19121- L03 - Further Information Request Response - Page 1 of 6 Our Ref: 19121 – Information Request Response 28 April 2020 ATT: WILL HARDY Logan City Council 150 Wembley Road, Logan Central QLD 4114 PO Box 3226 Logan City DC QLD 4114 Sent via email: [email protected]Dear Will, RE: MCUC/3/2020 – INFORMATION REQUEST RESPONSE 42A BAYES ROAD, LOGAN RESERVE QLD 4133 This letter forms a response to the Material change of use further information request provided by Logan City Council dated 2 nd April 2020 regarding the above development. STORMWATER QUALITY 2. Submit As the proposed development involves a material change of use on a premises greater than 2500m² the Stormwater quality management design objective must be achieved. Provide a Conceptual site based stormwater management plan or deemed to comply solution in accordance with Section 6.2.5 Planning scheme policy 5 – Infrastructure to demonstrate how the proposed development will achieve the stormwater quality design objective and the waterway stability design objective. Note: Stormwater Quality assessment is required for premises over 2,500m² as prescribed by the SPP trigger being “a material change of use for an urban purpose that involves a premises 2500m² or greater”. This is irrespective of the Development Area. PO Box 26, Carina, Qld 4152 www.vtce.com.au [email protected]1300 185 737 vT CONSULTING ENGINEERS PTY LTD (ACN 060 590 132), as Trustee for van Tonder Family Trust (ABN 73 781 850 547), trading as vT Consulting Engineers Pty Ltd
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19121- L03 - Further Information Request Response - Page 1 of 6
Our Ref: 19121 – Information Request Response
28 April 2020
ATT: WILL HARDY Logan City Council 150 Wembley Road, Logan Central QLD 4114 PO Box 3226 Logan City DC QLD 4114 Sent via email: [email protected] Dear Will,
RE: MCUC/3/2020 – INFORMATION REQUEST RESPONSE 42A BAYES ROAD, LOGAN RESERVE QLD 4133 This letter forms a response to the Material change of use further information request provided by Logan City Council dated 2nd April 2020 regarding the above development. STORMWATER QUALITY
2. Submit As the proposed development involves a material change of use on a premises greater than 2500m² the Stormwater quality management design objective must be achieved. Provide a Conceptual site based stormwater management plan or deemed to comply solution in accordance with Section 6.2.5 Planning scheme policy 5 – Infrastructure to demonstrate how the proposed development will achieve the stormwater quality design objective and the waterway stability design objective.
Note: Stormwater Quality assessment is required for premises over 2,500m² as prescribed by the SPP trigger being “a material change of use for an urban purpose that involves a premises 2500m² or greater”. This is irrespective of the Development Area.
PO Box 26, Carina, Qld 4152 www.vtce.com.au [email protected] 1300 185 737 vT CONSULTING ENGINEERS PTY LTD (ACN 060 590 132), as Trustee for van Tonder Family Trust (ABN 73 781 850 547), trading as vT Consulting Engineers Pty Ltd
William Hardy
Approved document
19121- L03 - Further Information Request Response - Page 2 of 6
Response: It is proposed to use a bio-retention/detention basin system to satisfy the water quality objectives as shown in Table 2.1 below. Water quality parameters and the proposed limits applicable to this site have been selected in accordance with SPP2014 Appendix 3, Table B and MUSIC Modelling Guidelines for South East Queensland Version (2010). It is proposed that best practice stormwater treatment be used and therefore it is required to be demonstrated that achieve the following load reduction targets:
POLLUTANT TYPES WATER QUALITY OBJECTIVE (WQO)
Total Suspended Solids (TSS) 80% reduction of average annual load
Total Phosphorus (TP) 60% reduction of average annual load
Total Nitrogen(TN) 45% reduction of average annual load
Litter/gross pollutants 90% reduction of average annual load
Table 2.1: Water Quality Objectives
The software program Model for Urban Stormwater Improvement Conceptualisation (MUSIC) Version 6, was used to assess pollutant generation and the performance of the stormwater treatment measures for the proposed development. Selection and testing of stormwater management options was undertaken in accordance with MUSIC Modelling Guidelines prepared by Water by Design (2010). The catchment was further split to include pavement areas, road areas and landscaped areas in accordance with the MUSIC Modelling Guidelines prepared by Water by Design (2010). The stormwater quality treatment train used in the MUSIC model is shown in the figure below.
19121- L03 - Further Information Request Response - Page 3 of 6
Figure 2.1 Music Model Treatment Parameters
The bioretention system is designed to treat the stormwater runoff by filtering the runoff through densely planted vegetation and percolating the runoff through the filter media. The proposed design is in accordance with the Water Sensitive Urban Design Technical Design Guidelines (by Water by Design) and a typical system is shown in the figure below.
Figure 2.2 Water by Design Bioretention System
19121- L03 - Further Information Request Response - Page 4 of 6
The bioretention treatment node parameters used in the MUSIC model are shown in the table below.
PARAMETER BIORETENTION
BASIN
Low Flow By-Pass (m3/s) 0.00
High Flow By-Pass (m3/s) 100
Extended Detention (m) 0.30
Surface Area (m2) 36
Filter Media Area (m2) 36
Sat. Hydraulic Conductivity (mm/hr) 200
Filter Depth (m) 0.60
TN Content of Filter Media (mg/kg) 600
Orthophosphate Content of Filter Media (mg/kg)
50.0
Exfiltration Rate (mm/hr) 0.00
Vegetated with Effective Nutrient Removal plants
Yes
Underdrain Present? Yes
Table 2.2: Water Quality Treatment Bioretention Nodes
Using the MUSIC software. The treatment train for the catchment areas was designed to comply with the water quality objectives (WQO). It was determined that the water quality objectives for the whole proposed development where met as shown in the table below:
POLLUTANT TYPES Pre-
Development Post-
Development Reduction
(%) Complying With WQO
Total Suspended Solids (kg/yr) 186 20.8 88.9
Total Phosphorus (kg/yr) 0.424 0.169 60.0
Total Nitrogen (kg/yr) 2.98 1.22 59
Litter/gross pollutants (kg/yr) 29.9 0 100.0
Table 2.3 Water Quality Treatment Results
As shown by the above results, the proposed stormwater treatment train adopts best practice stormwater treatment and will achieve the required Water Quality Objectives. The proposed design is in accordance with the Water Sensitive Urban Design Technical Design Guidelines (by Water by Design).
19121- L03 - Further Information Request Response - Page 5 of 6
It’s also proposed to utilise the proposed basin for detention requirement. The detention basin was sized using the XP Storm model, the results of which are shown in Figure 2.3. This figure shows comparisons of the flow events for pre- and post-development scenarios using a detention volume of 42m3. Importantly the stormwater flows for the developed scenario are less than the corresponding storm flows in the existing scenario.
Figure 2.3: Post Development Stormwater Hydrographs
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Table 2.4 below provides comparison between pre and post-development scenarios
following the XP Storm modeling for the site:
Event Pre-Development (l/s)
Post-Development (l/s)
2yr 25 20
5yr 43 27
10yr 46 33
20yr 56 52
50yr 86 69
100yr 99 77 Table 2.4 Pre- and Post-Development outlet flows
Settings within the XP Storm model are shown in Table 2.5 below:
Parameter Detention Tank
Detention Volume (m3) 42.00
Base Area (m2) 58.00
Minor Orifice Area (m2) 0.0177 (0.150m dia)
Major Orifice IL Above Minor Orifice IL (m) 0.55
Major Orifice Area (m2) 0.36 sqm Weir (600x600 gully pit)
Table 2.5 Detention Parameters
It is proposed that the stormwater drainage for the proposed development will be collected in pits and piped to the detention tank. Refer attached updated DWG NO. P003 for proposed layout plans and details. Also attached updated preliminary drawing set. Please do not hesitate to contact me should you require any further information.
Kind Regards Abbas Alkamachy Civil Engineer Encl. DWG NO. 19121-P001-B, 19121-P002-B, 19121-P003-C, 19121-P004-B & 19121-P005-C MUSIC Model
HD HD HOUSE DRAINAGE
BULK EARTHWORKS LEVEL (BEL)BEL0.000
LEGENDEXISTING PROPERTY BOUNDARY
PROPERTY BOUNDARY
EXISTING EASEMENT BOUNDARY
EASEMENT BOUNDARY
X X X X X X X X ABANDON EXISTING SERVICE
BUILDING
EXISTING BUILDING
EXISTING CONTOUR - MAJOREXISTING CONTOUR - MINOR
1.00
EXISTING KERB AND CHANNELSW EXISTING STORMWATER DRAINAGERW EXISTING ROOFWATER DRAINAGES EXISTING SEWERW EXISTING WATER
II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I
II
I
I
I
II
I
II
I
CONSTRUCTIONENTRY/EXIT
SEDIMENT FENCE
EXCAVATED SEDIMENT TRAP. CAPTURED DIRTYWATER TO BE DISCHARGED AFTER TREATING ANDSUCCESSFUL INDEPENDENT TEST RESULTS, ORDIRTY WATER TO BE DISPOSED OFF SITE BYVACUUM TRUCK AT APPROVED SITE. TYPICAL
RESIDENTIAL DEVELOPMENT 34-38 BAYES ROAD, LOGAN RESERVE 19121LACEY
DEVELOPMENTS
NOTES:1. REFER TO DRAWING C002 FOR TYPICAL DETAILS.
LAYOUT PLANSCALE 1:200
B 28.04.20 GENERAL AMENDMENTS SC AvT
OVERLAND FLOW
TYPICAL SEDIMENT FENCE SECTIONNOT TO SCALE
50 x 50 HWD STAKEOR STEEL PICKET1200 MIN LONG
0.20
BACKFILL
FIX TO TOP OF STAKE WITHSHADECLOTH FASTENEROR TIE TO STEEL PICKET
GEOTEXTILE FABRIC ANDSL42 MESH
0.60 N
OMIN
AL
TYPICAL SEDIMENT FENCE ELEVATIONNOT TO SCALE
OVERLAND FLOW
TYPICAL EXCAVATED SEDIMENT TRAP SECTIONNOT TO SCALE
50 x 50 HWD STAKEOR STEEL PICKET1200 MIN LONG
SEDIMENT FENCE AND1m WIDE SEDIMENTWEIR TO DETAIL
0.50
3.0 SQUARE
SEDIMENT TRAP. MONITORDAILY OR AFTER HEAVY
RAINFALL AND CLEAN ASREQUIRED
II
ORANGE SAFETYMESH AROUND TRAP
CONSTRUCTION SITE
KERB & CHANNEL
PROPERTY ALIGNMENTEXISTING, OR NEW ROADWAY
TYPICAL CONSTRUCTION ENTRY/ EXITNOT TO SCALE
RUNOFF TO BE DIRECTED
TO A SEDIMENT TRAP
GEOTEXTILE FABRIC BIDUMU34 OR SIMILAR
3.0m MIN.
NOMI
NAL
100m
m
300m
m
10.0m MIN.
WELL GRADED, HARD,ANGULAR, EROSION RESISTANT
75mm CRUSHED ROCK
300m
mMI
N.
EXISTING KERB AND CHANNEL TO BEPROTECTED DURING CONSTRUCTIONAND REINSTATED IF DAMAGED
TYPICAL SAG KERB INLET SEDIMENT TRAPNOT TO SCALE
SIDE INLET TO REMAIN OPENFILTER SOCKGULLY GRATE WRAPPED IN NON-WOVENFILTER FABRIC (MINIMUM BIDIM A34 ORAPPROVED EQUIVALENT
50 x 50 HWD STAKEOR STEEL PICKET1200 MIN LONG
TYPICAL SEDIMENT WEIR ELEVATIONNOT TO SCALE
0.30
SPILL THROUGHWEIR
EXISTING/ PROPOSEDFIELD INLET
EXISTING GRATE TO BE WRAPPED INNON-WOVEN FILTER CLOTH (WOVEN
SEDIMENT FENCE FABRIC TO ONLY BEUSED IN HEAVY TRAFFIC AREAS)
EXISTING OUTLET PIPE.REFER TO PLAN FOR
DETAILS
TYPICAL FIELD INLET SEDIMENT TRAPNOT TO SCALE
SEDIMENT COLLECTION PIT TO BEEXCAVATED ALL AROUND INLET.MONITOR DAILY OR AFTER HEAVYRAINFALL AND CLEAN AS REQUIRED
0.20
0.20
REMOVE SEDIMENT ANDREINSTATE TO MATCHEXISTING FOLLOWING
COMPLETION OF ALL WORKS.
ENVIROPOD BASKET TOMANUFACTURERS SPECIFICATIONS.CONTRACTOR TO ENSURE THATBASKET IS KEPT CLEAN AND FREEOF DEBRIS. BASKET TO BE CLEANEDIMMEDIATELY PRIOR TO HAND OVEROF PROJECT
NOTE:· INLET SEDIMENT TRAP TO BE PLACED ON ALL
EXISTING INLETS WITHIN 50m OF SITE· INLET SEDIMENT TRAP MAY BE OMITTED
WHERE IT CAUSES A SAFETY HAZARD, BUT ISTO BE PROVIDED PRIOR TO A RAINFALL EVENT
OVERLAND FLOW50 x 50 HWD STAKE OR STEELPICKET 1200 MIN LONGDRIVEN 600mm INTO GROUND
GEOTEXTILE FABRIC AND SL42 MESH TOAS1304. FABRIC TO BE LAPPED AT LEAST ONESEGMENT LENGTH (STAKE TO STAKE).
DISTURBED AREA
UNDISTURBED AREABACKFILL
3.0m MAX. WITH MESH
2.0m MAX. WITHOUT MESH
1m RETURNS TO BE INSTALLED AT20-30m SPACINGS ALONG ANYSEDIMENT FENCING WITHOUT
REGULAR SEDIMENT TRAPS
OVERLAND FLOW
SPILL THROUGH WEIR AT20-30m SPACINGS
NOTE:MAXIMUM 180m2 CATCHMENT TOEACH 3mX3m EXCAVATED SEDIMENTTRAP AS A TYPE 2 DEVICE
SETTLING ZONE
SEDIMENT STORAGE ZONE
0.50
11
NOMINAL PIT. SIZE TOTABLE
LIGHT DUTY (CLASS C) BOLTDOWN LID. TYPICAL
CONCRETE BASE.MINIMUM 150mm THICK
FALL
OUTLET PIPE. REFERTO PLAN FOR DETAILS
TYPICAL GRATED PIT (G.PIT) DETAILSCALE 1:20
ENVIROPOD BASKET (OR APPROVEDEQUIV.) TO MANUFACTURERSSPECIFICATIONS. ENSURE BASKET ISINSTALLED AT HEIGHT TO ENSURETHAT OUTLET PIPE IS NOT BLOCKED.BASKET TO BE INSTALLED IN ALLSTORMWATER INLET STRUCTURES.
EXISTING 150Ø DICL WATER MAIN EXISTING 100Ø DICL WATER MAIN
EXISTING 150Ø PVC-M WATER MAIN
EXISTING FH EXISTING FHEXISTING FH
PROPOSED DN40 WATER METER TOSERVICE PROPOSED SITE TO SEQWATER STD DWG No. SEQ-WAT-1107-3
DN63 PE SERVICE, MAIN TO METER ANDCONDUIT TO SEQ WATER STD DWG No.SEQ-WAT-1107-1. COVER BENEATH ROADTO BE 600mm MIN WITH 100Ø CONDUIT.REINSTATE ROAD TO SEQ WATER STDDWG No. SEQ-WAT-1204-1 AND TRENCHRESTORATION TO IPWEAQ STD DWG NO.RS-170
W
LIVE CONNECTION TO EXISTINGWATER MAIN. TAPPING BAND ANDBALL VALVE TO SEQ WATER STDDWG No. SEQ-WAT-1107-2
