SW3210301_Plansheet Phase 2 C3.23 - SCM Details_20211118

1-2"x2%1/4" GALV
STEEL ANGLE (TYP)
WELDED FRAME FOR
BAR GRATE PANELS
I-
tee•
FRAME BOLTED TO
TOP OF CONCRETE
STORM BOX WITH
60"X60' INSIDE
AND
72"X72' OUTSIDE
DIMENSIONS
Pi
72"
N
r
L2"x2"xI/4" GALVANIZED ANGLE
OVERLAPPED AND BOLTED TO
RESTRAIN BAR GRATE AND AND
STILL ALLOW REMOVAL
I" THICK
BAR GRATE
I/4" x I" GALVANIZED HEXHEAD
BOLT, WASHERS, 81 NUT
I
TACK -WELD NUT TO BACK SIDE
L 61" x 61" LOWER WELDED
FRAME L2"x2"xI/4"
OTY=1 GALVANIZED ANGLE
5/16' HOLES 72" x 72"
FOR CONC ANCHOR 1%3" GALV STEEL OR 1/4 0" GALV STEEL
BOLTS (TYP) ALUMINUM BAR GRATE CONCRETE EXPANSION BOLT
FRAME & BAR GRATE CONSTRUCTION BAR GRATE INSTALLATION
NTS N T S
EXPANDED METAL GRATE TRASH RACK FOR RISER
PROVIDE
WATERTIGHT
CONNECTION
12" THICK (MIN.)
CAST -IN -PLACE OR PRECAST
CONCRETE COLLAR
(MIN. 2000 PSI)
COMPACTED SOIL (CLAY) LINER
SPECIFICATIONS
THE BMP POND SHALL INCLUDE A COMPACTED
SOIL LINER. THE EARTHWORK CONTRACTOR SHALL
FURNISH ALL LABOR, MATERIAL, SUPERVISION, AND
EQUIPMENT TO COMPLETE THE COMPACTED SOIL
LINER FOR THE POND INCLUDING THE FOLLOWING
OPERATIONS: HAULING, SIEVING, RAKING, DISCING,
COMPACTING, DRYING, WETTING, REMOVAL OF
RAINWATER, REMOVAL OF ALL PREVIOUSLY PLACED
MATERIAL RENDERED UNSUITABLE DUE TO
WEATHER CONDITIONS OR CONSTRUCTION
OPERATIONS, FINAL GRADING AND SEALING, AND
ALL NECESSARY AND INCIDENTAL ITEMS AS
DETAILED OR REQUIRED TO COMPLETE THE
COMPACTED LINER.
SOIL LINER FILL MATERIALS ARE POTENTIALLY
ON -SITE. ON -SITE SOILS THAT MEET THE
FOLLOWING REQUIREMENTS SHALL BE CLASSIFIED
AS SOIL LINER FILL MATERIAL AND MAY BE USED
IN THE CONSTRUCTION OF THE COMPACTED SOIL
LINER:
1. LIQUID LIMIT, PLASTICITY INDEX, AND PERCENT
PASSING THE NO. 200 SIEVE WILL BE
CONSIDERED FOR PROPER CLASSIFICATION. THE
SOIL LINER MATERIAL SHALL HAVE A PLASTICITY
INDEX GREATER THAN 20 OR AS SUBSEQUENTLY
SPECIFIED BASED ON LABORATORY TESTING, AND
HAVE A SOIL PERMEABILITY OF 1 E-5 CM/SEC
OR SLOWER AS DETERMINED BY SOIL
PERMEABILITY (ASTM D5084).
2. SOIL LINER FILL MATERIALS SHALL BE
REASONABLY FREE OF GYPSUM, FERROUS,
AND/OR CALCAREOUS CONCRETIONS AND
NODULES OR OTHER DELETERIOUS SUBSTANCES.
SOIL LINER MATERIAL SHALL BE RAKED OR
SIEVED BY THE EARTHWORK CONTRACTOR, IF
NECESSARY, TO REMOVE ALL AGGREGATE
GREATER THAN 1 INCH IN DIAMETER. NO MORE
THAN 5 PERCENT OF THE SOIL LINER FILL
MATERIAL SHOULD BE RETAINED IN THE NO. 4
SIEVE.
3. PRIOR TO COMPACTION, ALL CLAY CLODS WILL
BE BROKEN DOWN WITH TILLERS AND/OR DISCS
TO PROVIDE A HOMOGENEOUS CLAY SOIL THAT
IS FREE OF CLAY CLODS LARGER THAN 2
INCHES IN DIAMETER.
CONSTRUCTION
1. CONSTRUCTION METHODS, SAMPLING AND
TESTING WILL BE RECOMMENDED BY THE
GEOTECHNICAL. TYPICAL TESTS TO BE INCLUDED
ARE MOISTURE CONTENT, IN -PLACE DENSITY,
ATTERBERG LIMITS AND PERMEABILITY TESTING..
2. PRIOR TO SOIL LINER PLACEMENT, THE
PREPARED SUBGRADE SHALL BE PROOFROLLED
WITH A LOADED DUMP TRUCK (MIN. 20 TONS)
OR SIMILAR RUBBER TIRED PNEUMATIC VEHICLE,
A MINIMUM OF TWO PASSES IN EACH DIRECTION.
3. LOOSE SOIL LINER FILL LIFT THICKNESS, PRIOR
TO COMPACTION, SHALL BE A MAXIMUM OF 6
INCHES. THINNER LIFTS ARE PERMISSIBLE TO
ACHIEVE DESIGN GRADE AND/OR SOIL LINER
PROPERTY SPECIFICATIONS.
4. EQUIPMENT OR TRUCK TRAFFIC SHALL NOT BE
PERMITTED DURING THE PERIOD BETWEEN
SCARIFYING AND COMPACTION OF A LIFT UNLESS
APPROVED BY THE ENGINEER.
5. SOIL LINER FILL SHALL NOT BE PLACED OR
COMPACTED DURING SUSTAINED PERIODS OF AIR
TEMPERATURES BELOW 32 DEGREES F. IF THE
SOIL LINER FILL FREEZES OR ICES THE FILL
SECTION SHALL BE RE -SCARIFIED AND
RE -COMPACTED.
6. THE COMPACTED SOIL LINER SHALL BE
CONSTRUCTED TO THE MINIMUM THICKNESS
SPECIFIED BY THE PROJECT PLANS.
7. AFTER COMPLETION OF A SEGMENT OF
COMPACTED SOIL LINER, BUT BEFORE
INSTALLATION OF THE TOPSOIL PROTECTIVE
LAYER, THE SURFACE OF THE SOIL LINER SHALL
BE SURVEYED BY THE CONTRACTOR TO ENSURE
THE SPECIFIED THICKNESS OF COMPACTED SOIL
LINER.
04
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- THOMAS
& HUTTON
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MINIMUM MAINTENANCE SCHEDULE
1. AFTER EVERY SIGNIFICANT RUNOFF PRODUCING
RAINFALL EVENT AND AT LEAST MONTHLY:
1.1 INSPECT THE DETENTION BASIN SYSTEM
FOR SEDIMENT ACCUMULATION, EROSION, TRASH
ACCUMULATION, VEGETATED COVER, AND
GENERAL CONDITION.
1.2 CHECK AND CLEAR THE ORIFICE OF ANY
OBSTRUCTIONS THAT WOULD INTERFERE WITH
THE DRAW DOWN
OF THE TEMPORARY POOL AS DESIGNED.
2. REPAIR ERODED AREAS IMMEDIATELY. RE -SEED
THE EMBANKMENT AS NECESSARY TO MAINTAIN
GOOD VEGETATIVE COVER. MOW VEGETATIVE
COVER ON EMBANKMENT TO MAINTAIN A
MAXIMUM HEIGHT OF SIX INCHES, REMOVE
TRASH AS NEEDED.
3. INSPECT AND REPAIR THE COLLECTION SYSTEM
(I.E. CATCH BASINS, PIPING, SWALES, RIP RAP,
ETC.) QUARTERLY TO MAINTAIN PROPER
FUNCTIONING.
4. REMOVE WOODY VEGETATION NOT PART OF THE
APPROVED PLAN ALONG THE DAM EMBANKMENT.
5. REMOVE ACCUMULATED SEDIMENT FROM THE WET
DETENTION BASIN SYSTEM SEMI-ANNUALLY OR
WHEN THE DEPTH IS REDUCED TO 75% OF THE
ORIGINAL DESIGN DEPTH. REMOVED SEDIMENT
SHALL BE DISPOSED OF IN AN APPROPRIATE
MANNER AND SHALL BE HANDLED IN A MANNER
THAT WILL NOT ADVERSELY IMPACT WATER
QUALITY (I.E. STOCKPILING NEAR A WET
DETENTION BASIN OR STREAM, ETC.).
6. PERFORM ANNUAL INSPECTION OF THE BASIN
(ANNUAL INSPECTION REPORTS TO BE KEPT BY
THE OWNER). PRIOR TO INSPECTION NOTIFICATION
MUST BE GIVEN TO STORM WATER SERVICES.
NOTE
THE PRECAST MANUFACTURER IS TO PREPARE AND
SUBMIT TO THE ENGINEER DESIGN DETAILS AND
CALCULATIONS FOR THE STRUCTURES SHOWN
BASED ON THE DESIGN CRITERIA SPECIFIED. THE
DESIGN SHALL BE PERFORMED UNDER THE DIRECT
SUPERVISION AND SEALED BY A PROFESSIONAL
ENGINEER REFEREED IN THE STATE OF NORTH
CAROLINA EXPERIENCED IN THE DESIGN OF
PRECAST CONCRETE. THE DESIGN SHALL INCLUDE
PROVISION S FOR HANDLING STRESSES AND
CONSTRUCTION LOADS. REPRODUCED COPIES OF
ASTM C789 "STANDARD SPECIFICATIONS FOR
PRECAST REINFORCED CONCRETE BOX SECTIONS
FOR CULVERTS, STORM DRAINS, AND SEWERS" WILL
NOT BE ACCEPTED AS A SUBSTITUTED FOR DESIGN.
EMBANKMENT CONSTRUCTION NOTES
GENERAL
1. THE POND AND DAM AREA SHALL BE CLEARED,
GRUBBED AND STRIPPED OF ALL VEGETATIVE
MATERIAL AND TOPSOIL PRIOR TO DAM
CONSTRUCTION, THE DISPOSAL OF TREES,
STUMPS, CONSTRUCTION DEBRIS, VEGETATIVE
MATERIAL, ETC. SHALL NOT BE PERMITTED IN
THE DAM OR POOL AREA OF THE POND. WHEN
BLASTING IS USED TO REMOVE ROCK FROM THE
POOL AREA, THE BLASTED AREA SHALL BE
OVER -EXCAVATED TO A DEPTH OF AT LEAST
TWO FEET (2) BELOW FINISH GRADE AND
BROUGHT BACK TO FINISH GRADE WITH CLEAN
RELATIVELY IMPERVIOUS SOIL MATERIAL
COMPACTED IN PLACE.
EARTH FILL DAMS
1. SOIL MATERIALS USED FOR EARTH FILL WHICH
ARE HIGHLY PERMEABLE OR WHICH EXHIBIT
SIGNIFICANT.
2. EMBANKMENTS FILL MATERIAL TO BE COMPACTED
TO AT LEAST 95% STANDARD PROCTOR
COMPACTION.
3. SHRINKAGE SWELL, OR DISPERSION SHALL NOT
BE USED IN THE EMBANKMENT.
4.A CUTOFF TRENCH (CORE TRENCH) SHALL BE
PROVIDED WITH A MINIMUM WIDTH OF FIVE FEET
(5'). THE CENTERLINE OF THE CUTOFF TRENCH
SHALL NOT BE LOCATED DOWNSTREAM OF THE
INSIDE TOP OF SLOPE OF THE DAM. THE
CUTOFF TRENCH SHALL BE CAREFULLY
BACK -FILLED WITH HIGHLY IMPERMEABLE
MATERIAL AND COMPACTED TO AT LEAST
NINETY-FIVE PERCENT (95%) OF STANDARD
PROCTOR DENSITY.
5. THE MINIMUM TOP WIDTH OF THE DAM SHALL BE
TEN FEET (10') AND SLOPES SHALL NOT BE
STEEPER THAN 2:1 (TWO HORIZONTAL TO ONE
VERTICAL) ON THE DAM OR EMBANKMENTS
AROUND THE POND.
6. ALL DISTURBED GROUND AREAS AND
EMBANKMENTS SURROUNDING THE POND SHALL
BE MECHANICALLY STABILIZED AND HAVE
PERMANENT GROUND COVER ESTABLISHED IN
ACCORDANCE WITH THE PERMANENT SEEDING
SCHEDULE.
NOTE
NCDEQ WILL REQUIRE AN OPERATION AND
MAINTENANCE PLAN AND INSPECTION AND
MAINTENANCE AGREEMENT
EXPANDED METAL GRATE
TRASH RACK FOR RISER
(SEE DETAILS)
(COt
SD OUTLET F
SECTION A -A
GENERAL NOTES:
A ORIFICE OP NING
I
I
EXPANDED METAL GRATE
TRASH RACK FOR RISER
(SEE DETAILS)
OUTLET PIPE
I
A
I
I
WEIR OPENIING
I
L - - - - - - - - - - J
1. OUTFALL STRUCTURE SHALL HAVE 6" THICK WALLS AND 10" THICK BOTTOM.
2. INSIDE DIMENSIONS OF OUTFALL STRUCTURE SHALL BE 5'x5'.
3. ENDS OF ALL PIPES SHALL BE FLUSH WITH INSIDE WALL OF STRUCTURE.
4. PIPE OPENING TO BE WATERTIGHT
CONTROL STRUCTURE
NOT TO SCALE
.......................................................................
\s SAFETY FENCE
(ALONG PERIMETER)
POND SECTIONAL VIEW
S STORMWATER I� BASIN LENGTH (SEE PLAN) ISO' MINIMUM
RUN-OFF I II 1
-TOP OF EMBANKMENT = 571.5
° 100=YR WATER SURFACE ELEVATION=570.05 TRASH RACKCEA
- - EMERGENCY SPILLWAY =
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
_ _ _ _ _ _ _ _ _ _ _ _ _ 50-YR WATER SURFACE ELEVATION = 569.68 \ (SEE DETAIL)
25-YR WATER SURFACE ELEVATION= 569.25_
10-YR WATER SURFACE ELEVATION = 568.88
RISER CREST = 568.00RTHEN DAM \
ANTI -SEEP
COLLAR
SPECIFICATIONS
PIPE
RISER TO
ID
DIA
S
NO OF
FIRST
(IN)
(IN)
COLLARS
COLLAR
(FT)
WET POND
42
78
1
25
03
NOTES:
1. ALL COLLARS SHALL BE INSTALLED TO BE
WATER -TIGHT.
2. COLLAR DIMENSIONS TO EXTEND 18" (MIN) BEYOND
SPECIFIED PIPE DIAMETER ON ALL SIDES.
3. FIRST ANTI -SEEP COLLAR TO BE LOCATED SLIGHTLY
DOWNSTREAM OF DAM CENTER LINE.
ANTI -SEEP COLLAR
\
/
B4S1 N INLET \
MIN. 2'
I 6' (TYP) I
VEGETATIVE
- J�
MITI -SEEP COLLAR
S
6:1 SLOP HEIFo
E
NORMAL WATER = 565
-
corrtROL
SEE DETAIL
\'I\(CSEE
ATfVESHELF
STRUCTURE
(sEE
PRAP APRON
SEDIMENT
o 0 0 6�PERMANENT
VEGET
6lf SLOPE
DETAIL)
DETAIL)
\ FOREBAY
F REBA ER POOL DEPTH
- - - -
- - - -
CL-II RIPRAP \
(SEE DETAIL) STORAGE ELEV = 559.50
_
7
STABIILIZATION - - - - -
- -
- - -
- -
RACIN RnTTOM = RRO M
-- -
FOREBAY ENTRANCE
ELEV: 558.50
SEDIMENT STORAGE
FOREBAY ENTRANCE
ELEV: 559.00
SEDIMENT STORAGE
FOREBAY EXIT
ELEV: 559.50
FOREBAY EXIT 12" CLAY LINER SHALL BE CONSTRUCTED
ELEV: 559.00 OR COMPACTED SUCH THAT INFILTRATION
RATE IS NOT MORE THAN 0.01 IN/HR
WET DETENTION POND 3
NOT TO SCALE
BASIN BOTTOM SLOPE RISER ANTI -FLOATATION GLASS IV RCP
(0.5% MIN.) OUTLET PIPE WITH
DUCTILE IRON MAINTENANCE WATERTIGHT JOINTS
DRAIN PIPE WITH SLUICE
GATE OR VALVE AT RISER
(0.50% SLOPE, MIN.) NOTE: SEE GRADING PLAN SHEET C3 9
FOR PIPE INVERTS, PIPE SIZE, AND PIPE
SHWT WAS NOT ENCOUNTERED IN THIS AREA. LENGTHS
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AWN:
FDE
J-27842 0002
09/16/21
JAC
SIGNED:
JAC
REVIEWED:
JLG
APPROVED:
JLG
SCALE:
########
C3.23
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