SW6211101_Plansheet C15 - Notes_20211130

PROJECT INFORMATION:
PROJECT LOCATED IN PHASE II AREA
RIVER BASIN. CAPE FEAR
WATERSHED DISTRICT: NA
FLOOD ZONE: MINIMAL FLOOD RISKAS PER DFIRM 37085 C PANEL 9588
WETLANDS: DELINEATED BY HAL OWEN & ASSOCIATES (2-9-2021) AS SHOW IN PLANS. WETLANDS
WON'T BE DISTURBED.
SOILS: SHOWN IN SHEET C13
THE SITE IS MOSTLY WOODLANDS.
11-10-2021
PROJECT IS LOW DENSITY. STORMWATER WILL BE MANAGED BY CONVEYANCE SWALES ALONG THE
ROADS AND DISPERSED FLOW IN THE LOTS.
TWO DRY PONDS WILL BE INSTALLED TO REDUCE THE POST -DEVELOPMENT FLOW
IN ACCORDANCE WITH TITLE 15 NCAC 2H.1000 AND S.L. 2006-246, THE STORMWATER MANAGEMENT
REGULATIONS, DEED RESTRICTIONS AND PROTECTIVE COVENANTS ARE REQUIRED FOR LOW DENSITY
RESIDENTIAL SUBDIVISIONS WHERE LOTS WILL BE SUBDIVIDED AND SOLD. DEED RESTRICTIONS AND
PROTECTIVE COVENANTS ARE NECESSARY TO ENSURE THAT THE DEVELOPMENT MAINTAINS A
"BUILT -UPON" AREA CONSISTENT WITH THE APPLICABLE REGULATION GOVERNING THE DENSITY
LEVEL.
Conveyance Swale Design Information based on th 10 yr-storm -Mason Ridge
Swale
No.
Drainage
Area ac
Impervious
Area ac
Pervious
Area (ac)
C
Q (cfs)
Slope (%)
V allow
(f s
Vactual
(fps)
Flow Depth
ft
Type
Side Slope
Bottom
Width (ft)
Freeboard
Top Width
(ft
Liner
1
0.27
0.08
0.19
0.39
0.84
4.7
4.5
1.26
0.5
TRI
4:1
0
0.5
8.00
Straw with Net
2
1.42
0.15
1.27
0.23
3.34
5.50
4.50
2.31
0.65
TRI
4:1
0
0.5
9.20
NC Green C125
3
0.20
0.05
0.15
0.35
0.55
5.50
4.50
0.971
0.50
TRI
4:1
0
0.5
8.00
Straw with Net
4
0.74
0.29
0.45
0.46
2.69
5.00
4.50
1.80
0.70
TRI
4:1
0
0.5
9.50
NC Green C125
5
0.32
0.08
0.24
0.35
0.88
4.70
4.50
1.26
0.50
TRI
4:1
0
0.5
8.00
NC Green C125
6
0.88
0.31
0.57
0.43
2.98
5.60
4.50
2.21
0.60
TRI
4:1
0
0.5
8.80
NC Green C125
7
0.75
0.28
0.47
0.45
2.64
5.60
4.50
2.21
0.60
TRI
4:1
0
0.5
8.80
NC Green C125
8
0.21
0.07
0.14
0.42
0.69
1.00
4.50
0.47
0.75
TRI
4:1
0
0.5
10.00
Straw with Net
9
1.68
OAS
1.23
0.36
4.80
4.90
4.50
2.68
0.70
TRI
4:1
0
0.5
9.60
NC Green C125
10
0.46
0.10
0.36
0.32
1.17
4.90
4.50
1.28
0.50
TRI
4:1
0
0.5
8.00
Straw with Net
11
5.65
1.50
4.15
0.36
16.07
2.431
4.50
2.94
1.20
TRI
4:1
0
0.5
13.60
NC Green C125
121
2.07
0.521
1.55
0.35
5.70
3.60
4.50
2.51
0.80
TRI
4:1
0
0.5
10.40
NC Green C125
13
0.31
0.10
0.21
0.41
0.99
3.60
4.50
1.03
0.60
TRI
4:1
0
0.5
8.80
NC Green C125
14
1.77
0.17
1.60
0.301
4.17
3.20
4.50
0.96
0.60
TRI
4:1
1 0
1 0.5
6.60
INC Green C125
15
1.94
0.79
1.15
0.48
7.25
1.00
4.50
1.46
1.20
TRI
4:1
0
1 0.5
1 13.60
NC Green C125
16
0.51
0.05
0.46
0.30
1.20
1.90
4.50
0.901
0.60
TRI
4:1
0
1 0.5
1 8.80
NC Green C125
PROVIDE O.S' FREEBOARD MINIMUM. TOP WIDTH IS AT FREEBOARD
USE BERMUDA GRASS OR EQUAL
TYPICAL TRIANGULAR SWALE
1 "=20'
SEE TABLE AT TOP OF THIS PAGE FOR DIMENSIONS AND LINER
0.5' FREEBOARD
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MASON RIDGE SUBDIVISION - BUILT UPON AREA
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Total Property Area = 35 AC 1,524,600 SF
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Area below NHWL= 1.49 Ac 64,904 SF
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Total Project Area (TPA) = 33.51 Ac 1,459,696 SF
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Exist. Asphalt (EBUA)= 0 AC - SF
DESCRIPTION
NO. LOTS
BUA (sf)
TOTAL BUA
sf
Proposed Roads Asphalt
92300
92,300
Proposed Lots BUA
51
50001
255,000
Mail sidewalk -kiosk
1,000
TOTAL BUA 348,300
15A NCAC 2H .1003(1): CALCULATION OF PROJECT DENSITY.
(b) A project with existing development may use the calculation method in Sub- Item (1)(a) or shall have
(1) TBUA - EBUA 348,300 - 348,300 sf
(2) TPA-EBUA = 1,459,696 - 1,459,696 sf
PROJECT
DENSITY = (1) / (2) 23.86%
Since the density is less than 24% it is a Low Density Project
BUA INCLUDES (IMPERVIOUS SURFACE AND PARTIALLY IMPERVIOUS
SURFACE TO THE EXTENT THAT THE PARTIALLY IMPERVIOUS
SURFACE DOES NOT ALLOW WATER TO INFILTRATE THROUGH THE
SURFACE AND INTO THE SUBSOIL: BUILDINGS, SIDEWALKS,
DRIVEWAYS.
"Built -upon area" does not include:
- a slatted deck;
- the water area of a swimming pool;
- a surface of number 57 stone, as designated by the American
Society for Testing and Materials, laid at least four inches thick over
a geotextile fabric;
- a trail as defined in G.S. 113A-85 that is either unpaved or paved
as long as the pavement is porous with a hydraulic conductivity
greater than 0.001 centimeters per second (1.41 inches per hour); or
- landscaping material, including, but not limited to, gravel, mulch,
sand, and vegetation, placed on areas that receive pedestrian or
bicycle traffic or on portions of driveways and parking areas that will
not be compacted by the weight of a vehicle, such aS THE AREA
BETWEEN SECTIONS OF PAVEMENT THAT SUPPORT THE
WEIGHT OF A VEHICLE.
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THE GRASS SPECIES IN THE SWALE SHALL BE:
(A) NON -CLUMPING AND DEEP-ROOTED BERMUDA OR TALL FESCUE;
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BOTTOM WIDTH
(B) ABLE TO WITHSTAND A VELOCITY OF FOUR FEET PER SECOND,
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(C) MANAGED AT AN AVERAGE OF SIX INCHES; AND
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(D) NOT BE CUT LOWER THAN FOUR INCHES.
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TYPICAL TRAPEZOIDAL SWALE
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(E) GRASS NEEDS TO BE WATERED FREQUENTLY FOR THE FIRST
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1 "=20'
THREE WEEKS AFTER PLANTING.
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(F) IF GRASS IS NOT IN GOOD CONDITION, SOD WILL BE REQUIRED.
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C15
FOR AGENCY REVI EW 11 - 10-2021
FILE:
CP-202101-MASON RIDGE