SW4191202_17-042_C1.8 POND_1/2/2020

l©
1 2 3 4 5
�%%ice••: S%%%�a,�
i/I� :�/•�-elf/••
OWN-
�� •
NV OUT=8 6.86 9
i�
%
\\ N
8 9. 0
- 6.�� A R L )
i
OUT=80 . 3
o
\ \
o
\INV C1�T
8800
'
\
`nn �
A
H 2
1
I
p
i
/ STM 9
RIM=2681.
\
\ \ a
\
i i
� � � 2
8"
E
INV IN=815.00 (10)
\
-"
INV IN=814.62 (
fl)
INV OUT=812.68
STONE
/ BAFFLE
STM 3 �
/
-
RIM=812.00
T
INV IN=806.48 (4)
( INV IN=806.30 (2)
INV IN=804.48 (5)
>
INV OUT=804.71 ()_
STORM POND PLAN
SCALE: 1'=20'
P►1•I���IC�I•Nhi
1 1/2" VENT WITH GREEN TIP
2 1 /2" PVC FLOAT
1 1/2" SCH. 40 SOLID PVC BARREL
OR "ARM" SUPPLIED BY USER
.,n^l 1 In
ALUMINUM STRAPS
SUSPENDING INLET
'29'_
2 1/2" INLET EXTENSION- `CENTER OF INLET
1 1/2" HOSE, SS CLAMPS AND ORIFICE
2" THREADED MALE PATENT #5,820,751
NIPPLE ON OUTLET END 2 1/2" FAIRCLOTH
SKIMMER DETAIL
NOT TO SCALE
100 YR. FLOOD STAGE 815.36
EL. 814.75
10 YR. FLOOD STAGE 814.74
EL. 813.75
2 YR. FLOOD STAGE 813.97 RISER - SEE DETAIL
6' 1 YR. FLOOD STAGE 813.80 EL. 812.
6' VEG. SHELF (10H/1 V) 00 10' 6'
T/SHELF 812.50 SHELF TE P B FF ES TO RE
CONSTRUCT DAM WITH IMPERMEABLE
SOILS. COMPACTED TO 98% STD.
PROCTOR DENSITY W/ A MOISTURE
CONTENT OF -1% TO +3% OF
OPTIMUM. SOILS SHALL BE UNIFORM
IN CHARACTER & INSTALLED IN 8"
MAXIMUM LIFTS. SOILS SHALL BE
FREE OF ORGANICS & PARTICLES OF
2" OR GREATER.
B/SHELF 811.50
MA L MAIN IN
PLACE DURING CONSTRUCTIONFOREBAY
EL. 808.00
MIN.
SHELF
SEEPLAN
F�ql_.
1
INSTALL AFTER ALL AREAS DRAININGEL.
807.00
816.50
INTO POND ARE STABILIZED
-
V_
-
-
-
-
FLOODWATER STAGE
-
- -
1 EMER .
SPILLWAY 3 MAX.SLOPE
TEMP. W.Q. STORAGE
- -
2
_ _
_
EL. 814.75
3 �
1 1 /8"x6' SQ. ALUM. PL
1 FOREBAY
1'
4' 2
2
PERM. W.Q. STORAGE
10, OC
I--
INV. OUT EL. 806.70
3'
3'
6.5
RIPRAP OUTLET FROM PIPE
PER
. SEDIMENT STORAGE
TO BOTTOM OF POND
1
NOTE - VOLUME BELOW TO DRAIN PIPE
NCDOT CLASS B STONE,
0
IS TO BE PUMPED OUT AT TIME OF 1' THK. NCDOT
INSTALL DURING TRANSITION
a
(4) ANTI -SEEP PLATES AT
CLEANING OR DURING MAINTENANCE. #57 STONE SHWT 1
FROM SED. BASIN TO WET
INV. 808.00
2'
2'
FLANGE JOINTS WITH
803.0
DETENTION POND
70 LF 12"b
2 NEOPRENE GASKETS
(1 FOR EACH SIDE) TO
THE SOIL IN THE POND BOTTOM WILL BE EVALUATED TO DETERMINE
WHETHER A LINER IS REQUIRED. THE PERMANENT POOL ELEVATION
TEMP. FAIRCLOTH SKIMMER,
CAP ®1.00%
ENSURE WATERTIGHT
MUST BE MAINTAINED AT THE PROPOSED PERMANENT POOL ELEVATION
ATTACH TO 8" 0 DRAIN
V
SEAL.
TO INSURE THE SURVIVAL OF THE PLANTS ON THE VEGETATED SHELF.
(TO BE REMOVED ON TRANSITION
SHWT 2
CUT-OFF TRENCH
IF A LINER IS USED. A LINER SHALL BE CONSTRUCTED OR COMPACTED
SUCH THAT THE INFILTRATION RATE IS NO MORE THAN 0.01 IN./HR.. TOP
TO PERMANENT POND AND VALVE
800.0
ACKFILL W/IMPERMEABLE
CLOSED OFF)
SOIL FOR VEGETATION MUST BE PLACED ON TOP OF LINER.
SOILS COMPACTED
TO
95% STD. PROCTOR
DENSITY
WET DETENTION
POND / SEDIMENT BASIN
-NOTE-
DETAIL
TEMPORARY SEDIMENT BASIN SHALL BE COMPLETELY CLEANED OF SEDIMENT
AND UPGRADED TO FUNC11ON AS PERMANENT DETENTION POND AFTER ALL PERMANENT
NO SCALE
EROSION CONTROL METHODS ARE ESTABLISHED AS INDICATED ON FINAL SIIEWORK
PACKAGE DRAWINGS.
EL. 814.75
�1
3
PROFILE EMERGENCY SPILLWAY
12'
EL. 816.50 3
�1
814.75
SECTION - EMERGENCY SPILLWAY CREST
EMERGENCY SPILLWAY
(100 YEAR DESIGN STORM)
DETAIL
NO SCALE
FLOODWATER STORAGE
TOP OF RISER
EL. 813.75
0
N
NORMAL POND LEVEL EL. 812.00
SUPPORT
TEMP. FAIRCLOTH SKIMMER, BRACKET,
ATTACH TO 8" 0 DRAIN SEE DETAIL
TO BE REMOVED ON TRANSITION
POND 0 PERMANENT POND AND VALVE
OSED OFF
N V. 808.0
B STONE
8" 0 DRAIN
24"
CAP
ALUM. EXPANDED
METAL TRASH
GUARD TOP
#4 ® 6" O.C. E.W.
2- 1 /8" THK. ANTI -VORTEX
ORIFICE, 1.0" 0
EL. 808.00 SEDIMENT LEVEL HELICAL ALUM.
14 GAGE PIPE
1.0'
a_
NV. 808.00 Q10=8.84 CFS 0
EL. 807.00 _ =IIIIII-III I EL. 806.00 FILL W CONC TO INV ELEV
WET DETENTION POND CALCULATIONS TOTAL DESIGN
PROPOSED FUTURE BUILT -UPON AVG. PERM. POND TEMP. W.Q. TEMP. W.Q. PERMANENT PERMANENT
POND DRAINAGE FUTURE TOTAL BUILT -UPON BUILT -UPON DRAINAGE W.Q. POND AREA AREA STORAGE STORAGE SEDIMENT SEDIMENT
No. AREA DRAINAGE AREA DRAINAGE AREA DRAINAGE AREA DRAINAGE AREA AREA STORAGE DEPTH SA/DA REQUIRED PROVIDED REQ'D. PROVIDED STORAGE REQUIRED STORAGE PROVIDED
1 3.38 AC.
0.00 AC. 3.38 AC. 2.49 AC. 0.00
AC. 2.49
AC. 3.35 FT (AVG.)
2.50
3681 SF
3808 SF 8748 CF 10925 CF
SKIMMER BASIN #1
CALCULATIONS
DIAMETER
DIAMETER
BASIN DRAINAGE
DISTURBED SURFACE AREA SURFACE AREA SED. STORAGE
SED. STORAGE
DESIGN
DEWATER
FAIRCLOTH
SKIMMER WEIR
No. AREA
AREA REQUIRED PROVIDED REQUIRED
PROVIDED
OUTLET FLOW (Q10)
TIME
SKIMMER
ORIFICE LENGTH
1 3.02 AC.
1.97 AC. 3480 SF 3800 SF 3546 CF
11424 CF
10" 10.71 CFS
3 DAYS
2.5"
2.0"0 24" RISER
I rl
�•I��1������
F
6
,b i
STORM POND LANDSCAPE PLAN
SCALE: 1'=20'
S
1
LFLANGE JOINTS WITH
3/8" NEOPRENE
GASKET
4' 3.5'x3.5'
FROM TOE OF DAM
ANCHOR INTO CONC.
NOTE - VOLUME BELOW 8"- DRAIN PIPE
IS TO BE PUMPED OUT AT TIME OF
CLEANING OR DURING MAINTENANCE. POND RISER
(10 YEAR DESIGN STORM)
(1 REQUIRED)
DETAIL
NO SCALE
FOREBAY
MAIN POOL VOLUME FOREBAY
VOLUME REQUIRED VOLUME W.Q. W.Q. RELEASE WEIR
(15-20%) PROVIDED OUTLET TIME RISER BARREL LENGTH
6" 12" 10977 CF 1647-2195 CF 2640 CF 1.0"o 3.66 DAYS 24"0 12"0 12'
ALUM. ALUM.
HIGH MARSH _874_ SF
Plant requirement = 50/200 sf. Plants provided 219
HERBACIOUS SCHEDULE
Scientific Name
Common Name
Size
uantit
Carex Tenera
Quill Sedge
1 qt
73
HERBACIOUS SCHEDULE
Scientific Name
Common Name
Size
uantit
Iris Virginica
Blue Flag Iris
1 qt
68
Juncus Effusus
Soft Rush
1 qt
69
Sagittaria Latifolia
Duck Potato
1 qt
69
DAM
6
SEDIMENT TRAP AND SEDIMENT BASIN MAINTENANCE NOTES
1. INSPECT TEMPORARY SEDIMENT TRAPS AND SEDIMENT BASINS AT LEAST WEEKLY AND AFTER EACH SIGNIFICANT
(c" OR GREATER) RAINFALL EVENT AND REPAIR IMMEDIATELY.
2. WHEN SEDIMENT REACHES ONE-HALF THE DESIGN DEPTH OF THE TRAP OR BASIN, REMOVE SEDIMENT AND
RESTORE TRAP OR BASIN TO ITS ORIGINAL DIMENSIONS. PLACE SEDIMENT THAT IS REMOVED IN A DESIGNATED
DISPOSAL AREA.
3. REPLACE ANY PART OF THE GRAVEL FACING THAT IS IMPAIRED BY SEDIMENT.
4. PERIODICALLY CHECK THE DEPTH OF THE SPILLWAY TO ENSURE IT IS A MINIMUM OF 1.5 FEET BELOW THE LOW
POINT OF THE EMBANKMENT.
5. IMMEDIATELY FILL ANY SETTLEMENT OF THE EMBANKMENT TO SLIGHTLY ABOVE DESIGN GRADE.
6. ANY RIP -RAP DISPLACED FROM THE SPILLWAY MUST BE REPLACED IMMEDIATELY.
STORMWATER NOTES
1. THE ENGINEER'S CERTIFICATION OF COMPLETION WILL BE REQUIRED PRIOR TO THE FINAL PLAT OF
CERTIFICATE OF OCCUPANCY. THE STORMWATER CONTROL IS TO BE INSPECTED TO ENSURE IT IS
FUNCTIONING AS DESIGNED AND HAS FULL DESIGN VOLUME PRIOR TO ISSUANCE OF THE FINAL
CERTIFICATE OF OCCUPANCY.
2. THE PROPERTY OWNER IS RESPONSIBLE FOR MAINTAINING THE STORMWATER CONTROL ACCORDING TO THE
APPROVED MAINTENANCE PLAN AND DIRECTION OF THE CITY OF MEBANE.
3. THE CITY OF MEBANE AND THEIR ASSIGNS HAVE RIGHT TO ACCESS THE STORMWATER CONTROL FOR
INSPECTIONS OR MAINTENANCE, AS NECESSARY.
4. ALL NECESSARY APPROVALS HAVE BEEN/WILL BE OBTAINED FROM THE STATE/CORPS FOR ANY WETLAND
DISTURBANCE, STREAM CROSSING/DISTURBANCE.
5. IN ACCORDANCE WITH GS-143-215.25A AND 143-215.26 OF THE NC DAM SAFETY LAW AND
ADMINISTRATIVE CODE 15A NCAC 2K.0200, THE STATE DAM SAFETY OFFICE HAS BEEN/WILL BE
CONTACTED FOR DETERMINATION OF THE HAZARD CLASSIFICATION OF THE PROPOSED DAM.
CONSTRUCTION SEQUENCE FOR WET POND
1. CLEAR AREA FOR POND AND POND DAM.
2. BEGIN CONSTRUCTION OF POND DAM BEGINNING WITH THE INSTALLATION OF THE DAM's CUT OFF TRENCH
AS SHOWN ON C2.1 OF THE APPROVED DRAWINGS.
3. CONTINUE WITH THE DAM CONSTRUCTION, AND INSTALL THE DAM's RISER AND BARREL KIT AND ANTI SEEP
PLATES AS THE GRADING PROGRESSES. COMPACT SOILS WITHIN DAM AND AROUND BARREL AS INDICATED
WITHIN THE POND DETAILS AND WET POND CONSTRUCTION NOTES.
4. INSTALL OUTLET STABILIZATION DEVICE AT THE POND BARREL OUTLET AS INDICATED ON THE PLANS AND
STABILIZE.
5. ONCE THE POND DAM IS CONSTRUCTED AND THE POND AREA HAS BEEN EXCAVATED AS INDICATED ON
THE PLANS, STABILIZE DISTURBED AREAS AND DAM FACE WITHIN 14 DAYS OF REACHING FINISHED GRADE.
6. SET UP POND AS A TEMPORARY SEDIMENT BASIN FOR EROSION CONTROL PURPOSES.
7. AS GRADING ON SITE PROGRESSES AND STORMDRAIN NETWORK IS INSTALLED, INSTALL THE REQUIRED
OUTLET STABILIZATION STRUCTURES WITHIN THE POND AS INDICATED ON THE PLANS.
8. ONCE BUILDING CONSTRUCTION IS COMPLETE AND ALL AREAS DRAINING TO POND HAVE BEEN STABILIZED
WITH PERMANENT VEGETATION, CLEAN OUT WET POND AND FINE GRADING MAKING SURE POND BOTTOM,
SHELF, AND DAM ARE AT THE ELEVATIONS AS INDICATED ON THE APPROVED DRAWINGS.
9. INSTALL STONE FOREBAY BAFFLE AND REMOVE E&SC BAFFLES FROM POND.
10. CLEAN ALL RIP RAP ENERGY DISSIPATERS INTO POND AND BELOW POND DAM OF ANY SEDIMENT,
REPLACING RIP RAP IF REQUIRED.
11. DISPOSE OF THE SEDIMENT REMOVED FROM THE POND BOTTOM WITHIN AN APPROVED LOCATION.
12. CLOSE 8" DRAIN VALVE AND REMOVE SKIMMER FROM POND.
13. PLANT VEGETATED SHELF AS REQUIRED.
14. ALLOW POND TO FILL TO NORMAL POOL ELEVATION FROM STORM RUNOFF.
WET DETENTION POND OPERATION & MAINTENANCE
A. THE FOLLOWING TASKS SHALL BE PERFORMED AFTER EVERY RUN-OFF PRODUCING RAINFALL EVENT, OR MONTHLY
AS A MINIMUM.
1. REMOVE DEBRIS FROM TRASH RACK.
2. CHECK/CLEAR OBSTRUCTIONS FROM ORIFICE OUTLET.
3. CHECK POND SIDE SLOPES AND DAM EMBANKMENT. REMOVE TRASH AND REPAIR ERODED AREAS.
4. CHECK SEDIMENT LEVELS BEHIND BAFFLES. REMOVE SEDIMENT WHEN DEPTH REACHES 1/2 BAFFLE HEIGHT.
B. THE FOLLOWING TASKS SHALL BE PERFORMED EVERY THREE MONTHS.
1. INSPECT STORMWATER COLLECTION SYSTEM (PIPING, STRUCTURES, SWALES) FOR PROPER OPERATION. REMOVE
TRASH, SEDIMENTS & OBSTRUCTIONS FROM SYSTEM.
2. INSPECT RIPRAP ENERGY DISSIPATORS FOR EROSION AND UNDERCUTTING. REPAIR AS REQUIRED.
3. REPAIR ERODED AREAS AND RESEED BARE SPOTS THROUGHOUT, TO REDUCE SEDIMENT GENERATION.
4. INSPECT POND OUTLET DEVICES AND CHANNEL DOWNSTREAM OF DAM. REPAIR UNDERCUTTING OR DAMAGE TO
CHANNEL LINING.
5. CHECK DOWNSTREAM DAM FACE FOR EVIDENCE OF SEEPAGE OR OVERTOPPING.
C. THE FOLLOWING TASKS SHALL BE PERFORMED EVERY SIX MONTHS.
1. INSPECT INTERIOR OF OUTLET STRUCTURE. REMOVE ACCUMULATED SEDIMENTS OR OBSTRUCTIONS.
2. CHECK POND DEPTH AT VARIOUS LOCATIONS. REMOVE ACCUMULATED SEDIMENTS IF DEPTH IS LESS THAN 3/4
SPECIFIED.
3. CLEAR TREES AND SAPLINGS FROM DAM EMBANKMENT.
D. GENERAL
1. MOW POND SIDES REGULARLY TO MAINTAIN MAXIMUM GRASS HEIGHT OF 6".
2. REMOVE VEGETATION WHICH GROWS WITHIN POND, EXCEPT WETLAND GRASSES ALONG PERIMETER.
3. MONITOR POND DRAWDOWN TIME. IF DRAWDOWN EXCEEDS TABULATED TIME, REMOVE OBSTRUCTIONS FROM
RISER ORIFICE.
4. INSPECT EMERGENCY SPILLWAY. REPAIR ERODED AREAS AND REMOVE OBSTRUCTIONS.
WET POND CONSTRUCTION NOTES
1. ANTI -SEEP COLLARS SHALL BE INSTALLED IN ACCORDANCE WITH THE REQUIREMENTS OF THE NORTH CAROLINA STORMWATER
MANUAL.
2. ALL AREAS LOCATED ALONG AND ABOVE THE POND BENCH SHALL RECEIVE A MINIMUM OF 4 INCHES OF TOPSOIL AND BE
PERMANENTLY SEEDED. SOIL STABILIZATION BLANKET SHALL BE APPLIED TO ALL AREAS WITH A FINISHED GRADE OF 6/1 OR
GREATER. ALL METHODS AND MATERIALS FOR SOIL STABILIZATION BLANKET SHALL BE IN ACCORDANCE WITH THE NORTH
CAROLINA EROSION AND SEDIMENTATION CONTROL MANUAL. SODDING MAY BE SUBSTITUTED IN PLACE OF SOIL STABILIZATION
BLANKET.
3. THE BOTTOM OF THE BASIN AND THE SIDE SLOPE UP TO 18 INCHES ABOVE THE WATER SURFACE ELEVATION SHALL BE OVER
EXCAVATED BY A MINIMUM OF 12 INCHES AND REPLACED WITH A LAYER OF SILTY CLAY (CL) UNLESS OTHERWISE DIRECTED BY
THE GEOTECHNICAL ENGINEER. THE SILTY CLAY LAYER SHALL BE PLACED ON APPROVED SUBGRADES IN MAXIMUM 8 INCH
LOOSE LAYER LIFTS AND SHALL BE COMPACTED TO AT LEAST 90 PERCENT OF THE STANDARD PROCTOR COMPACTION.
COMPACTION SHALL BE ON THE WET SIDE OF THE OPTIMUM MOISTURE CONTENT.
4. ALL BASINS SHALL FUNCTION AS A TEMPORARY SEDIMENT BASIN DURING CONSTRUCTION. UPON COMPLETION OF
CONSTRUCTION, THE BASINS SHALL BE CLEANED OF SEDIMENT AND CONVERTED TO A STROMWATER MANAGEMENT FACILITY.
5. THE CONTRACTOR SHALL ENGAGE THE SERVICES OF A STATE REGISTERED LAND SURVEYOR TO PROVIDE AN AS -BUILT AND
VOLUME COMPUTATIONS OF THE STORMWATER MANAGEMENT FACILITY AND SHALL PROVIDE THE AS -BUILT TO THE OWNER AND
ENGINEER.
6. THE BERMS AROUND THE POND(S) SHALL BE CONSTRUCTED OF COMPACTED STRUCTURAL FILL CLASSIFIED AS SM, SM-SP, SP,
SC OR BETTER CONTAINING LESS THAN 30% BY WEIGHT SILT OF CLAY AND FREE OF DEBRIS. THIS MATERIAL SHALL BE
PLACED ON APPROVED SUBGRADES AND IN HORIZONTAL LIFTS NOT EXCEEDING 8 INCHES IN LOOSE THICKNESS MOISTURE
CONDITIONED TO WITHIN -1% TO +3% OF OPTIMUM MOISTURE CONTENT AND COMPACTED TO MINIMUM OF 95% OF THE MAXIMUM
DENSITY OBTAINED IN ACCORDANCE ASTM D698 STANDARD PROCTOR METHOD. SOILS SHALL BE FREE OF ORGANICS AND ANY
PARTICLES LARGER THAN 2" IN DIAMETER. EACH LIFT OF BERM SHALL BE SCARIFIED PARALLEL TO THE BERM CREST AXIS TO
A DEPTH OF 3 INCHES BEFORE PLACEMENT OF THE COMPACTED STRUCTURAL FILL. STRUCTURAL FILL SHALL BE ANALYZED AND
APPROVED BY THE PROJECT GEOTECHNICAL ENGINEER PRIOR TO USE ON EMBANKMENT. AT ALL TIMES DURING THE
CONSTRUCTION OF BMP EMBANKMENT, THE CONTRACTOR SHALL ENSURE THAT THE GEOTECHNICAL INSPECTOR IS PRESENT AND
OBSERVING THE INSTALLATION.
7. BEFORE THE PLACEMENT OF THE COMPACTED STRUCTURAL FILL FOR THE BERM THE SUBGRADES SHALL BE INSPECTED BY A
GEOTECHNICAL ENGINEER. UNSUITABLE SOILS CONTAINING BUILDING RUBBLE AND OTHER DEBRIS SHALL BE REMOVED FORM THE
BERM AREA. SUITABLE, COMPACTED BERM FILL SUBGRADE SHALL BE SCARIFIED PARALLEL TO THE BERM CREST AXIS TO A
DEPTH OF 3 INCHES BEFORE PLACEMENT OF THE COMPACTED STRUCTURAL FILL.
8. THE GEOTECHNICAL ENGINEER SHALL DETERMINE MATERIALS SUITABLE FOR STRUCTURAL FILL.
9. SEED ALL SIDE SLOPES AND EMBANKMENTS PER THE SEEDING SCHEDULE SHOWN ON SHEET C2.1
10. STABILIZE SIDE SLOPES AND EMBANKMENTS GREATER THAN 3/1 PER THE NCDENR EROSION AND SEDIMENTATION CONTROL
MANUAL.
11. INSTALLATION SHALL BE IN GENERAL CONFORMANCE WITH NCDENR STATE STORMWATER MANUAL LATEST EDITION.
1 2 3 4 5 6
© .
ici
offal
NEW
10;�OF
triaddesignesroup
Architecture I Engineering I Interior Design
Triad Design Group, P.C.
4807-C Koger Boulevard
Greensboro, NC 27407
Telephone [phone]
Facsimile 336-218-8010
www.triad-designgroup.com
NC Architecture Reg. 50709
NC Engineering Lic. C-1108
\1WW111����
•��\F,S\� N
O ,.•• �P O�Rq' G
-ry-= SEAL
1994
���11111W��
°°aan000000a0
QQo00
o4.�,� caRa00.
0 o a
o cz
°
p o O
° ° o
0
00 °°°�+ I N Ea°° Qoo
%,14 .N N po
000°oaaona°aao
DECEMBER 19, 2019
PROFESSIONAL OF RECORD:
L. ALLAN HILL, P.E.
V )
Z
Uj
7
Ca
0
Ca
O
U
w
L
0
o
Z
�LO
E
W
00
0
v
Mk Date Description
Revisions
STORM POND &
STORM POND
LANDSCAPE
PLAN & DETAILS
Date: AUGUST, 2019
Drawn: Check: LAH
Job Number: 17-042
Sheet:
C1.8