Topaz Street Op Works · OPW11/0320

 

 

GRATE TO BE GEOFABRIC
WRAPPED.

   
  
 

ROLL OF NETTING FILLED
WITH 50 TO 70mm GRAVEL.

KERB_INLET PROTECTION
NTS.

VERA TRAPPED SEDIMENT
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TURF FLARES TO
RESTRICT SCOURING
ALONG TURF ew

       

TURF. STRIP Sy
BEHIND KERB RR
YN
RON road surface
Oy
Ry

GRASSED FILTER STRIPS

NOT TO REGULAR SCALE

STORMWATER TREATMENT DETAILS
SEDIMENT FLOCCULATION

SEDIMENT AND EROSION CONTROL

DETAILS

EARTH BUND CONSTRUCTION NOTES

1. BUILD WITH GRADIENTS BETWEEN 1 PERCENT AND 5 PERCENT.

2. AVOID REMOVING TREES AND SHRUBS IF POSSIBLE — WORK AROUND THEM.

3. ENSURE THE STRUCTURES ARE FREE OF PROJECTIONS OR OTHER IRREGULARITIES THAT COULD IMPEDE
WATER FLOW.

3. BUILD THE DRAINS WITH CIRCULAR, PARABOLIC OR TRAPEZOIDAL CROSS SECTIONS, NOT V SHAPED.

4. ENSURE THE BANKS ARE PROPERLY COMPACTED TO PREVENT FAILURE.

5. COMPLETE PERMANENT OR TEMPORARY STABILISATION WITHIN 10 DAYS OF CONSTRUCTION.

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BATTER GRADE
1:2: max.

 
   
 

 

     
  

CHANNEL STABILISATION “ITT | — V

y
UNDISTURBED
AREA

 

     
 
 

AS. REQUIRED aa
NOTE:— =| | |-=
Min. GRADE 0.25% TTT
Max. GRADE 0.75% —
MUST HAVE A ‘STABILISED OUTLET.
MAYBE USED AS CONTOUR DRAINS
CAN BE CONSTRUCTED WITH
OR WITHOUT CHANNEL
GRADIENT OF DRAIN ALL BATTER GRADES
2(H):1(V) MAX.
DIRECTION
OF FLOW
—- _
INI 300’mm min
150'mm min. / .
L : 5

NOTE: ONLY TO BE_USED AS TEMPORARY BANK
WHERE MAXIMUM UPSLOPE LENGTH IS 80 METRES.

EARTH BUND CUT OFF DRAIN

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

to be drawn together and settle under gravity.

METHOD OF APPLICATION

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.
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

should be calibrated after the first two storm events to assess the actual flocculent application rate and settling time required for the site.
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%).

METHOD OF TESTING THE STORMWATER

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

access so no sediment is resuspended while the testing is being conducted.

The stormwater detained in the sediment basin will be tested with the TPS 90-FLT water quality logger.

pH, turbidity and temperature of the stormwater.

The TPS 90-FLT unit samples and records the dissolved oxygen, conductivity,

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

water and then hold it up to the light.

METHOD OF DEWATERING

The sediment basin can be dewatered as soon as the water quality criteria met (refer table below).

settled sediments from being removed from the basin.
the sediment layer are not discharged in the pumping process.

STORMWATER DISCHARGE QUALITY CRITERIA

 

 

 

 

 

 

If seeing clearly through the sample is not possible, then the sample is probably above the 50 NTU level.

A pump is to be used to decant the basin with a floating inlet to prevent the

The pumping must cease prior to the settled sediments being drawn Into the intake pipe, If Is essential that materials from

 

 

 

 

 

ACCEPTABLE TSS ACCEPTABLE PH DISSOLVED 0,
50mg/L 65 — 85 > 80%
SEDIMENT BASIN FLOCCULENT APPLICATION
AGENT INDICATIVE DOSAGE COMMENTS PRECAUTIONS & CONSTRAINTS MIN. REQD. ON SITE
GYPSUM 32kg/100cub.m LITTLE PH CHANGE, SLIGHT INCREASE IN | NEEDS TO BE SPREAD EVENLY ACROSS POND. | 260 kgm
SALINITY CAN CAUSE SCUM DEPOSITS IN EQUIPMENT.

 

 

 

 

NOTE: NOTIFY ENGINEER TO CONFIRM DOSAGES & APPLICATION PRIOR TO USE.

   

J SEDIMENT

TYPICAL GRASS FILTER STRIP DETAIL

N.T.S.

     

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WHA
AN
NOC)

SURFACE _ROUGHENING

SPILLWAY

150 MM MIN. = 459 MM MIN.

|

ROCK TRENCHED 200 MM INTO GROUND

SPACING OF CHECK DAMS ALONG CENTRELINE
AND SCOUR PROTECTION BELOW EACH CHECK
DAM TO BE SPECIFIED ON SWMP/ESCP

ROCK CHECK DAM

ROCK CHECK DAM CONSTRUCTION NOTES

1. CHECK DAMS CAN BE BUILT WITH VARIOUS MATERIALS, INCLUDING ROCKS, LOGS, SANDBAGS AND STRAW BALES. THE
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.

2. TRENCH THE CHECK DAM 200 MM INTO THE GROUND ACROSS ITS WHOLE WIDTH. WHERE ROCK IS USED, FILL THE
TRENCHES TO AT LEAST 100 MM ABOVE THE GROUND SURFACE TO REDUCE THE RISK OF UNDERCUTTING.

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.

4. SPACE THE DAMS SO THE TOE OF THE UPSTREAM DAM IS LEVEL WITH THE SPILLWAY OF THE NEXT DOWNSTREAM
DAM.

         

STiBILISE STOCKPILE.
EARTH BANK SURFACE

SEDIMENT FENCE

TOPSOIL STOCKPILE

TOPSOIL STOCKPILE CONSTRUCTION NOTES

1. PLACE STOCKPILES MORE THAN 2 (PREFERABLY 5) METRES FROM EXISTING VEGETATION, CONCENTRATED.
WATER FLOW, ROADS AND HAZARD AREAS.

2. CONSTRUCTION ON THE CONTOUR AS LOW, FLAT, ELONGATED MOUNDS.

3. WHERE THERE IS SUFFICIENT AREA, TOPSOIL STOCKPILES SHALL BE LESS THAN 2 METRES IN HEIGHT.

4, WHERE THEY ARE TO BE IN PLACE FOR MORE THAN 10 DAYS, STABILISE FOLLOWING THE APPROVED.

ESCP OR SWMP TO REDUCE THE C—FACIRCUITOR TO LESS THAN 0.10.

. CONSTRUCTION EARTH BANKS (STANDARD DRAWING 5-5) ON THE UPSLOPE SIDE TO DIVERT WATER AROUND
STOCKPILES AND SEDIMENT FENCES (STANDARD DRAWING 6-8) 1 TO 2 METRES DOWNSLOPE.

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LINDSA Y CONSULTING [7 |

STRUCTURAL AND CIVIL

 

 

 
 
  

 

OFF. 2C/82 PARKER STREET/MAROOCHYDOR