.6-5.5
I I
1 <2 [Low ---------
I 1
10 28
I
1 1
I I
I I I
Pits 1 1 1
{ I !
I
I
I I
I I
I I
I I
I I
I I
I
!
1
I I
I 1
I V
---------I 1 0-151 5-2011.30-1.601
2.0-6.0
14.10-0.14I4.5-6.5
l <2 (Low ---------
10.20
15 1 1-6
Rains 115-72118-3511.30-1.501
0.6-2.0
10.11-0 15145-5.5
1 <2 ILow
---------
10.24
1 1
172-80118-4011.30-1.501
0.6-2.0
10.10-0:1514.5-5.5
1 <2 ILow---------
I I
10.28
I
1 1
I I
--`------------1 0-121 2-8 11.60-1 751
6.0-20
10.04-0 1014.5-5.5
1 <2 1Low----------
10 10
1 5 I 5-2
mahawk 112-231 5-1511.45-1.651
2.0-6.0
10.10-0.1414.5-55
1 <2 1Low
---------
10.15
I 1 .
123-801 2-8 11.60-1 751
I i V
6.0-20
I
10.04-0.0814.5-6..5
I I
1 <2 ILow------
I V
I
I I
L
irp
rte
lot
?is'
IS
Ire
na
18l

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
BASIN DATA
Proj No.700-19
11118102
infiltswale-#1.xls
1 of4
Dramage�Rrea DesEgriat�on'l _ �° ""'t��
�'DRAtNAGE�AREA
Receiving stream class
SAjwaters
Onsite Area =
;; 270.
acres
Onsite Impervious Area
0.43
acres
Offsite Area =
0.00
acres
Offsite Impervious Area =
00
acres
Total Area = 0.70 acres
Total Impervious Area = 0.43 acres
Percent impervious = Impervious drainage area (acres)/D rain age area (acres) = 61.4
A) Determine volume to be controlled from storm (1.5 inch event for SA waters, 1 inch event for others)
Using the runoff volume calculations per "Simple Method" as described by Schueler (1987):
where: Rv = runoff coefficient = storm runoff (inches) / storm rainfall (inches)
= Percent Impervious = Drainage area (acres) / Impervious portion of the drainage area (acres)
Rv=0.05+0.009(I)
Rv = 0.05 f 0.009 * 61.4 = 0.603 (in/in)
Volume to be controlled from the design storm event:
where: Design rainfall
Rv
Drainage Area
1.5 (in)
= 0.603 (in/in)
= 0.70 (acres)
Volume required (cf) = rainfall (in) x Rv (in/in) x Drainage Area (acre) x 1/12(feet/inches) x 43560 (sf/acre)
Vreq'd = 1.5 * 0.603 * 0.7 * 1/12 * 43560 = 2298 cubic feet

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
Determine the volume of the proposed pond/swale:
POND GEOMETRY
Proj No.700-19
11118/02
infiltswale-#1.xls
2of4
Comments
Contour Contour
Elevation Area
(msl) (so
Incremental Storage
(cf)
Bottom Elevation
8.25 3502
1040
8.5 4814
1425
Storage Elevation
8.75 6587
Total Volume of Pond/Swale = 2465 cubic feet
lCompare volume proposed to volume required from the design storm event:
2465 cf > Vreq'd 2298 cf
(OK -proposed basin volume is greater than minimum required volume)

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
Proj No.700-19
11/18/02
infiltswale-M.As
3of4
B) Check pond infiltration rate for capacity to control the 25 year-24 hour storm event with no discharge
The average weighted coefficient of runoff is determined by:
C ave = Sum[CA ] 1 Sum[A]
Description AREA C CA
Impervious Area 0.43 80!95 0.409
Pervious Area 0.27 `j0 30 0.081
Sum A = 0.7 Sum CA = 0.49
C ave = 0.49 / 0.7 = 0.699
Determine required discharge from 25 year-24 hour storm event:
Qregd= CavgxIxA
Q regd = 0.70 ` 0.33 0.7 = 0.16 cfs
where: I = intensity for 25 year-24 hour storm event from Chart E-6 =r,=°= tp:33 in/hr
A = drainage area = - 0.7 acres
Cavg = weighted coefficient of runoff - 0.70
Check available rate of infiltration provided by proposed swale:
where: I = infiltration rate of soil (4 to 12 in/hr per Soils Report) Use: _ 1 °::6 in/hr
A = bottom area of swale = = 1959 sf
Qavaii = IA = 6 inlhr 1959 sf " 1 ft112 in ' 1 hr/3600sec - 0.27 cfs
re rate of infiltration with runoff rate from the 25 year storm event:
0.27 cf > Q regd = 0.16 cf
(OK -No Discharge for 25 yr-24 hr storm event)

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
Proj No.700-19
11 /18/02
infiltswale-#1.xis
4of4
C) Check the 10 year-10 minute storm event to confirm that basin has capacity without flushing system
where: I = intensity for 10 year-10 minute storm event from Chart E-6 = ;; ' 6.3 inihr
A = drainage area = - 0.7 acres
Cavg = weighted coefficient of runoff = 0.70
Determine discharge rate from 10 year-10 minute storm event:
Q 10-yr = Cavg x I x A
Q 10-yr = 0.70 * 6.3 * 0.7 = 3.08 cfs
Determine discharge volume from 10 year-10 minute storm event:
V 10-yr = Q 10-yr * 10 min. duration * 60 sec/min. = 1850 cf
Check available volume of the proposed infiltration basin:
V avail = design volume (from geometry table) = 2465 cf
Compare design volume of infiltration basin to discharge volume from 10 year storm event of 10 minute duration:
Vavail = 2465 cfs > V 10-yr = 1850 cfs
(OK -basin has adequate capacity for 10-yr event without flushing)
Compare infiltration system drawdown time to maximum drawdown period of 5 days
T= V reqd I Q avail 1 hr13600 sec
T = 2298 cf 1 0.27 cfs * 1 hr13600 sec = 2.35 hours
(OK-. system draws down in less than 5 days)

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
BASIN DATA .
Proj No.700-19
11/18/02
infiltswale-#2.xis
1 of4
age1 DR4INAGE AREA
DrainAreaes DEgnation i " +s
Swa�esFgnation. 1�ly�: Infiltration Swale#2,
Receiving stream class
SA waters
Onsite Area =
0?09 acres
Onsite Impervious Area =
0.01 acres
Offsite Area =
0.00 acres
Offsite Impervious Area =
,0,00 acres
Total Area = 0.09 acres
Total Impervious Area = 0.01 acres
Percent Impervious = Impervious drainage area (acres)/Drainage area (acres) = 12.2
A) Determine volume to be controlled from storm (1.5 inch event for SA waters, 1 inch event for others)
Using the runoff volume -calculations per "Simple Method" as described by Schueler (1987):
where: Rv = runoff coefficient = storm runoff (inches) / storm rainfall (inches)
= Percent Impervious = Drainage area (acres) / Impervious portion of the drainage area (acres)
Rv = 0.05 + 0.009(I)
Rv = 0.05 + 0.009 * 12.2 = 0.160 (in/in)
Volume to be controlled from the design storm event:
where'. Design rainfall
Rv
Drainage Area
- 1.5 (in)
0.160 (in/in)
= 0.09 (acres)
Volume required (cf) = rainfall (in) x Rv (inlin) x Drainage Area (acre) x 1/12(feetlinches) x 43560 (sflacre)
Vreq'd = 1.5 * 0.160 * 0.09 * 1112 * 43560 = 78 cubic feet

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale .
Determine the volume of the proposed pond/swale:
POND GEOMETRY
Proj No.700-19
11/18/02
infiltswale-42.xis
2of4
Comments
Contour Contour
Elevation Area
(msI) (sf)
Incremental Storage
(cf)
Bottom Elevation
8.25 94
64
8.5 415
154
Storage Elevation
8.75 813
total Volume of Pond/Swale = 217 cubic feet
(Compare volume proposed to volume required from the design storm event:
217 cf > Vreq'd ' = 78 cf
(OK -proposed basin volume is greater than minimum required volume)

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
Proj No.700-19
11 /18/02
infiltswale-#2.xls
3of4
13) Check pond infiltration rate for capacity to control the 25 year-24 hour storm event with no discharge
The average weighted coefficient of runoff is determined by:
C ave = Sum[CA ] 1 Sum[A]
Description AREA C CA
Impervious Area 0.01(}!95 0.01
Pervious Area 0.08 ??0'30 0.024
Sum A = 0.09 Sum CA = 0.034
C ave = 0.034 / 0.09 = 0.379
Determine required discharge from 25 year-24 hour storm event:
Q regd = Cavg x I x A
Q regd = 0.38 * 0.33 0.09 = 0.01 cfs
where: I = intensity for 25 year-24 hour storm event from Chart E-6 = i' {:d0r33 in/hr
A = drainage area = = 0.09 acres
Cavg = weighted coefficient of runoff = 0.38
Check available rate of infiltration provided by proposed swale:
where: I = infiltration rate of soil (4 to 12 in/hr per Soils Report) Use: _ ;'. 6 in/hr
A = bottom area of swale = = 1959 sf
Qavail = lA = 6 in/hr 1959 sf * 1 ft/12 in * 1 hr/3600sec = 0.27 cfs
7pare rate of infiltration with runoff rate from the 25 year storm event:
ail = 0.27 cf > Q regd = 0.01 cf
(OK -No Discharge for 25 yr-24 hr storm event)

INFILTRATION BASIN - Schueler Method
Design Calculations for The Gauntlet Clubhouse Tennis Court Site,
High Density Area, Infiltration Swale
Proj No.700-19
11 /18/02
infltswale-#2.xls
4of4
C) Check the 10 year-10 minute storm event to confirm that basin has capacity without flushing system
where: I = intensity for 10 year-10 minute storm event from Chart E-6 =, t� .fi`3 in/hr
A = drainage area = = 0.09 acres
Cavg = weighted coefficient of runoff = 0.38
Determine discharge rate from 10 year-10 minute storm event:
Q 10-yr = Cavg x i x A
Q 10-yr = 0.38 ' 6.3 * 0.09 - 0.22 cfs
Determine discharge volume from 10 year-10 minute storm event:
V 10-yr = Q 10-yr * 10 min. duration * 60 sec/min. = 129 cf
Check available volume of the proposed infiltration basin:
V avail = design volume (from geometry table) - 217 cf
Compare design volume of infiltration basin to discharge volume from 10 year storm event of 10 minute duration:
Vavail = 217 cfs > V 10-yr = 129 cfs
(OK -basin has adequate capacity for 10-yr event without flushing)
Compare infiltration system drawdown time to maximum drawdown period of 5 days
T = V reqd 1 Q avail * 1 hrl 3600 sec
T = 78 cf 1 0.27 cfs 1 hr/ 3600 sec - 0.08 hours
(OK -,system draws down in less than 5 days)

SEDIMENT STORAGE CALCULATIONS
DISTURBED AREA #1 CALCULATIONS
(30,492 CF)(0.5)(1/12) = 1,270 CF
INFILTRATION SWALE #1 DATA:
(FOR TEMP. SEDIMENT TRAP)
CONTOUR
ELEVATION
(MSL)
CONTOUR
AREA
(SF)
INCREMENTAL
STORAGE
(CF)
BOTTOM EL.
8.25
3502
'040
8,50
4815
1425
STORAGE EL.
8.75
6587
STORAGE
PROVIDED
STORAGE
i REQUIRED
i2465 CF
% 1270 CF
DISTURBED AREA #2 CALCULATIONS
(3,920 CF)(0.5)(1/12) = 163 CF
INFILTRATION SWALE #2 DATA: (FOR TEMP. SEDIMENT TRAP)
CONTOUR
ELEVATION
(MSL)
CONTOUR
AREA
(SF)
INCREMENTAL
STORAGE
(CF)
BOTTOM EL.
8.25
94
64
8.50
415
154
STORAGE EL,
8.75
813
STORAGE
PROVIDED
STORAGE
i REQUIRED
217 CF
> 163 CF

Erosion and Sedimentation Control
1.01 General: The contractor shall be responsible for erosion and sedimentation
control within the construction limits; for prevention of sediment laden runoff Ieaving the
construction limits or entering ditches, streams or water impoundments; and for
implementation of necessary erosion and sedimentation control measures to meet the
requirements of the North Carolina Department of Environment, Health, and Natural
Resources. The Contractor shall also be responsible for all damages or fines resulting
from erosion or sediment laden runoff in the execution of his contract.
1.02 Construction Sequence: While the use of erosion and sedimentation control
devices is especially important on areas of steep topography, easily erodible soils and
sites in close proximity to water courses throughout the construction period, the control
measures should be installed prior to the commencement of land clearing and shall be
fully maintained and periodically inspected until final restoration and stabilization is
completed. Unrestored cleared areas shall be kept to a minimum. Disturbed areas
ahead of construction shall only be accomplished on those segments for the shortest
practical distance as required for continual progress.
Final restoration shall not be delayed until completion of the project but will be carried
out in phases as the work proceeds. Under no circumstances will any areas be left
denuded for more than (30) thirty calendar days without some form of stabilization until
final restoration is complete.
1.03 Sedimentation: Control Measures: The following are some of the sediment
control devices or measures that may be required to prevent sedimentation of streams,
water courses, or drainage structures:
I . Earth berms and/or diversion and intercept ditches.
2. Sediment traps
3. Filter berms
4. Filter inlets
5. Silt fences - not to be.placed in streams or ditches perpendicular to flow.
6. Check dams gravel filter
7. Gravel construction exit
1.03.1 Erosion Control Measures: Some of the soil erosion control measures which
may be required in this contract are:
I . Earth slope protection
2. Diagonal water break diversion berms
3. Diversion channels
4. Preservation of existing vegetation
Storm inlet protection

6. Stream crossings
7. Energy dissipators
8. Matting of re -seeded areas
1.03.2 Detail Drawing: Examples of sedimentation and erosion control details are
shown in these plans for installation at locations designated in the plans or as otherwise
required by the regulating agency, or the owner as work proceeds.
1.04 Stream Protection Where construction activities are necessary in close proximity
to streams, and other waterways, they shall be performed in a manner that does not
contribute to degradation of or blockage of the stream -flow. In order to prevent possible
degradation or blockages, the contractor shall be required to:
1. Keep all construction debris, excavated materials, brush, rocks, refuse and topsoil
as far from these waterways as possible. Restrict machinery operation or stream
crossings in waterways to the extent necessary for construction of utilities crossings.
2. If construction work areas are necessary in a waterway, they shall be protected as
indicated on the plans.
3. If temporary roadways are essential for the construction activities, they shall be
constructed of soils which are not highly erodible materials and must not span more than
half way across the water course or wetland area at any one time unless otherwise
approved by the Engineer. These temporary roadways shall be entirely removed as soon
as their requirement is met. Work in these areas shall follow the requirements of the
Corp of Engineers or CAMA permit, or plans as applicable.
1.05 Construction Access: The travel of equipment to and from the construction areas
shall be minimized not only to protect areas that will not be denuded, but also to prevent
the spreading of sediment within and outside of the construction areas. Therefore, special
construction equipment travel corridors will be established for this use and instructions
shall be issued for their use. Use of these corridors must be fully enforced. Other non-
essential traffic will be restricted or discouraged. Indiscriminate and convenience traffic
shall not be allowed.
1.06 Stockpile/Barrow Areas: The Contractor shall be responsible for selecting,
obtaining and maintaining stockpile or borrow areas which he may require to complete
the contract. He is also required to design and incorporate all necessary sediment and
erosion controls measures necessary to prevent erosion and contribution of sediment to
adjacent areas. The Contractor is responsible to obtain all necessary permits or approvals
for borrow or spoil areas outside the construction limits.
1.07 Disposal of Excess Water From Excavations: The Contractor shall practice
management of excess water pumped from excavation to reduce the production and
spreading of sediment. Pumped water shall be discharged onto stabilized surfaces and
allowed to filter through existing vegetation if possible, otherwise, additional control

measures may be necessary. If ditches are required to remove pumped water from
construction excavations, they shall be given the same consideration as any other man-
made waterway and they shall be stabilized as to not degrade and produce sediment.
1.08 Excavation and Backfill: Excavation shall be closely controlled and all the
material removed from the excavation shall be selectively stockpiled in areas where a
minimum of sediment will be generated and where other damage will not result from the
piled material. Drainage ways shall be protected at all times and the placement of
material in Drainage ways for convenience shall not be allowed. Backfilling operations
shall be performed in such a manner that remaining trees are not damaged.
1.09 Final Grading and Seeding: Finish grading, topsoiling, seeding and/or sodding
shall be performed after the construction phase is complete. Permanent vegetation of the
areas, that have been disturbed, shall be re-established as rapidly as possible. If the
completion of the construction activities do not coincide with a season in which
permanent vegetation can be generated, an interim or temporary program is required.
This shall include soil conditioners and mulching as necessary for soil stabilization. In
any case, sediment and erosion controls shall be installed promptly and their maintenance
assured.
1.10 Approval: The approved Erosion Control Plan will be provided by the Owner.
Any standard conditions relating to soil erosion and sediment control issued to the
Contractor as a part of any permits shall be available at the job site at all times.

Project Name: GQu,1 &42 2 S JP earns &-A-f 5 Location: 5?'-T10 - &-Ull SWIi::
2.
DIVISION OF WATER QUALITY
INFILTRATION SYSTEM INVESTIGATION
The minimum bore depth
Existing ground elevation:
Proposed Bottom elevation
Add 2'
Depth:
The type of soil:
75
9.25
2.25
+2
J,75
+2 +2 +2
/, Z5 _
Leon
3. The expected infiltration rate:
GC 11 - 2011
4. The depth to the Seasonal High Water Table: 5. Additional comments:: kepy 2 10!1 of lb,(J-`olI 's b2C16fC
,�i.
Signature of Regional Office Personnel:
Linda Lewis, DWQ
Permit Application No.
S:\WQS\STORMWATTORMS\fNFfNVST.FOR
Vincent Lewis; Soil Scientist
Date