Xpert Witness Statement

Expert Witness Statement

1. Full Name: Cameron Farrar

2. Company Name: St. Quentin Consulting

3. Position: Geotechnical Manager

4. Address: 51 Little Fyans Street, Geelong VIC 3220

Education and Career

• I am a qualified geotechnical engineer with a graduate degree from University of Ballarat.

• I have been working as a professional engineer for 21 years. My early experience has included specialist geotechnical consultancy in Country Victoria and Metropolitan Melbourne. For the last 9 years I have been based in the Geelong area however have continued to work in various locations throughout the state.

• My experience has included all facets of geotechnical engineering, including domestic and commercial construction that has included field investigation, field testing, analysis and design. Details are included in Annexure A

• Memberships: Institute of Engineers, Australian Geomechanics Society (AGS), C.E.T. certified training (specific to land capability assessment for domestic water), Australasian Land & Groundwater Association (ALGA) Ltd.

Relevant Expertise

I have conducted numerous land capability assessment investigations for onsite wastewater disposal in a variety of soil conditions across the State of Victoria, including:

• Land Capability Assessment consultancy services within the greater Geelong Region for private and government organisations including City of Greater Geelong, Surf Coast Shire and Golden Plains Shire including advisory and peer review services.

• I have conducted land capability assessment investigations specific to and within the Golden Plains Region for at least 20 years.

Scope of Report

• St Quentin Consulting has been requested by our client, Ramsey Property Group to provide a preliminary report to inform domestic wastewater in proposed low- density residential development areas affected by the proposed C87 Amendment, Inverleigh.

• Our report includes:

o Review of data, including geology and geomorphology, aerial photos and previous investigations

o Review of council correspondence, including resident submissions and • Assessment of design thickness against the as-built thickness

• Assessment of possible causes of pavement failure

Report on Findings

• My findings are set out in the accompanying report 16472G, Preliminary Assessment Report, C87 Amendment, March 2020

Declaration

I declare I have made appropriate inquiries regarding the matters in question and have not withheld any information relevant to the case.

• • • •

CAMERON FARRAR Manager Geotechnical Engineering

16/03/2020

Page 2

Annexure A - Qualifications

Relevant Qualifications University of Ballarat, Bachelor of Engineering (Civil) 1995

Employment History 2015- ongoing: Geotechnical Engineer Manager; St Quentin Consulting 2010-2015: Branch Manager/ Geotechnical Engineer; Saunders Consulting 2001-2010: Geotechnical Engineer; Structural Works 1998-2000: Geotechnical Engineer; Black/Central Victoria & Riverina Geotechnical 1996-1997: Civil Engineer; City of Ballarat

Selected Client List • City of Greater Geelong • Surf Coast Shire • Golden Plains Shire • City of Ballarat • Borough of Queenscliffe • Fulton Hogan/VicRoads Alliance • Ford Asia Pacific • Deakin University • GHD • Beveridge Williams • Tract • Lend Lease • Holcim • Jacobs • Icon Group • Kane Constructions

Professional Associations Institute of Engineers Australia Australian Geotechnics Society Australasian Land & Groundwater Association (ALGA) Ltd.

Page 3

PRELIMINARY LAND CAPABILITY ASSESSMENT REPORT

Amendment C87 Inverleigh Structure Plan, Inverleigh

Prepared for: Ramsey Property Group

Report No: 16472G-LCA

March 2020 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

CONTENTS SECTION PAGE

1.0 EXECUTIVE SUMMARY ...... 1 2.0 INTRODUCTION ...... 3 3.0 PRACTITIONER ...... 3 4.0 PROPOSED DEVELOPMENT ...... 3 5.0 SITE FEATURES ...... 3 6.0 TESTING PROGRAM AND RESULTS ...... 4 6.1 SOIL PROFILE AND GEOMORPHOLOGY ...... 4 6.2 WATER TABLE ...... 6 6.3 LAND ASSESSMENT AND CONSTRAINTS ...... 6 6.4 SOIL ASSESSMENT AND CONSTRAINTS ...... 8 6.5 GOLDEN PLAINS DOMESTIC WASTEWATER MANAGEMENT PLAN (DWMP) MINIMUM REQUIREMENTS 8 6.6 WASTEWATER VOLUME ...... 9 6.7 ORDINARY COUNCIL MEETING, 26 NOVEMBER 2019 KEY OBJECTIONS ...... 9 7.0 CONCLUSIONS AND RECOMMENDATIONS ...... 10 7.1 EFFLUENT DISPOSAL AREA SITING ...... 10 7.2 RESERVE FIELD ...... 11 7.3 VEGETATION COVER ...... 11 7.4 DRAINAGE MANAGEMENT ...... 11 7.5 MONITORING, CARE AND OPERATION ...... 11 REFERENCES ...... 13

REPORT LIMITATIONS AND GENERAL ADVISE ...... ADDENDUM

16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

1.0 EXECUTIVE SUMMARY

The purpose of our preliminary land capability assessment report is to provide specific expertise relating to land capacity (capability) for domestic wastewater treatment following proposed amendment C87 Inverleigh Structure Plan, that will see potential increase of low-density residential land with minimum allotment sizes of 4000m2. Our assessment pertains specifically to land holdings managed by Ramsey Property Group.

We have judged that practical implementation of development sites of this size are feasible. However, any development needs to consider area constraints, (most notably the anticipated ‘slow’ soil permeability and other relevant but relatively isolated constraints including inundation/flood zones, waterways and steep areas).

Each effluent system requires appropriate planning and design and must consider requirements outlined in the Golden Plains Domestic Wastewater Management Plan 2nd Edition Volume 2 (DWMP), EPA Code of Practice Onsite Wastewater Management 891.4 July 2016 and Australian Standard AS/NZS1547:2012 On-site Domestic Wastewater Management.

However, subject to constraints and our specific recommendations the dispersal of wastewater in the region poses a low and manageable environmental risk.

We understand a single objector raised the following queries relating domestic wastewater: • Possible seepage, • Adding to nutrient load of Leigh River.

We can offer the following specific response relating to these queries:

1) Wastewater designs (included recommend treatment and disposal field) are based on EPA guidance, Australian Standard and Golden Plains Shire DWMP that ensure a low and manageable environmental risk. The principle objective of guidelines is to ensure that wastewater remains onsite. The proposed development sites, in-context with these guidelines is not significant, given multiple safety factors integrated into the design procedure, including and not limited to: a) Inherent high wastewater load volumes recommended by AS/NZS1547:2012 b) Capped bedroom frequency (wastewater load), to reduce accumulative load recommended by Golden Plains Shire DWMP

2) The distance to the river edge (and any inferred flood zone) is substantial and therefore the risk of impact from untreated wastewater would be unlikely. 3) Nutrient load in the anticipated constraining ‘clay’ stratum is not expected to be critical, compared to sandy soils, which have higher limitations to nutrient loading.

We have judged the proposed minimum allotment sizes of 4000 m2 are appropriate given the proposed development size. However, in accordance with Golden Plains DWMP the bedroom frequency (which is used to determine the wastewater load), be limited to 4 bedroom residences. This is required to reduce the accumulative impact of development. Note however, we have judged that where allotment sizes exceed 4,500m2 5 bedroom residences will be possible. Similarly, large capacity dwellings are possible, provided the allotment size is scaled appropriately (refer Table 2).

Final development layout would be subject to a detailed land capability assessment, which would delineate any areas of concern (key constraints) and must include exploratory test, in-situ permeability and laboratory testing.

Based on the above, we consider that suitably treated household wastewater can be dispersed and retained on the allotments with low and acceptable environmental risk to the development areas and adjoining land and environment.

Page 1 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

As a minimum, we recommend that the proposed household wastewater receive secondary treatment and that the treated effluent be dispersed by any appropriate method (that usual includes shallow pressure compensated sub-surface irrigation or alternatively evapotranspiration bed). Secondary treatment is required to ensure that '20/30 standard' (i.e. 20 mg/l Biochemical Oxygen Demand and 30 mg/l Suspended Solids) effluent is produced prior to land application by an appropriate method. Treatment of household wastewater to '20/30 standard' with treated wastewater dispersion will maximise the potential for evapo-transpiration and minimise the risk of contamination of adjoining sites.

Note that the above requirement of ‘secondary treatment’ is not unique to the proposed development area and a minimum requirement for all onsite wastewater treatment in Victoria (in accordance with EPA Code of Practice Onsite Wastewater Management 891.4 July 2016) and will maximise the likelihood for a safe and sustainable environmental outcome for the site and the surrounding sites. Note that the use of ‘primary treatment’, is not recommended for domestic wastewater, in accordance with EPA guidance.

The treated effluent field must be positioned in accordance with offset and siting requirements as outlined in section 7.1 of our report ‘Effluent disposal area siting’.

Guidance is given concerning the design and layout of suitable systems.

Final approval is subject to any specific policy requirements or other limiting environmental constraints not previously brought to our attention.

Important information concerning the limitations of our investigation and of this report as well as General Recommendations and Advice is given in the attached “Land Capability Assessment Addendum” which must be read in conjunction with this report.

Page 2 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

2.0 INTRODUCTION

St Quentin Consulting was commissioned by the client Ramsey Property Group to provide a Preliminary Land Capability Assessment report for the proposed Amendment C87 Inverleigh Structure Plan development area. The report aims to provide an overview of the domestic wastewater requirements and also identify possible regional constraints in the proposed development area managed by Ramsey Property Group.

The aims of the assessment were:

1. To assess various features of the region in their present condition in accordance with published standards and guidelines, principally various Septic Tanks Codes published by EPA Victoria and others. 2. Recommend an appropriate and environmentally sustainable treatment and disposal method for domestic wastewater.

3.0 PRACTITIONER

The author of this report is Cameron Farrar who is a professional geotechnical engineer with a Bachelor of Engineering degree and registered member of Engineers Australia and of Australian Geomechanics Society. The author has more than 20 years of experience in the land capability assessment for effluent disposal.

4.0 PROPOSED DEVELOPMENT

The proposed development involves the development of privately owned land holdings, currently farm zoned into residential low-density residential development with allotments of about 4000 m2.

5.0 SITE FEATURES

The subject site is on the east side of Amendment C87 Inverleigh Structure Plan, with two main regions, with one area bound by Common Road (to the east) and the Leigh River (to the west), and a separate area bound by Hopes Plain Road (to the east) and various existing large land parcels (to the west). A satellite view of the site is presented in Figure 1. The site is virtually flat. The site aspect is good with respect to exposure to sunshine and wind. Surface drainage is considered to be poor. The natural soil types comprise sands and clays prominently developed from Tertiary age sediments (Black Rock Sandstone). The site is generally clear of trees.

I am also instructed that the Brethon Park land, being the eastern lot of the two lots adjacent to the Leigh River, is subject of a planning permit and has had plans for subdivision endorsed which create lots of 0.45 hectares.

Page 3 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

Figure 1: Aerial photograph of the site and proposed RPG development area, nearmap.com.

6.0 TESTING PROGRAM AND RESULTS

6.1 Soil profile and geomorphology A preliminary inspection of the study area was completed by a qualified geotechnical engineer to visual appraise the site features and identify any important land features. A desktop study was conducted to assess soil descriptions in published reports, maps and charts from Department of Primary Industries (DPI) and other sources.

The resulting soil and land description is as follows:

Landform: Plains Limiting Geology: Residual clay derived from Tertiary age sediments Aust. Soil Classification: Brown Vertosol

Geology mapping with contours is presented in Figure 2. A description of the soils typically encountered during our drilling and sampling is presented on the attached sheet in Appendix B.

Page 4 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

Legend Geological Features Development boundary

Alluvium deposits

Newer Volcanic Group-basalt flows Watercourse / waterbody

Batesford Limestone

Blackrock Sandstone

Figure 2: Site geology, source: geovic.vic.gov.au

Page 5 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

Legend Overlay Development boundary

LSIO: land subject to inundation overlay

FO: flood overlay

Figure 2: Site geology, source: geovic.vic.gov.au

6.2 Water table No permanent or perched water table was encountered during testing however a transient perched water table may develop in very wet conditions above the clay layer. For this reason, it is important upslope and downslope cut-off drains are provided to prevent/reduce transient water flows near the effluent area.

6.3 Land assessment and constraints Various features of the site were assessed in accordance with the guidelines of the EPA Publications and reported in accordance with constraint levels outlined in VLCA-2nd Ed.

Page 6 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

Our preliminary assessment has found key land constraints include:

• steep areas, that may or may not exhibit potential erosion (isolated regions only) • flood/inundation areas (isolated regions only)

Whilst areas impacted by erosion and flood/inundation remain a key constraint, we understand they not utilised as residential development. These areas will be delineated subject to geotechnical detailed studies to inform the final overall development plan. Table 1 shows key land constraints.

Table 1: Land Constraints Level of Result Mitigation Constraint Buffer distances achievable. Refer to Buffer Distances section 7.1 for relevant offset Nil Not Required requirements Rainfall approximates Median rainfall* evaporation in the wettest Bannockburn ~ 515 mm/yr, Climate Minor months. Adopt shallow Median evaporation# subsurface irrigation and Durdidwarrah ~ 1125 mm/yr cut-off drains Drainage Proposed effluent area well drained Nil Not Required Requires assessment by a Erosion or Potential for erosion noted on site Moderate suitable qualified Landslide Risk geotechnical engineer Good exposure to wind and sun: Exposure & surrounding area consisting of open Nil Not Required Aspect grassland Ensure minimum 30m Flooding not evident Flooding Moderate offset from development (>1:100 year flood level) areas to 1:20 flood level Groundwater Groundwater not evident above 1.8 m Nil Not Required Imported Fill Likely minor disturbed surface+ Minor Not Required The site receives negligible run-off and Site Drainage Nil Not Required provides significant run-on. Slope Generally low slope angle (<5°) Nil Not Required No significant features were noted on Requires assessment by a or near the site, aside from the river Landform Minor suitable qualified terraced region, adjacent to the Leigh geotechnical engineer River Vegetation Good grass cover Nil Not Required Re-location of existing Surface Waters Drainage course within 30m Major effluent disposal area required Rock Outcrops Not present Nil Not Required Considering the site constraints and Adopt a maximum 5 proposed development size the Lot size Minor bedroom dwelling to limit allotment has sufficient area for effluent effluent load disposal * Closest / longest rainfall recording station record in the area. # Closest / longest evaporation recording station record in the area.

Based on the land assessment criteria, we have judged the land capability of the site is acceptable, provided constraints are addressed with corresponding and appropriate mitigation measures.

Page 7 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

6.4 Soil assessment and constraints We have previously conducted testing near the proposed development area, in very similar geological and geomorphic conditions. Based on this, we anticipate the limiting geological stratum as strongly structured ‘sandy clay’. As outlined in AS/NZS1547:2012 we have adopted an indicative permeability (Ksat) of < 0.06 m/day and a drip irrigation rate of 2 mm/day.

This is regarded as a low permeability rate (lowest suggested in AS/NZS1547:2012), which is conservative but judged to be appropriate for the purposes of design. However, based on the above soil assessment criteria, we have judged the soil capability of the region is acceptable subject to relevant outlined mitigation procedures.

6.5 Golden Plains Domestic Wastewater Management Plan (DWMP) minimum requirements The implementation of the Golden Plains Domestic Wastewater Management Plan (DWMP) in July 2015, authored by RMCG, suggested minimum requirements for smaller proposed unsewered residential development.

Specifically, the following minimum requirements have been outlined:

The minimum lot size for subdivision in unsewered areas is 4,000 m2, subject to:

• Maximum of 15% of each lot is to be set aside for land application areas • House size is limited and water reduction fixtures/fittings used to achieve 750 L/day • Secondary treatment and drip irrigation with a minimum land application area of 375 m2 • Stormwater cut-off drains upslope of land application area • Soil preparation to provide at least 150mm depth of good quality topsoil (in-situ or imported) • Application of gypsum to clay based soils

We have judged the adoption of these figures is arbitrary and not based on scientific data or legislative requirements, however we accept the principle purpose of this policy is to reduce the cumulative impact of the total effluent load.

Using the Golden Plains DWMP 15% methodology and based on Table 2, shown below and Table 2 and 4-1 within the Golden Plains DWMP we have calculated the following effect on minimum irrigation areas and corresponding lower limit of allotment sizes. We have judged these minimum allotment sizes are conservative, when considering the guidance offered in the most recent EPA Code of Practice Onsite Wastewater Management 891.4 July 2016 and Australian Standard AS/NZS1547:2012 On-site Domestic Wastewater Management.

Table 2: Minimum allotment size Minimum land application Daily Wastewater Minimum land application Minimum area required based on a House size volume / max subsurface irrigation area allotment 15% of allotment area flows (L/day) (m2) size (m2) with setbacks (m2) 3 bedrooms 600 300# 465## 3,000## 4 bedrooms 750 375# 580# 4,000# 5 bedrooms† 900 450# 675## 4,500## 6 bedrooms† 1,050 525## 790## 5,300## 7 bedrooms† 1,200 600# 900# 6,000# 11 bedrooms† 1,800 900# 1,200# 8,000# † Residence sizes > 5 bedrooms not recommended for development sites equal to our less than 4,500m2. # Golden Plains data: Golden Plains DWMP Volume 2 – Technical Reports, Table 2 and 4-1 ## Interpolated data from Golden Plains data: Golden Plains DWMP Volume 2 – Technical Reports, Table 2

Page 8 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

6.6 Wastewater volume In accordance with the EPA Code of Practice Onsite Wastewater Management 891.4 July 2016 and Australian Standard AS/NZS1547:2012 On-site Domestic Wastewater Management the following daily wastewater flows can be adopted:

Unlimited water supply (where a reticulated water supply is proposed) Daily flow = (No of bedrooms + 1) x 150 litres per day

Limited water supply (where water is sourced only from rain water collection from roofs) Daily flow = (No of bedrooms + 1) x 120 litres per day

Given the location of the site, and proximity to reticulated water supply we have adopted unlimited water supply.

On this basis we recommend the estimated wastewater volume produced to be:

• 900 L/day (5 bedroom residence bedroom residence) • 750 L/day (4 bedroom residence bedroom residence) • 600 L/day (3 bedroom residence bedroom residence)

6.7 Ordinary Council Meeting, 26 November 2019 Key Objections We understand a number of concerns were raised in submissions relating to proposed Amendment C87 Inverleigh Structure Plan, as detailed in the Ordinary Council Meeting, 26 November 2019.

We understand a single objector raised the following queries relating domestic wastewater: • Possible seepage, • Adding to nutrient load of Leigh River.

We can offer the following specific response relating to these queries:

1) Wastewater designs (included recommend treatment and disposal field) are based on EPA guidance, Australian Standard and Golden Plains DWMP that ensure a low and manageable environmental risk. The principle objective of guidelines is to ensure that wastewater remains onsite. The proposed development sites, in-context with these guidelines is not significant, given multiple safety factors integrated into the design procedure, including and not limited to: a) Inherent high wastewater load volumes recommended by AS/NZS1547:2012 b) Capped bedroom frequency (wastewater load), to reduce accumulative load recommended by Golden Plains Shire DWMP

Page 9 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

7.0 CONCLUSIONS AND RECOMMENDATIONS

Our land capability assessment has established that the proposed Amendment C87 Inverleigh Structure Plan lot subdivision is acceptable for effluent disposal. However, our assessment has identified some constraints (most notably the anticipated ‘slow’ soil permeability and other relevant but relatively isolated constraints including inundation/flood zones, waterways and steep areas) which will need to be considered to enable safe and sustainable on site effluent disposal.

These constraints do not prevent the satisfactory completion of the proposed development however the effluent system does require appropriate planning and design. Subject to constraints and our recommendations the dispersal of wastewater on the development poses a low and manageable environmental risk.

We have judged the proposed allotment size (of ≥4000 m2) is appropriate for effluent disposal given the site constraints.

Given the proposed allotment sizes and total development area we recommend the majority of sites be limited to 4 bedroom residences (750 L/day). Where allotment sizes exceed 4,500m2 we have judged 5 bedroom residences will be possible.

In accordance with the Golden Plains DWMP we recommend a maximum of 15% of the land area be reserved for effluent disposal (based on Table 2 and 4-1 of the DWMP). This will reduce the accumulative impact of treated effluent and allow optional disposal siting and a significant area for access roads, dwelling and outbuilding locations as required.

Based on our assessment we consider that suitably treated household wastewater can be dispersed and retained on the allotments with a very low and acceptable environmental risk to this and adjoining land.

Secondary treatment is recommended and required so that '20/30 standard' (i.e. 20 mg/l Biochemical Oxygen Demand and 30 mg/l Suspended Solids) effluent is finally produced prior to dispersal on the land by sub-surface irrigation. Treatment of household wastewater to '20/30 standard' with dispersal of the treated wastewater by sub-surface irrigation will maximise the potential for evapo-transpiration and minimise the risk of contamination of adjoining sites. This will ensure a sustainable environmental outcome for the site and the surrounding sites.

7.1 Effluent disposal area siting We have judged there are no specific restrictions on the effluent disposal siting, notwithstanding minimum offset requirements presented below.

The effluent irrigation area must be located as follows:

1. In an area not subject to vehicular traffic. 2. No closer than 3.0m from a gas or water pipe (primary treatment). 3. No closer than 3.0m on the low side or 6.0m on the high side of a property boundary (primary treatment). 4. No closer than 1.5m from a gas or water pipe (secondary treatment). 5. No closer than 1.5m on the low side or 3.0m on the high side of a property boundary (secondary treatment). 6. No closer than 3.0m from a swimming pool or stormwater drain. 7. No closer than 7.5m from an underground tank, cutting or escarpment. 8. No closer than 10m from a non-potable groundwater bore. 9. No closer than 30m from a dam, stream or channel (non-potable). 10. No closer than 100m from a stream or river in a potable water supply catchment.

Page 10 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

The irrigation area must be permanently dedicated and marked with at least two clear warning signs and the sub-surface irrigation drippers must be permanently fixed to distribution lines buried at least 200 mm deep.

7.2 Reserve field The EPA Septic Tanks Code of Practice requires that provision for a “reserve” effluent disposal field in the event that the primary disposal field fails, proves to be inadequate or needs to be rested. The reserve field must be not less than the size of the primary field and must be located on the site in compliance with all the minimum setback distances etc. as described above.

Note that a reserve field is not required for wastewater that has been treated to '20/30 standard', as is proposed for this site.

7.3 Vegetation cover Efficient effluent disposal assumes good vegetative cover. Therefore, it is recommended to establish and maintain grasses over distribution lines, with suitable trees and shrubs in the spaces between the lines. Such vegetation can significantly assist the overall disposal process by transpiration from leaves and by maintaining soil permeability through fine root channels. Refer to the attached “Land Capability Assessment Addendum” for additional information and indicative list of suitable plant species.

Large trees should be retained wherever possible. Where large tree removal is necessary, they should be cut off at ground level with the root structures left intact.

7.4 Drainage management Careful attention to drainage is essential to reduce risk of system failure. Surface water must therefore be prevented from ponding anywhere on or near the site.

The drains must be positioned and constructed with sufficient fall to discharge completely to prevent water from accumulating in the soil anywhere near the buildings. Any blockages must be cleared and repaired promptly.

Care must also be taken to ensure that all levelled areas (vehicle parking bays, recreation areas etc.) have a slight fall (≥2°) to prevent surface water from ponding or seeping into the ground and diverted away from the buildings.

7.5 Monitoring, care and operation Secondary treatment is required so that '20/30 standard' (i.e. 20 mg/l Biochemical Oxygen Demand and 30 mg/l Suspended Solids) effluent is finally produced prior to dispersal on the land by sub-surface irrigation. Treatment of household wastewater to '20/30 standard' with dispersal of the treated wastewater by sub-surface irrigation will maximise the potential for evapo-transpiration and minimise the risk of contamination of adjoining sites.

The septic system requires regular servicing and maintenance by an approved contractor to meet the conditions on the council approval certificate and the requirements of the manufacturer to ensure that the minimum '20/30 standard' of effluent is consistently achieved.

A healthy system should include a biological scum on the surface and be relatively free from strong odours. We recommend the effluent disposal system be checked by a suitably qualified plumber / drainer every 12 months. The tank level and quality should also be assessed. If necessary, the tank should be ‘desludged’ i.e. pumped out and any faulty mechanics repaired. Desludging is required concurrently at 3 to 5 year intervals. Similarly, when constructed, sand filter media should be checked concurrently every 3 to 5 years and media replaced where required. Drainage lines should be checked for blockages or fixture failures. Grease trap should be checked for blockages and pumped every 6-12 months.

Page 11 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

The following guidelines regarding the care and operation of septic tanks as recommend in the EPA Septic Tanks Code of Practice:

• Restrict germicides such as strong detergents, disinfectants, toilet clears with high acid content, nappy sanitisers, bleaches etc. that are likely to kill bacteria and affect the operation of the septic system, • Use cleaning products, detergents etc. sparingly and check their suitability for septic tank systems, • Use detergents with low levels of salt, phosphorus and chlorine. Detergents with low phosphorus and sodium are best suited for septic tanks and the environment. For more information regarding detergents we highly recommend visiting Lanfax Laboratories at lanfaxlabs.com.au under “Laundry Products Research” and click the downloadable “laundry brochure”. • Do not flush sanitary napkins, disposable nappies or similar products into the system, • Minimise the amounts of oil and fat washed into the system, • Use a sink strainer to restrict food scrapes entering system, • Do not use garbage disposal units, • Where odours occur, we recommend flushing approximately one cup of lime each day, • To reduce odours, we recommend filling the tank with water after installation or after desludging, • Grease trap should be checked for blockages and pumped every 6-12 months, • Inspect the system once a year by a qualified plumber or drainer, • Tank should be pumped concurrently every three years, • Do not modify the system without council approval, • Conserve water.

Prepared by: Reviewed by:

C. Farrar (B. Eng, MIE Aust) O. Reyes (B. Civil Eng, MIE Aust) Geotechnical Manager Geotechnical Engineer St. Quentin Consulting Pty Ltd St. Quentin Consulting Pty Ltd

Page 12 16472G-LCA Amendment C87 Inverleigh Structure Plan, Inverleigh

References

Australian Standard AS/NZS1547:2012 On-site Domestic Wastewater Management, Standards Australia, 2012

Australian Standard AS1726-2017 Geotechnical site investigations, Standards Australia, 2017

Australian Soil Resource Information System (ASRIS). Accessed March 2020 https://www.asris.csiro.au

EPA Publication 891.4 Code of Practice - Onsite Wastewater Management, July 2016

EPA Publication 746.1 Land Capability Assessment for Onsite Domestic Wastewater Management, March 2003

GeoVic 3 Energy and Earth Resources, State Government of Victoria. Accessed March 2020 http://www.energyandresources.vic.gov.au/earth-resources/maps-reports-and-data/geovic

Google Earth. Accessed March 2020 https://earth.google.com/web/

Nearmap, nearmap.com. Accessed March 2020 https://au.nearmap.com/

RMCG Golden Plains Shire Domestic Wastewater Management Plan Volume 1 Report, July 2015

RMCG Golden Plains Shire Domestic Wastewater Management Plan Volume 2 Report, July 2015

Victorian Land Capability Assessment Framework, VLCA-2nd Ed, January 2014

Page 13

LAND CAPABILITY ASSESSMENT ADDENDUM

LIMITATIONS

The purpose of this report is to determine the capability of the site to contain effluent with regard to the soil and land constraints. It is beyond the scope of this report to provide specific effluent system design. Where any variation or anomalies are encountered, we recommend additional investigation and reporting by us to resolve any potential issues.

This report has been prepared by qualified persons and based on current available standards.

Recommendations are based on information regarding the site and development type provided by the client Ramsey Property Group. If information supplied is not accurate or if significant changes are required, our report may be inappropriate. We cannot accept responsibility for significant changes and anticipate additional fees should further tests or report update be required.

We have prepared this report for this project at Amendment C87 Inverleigh Structure Plan, Inverleigh in accordance with the scope of works provided by the client. This report has been prepared for the sole use of Ramsey Property Group or authorised agents. Therefore, it should not be used for any other different purpose or used by a non-authorised agent or third party.

Whilst care has been taken to accurately report on the sub-surface conditions across the site it is not possible to anticipate unexpected sub-surface variations given the limited testing performed. Therefore, further testing may be required where significant variations on sub-surface conditions are encountered.

St Quentin Consulting does not accept responsibility for our report where it has been altered or not reproduced in full, including addendum.

Changes in legislative policy may require report update or additional testing.

GENERAL COMMENTS

Dimensions, slope, test locations are approximate only and must not be used for calculation of positioning.

Offset distance to septic tanks or any subsurface excavations must not exceed the minimum angle of repose for the in-situ naturally occurring soil. We estimate the maximum angle of repose for sand is 30° and 45° for clay soils. We do not recommend steeper angles unless competent rock is encountered.

VEGETATION FOR TRANSPIRATION

Good vegetative cover is important to achieve effective transpiration of effluent disposal. It is therefore recommended to establish and maintain good grass cover over distribution areas and suitable shrubs or trees between distribution lines. Where trees are planted near drainage line, difficulties with root invasion can be anticipated. We do not recommend planting crops in disposal area.

The following list includes some suitable water tolerant plants:

Botanical Names Common Names Phragmites australis Canna x generakis Canna Lily, Calla Lily, Ginger Lily Acacia Howittii Sticky Wattle Callistemon citrinus Crimson Bottlebrush Callistemon macropunctatus Scarlet Bottlebrush Leptospermun lanigerum Wooley Tea-Tree Melaleuca decussate Cross Honey Myrtle Melaleuca ericifolia Swamp Paperbark Melaleuca halmaturorum Salt paperbark Tamarix juniperina Flowering Tamarisk Eleocharis acuta Cannas Common Spike-Rush Buffalo / kikuyu Geranium Hydrangeas Tall wheat grass Strawberry Clover, White Clover Perennial Rye Bougainvilliea

stqc.com.au