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RFI - App B - Updated Engineering - 11 Robert St
Original PDF page 7, section 3. The text section number identifies this passage in the reader.
A
PER
SPILLWAY HOLD IN PLACE T Y L
GRASSED FILTER STRIPS 2 metres min.
150 MM MIN. 150 MM MIN. CENTRELINE SECTION AT POINTS "A" WITH SAND BAGS
INE
SEDIMENT
90 DEG
FILL TRENCH WITH SOIL TRAP
NOT TO REGULAR SCALE NOTE: ONLY TO BE USED AS TEMPORARY BANK AND COMPACT ent GEOTEXTILE FILTER SOCK A
WHERE MAXIMUM UPSLOPE LENGTH IS 80 METRES. nm FILLED WITH 25MM GRAVEL
OVERLAP-BURY UPPER END OF 15. Alig
rty
STORMWATER TREATMENT DETAILS EARTH BUND CUT OFF DRAIN ROCK TRENCHED 200 MM INTO GROUND LOWER BLANKET AS IN "A". OVERLAP STAPLES: 8
GAUGE (4mm)
MIN 0m
Pr ope
AGGREGATE OR RECYCLED CONCRETE. END OF TOP BLANKET 300mm AND
STAPLE AT 150 CRS. WIRE
Berm (300mm MIN height)
KERB INLET PIT SEDIMENT BARRIER
NOM
SEDIMENT FLOCCULATION SEDIMENT
200
FLO TRAP
The job of a flocculent is to effectively break down the dominance of the clay particles that contain a residual negative eleCIRCUITro-magnetic charge and thus allowing individual particles W FLOW
to be drawn together and settle under gravity. 50m NOTE: POINTS A AT SAME
Geotextile fabric, MAX ELEVATION
Bidum U34 or similar 1.5m TIMBER STAKES
METHOD OF APPLICATION SPACING OF CHECK DAMS ALONG CENTRELINE
m
3.0 N AT MAX 2.5m CENTRES
MI
Large sediment basins such as the one this site, require that the gypsum is mixed into a slurry with water and then sprayed over the surface of the turbid water in the sediment
basin. It is essential that the gypsum is spread evenly over the entire surface for efficient treatment of the turbid water.
AND SCOUR PROTECTION BELOW EACH CHECK
DAM TO BE SPECIFIED ON SWMP/ESCP
CENTRELINE SECTION AT POINTS "B" Unbound pavement material (gravel) to Grading
B, Table 9 of QT Specification MRS11.05, cha
nne
l
dwa
y SELF-SUPPORTING
GEOTEXTILE SEDIMENT FENCES
& roa
Generally the gypsum should be applied at a rate of about 32 kgm per 100 cubic metres of detained turbid water, as per the adjacent table. The above dosing rate for the site ROCK CHECK DAM exclude material finer than sieve 2.36mm Ker
b
r n ew Sediment Fence installed across the contour
should be calibrated after the first two storm events to assess the actual flocculent application rate and settling time required for the site.
ting
,o
500mm TO 600mm DIRECTION OF
FLOW - uncontoured concentration of flow should be avoided REVISION LIST
Exis
The final application rate should be sufficiently high to permit adequate sediment sediment flocculation (less than 50 NTU) and basin dewatering within two days (48 hours) from the
conclusion of each storm event, whilst maintaining other required water quality criteria such as pH (6.5 - 8.5) and dissolved oxygen (>80%). ROCK CHECK DAM CONSTRUCTION NOTES A NOT TO REGULAR SCALE
1. CHECK DAMS CAN BE BUILT WITH VARIOUS MATERIALS, INCLUDING ROCKS, LOGS, SANDBAGS AND STRAW BALES. THE A ORIGINAL ISSUE 5/10/24
METHOD OF TESTING THE STORMWATER MAINTENANCE PROGRAM SHOULD ENSURE THEIR INTEGRITY IS RETAINED, ESPECIALLY WHERE CONSTRUCTED WITH STRAW
BALES. IN THE CASE OF BALES, THIS MIGHT REQUIRE THEIR REPLACEMENT EVERY TWO TO FOUR MONTHS.
Runoff from pad directed to sediment trap 600mm MIN B REVISED 29/10/24
The stormwater detained in the sediment basin will be tested at a suitable location that will be decided upon at the site. The sample should be taken at a location that has adequate ON SOIL, 150mm x 100mm
access so no sediment is resuspended while the testing is being conducted. 2. TRENCH THE CHECK DAM 200 MM INTO THE GROUND ACROSS ITS WHOLE WIDTH. WHERE ROCK IS USED, FILL THE TRENCH WITH COMPACTED
The stormwater detained in the sediment basin will be tested with the TPS 90-FLT water quality logger. The TPS 90-FLT unit samples and records the dissolved oxygen, conductivity, TRENCHES TO AT LEAST 100 MM ABOVE THE GROUND SURFACE TO REDUCE THE RISK OF UNDERCUTTING. BACKFILL AND ON ROCK, SET C REVISED 24/2/25
pH, turbidity and temperature of the stormwater. For further details and specifications on the TPS 90-FLT please refer to Appendix B.
If the TPS 90-FLT unit is not present a practical field test that approximates the required 50 NTU level is to fill a clear plastic or glass 65mm diameter soft drink bottle with the
3. NORMALLY, THEIR MAXIMUM HEIGHT SHOULD NOT EXCEED 600 MM ABOVE THE GULLY FLOOR. THE CENTRE SHOULD
ACTING AS A SPILLWAY, BEING AT LEAST 150 MM LOWER THAN THE OUTER EDGES.
B TEMPORARY CONSTRUCTION ENTRY/EXIT SEDIMENT TRAP
Not to Scale
SECTION DETAIL INTO SURFACE CONCRETE
D REVISED 11/8/25
water and then hold it up to the light. If seeing clearly through the sample is not possible, then the sample is probably above the 50 NTU level. 4. SPACE THE DAMS SO THE TOE OF THE UPSTREAM DAM IS LEVEL WITH THE SPILLWAY OF THE NEXT DOWNSTREAM
CATTLE GRID 3.0m NOM WIDTH
METHOD OF DEWATERING
DAM.
STAPLE BLANKETS
AT GRID OF
SET 300mm ABOVE GROUND E REVISED FOLLOWING RFI 16/10/25
CONSTRUCTION SITE
1m CENTRES T
5 m IN
The sediment basin can be dewatered as soon as the water quality criteria met (refer table below). A pump is to be used to decant the basin with a floating inlet to prevent the B MEN
M
NOM LIGN
200
settled sediments from being removed from the basin. The pumping must cease prior to the settled sediments being drawn into the intake pipe, it is essential that materials from
STABILISE STOCKPILE A
TY
PER
the sediment layer are not discharged in the pumping process.
SURFACE L
X.) ;SEDIMENT FENCE CONSTRUCTION NOTES
EARTH BANK
PRO HANNE
10 IN
(MA 2:1
m
M
B
PE 1. CONSTRUCTION SEDIMENT FENCES AS CLOSE AS
FLOW
SLO C
FLOW SLO PE GEOFABRIC FABRIC, BIDIM A34 & WAY KERB INLET PIT SEDIMENT BARRIER POSSIBLE TO BEING PARALLEL TO THE CONTOURS OF THE
2:1 OAD
300
STORMWATER DISCHARGE QUALITY CRITERIA (MA E RB R
3MmIN
STAPLE OUTSIDE EDGES OR SIMILAR K SITE, BUT WITH SMALL RETURNS. THE CATCHMENT AREA
X.)
AT 300mm CRS. N EW CONSTRUCTION NOTES SHOULD BE SMALL ENOUGH TO LIMIT WATER FLOW IF
ACCEPTABLE TSS ACCEPTABLE PH DISSOLVED O2 , OR 1. FABRICATE A SLEEVE FROM GEOTEXTILE OR WIRE MESH CONCENTRATED AT ONE POINT.
TIN G LONGER THAN THE LENGTH OF THE INLET PIT AND FILL 2. CUT A 150-mm DEEP TRENCH ALONG THE UPSLOPE
RUNOFF TO BE DIRECTED TO A SEDIMENT TRAP,
SEDIMENT FENCE REFER STANDARD DRAWING D-0041. EXIS WITH 25mm TO 50mm GRAVEL. LINE OF THE FENCE FOR THE BOTTOM OF THE FABRIC TO
50mg/L 6.5 - 8.5 > 80%
TOPSOIL STOCKPILE CLEAN/DIRTY DIVERSION DRAINS 2. FORM AN ELLIPTICAL CROSS-SECIRCUITION APPROX. 150mm
HIGH, 400mm WIDE.
BE ENTRENCHED.
3. DRIVE TIMBER STAKES INTO GROUND AT 2.5m
TOPSOIL STOCKPILE CONSTRUCTION NOTES TEMPORARY ENTRY/EXIT 3. PLACE THE FILTER AT OPENING LEAVING AT LEAST INTERVALS (MAX) AT THE DOWNSLOPE EDGE OF THE TRENCH.
4. FIX SELF-SUPPORTING GEOTEXTILE TO THE UPSLOPE
100mm BETWEEN KERB INLET AND SLEEVE. MAINTAIN
SEDIMENT BASIN FLOCCULENT APPLICATION 1. PLACE STOCKPILES MORE THAN 2 (PREFERABLY 5) METRES FROM EXISTING VEGETATION, CONCENTRATED DIVERSION DRAIN CONSTRUCTION NOTES OPENING WITH SPACER BLOCKS. SIDE OF THE POSTS ENSURING IT GOES TO THE BASE OF
WATER FLOW, ROADS AND HAZARD AREAS. TEMPORARY ENTRY/EXIT CONSTRUCTION NOTES 4. FORM A SEAL WITH KERB TO PREVENT SEDIMENT THE TRENCH. FIX THE GEOTEXTILE WITH WIRE RECOMMENDED Computer File
2. CONSTRUCTION ON THE CONTOUR AS LOW, FLAT, ELONGATED MOUNDS. 1. REMOVE ANY ROCKS, CLODS, STICKS OR GRASS FROM THE SURFACE BEFORE LAYING PLASTIC. BYPASS. BY THE MANUFACTURER. THE USE OF SHADE CLOTH FOR
AGENT INDICATIVE DOSAGE COMMENTS PRECAUTIONS & CONSTRAINTS MIN. REQD. ON SITE 3. WHERE THERE IS SUFFICIENT AREA, TOPSOIL STOCKPILES SHALL BE LESS THAN 2 METRES IN HEIGHT. 2. ENSURE THAT TOPSOIL IS AT LEAST 75mm DEEP. 5. SANDBAGS FILLED WITH GRAVEL CAN SUBSTITUTE FOR THIS PURPOSE IS NOT SATISFACTORY. 240771OPW.DWG
1. STRIP THE TOPSOIL, LEVEL THE SITE AND COMPACT THE SUBGRADE. 5. JOIN SECTIONS OF THE FABRIC AT A SUPPORT POST
4. WHERE THEY ARE TO BE IN PLACE FOR MORE THAN 10 DAYS, STABILISE FOLLOWING THE APPROVED 3. ENSURE PLASTIC WILL BE CONTINUOUSLY IN CONTACT WITH THE SOIL BY GRADING THE SURFACE 2. COVER THE AREA WITH NEEDLE-PUNCHED GEOTEXTILE. THE MESH OR GEOTEXTILE PROVIDED THEY ARE PLACED
GYPSUM 32kg/100cub.m LITTLE PH CHANGE, SLIGHT INCREASE IN NEEDS TO BE SPREAD EVENLY ACROSS POND. 260 kgm ESCP OR SWMP TO REDUCE THE C-FACIRCUITOR TO LESS THAN 0.10. CAREFULLY FIRST. SO THAT THEY FIRMLY ABUT EACH OTHER AND WITH A 150mm OVERLAP. DRAWING NUMBER SHEET REV.
SALINITY CAN CAUSE SCUM DEPOSITS IN EQUIPMENT. 3. CONSTRUCTION A 200mm THICK PAD OVER THE GEOTEXTILE USING ROAD BASE OR 30mm. 6. BACKFILL THE TRENCH OVER THE BASE OF THE FABRIC
5. CONSTRUCTION EARTH BANKS (STANDARD DRAWING 5-5) ON THE UPSLOPE SIDE TO DIVERT WATER AROUND 4. LAY FABRIC IN "SHINGLE FASHION", WITH THE END OF EACH UPSTREAM ROLL OVERLAPPING THOSE 4. ENSURE THE STRUCTURE IS AT LEAST 15m LONG OR TO BUILDING ALIGNMENT AND AT SEDIMENT LADEN WATERS CANNOT PASS BETWEEN.
24-0771-OPW7
AND COMPACT IT THOROUGHLY OVER THE GEOTEXTILE.
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