SW5140801_Plansheet C-5.4 - SCM Detail_20220923

AQUATTIC BENCH ELEV: 484.50
OUTSIDE EDGE OF AQUATIC BENCH IS
6-IN ABOVE PERMANENT POOL ELEV
DRY DETENTION BASIN MAINTENANCE SCHEDULE
DESCRIPTION
METHOD
FREQUENCY
SEASON
EMBANKMENT
INSPECT AND REPAIR
EROSION/ANIMAL NESTINGS
VISUAL
ONCE PER YEAR
ALL
INSPECT AND RESEED
GRASS COVERAGE
VISUAL
WHENEVER NEEDED
ALL
OUTLET STRUCTURE
DEBRIS / OBSTRUCTIONS
BY HAND
WHENEVER NEEDED
ALL
EROSION A
OUTLET DISCHARGE
VISUAL
ONCE PER YEAR
ALL
FOREBAY/ MAIN POOL
SEDIMENT / DEBRIS
BY HAND
ONCE PER YEAR
ALL
REMOVE TRASH
BY HAND
WHENEVER NEEDED
ALL
CONTRACTOR SHALL BE RESPONSIBLE FOR MAINTENANCE UNTIL SUBSTANTIAL
COMPLETION AT WHICH TIME OWNER WILL ASSUME MAINTENANCE RESPONSIBILITY.
SEQUENCE OF CONVERSION FROM SEDIMENT BASIN TO STORMWATER CONTROL MEASURE
1. MAINTAIN EXISTING BARREL AND OUTLET STRUCTURE
2. UPDATE EMBANKMENT AND ALL OTHER POND COMPONENTS.
3. INSTALL TEMPORARY SKIMMER TO OUTLET STRUCTURE.
4. EXCAVATE POND TO TEMPORARY SKIMMER BASIN DIMENSIONS, SEE EROSION
CONTROL PLAN.
5. INSTALL BAFFLES AND OTHER TEMPORARY SKIMMER BASIN COMPONENTS, SEE
TEMPORARY SKIMMER BASIN DETAIL.
6. REFER TO TEMPORARY SEDIMENT SKIMMER BASIN DETAIL FOR ELEVATION OF
SKIMMER CONNECTION.
7. SEE CONSTRUCTION SEQUENCE ON EROSION CONTROL PLAN FOR INFORMATION.
8. ONCE SITE IS APPROVED BY NCDEQ, REMOVE TEMPORARY SKIMMER, BAFFLES AND
OTHER TEMPORARY COMPONENTS
9. FILL HOLE IN OUTLET STRUCTURE FROM SKIMMER WITH NON -SHRINK GROUT.
PROVIDE PERMANENT WATERTIGHT SEAL.
10. EXCAVATE SEDIMENT AND GRADE TO FINAL CONTOURS, SEE GRADING PLAN.
11. CONSTRUCT WET POND STORMWATER CONTROL MEASURE AS SHOWN ON THE
DRAWINGS.
4S-BUILT SURVEY REQUIREMENTS
NOTE: CONTRACTOR SHALL PROVIDE AS -BUILT TOPOGRAPHIC SURVEY
PERFORMED BY A PROFESSIONAL LAND SURVEYOR CERTIFYING WET
DETENTION POND AREA DIMENSIONS AND ELEVATIONS OF THE FOLLOWING:
1. TOPOGRAPHIC SURVEY OF THE WET POND AND EMBANKMENT
2. OUTLET STRUCTURE TOPS AND INVERTS
3. OUTLET STRUCTURE DIMENSIONS
4. ORIFICE DIAMETERS
5. BARREL PIPE SIZES AND INVERTS
6. EMERGENCY SPILLWAY ELEVATION AND DIMENSIONS.
OUTLET STRUCTURE NOTES
1. CAST -IN -PLACE CONCRETE RISER IS REQUIRED WITHOUT EXCEPTION.
2. CLASS "A" (3,000 PSI) CONCRETE TO BE USED.
6. ALL MORTOR JOINTS ARE 1/2" f 1/8".
7. GROUT SHALL BE NON -SHRINK (ASTM-C1107)
S. ALL STRUCTURES OVER 3'-6" IN DEPTH TO BE PROVIDED WITH STEPS
V-2" ON CENTERS. STEPS SHALL BE IN ACCORDANCE WITH STANDARD
840.66.
9. LOCATE MANHOLE OVER STEPS.
PIPE
CONCF
ANC
6' WIDE AQUATIC BENCH
AROUND ENTIRE POND
(SEE SHEETS C3.0 & C3.1)
31 3' SUBMERGED
1
10-FT WEIR WIDTH
1 FOREBAY WEIR CREST
ELEV:483
FOREBAY WEIR SECTION
CFOREBAYWEIR
RM
AQUATIC BENCH ELEV: 483.50 5.00
INSIDE EDGE OF AQUATIC NGTH
BENCH IS 6-IN BELOW
PERMANENT POOL ELEV 83.00
PERMANENT POOL ELEV: 4 4.00
3 1 ENTRANCE ELEV: )�,
EBAY
478.00
EXIT ELEV: 479.00
RIPRAP PAD
EX. 15" INLET PIPE J TOP OF PERM. SED. STOR.
FOREBAY ENTRANCE
ELEV: 478.00
BOT. OF PERM. SED. STOR.
FOREBAY ENTRANCE
ELEV: 477.00
BOT. OF PERM. SED.
STOR. FOREBAY EXIT
ELEV: 477.50
SCHEDULE A PRE -INSTALLATION
CONFERENCE PRIOR TO
13 CONSTRUCTION OF THE STORMWATER
CONTROL MEASURE
24-IN THICK CLASS B
RIPRAP OVER FILTER
FABRIC
TOP OF EMBANKMENT ELEV: 487.00
100-YR STORM ELEV
486.48
10-YR STORM ELEV
486.02
2-YR STORM ELEV
485.56
1-YR STORM ELEV
485.36
10-FT WEIR WIDTH
SPILLWAY CREST ELEV: 486.00
EXISTING CONCRETE EMERGENCY SPILLWAY SECTION
OUTLET STRUCTURE
WITH TRASH RACK
6-FT WIDE ACCESS PAD
TO OUTLET STRUCTURE
6-IN BELOW WEIR 10-FT
1F
1 3 5 _ _ EMERGENCY SPILLWAY CREST ELEV: 486.00
FLOATING TEMPORARY SKIMMER I•'
PROVIDE 6' X 6' DEPRESSED AREA PRINCIPAL EXISTING
SMANUFACTURER: J.W.
2-FT BELOW PRINCIPAL SPILLWAY SPILLWAY OUTLET
FAIRCLOTH &SONS WITHIN AQUATIC BENCH FOR �: i STRUCTURE I j�
ADEQUATE DRAINAGE I SEE DETAIL ON �' .� L 6-IN COMPACTED
PERMANENT POOL ELEV: 484.00 - I THIS SHEET f• .? SELECT FILL?
- - INV= 484.00 I •�
EX. INV= �478.00 PLUG _ _ _ _
FOREBAY 11 MAIN POOL i EXISTING 4" - - - - - -
EMBANKMENT ` I INV= 483.78 FLOW
TOP OF PERM. SED. STOR. EL : 478.00
BOT. OF PE D TOR.
0
I III
FI V 477.nn a' ' CUT -OFF (KEY TRENCH)
TOP OF PERM. SED.
STOR. FOREBAY EXIT
ELEV: 478.00 8" IMPERVIOUS FILL
LAYER UNDER ALL
WATER SURFACES
/ END CAP WITH \
/ DRILL OPENING \
/ DIAMETER \
/A A A\
/ ANCHOR \
DRAWDOWN \
e PIPE TO \
10-IN WALL
4"PVC
I 4"PVC ° d PRIMARY
1. -•- = - UNDISTURBED SOIL 5' WIDE X 2' DEEP MIN. INTO
EXISTING 6" �.• . '_ _ -I_.a UNDISTURBED SOIL ALONG
DUCTILE IRON - - i LENGTH OF EMBANKMENT
DRAIN PIPE 1:1 SLOPE
EXISTING OUTLET
STRUCTURE
POND AND EMBANKMENT SECTION
WET DETENTION BASIN MAINTENANCE SCHEDULE
DESCRIPTION
METHOD
FREQUENCY
SEASON
EMBANKMENT
INSPECT AND REPAIR
EROSION / ANIMAL NESTINGS
VISUAL
ONCE PER YEAR
ALL
INSPECT AND RESEED
GRASS COVERAGE
VISUAL
WHENEVER NEEDED
ALL
OUTLET STRUCTURE
DEBRIS / OBSTRUCTIONS
BY HAND
WHENEVER NEEDED
ALL
OPERATE POND DRAIN VALVE
BY HAND
ONCE PER YEAR
ALL
EROSION AT OUTLET DISCHARGE
VISUAL
ONCE PER YEAR
ALL
FOREBAY / MAIN POOL
SEDIMENT / DEBRIS
BY HAND
ONCE PER YEAR
ALL
REMOVE TRASH
BY HAND
WHENEVER NEEDED
ALL
CONTRACTOR SHALL BE RESPONSIBLE FOR MAINTENANCE UNTIL PROJECT CLOSE OUT
AT WHICH TIME OWNER WILL ASSUME MAINTENANCE RESPONSIBILITY.
I TEE SPILLWAY I
INV=720.50
PERM. POOL ELEV: 484.00
I
I
I '.° WATERTIGHT
4"PVC NON -SHRINK
A. GROUT /
8-IN �°
ANCHORDRAWDOWN
/
\ °a PIPE TO WALL
\ ° ❑E
\ END CAP WITH / EXTEND EXISTING RISER TOP ELEVATION: 485.10 ❑E
\ DRILL OPENING /
\ DIAMETER:1.25-IN /
\ PRIMARY SPILLWAY / EX. RISER TOP ELEVATION: 484.83
\ \ ENLARGEMENT /
\ 8-IN
\ PRIMARY
d <z \ SPILLWAY /
iq
A W a. d. \
--- �.
LEI I
FTEMPORARY SKIMMER \ \ \ \ \
EXISTING Y
CONCRETE EXISTING 15" RCP
PVC PRIMARY
A
SPILLWAY ORIFICE
(�
DIAMETER: 1.25IN
8-IN
4-FT -
LL
d �
a
TEMPORARY SKIMMER TO
�A
BE REMOVED (SEQUENCE
OF CONVERSION FROM FILL
SEDIMENT BASIN TO SKIMMER
STORMWATER CONTROL HOLE WITH
MEASURE) NON -SHRINK
GROUT FOR
X
WATERTIGHT
SEAL
OUTLET STRUCTURE
PLAN VIEW
OUTLET BARREL
INV.: 479.19
4
a
TO BE REMOVED ( SEE
CONSTRUCTION \ \
SEQUENCE) \ \
TOP PERMANENT SEDIMENT STORAGE ELEV: 479.00 �° EX. 6" DUCTILE IRON DEWATERING PIPE
BOTTOM PERMANENT SEDIMENT STORAGE ELEV: 478.00
EX. CONCRETE
s/
/ \ / PIPE ANCHOR -
a \
/ �24-IN
/ . • . °.
I • • , ; . ° • ; 6-IN DIP ..
41
36-IN
I
°
•' , . s.
,° e
\ • ' ', °
j a
• A. • '
\ CONCRETE PIPE ANCHOR
\ ENLARGEMENT /
EXTEND EXISTING
VALVE STEM REINSTALL EX. ALUMINUM
WHEEL IF NEEDED TRASH RACK, BAR GRATING 5"
x 5" OPENINGS
OBSTRUCT ORIFICES DURING
EROSION CONTROL WITH WOOD
AND BUTYL ADHESIVE TAPE ON
THE INSIDE OF RISER
INV=484.00
OUTLET STRUCTURE
SECTION Y-Y
I
1
I8-IN L 6-IN
EX. OUTLET
BARREL
INV.: 479.19
DAM CORE
(SEE NOTES)
T
2-FT BELOW
UNDISTURBED SOIL
24-IN THICK CLASS
B RIPRAP OVER
FILTER FABRIC
#67 STONE BEDDING
1. 4" DRAIN OUTLET FOR DIAPHRAGM SHALL BE PROTECTED BY AN APPROPRIATE RODENT GUARD: 2" X 2" STAINLESS STEEL MESH
SECURED WITH STAINLESS STEEL CLAMP OR APPROVED EQUAL.
2. PIPE SHALL INCLUDE EXPANSION JOINTS SPACED EVERY 8 FEET ON CENTER.
3. JOINTS WRAPPED WITH DOUBLE LAYER OF NON -WOVEN GEOTEXTILE FILTER FABRIC ON OUTSIDE OF PIPE SHALL COVER 2 FEET BY 3
FEET OF PIPE CENTERED ON JOINT.
4. CONTRACTOR SHALL SUBMIT ONE (1) 5 GALLON BUCKET SAMPLE OF FILTER MEDIA TO THE GEOTECHNICAL ENGINEER FOR APPROVAL
PRIOR TO PLACEMENT IN THE FILTER DIAPHRAGM.
5. DURING CONSTRUCTION OF THE DAM, INSTALL DRAIN BEDDING COURSES AND HDPE DRAINS AS SHOWN ON THE DRAWINGS.
6. BACKFILL THE SOLID DRAIN PIPE WITH EMBANKMENT FILL AND COMPACT WITH HAND -OPERATED MECHANICAL COMPACTORS WITHIN 2
FEET OF THE TOP OF PIPE TO THE REQUIRED COMPACTIONS IN THE PREVIOUS SECTION.
7. BACKFILL THE SLOTTED DRAIN PIPE WITH FILTER MEDIA AND COMPACT WITH HAND -OPERATED MECHANICAL COMPACTORS.
8. REMOVE ANY SOIL CONTAMINATION AS DIRECTED BY THE GEOTECHNICAL ENGINEER OR HIS REPRESENTATIVE.
9. FILTER MEDIA SHALL BE PLACED IN 10 TO 12 INCH LOOSE LIFTS, ADEQUATELY WATERED AS NEEDED TO A NEAR -SATURATED CONDITION,
AND COMPACTED WITH A VIBRATORY ROLLER OR PLATE COMPACTOR TO THE SATISFACTION OF THE GEOTECHNICAL ENGINEER.
10. THE SEEPAGE FILTER CAN BE CONSTRUCTED CONCURRENTLY WITH THE EMBANKMENT OR THE SEEPAGE FILTER CAN BE
CONSTRUCTED BY CUTTING OUT PREVIOUSLY PLACED EMBANKMENT FILL AND BACKFILLING WITH FILTER MEDIA.
13-FT
MIN
/3.5 .51\\
SEED & MULCH EMBANKMENT SEE SEEDING SCHEDULE
T MIN (INSTALL SLOPE PROTECTION MATTING ON ALL
i 1 LOPES STEEPER THAN 6: 1)
AQOMPACTED
SELECT FILL?
EXISTING OUTFALL / \
- - - _ _ _ INV: 478.47 /
TOP OF DAM ELEV: 728.00 \
/ 2-FT FROM TOP OF DAM \
-- ----- --40 FT 70-FT
11 TOP ELEV: 726.00
/
6„ 11.17' \�
\ I
\ I 30"
- _ _ _ _ - RCP CONCRETE
I 21 PIPE CRADLE 2
1 1
2-FT /
\ -- 7 ELEV: 709.66
�{ 1. 5' 4
\ 10-FT 40 FT /
DAM CORE, CUTOFF TRENCH, AND EMBANKMENT FILL NOTES:
1. DAM CORE AND CUTOFF TRENCH FILL MATERIAL SHALL CLASSIFY AS ML, MH, CL OR CH
PER USCS. THIS MATERIAL MAY CONSIST OF MATERIAL FROM ON -SITE BORROW PITS, OR
APPROVED OFF -SITE BORROW SOURCES.
2. EMBANKMENT FILL SOIL MATERIAL SHALL CALSIFY SM, SC, ML OR CL PER USCS. THIS
MATERIAL MAY CONSIST OF MATERIAL FROM ON -SITE EXCAVATIONS, ON -SITE BORROW
PIS OR APPROVED OFF -SITE BORROW SOURCES.
3. UNSUITABLE EMBANKMENT FILL IS CLASSIFIED AS GW, GP, GM, GC, SW, SP, OH, OL PER
USCS
\ FILTER DIAPHRAGM
\ \ ENLARGEMENTS
EMBANKMENT CONSTRUCTION STANDARDS
1. CONTROLLED FILL, AS SPECIFIED BY THE GEOTECHNICAL ENGINEER, IN THE DAM EMBANKMENT SHALL BE PLACED IN 6-INCH LOOSE LAYERS (3-INCH LOOSE LAYERS WITHIN 3-FEET OF
EITHER SIDE OF THE PRINCIPAL SPILLWAY PIPE TO A DEPTH OF 2-FEET OVER THE PIPE) AND SHALL BE COMPACTED TO A DENSITY OF NO LESS THAN 95% OF THE STANDARD PROCTOR
MAXIMUM DENSITY AT A MOISTURE CONTENT OF + OR - TWO PERCENTAGE POINTS OF THE OPTIMUM MOISTURE CONTENT IN ACCORDANCE WITH ASTM D698.
2. ALL VISIBLE ORGANIC DEBRIS SUCH AS ROOTS AND LIMBS SHALL BE REMOVED FROM THE FILL MATERIAL PRIOR TO COMPACTION TO THE REQUIRED DENSITY. SOILS WITH ORGANIC
MATTER CONTENT EXCEEDING 5% BY WEIGHT SHALL NOT BE USED. STONES GREATER THAN 3-INCH (IN ANY DIRECTION) SHALL BE REMOVED FROM THE FILL PRIOR TO COMPACTION.
3. FILL MATERIAL PLACED AT DENSITIES LOWER THAN SPECIFIED MINIMUM DENSITIES OR AT MOISTURE CONTENTS OUTSIDE THE SPECIFIED RANGES OR OTHERWISE NOT CONFORMING
TO SPECIFIED REQUIREMENTS SHALL BE REMOVED AND REPLACED WITH ACCEPTABLE MATERIALS.
4. ANY FILL LAYER THAT IS SMOOTH DRUM ROLLED TO REDUCE MOISTURE PENETRATION DURING A STORM EVENT SHALL BE PROPERLY SCARIFIED PRIOR TO THE PLACEMENT OF THE NEXT
SOIL LIFT.
5. SURFACE WATER AND STREAM FLOW SHALL BE CONTINUOUSLY CONTROLLED THROUGHOUT CONSTRUCTION AND THE PLACEMENT OF CONTROLLED FILL.
6. FOUNDATION AREAS MAY REQUIRE UNDERCUTTING OF COMPRESSIBLE AND/OR UNSUITABLE SOILS IN ADDITION TO THAT INDICATED ON THE PLANS. ALL SUCH UNDERCUTTING SHALL
BE PERFORMED AT THE DISCRETION OF THE GEOTECHNICAL ENGINEER AND SHALL BE MONITORED AND DOCUMENTED. IN NO CASE SHALL THERE BE AN ATTEMPT TO STABILIZE ANY
PORTIONS OF THE FOUNDATION SOILS WITH CRUSHED STONE.
7. FILL ADJACENT TO THE RISER AND PRINCIPAL SPILLWAY PIPE SHALL BE PLACED SO THAT LIFTS ARE AT THE SAME LEVEL ON BOTH SIDES OF THE STRUCTURES.
8. HEAVY EQUIPMENT SHALL NOT BE ALLOWED TO PASS OVER CAST -IN -PLACE STRUCTURES (INCLUDING THE CRADLE) UNTIL ADEQUATE CURING TIME HAS ELAPSED.
9. TO RE-ESTABLISH VEGETATION AFTER CONSTRUCTION, PLACE A 3-INCH LAYER OF TOPSOIL ON THE DISTURBED EMBANKMENT SURFACE AND SEED AND MULCH OR HYDROSEED THE
AREA.
TESTING, OBSERVATION, AND CERTIFICATION
1. TESTS OF THE DEGREE (%) OF COMPACTION OF THE PLACED FILL IN THE DAM SHALL BE PERFORMED AS A PART OF THE CONTRACTOR'S NORMAL QUALITY CONTROL PROGRAM FOR THE
CONSTRUCTION OF THE DAM. TESTS SHALL BE CONDUCTED CONCURRENT WITH THE INSTALLATION OF THE COMPACTED FILL AND THE CONTRACTOR SHALL COORDINATE THE
CONSTRUCTION OF THE DAM SO THAT THE TESTING CAN BE COMPLETED. SHOULD THE RESULTS OF THE TESTS INDICATE THAT THE SPECIFIED DEGREE OF COMPACTION HAS NOT BEEN
OBTAINED; THE PORTIONS OF THE DAM REPRESENTED BY SUCH TESTS SHALL BE REWORKED OR REBUILT. ALL PORTIONS OF THE DAM SHALL ACHIEVE THE SPECIFIED MINIMUM DEGREE
OF COMPACTION.
6-FT WIDE ACCESS
PAD TO OUTLET
STRUCTURE 6-IN
BELOW WEIR
3.5
1�
PRIMARY
SPILLWAY
INV=484.00
I
OUTLET STRUCTURE
SECTION X-X
6-FT X 6-FT X 2.5-FT DEEP
DEPRESSION UNDER
PRINCIPAL SPILLWAY FOR
ADEQUATE DRAINAGE. TIE
BACK TO AQUATIC BENCH AT
3:1 SLOPE.
T 919 7818582
F 919 7813979
4600 Lake Boone Trail
Suite 205
Raleigh, NC 27607
[e-mail]
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2
9/23/22
NCDEQ STORM #2
ID
DATE
DESCRIPTION
DRAWN BY: JL
CHECKED BY: FS
SITE DETAILS
2021009 8 J U L 2022
PERMANENT WET DETENTION POND STORMWATER CONTROL MEASURE (SCM) NTSWET DETENTION POND STORMWATER CONTROL MEASURE (SCM) NTSS