SWA000058_C407-BMP WETPOND PLAN_10/23/2019

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PERMANENT CHANNEL
\4' WIDE BOTTOM _
'-2.1 SIDE SLOPES \
DAM ELEV. = 889.0
\D50 = 12" RIPRAP
SON FABRIC 885
- 56LF 42"0 RCP 0 1.00% n-
"*,W/ 0-RING GASKETS 880
42
" 875,
NV OUT = 875.00 EXISTING
PROPOSED RIP RAP DISSIPATOR
La=23', W=26.5', D5o=12"
EROSION TOP ELEV. = 889.00
CONTROL
MATTING 17' WIDE EMERGENCY OVERFLOW WEIR
ON SLOPE ELEV. = 887.50
6' PLANTING SHELF
TOP OF SHELF
ELEV. = 884.00 `-'7
BOT. OF SHELF
ELEV. = 883.00
6' PLANTING SHELF 6' PLANTING SHELF
PERM ELEV = 883.50 77
SANITARY SEWER /
MANHOLE le,
-
FOREBAYS TO BE INSTALLED WHEN --\
CONTRACTOR IS RELEASED TO REMOVE '
EROSION CONTROL MEASURES.
WET POND PLAN VIEW
SCALE: 1 " = 30'
SCALE IN FEET
0 30 60
EXISTING CONTOUR INTERVAL: 2'-0"
PROPOSED CONTOUR INTERVAL: 1'-0"
6" SEDIMENT STORAGE J
INV. ELEV. = 878.50
BOTTOM OF BASIN-
INV. ELEV. = 878.00
TOP OF SHELF 1 6:1
ELEV = 884.0 BOTTOM OF SHELF
BOTTOM ELEV ELEV = 883.0
6" SEDIMENT STORAGE INV. = 878.5 = 878.0
WET DETENTION POND SECTION (WIDTH)
NOT TO SCALE
6' X 6' PRECAST -
CONCRETE BOX
TOP ELEV. = 886.50
VALVE STEM
TOP ELEV. = 887.00
6" WATER QUALITY TEE W/
4"0 ORIFICE INV = 883.50
001 FI FV = RR-isn 7-7
TOP WIDTH 10'
TOP OF DAM ELEV. = 889.0
1/4 / FOOT
12" INLET W/ TRASH RACK
INV. = 878.00
(FOR POOL DRAINING/MAINTENANCE)
VALVE TO REMAIN SHUT
GRAVEL BEDDING UNDER DRAIN PIPE
SEE OUTLET CONTROL STRUCTURE DETAIL THIS SHEET
UNDERCUT EXISTING GRADE - MIN 1'
42"0 RCP WITH 0-RING GASKETS
910- \
5ED RIP RAP DISSIPATOR
W=38.5', D50=12"
0
i
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Sg0
----
)0='rEXIST/NG TOP OF Of %
BANK
EXISTING STREAM /
FOREBAY WEIR TOP ELEV. = 889.00
ELEV. = 883.00
FOREBAY DAM
ELEV. = 884.00 RIP RAP SPILLWAY SECTION ON FILTER FABRIC
DAM WIDTH VARIES SEE PLAN 1
( ) 6' PLANTING SHELF
12" DUCTILE IRON DRAIN PIPE
W/ 12" M.J GATE VALVE & BOX
INV IN = 878.50
INV OUT = 878.00
(NORMALLY CLOSED)
WET DETENTION POND SECTION (LENGTH)
NOT TO SCALE
9"
72" BOX
1" STAINLESS STEEL
BOLTS W/ STAINLESS
STEEL NUTS (- REQ'D)
ANCHORING
NOT TO SCALE
CONTRACTOR MAY FLATTEN -OUT
DAM SECTION WITH EXCESS
MATERIAL WHERE FEASIBLE
BACKFILL OF CORE AREA AROUND
BARREL TO INCLUDE CLAY MATERIAL
APPROVED BY GEOTECH ENGINEER
EROSION CONTROL MATTING
ON BACKSLOPE OF DAM
25.E
/-EXISTING GRADE
(2) 7.5' x 7.5' x 1.5'
THICK
/
CONCRETE ANTI -SEEP
COLLARS REQ'D
KEYWAY 10'
KEYWAY DEPTH
VARIES
MIN
2' TO 20' FIELD
VERIFY
WET
POND 1 DAM
SECTION
NOT TO SCALE
TOP OF SHELF
1 ELEV. = 884.00
VBOT. OF SHELF
ELEV. = 883.00
FOREBAY BOTTOM
ELEV. = 878.50
NOTES:
1. CONTRACTOR TO POST A CONSPICUOUS SIGN STATING WHO IS
RESPONSIBLE FOR THE REQUIRED MAINTENANCE AND ANNUAL
INSPECTION OF THE WET DETENTION POND.
2. WET DETENTION PONDS USED AS SEDIMENT BASINS DURING THE
CONSTRUCTION PERIOD TO BE FULLY CLEANED OUT PRIOR TO USE
AS A STORM WATER MANAGEMENT FACILITY
3. CONTRACTOR TO RIP/SCARIFY WET POND INVERT AND RE -COMPACT
TO 100% STANDARD PROCTOR AFTER SEDIMENT REMOVAL AND PRIOR
TO ESTABLISHING THE PERMANENT WET POND.
4. CONTRACTOR SHALL PROVIDE AS -BUILT SURVEY PERFORMED BY A
NC LICENSED SURVEYOR UPON COMPLETION OF WET POND. SURVEY
TO BE PROVIDED TO & REVIEWED BY CIVIL ENGINEER IN ORDER TO
PROVIDE CERTIFICATION OF THE STORMWATER MANAGEMENT FACILITY.
CIVIL ENGINEER WILL SUBMIT PROJECT CERTIFICATION TO THE TOWN
UPON FINDING PROJECT IS IN CONFORMANCE WITH THE DESIGN
PLANS. CONTRACTOR WILL NOT BE ABLE TO RECEIVE FINAL
CERTIFICATE OF OCCUPANCY FOR THE BUILDING UNTIL THE
STORMWATER MANAGEMENT FACILITY IS CERTIFIED.
5. ALL DISTURBED AREA SHALL RECEIVE PERMANENT SEEDING/GRASSING.
FIBERGLASS TRASH RACK TO BE
APPROVED BY ENGINEER
WELD BRACE TO 2" X 2"-\
ANGLE IRON AT BOX
1/2" VALVE STEM
W/ T-BAR HANDLE
THREADED CLEANOUT
CAP IN TOP
WQV ELEV. 7-7
885.20
6" WATER QUALITY TEE
W/ 4"0 ORIFICE
PERMANENT POOL
ELEV. 883.50
CAST IRON VALVE
BOX TO GRADE
EXTENDED TO DAYLIGHT
AT ELEVATION 878.00
DURING CONSTRUCTION
PHASE, ATTACH SKIMMER
TO END OF 12" PIPE
1' MIN.
HENRY RIVER OVERLAY DISTRICT STANDARDS:
WET POND DESIGN PARAMETERS
• TREAT FIRST 1" OF RUNOFF AND CONTROL 10-YEAR STORM
STORM DRAINAGE
-25 YR 24-HR STORM EVENT FOR ENTIRE
TO PRE-EXISTING CONDITIONS
SYSTEM
LUTETIUM CIRCLE & LOTS W2 & W3
• PROVIDE WATER QUALITY MEASURES FOR DEVELOPMENT
WET POND
-TREAT 1ST 1" OF RAINFALL
EXCEEDING 12% IMPERVIOUS COVERAGE
• 85% TSS REMOVAL REQUIRED
-WQV= 60,575 FT3 (REQUIRED)
ANTI -VORTEX
MAINTAIN 30' UNDISTURBED BUFFER AND 20' ADDITIONAL
-WQv= 60,921 FT3 (PROVIDED)
INSTALLATION OF TRASH
GRASSED BUFFER ALONG WATERWAYS
OUTLET STRUCTURE
-DESIGNED TO CONTROL THE 2 &
RACK MAY BE DONE
NOTES.
10YR 24-HOUR STORM EVENTS FROM
DURING POND CONVERSION
PRE -DEVELOPMENT RATES
1. SEE SHEET C001 FOR GENERAL NOTES.
cc
6" X 48" WIDE
WEIR WINDOW -
EMERGENCY SPILLWAY
-DESIGNED TO CONTROL THE 100-YR
O
TYP. EACH SIDE
2. CONTRACTOR SHALL REFER TO OTHER PLANS WITHIN
24-HOUR STORM EVENT WITH 1 FT OF
U
z
OF BOX
THIS DRAWING SET FOR OTHER PERTINENT
FREEBOARD BELOW TOP OF DAM.
LU
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INFORMATION. IT IS NOT THE ENGINEER'S INTENT
a
RISER ELEV. THAT ANY SINGLE PLAN SHEET IN THIS SET OF
Z
886.50
DOCUMENTS FULLY DEPICT ALL WORK ASSOCIATED
O
w
WIER ELEV.
885 50
WITH THE PROJECT.
N
-
o
STEPS ON OUTSIDE OF
STRUCTURE STARTING AT
PERMANENT POND TO
TOP (16" O.C.)
SEE PLAN VIEW FOR
LOCATION
TEE ELEV. 883.50
6' X 6' 6 X 6 CONCRETL
CLEAR INSIDE PRECAST BOX
12" GATE
VALVE
12" PVC C900
CLASS 200 0
1.0% MIN
INV IN = 878.50
1' GROUT
FILLED
INVERT, SLOPED
TO
DRAIN TO
OUTLET
42" RCP W/
0-RING
GASKETS 0
1.00%
INV. OUT =
878.00
4
�n
1" DIA. ANCHOR BOLTS a ° °
3" MIN � ^
6" MIN. WASHED STONE 8' X 8'
OR OTHER SUITABLE MATERIAL
(4) #5 BARS EXTENDING zl CONCRETE BASE W/
THROUGH BOX NO. 4 BAR 0 12" O.C.
BOTH WAYS
OUTLET CONTROL STRUCTURE SECTION
NOT TO SCALE
EROSION
CONTROL
MATTING
ON SLOPE
ANTI -VORTEX -
PLATE
TRASH RACK
U- BOLT
OOL
#4 BAR012" O.0
BOTH WAYS
DETENTION EMP WETPOND SUMMARY CHART
PEAK CONTROL
STORM EVENTS
PRE-
DEVELOPMENT
RUNOFF
POST-
DEVELOPMENT
RUNOFF
POST
DEVELOPMENT
��EIPOND
OUTFLOW
ELEVATION
Top of Dam
889.00
100YR-24HR
183.67 CFS
247.72 CFS
200.57 CFS
1 887.92
50EYR-24HR
154.51 CFS
217.94 CFS
167.03 CFS
887.72
10YR-24HR
93.81 CFS
152.34 CFS
82.87 CFS
887.12
2YR-24HR
43.88 CFS
91.79 CFS
20.53 CFS
886.02
1YR-24HR
27.77 CFS
69.70 CFS
4.84 CFS
885.68
6" WATER QUALITY TEE
W/ 4"0 ORIFICE
TRASH RACK
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FOR DRAIN PIPE
0
U
N
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O
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7
ih
2'
EXTENDED 12" DRAIN-
3' CONCRETE PAD
PIPE TO DAYLIGHT AT
ELEV= 878.00
110
12"
GV
6' X 6'
CLEAR INSIDE
8'
00 J
OUTLET CONTROL STRUCTURE PLAN
NOT TO SCALE
ANTI -VORTEX
1 /2" X 6" X 3"
#4 BAR
0 6" O.0
FIBERGLASS
TRASH RACK TO
BE APPROVED
BY ENGINEER
12" PVC
FIBERGLASS TRASH RACK BE DONE DURING POND CONVERSION
NOT TO SCALE
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ch
#4 BAR -
012" O.0
BOTH WAYS
6' X 6'
CLEAR INSIDE
PRECAST BOX
OPEN TOP
W/ TRASH RACK
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STEPS ON OUTSIDE OF
STRUCTURE STARTING
AT PERMANENT POND
TO TOP (16" O.C)
SEE DETAIL
THIS SHEET
FOR BOX
ANCHORING
TO PAD
CONCRETE BASE
8' X 8'
SECTION B-B
SECTION A -A OUTLET CONTROL STRUCTURE FOUNDATION
PLANT INDEX
Notes
SCARLET ROSE MALLOW -
HIBISCUS COCCINEUS
1. THE VEGETATED SHELF SHALL BE
PLANTED WITH A MINIMUM OF
THREE DIVERSE SPECIES OF
40
HERBACEOUS, NATIVE VEGETATION
STARRUSH WHITETOP -
RHYNCHOSPORA COLORATA
wff
AT A MINIMUM DENSITY OF 50
PLANTS PER 200 SQUARE FEET
OF SHELF AREA.
GREAT BLUE LOBELIA -
LOBELIA SIPHILITICA
DWARF JOE PYE WEED -
EUPATORIADELPHUS DUBIUS
TYPICAL
PLANTING PLAN FOR
200SF
OF VEGETATED SHELF
NOT TO SCALE
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C407
NORTH CAROLINA BOARD OF EXAMINERS FOR
SHEET 20 OF 39
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