REPORT NO. 117062

SITE AND SOIL EVALUATION FOR ONSITE WASTEWATER MANAGEMENT, LOT 100/DP1122908,

299 NANCARROW LANE, NASHDALE, NSW

ENVIRONMENTAL EARTH SCIENCES NSW REPORT TO DC PARTNERS (NOMINEES) PTY LTD DATE 11 OCTOBER 2017 VERSION 1.2

11 October 2017 DC Partners 2a Beecroft Road Beecroft NSW 2119 Attn: Mark Smith Dear Mark Site and soil evaluation for onsite wastewater management, Lot 100 DP1122908, 299 Nancarrow Lane, Nashdale, New South Wales Please find enclosed a copy of our report entitled as above. Thank you for the opportunity to undertake this work. If you have any queries concerning the investigation or the report please contact the undersigned. For and on behalf of Environmental Earth Sciences NSW Project Manager Stuart Brisbane Principal Soil Scientist

Project Director/ Internal Reviewer Matthew Rendell Associate

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EXECUTIVE SUMMARY Environmental Earth Sciences was engaged to assess the suitability for an on-site sewage treatment system, associated with the proposed Ecotourism facility at, Lot 100 DP1122908, 299 Nancarrow Lane, Nashdale, New South Wales (the site). The proposed development will based on ecotourism principals and involve the use of the former homestead building, construction of four single room cabins, a wedding garden and lawn, marquee and events area including a commercial kitchen. Estimated combined peak occupancy for the former homestead building and ecocabins is upto 16 persons / day and between 30-200 guests for the function area. A plan of the proposed development showed that there will be an agricultural area (approximately 3,500 – 4, 000 m2) in the south eastern portion of the lot suitable for effluent irrigation. A screening tree plantation around the northern and eastern perimeter approximately 10 m in width will provide another 2,500-3,500 m2 of area available for effluent irrigation. A conservative area of 7,000 m2 was calculated available for effluent irrigation. A site and soil evaluation found major constraints to land application of effluent. These were identified as:

• small lot size (2.002 Ha), which reduces buffer distances and potential reserve areas;

• shading from trees which may affect maximum evapotranspiration rates;

• cold wet winters limiting potential evaporation rates, and

• an onsite groundwater bore designated for a potential domestic water supply. The soil was classified as a Ferrosol (Isbell 2002) which is a gradational clay profile soil with high Fe / Mn content. Subsoil was well structured and well drained. Water holding capacity was conservatively estimated between 100 -150 mm/m which is adequate for water retention of irrigated water. Nutrient holding capacity of the soil was considered as moderate with a cation exchange capacity (CEC)

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Tertiary treated effluent should provide some flexibility in overcoming the site constraints identified in site and soil evaluation. Secondary treated effluent can also be considered however modelling suggests it will be constrained to wastewater quantities of

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TABLE OF CONTENTS

1 INTRODUCTION ......................................................................................................... 1

2 OBJECTIVES .............................................................................................................. 1

3 SITE IDENTIFICATION AND SETTING ...................................................................... 2

3.1 LOCATION AND PROPERTY DESCRIPTION 2

3.2 SITE LAYOUT AND ACTIVITIES 2

3.3 SITE SURROUNDS 2

4 CONCEPTUAL SITE MODEL DEVELOPMENT.......................................................... 5

4.1 PHYSICAL SETTING 5

4.1.1 Climate and meteorology 5

4.1.2 Topography and vegetation 6

4.2 GEOLOGY AND SOILS 6

4.3 HYDROGEOLOGY 6

5 PROPOSED DEVELOPMENT ..................................................................................... 8

6 FIELD PROGRAM ....................................................................................................... 9

6.1 SITE INSPECTION 9

6.2 FIELD SOIL SURVEY AND ASSESSMENT 11

6.3 SOIL STRATIGRAPHY 11

6.4 SOIL PHYSICAL ASSESSMENT 11

6.5 CHEMICAL ANALYSIS 12

6.6 CHEMICAL RESULTS 13

7 RELEVANT GUIDELINES ......................................................................................... 14

7.1 SUMMARY OF SITE AND SOIL CONDITIONS 18

8 ON-SITE WASTEWATER SYSTEM DESIGN RECOMMENDATIONS ...................... 20

8.1 ON-SITE SYSTEM SELECTION 20

8.2 TYPE OF LAND APPLICATION SYSTEM CONSIDERED BEST SUITED TO THE SITE: 20

8.3 TYPE OF TREATMENT SYSTEM CONSIDERED BEST SUITED TO THE SITE AND APPLICATION SYSTEMS: 21

8.4 WASTEWATER QUANTITY 22

8.5 DESIGN CONSIDERATIONS FOR TREATMENT SYSTEM 22

8.5.1 Disposal area calculation 23

8.6 DESIGN AREA CALCULATIONS: 25

8.6.1 Tertiary treated effluent 25

8.6.2 Secondary treated effluent 26

8.6.3 Modelling outcomes 26

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9 SYSTEM DETAILS .................................................................................................... 26

9.1 SITE PREPARATION 27

10 THE LIKELIHOOD OF GROUNDWATER CONTAMINATION FROM THE DEVELOPMENT........................................................................................................ 28

11 CUMULATIVE IMPACT THE DEVELOPMENT MAY HAVE ON GROUNDWATER.. 31

12 CONCLUSION ........................................................................................................... 32

13 LIMITATIONS ............................................................................................................ 33

14 REFERENCES .......................................................................................................... 33

15 GLOSSARY OF TERMS ........................................................................................... 35

FIGURES

FIGURE 1 SITE LOCATION ........................................................................................................ 3

FIGURE 2 SITE LAYOUT AND LAND USE ................................................................................ 4

FIGURE 3 SITE CHARACTERISTICS AND SAMPLING LOCATIONS ................................... 10

APPENDICES

A GROUNDWATER BORE LICENCES

B SOIL BORELOGS

C LABORATORY TRANSCRIPTS & CHAIN OF CUSTODY FORMS

D NUTRIENT AND HYDRAULIC MODELS

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1 INTRODUCTION Environmental Earth Sciences was engaged to assess the suitability for an on-site sewage treatment system, for the proposed Ecotourism development at, Lot 100 / DP1122908, 299 Nancarrow Lane, Nashdale, New South Wales (the site). The proposed development will based on ecotourism principals and involve the use of the former homestead building with a common kitchen, construction of four single room cabins, a wedding garden and lawn, marquee and events area including a commercial kitchen. The construction material will be energy efficient as well in keeping the eco theme. This assessment was completed in accordance with the relevant standards and guidelines, and targets the pertinent locations identified in plans provided by the registered proprietor, DC Partners via its Director. If the location of the proposed development is reassessed, then an additional assessment may be necessary to confirm the suitability of a new development configuration. Professional judgement was used to extrapolate between inspected areas, however even under ideal circumstances actual conditions may vary from those inferred to exist. The actual interface between materials and variations in soil quality may be more abrupt or gradual than the report indicates. The construction and installation of all systems should be undertaken in accordance with the appropriate construction standards. This report should be read in conjunction with the limitations and appendices detailed in Section 14 of this report.

2 OBJECTIVES The objectives of the study are to broadly identify land suitable for the development of a recommended effluent disposal system and to determine the minimum desirable land area based on the site and soil assessment findings. The scope of works included:

• an inspection and soil sampling program at the site including the onsite assessment of soils and landform suitability;

• assessment of preliminary nutrient and hydraulic balance; and

• preparation of a report outlining findings and recommendations for submission to council, including assessment of groundwater vulnerability in relation to the proposed development.

The work undertaken to achieve the above objective is reported in the following sections.

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3 SITE IDENTIFICATION AND SETTING

3.1 Location and property description The site is located on Nancarrow Lane, Nashdale in an area used for orchards, grazing and small lot or rural residential blocks. The surrounding localities of Nashdale and Canobolas have had a long history of agricultural activities dominated by orchards. Site identification details are provided in Table 1. A plan of the regional locality of the site, along with site lot configuration is provided in Figure 1. Figure 2 gives an indication of the proposed site layout and land-use.

TABLE 1 SITE IDENTIFICATION

Item Details

Address 299 Nancarrow Lane, Nashdale, NSW

Lot & Plan number Lot 100, DP1122908

Area Approx. 2.002 ha

Zoning RU2– Rural Landscape

Proposed land use Ecotourism Facility

Local Government Authority Cabonne

Site Location and Layout Figure 1 and Figure 2

3.2 Site layout and activities The site is a small lot of just in excess of two hectares containing a former homestead building, sheds and a grazing paddock. A large machinery shed at the rear of the former homestead building indicates that the site may have been used for agriculture (most likely an orchard) in the past. The paddock surrounding the former homestead building is currently used for grazing a small mob of sheep.

3.3 Site surrounds The surrounding area is predominantly used for apple and cherry orchards with accompanying coolstore, packing and machinery sheds. Small residential lots have also become common throughout the area. Grazing farms, National Parks and State Forest are also found in the local area.

NorthNorth

Client:

Drawn by: TRJ

Proj Man: SB

Location:

Title:

Scale: As shown

Date: 1 Sept. 2017

Job number: 117062

Source: See Ref.

Figure

Site Location Map

Mark Smith - DC Partners

1

297 Nancarrow Lane,

Lot 100, DP. 1122908, Nashdale, NSW

Regional

Locality Map

Nashdale, NSW

Site Locality Map -

297 Nancarrow Lane, Nashdale, NSW

Site LocationSite Location

0 1.5km

Scale (approx.)

Site LocationSite Location

Ref. Google Earth Pro digital image 2017.

0 50m

Scale

297

Client:

Drawn by: TRJ

Proj Man: SB

Location:

Title:

Scale: As shown

Date: 1 Sept. 2017

Job number: 117062

Source: See Ref.

Figure

Proposed Layout

Mark Smith - DC Partners

2

297 Nancarrow Lane,

Lot 100, DP. 1122908, Nashdale, NSW

Proposed Layout - 297 Nancarrow Lane, Nashdale, NSW

NorthNorth

Potential effluent

application areas

15 - 20m exclusion zone

6666groundwater boreLot 100 DP. 1122908Lot 100 DP. 1122908

0 50m10 20 30 40

Scale (approx.)

Ref. Compiled from dwg. titled Stage 2 Snowgums Ecotourism

Masterplan & Landscape Design. Ref. No. 16170444 Dated. 17/08/2017.

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4 CONCEPTUAL SITE MODEL DEVELOPMENT A conceptual site model (CSM) consists of the geophysical characteristics at play at the site, the contaminant source, potential receptors and the pathways to the receptors. Prior to undertaking field work a CSM is derived to design the sampling strategy, or to reduce uncertainties or data gaps in regard to the source of contamination, the pathway and the receptors.

4.1 Physical setting

4.1.1 Climate and meteorology

Regional meteorological data has been sourced from the Bureau of Meteorology (2015) (www.bom.gov.au, verified 16 August 2017) for the weather station at Canobolas State Forest (Site No. 063018) and the Orange Agricultural Institute (Site No. 063254). Mean maximum and minimum monthly temperatures and mean monthly rainfall values are presented in Table 2.

TABLE 2 AVERAGE MONTHLY CLIMATE DATA

Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec

Maximum Temperature (oC)

26.0 25.2 22.9 17.9 12.7 9.8 8.8 10.1 13.6 16.5 19.8 24.1

Minimum Temperature (oC)

12.4 12.9 10.8 6.8 3.5 1.9 0.2 1.1 3.0 6.1 7.1 9.9

Rainfall (mm) 87.9 80.9 66.1 63.1 81.8 90.2 111 118 94.0 101 92.1 80.3

Evaporation mean daily (mm) 217 170 148 96 62 42 46 65 93 133 165 210

Orange has a mild temperate climate with warm summers and cool winters. Average annual rainfall is 1108.1 mm and annual evaporation 1460 mm. Rainfall is generally winter, early spring dominated with August receiving the highest monthly rainfall total of 118 mm and March the driest with 66.1 mm (Table 2). Rainfall events during the summer months can consist of high intensity storm events which have the potential for erosion especially in the high sloping and low ground cover environments. January and February are the warmest months and July is the coldest. Mean daily temperatures in summer are in the 15-20 oC range with maximums >20 oC, while in winter maximum average temperatures reach 8-10 oC. There are approximately 26 days below zero and the area receives regular snow, with moderate to occasionally heavy snowfalls occurring several times each winter. Monthly evaporation and evapotranspiration rates were below monthly rainfall totals for the five months May, June, July, August and September. Illustrating that soil moisture status has the potential to be high in the cooler autumn, winter and spring months. It is during these times that most of the groundwater recharge and surface runoff is expected to occur in the local region.

http://www.bom.gov.au/https://en.wikipedia.org/wiki/Temperate_climate

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Soil moisture is generally low in the summer as characterised by the large difference between evaporation and rainfall during this time. Plant growth can be limited by low temperatures during the winter and by low moisture during the summer.

4.1.2 Topography and vegetation

Local topography has been described as undulating hills to rolling low hills, with elevation ranging from 980–1080 m. Local relief generally varies from 40–60 m and slopes are between 6–10%, but can be up to 20%. Slopes in drainage depressions range from 8% on higher areas to 1–2% in the lower lands (Kovac et al., 1999). Surface flow within the catchment is generally controlled by topography and drainage depressions towards Molong Creek, Lake Canobolas and Heifer Station Creeks >500 m from the site. Surface flow along the drainage lines is controlled by numerous large capacity (>2-3 ML) irrigation dams.

4.2 Geology and soils Local geology is comprised of Tertiary aged (65 ma – 2 million years ago) volcanics derived from the adjacent Mount Canobolas. Volcanics comprise of pyroxene olivine basalt, plagioclase basalt, alkali basalt, trachybasalt and trachyandesite (Meakin et al., 1997). Basalt flows are separated by layers of volcanic ash (Kovac et al., 1999). Colluvial-alluvial materials derived from parent rock is commonly 1–10 m deep but may be up to 90 m deep in drainage depressions ash (Kovac et al., 1999). The area has been recognised in the Soil Landscape of Bathurst 1:250 000 as part of the Towac Soil Landscape. A soil landscape is an area of land that has recognisable and specifiable topographies and soils. Ferrosols are the dominant soils in the Towac Soil Landscape and occur on the upper to midslopes environments. Red Chromosols / Ferrosol intergrades are found on upper slopes, with yellow Chromosols and Sodosols in drainage lines and depressions (Kovac et al., 1990). Soils of the Towac Landscape are well drained, are moderate to slightly permeable with high water holding capacity. Fertility is moderate to low, salinity low and erodibility has been classified as moderate due to the high slope environments of the region. A moderate to high shrink swell potential could represent a foundation hazard (Kovac et al., 1999).

4.3 Hydrogeology Groundwater information was obtained from the Natural Resource groundwater atlas (http://nratlas.nsw.gov.au.; verified 18 August 2017). A total of ten bores were located within a 500 m radius of the site. Information for five of the closest bores plus a recently installed onsite bore has been included into Table 1. This information will aid in illustrating the type of groundwater and water bearing zones associated the local area.

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TABLE 3 SUMMARY OF LICENSED BORES

Bore no. Final Depth

Water bearing zone

Geology Use SWL / Yield

GW804095

99 89-91 m

0-0.2m: topsoil, 0.2-25m sandy clay, 25-33m decomposed basalt with sandy clay bands, 33-61m, basalt with clay bands, 61-64m decomposed basalt and clays, 64-85m basalt grey, 85-99m basalt grey and green.

stock and domestic

70 m / 0.51 L/s

GW047402

68.60

22.90 m

58.20-58.50 m

59.80-60.10 m

65.50-66.2 m

0-0.3m topsoil, 0.3-4.60m clay, 4.60-11.0 loamy sand, 11.0-15.80 grey basalt, 15.80-18.30 rock, 18.30-32.30 rock serpentine soak, 32.30-39.60 m rock, 39.60-53.70m rock serpentine

irrigation, stock and domestic

18.30 m / 1.96 L/s

GW057509

121.9 57.90-59.40

m

0-0.6m topsoil, 0.6-5.70m clay, 5.70-24.40m shale, 24.40-70.10m basalt, 70.1-73.20m clay, 73.20-74.70m basalt honeycomb, 74.70-80.80m basalt, 80.80-112.20m basalt honeycomb, 112.2-121.90m basalt

stock and domestic

54.90 m / 0.25 L/s

GW805442

No data sheet available

GW049714

76.90 4.6-65.20 m

0-0.3m topsoil, 0.3-4.60m red clay, 4.6-9.20m clay bands white water supply, 9.2-18.50m basalt decomposed water, 18.50-36.00m basalt water, 36.0-39.40m siltstone grey water, 39.40-43.00 basalt water supply, 43.0-76.3 conglomerate green water supply, 76.30-76.90m clay red

stock and domestic

3.0 m / 3.30 L/s

Recently installed onsite

bore

78.00

59-60 m

64-66 m

71-72 m

0-1m topsoil, 1-13m clay, 13-16m decomposed basalt, 16-24 basalt, 24-33 decomposed basalt, 33-42 basalt,

42-53 soft basalt, 53-78 basalt

stock and domestic

58 m / 1.13 L/s

Note(s):

1. Source: Groundwater Works Summary from NSW Office of Water (http://allwaterdata.water.nsw.gov.au/water.stm August, 2017)

2. See Appendix A for all search data

All of the groundwater bores investigated were registered for domestic, stock use and / or irrigation (Table 3). The aquifer was encountered at depths greater than 20 m below ground level (bgl) and is generally associated with fractures within the basalt. Groundwater was not observed in the thick clay layers and decomposed basalt up to 20 m in depth across the catchment. Fractured rock aquifers generally have very low storage capacity and with the yield measured at

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Groundwater is likely to be both locally and regionally sourced given the prominence of fractures present in the basalt rock. Groundwater is suitable for stock and domestic use with the natural resources atlas (http://nratlas.nsw.gov.au.; verified 20 August 2017) indicating the saline levels as good or fresh . Groundwater is considered of generally high quality and can be of potable quality.

5 PROPOSED DEVELOPMENT Proposed development layout has been provided in Figure 2 and will generally consist of:

• the former homestead building reverting to 3 office rooms, a three (3) room ecotourism facility, common kitchen, toilet, bathroom and kitchen;

• construction of four ecocabins, each cabin containing a bathroom, toilet and kitchenette;

• construction of a commercial wedding garden, lawn, events and marquee area which will also include a commercial kitchen and toilets. Estimated capacity between 30-200 guests for a function;

• an effluent storage tank in the north eastern corner with an estimated capacity of 125,000 -300, 000L;

• an agricultural area in the south eastern portion of the lot suitable for effluent irrigation was calculated as 3,000 – 4,000 m2 in area

• a windbreak or screening tree plantation around the northern and eastern perimeter approximately 10 m in width resulted in another 2,500-3,500 m2 of area available for effluent irrigation; and

• potential for further development in the northern vacant areas. Development will be undertaken in stages with the initial stage involving the former homestead building converting to three (3) room office (for reception, administration and meetings/boardroom), 3 of the former bedrooms remaining in its present configuration with the original bedrooms converting to an ecotourism facility. It has been anticipated occupancy may be as low as 50% (mostly weekends) during the start-up phase with meetings and functions targeted for mid-week after a ramp-up period. The initial phase will also involve the construction of the four ecocabins leased at 50% occupancy rate ramping up in line with the former homestead. Bathrooms will only have showers and water saving devices will be fitted to showers, taps and duel flushing toilets. The design will be energy efficient in keeping with ecotourism principals.

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6 FIELD PROGRAM

6.1 Site inspection Fieldwork was undertaken on 1 August 2017 and comprised of a site inspection and soil assessment. Five boreholes (BH1 to BH5) were drilled across the site using a hand auger to a depth of 1-1.5 m. Site characteristics and sampling locations are shown in Figure 3. The L shaped block, measuring 2.002 hectares in area comprised of former homestead building and surrounding paddock. The former homestead building and gardens are contained within a small fenced paddock in the south western corner. Galvanised iron sheds used in conjunction with the former homestead building and a farm machinery shed were located south of the former homestead building. A small grazing paddock (

,,,,

NorthNorth

Site Characteristics

90m 90m 00 ScaleScale

Client:

Drawn by: TRJ

Proj Man: SB

Location:

Title:

Scale: As shown

Date: 1 Sept. 2017

Job number: 117062

Source: See Ref.

Figure

Site Characteristics

Mark Smith - DC Partners

3

297 Nancarrow Lane,

Lot 100, DP. 1122908, Nashdale, NSW

Shed

Shed

House

garden

6666

existing adsorption trench

o r c h a r d

o r c h a r d

Nancarro

w Lane

,,,, ,,,,

,,,,

,,,,

BH1

BH2

BH3

BH4BH5 297 - Lot 100

DP. 1122908

borehole locations (2017) 6666 groundwater bore

Key:

,,,,

....................soil ?

groundcover 95-100%

exotic perennials & annuals

slope (linear)

5%

8%

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6.2 Field soil survey and assessment Five boreholes were drilled to a maximum depth of 1.5 m, which provided a detailed assessment of the soil stratigraphy. Undisturbed samples were taken every 0.5 m or every change in lithology at the five sampling locations. Cuttings from a groundwater bore were also investigated during the site investigation. The soil profile of each borehole was logged and a soil description including colour, texture, field pH and structure was recorded (Appendix B – borelogs).

6.3 Soil stratigraphy Soil was consistent across all of the bores and characterised as a Red Ferrosol (Isbell, 1997). Ferrosols have a B2 horizon with a free iron oxide content greater than 5% Fe in the fine earth fraction (

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6.5 Chemical analysis As the soil stratigraphy was similar across the site, four sub-samples from the surface (0-0.1 m) and subsurface (0.5-0.6 m) were each composited two form two samples. The composite samples were labelled SS1 (0-0.1 m) and SS1 (0.5-0.6 m). Samples were collected during the investigation and analysed for pH, electrical conductivity, cation exchange capacity (CEC) and phosphorus sorption capacity at Sydney Analytical Laboratory (SAL). Exchangeable sodium percentage (ESP) was calculated from the CEC values. Laboratory results are presented in Table 6 with laboratory transcripts provided in Appendix C. Electrical conductivity (EC) results of the 1:5 (soil: water suspension) were converted to saturated extracts (ECe) as most of the data in relation to plant growth is expressed as ECe. EC (1:5) values are converted to ECe by using a multiplier factor (Hazelton and Murphy 1992), which is dependent on the soil texture. The multiplier factors for converting EC 1:5 (soil:water suspension) to ECe are shown in Table 4. Classification of saline soils were based on the definitions presented in Table 5 and are based on an agricultural rating in relation to plant development.

TABLE 4 MULTIPLIER FACTORS FOR ECE CONVERSION

Soil Texture Multiplier Factor

Loamy sand, clayey sand, sand l 17

Sandy loam, fine sandy loam, light sandy clay loam 11

Loam, loam fine sandy, silt loam, sandy clay loam 10

Clay loam, silty clay loam, fine sandy clay loam, sandy clay, silty clay, light clay 9

Light medium clay 8

Medium clay 7

Heavy clay 6

Notes:

1. Adapted from Hazelton and Murphy (1992)

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TABLE 5 SALINITY RATINGS BASED ON ECE READINGS

Salinity Rating ECe (dS/m) Effects on Plants

non saline (NS) 0-2 Salinity effects negligible

slightly saline (SS) 2-4 Very salt sensitive plant growth restricted

moderately saline (MS) 4-8 Salt sensitive plant growth restricted

highly saline (HS) 8-16 Only salt tolerant plants unaffected

extremely saline (ES) >16 Only extremely tolerant plants unaffected

Notes:

Adapted from Hazelton and Murphy (1992) ECe Electrical conductivity of a saturated extract

6.6 Chemical results The results of the chemical and physical analysis are presented in Table 6.

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TABLE 6 CHEMICAL RESULTS

Sample ID Units SS1 SS1

Depth 0–0.1 m 0.5–0.6 m

pH mS/cm 5.9 5.8

EC μS/cm 120 55

ECe dS/m 1.2 0.06

Sodium meq/100g 0.03 0.03

Potassium meq/100g 0.81 1.00

Calcium meq/100g 5.1 5.0

Magnesium meq/100g 1.15 2.01

Manganese meq/100g 0.72 0.68

Aluminium meq/100g

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When addressing site and soil characteristics for on-site sewerage management, we refer to the following guidelines:

• DECC (2004) Use of effluent by irrigation. NSW department of Environment and Conservation.

• Australian/New Zealand Standard AS/NZ 1547 (2012) On-site domestic wastewater management;

• Environmental and Health Protection Guidelines (1998) On-site sewerage management for single households, Department of Urban Affairs and Planning;

• VIC EPA (2016). Onsite wastewater (http://www.epa.vic.gov.au/your-environment/water/onsite-wastewater verified 20 August 2017)

The relevant guidelines mainly focus on the on-site management of wastewater and involve the application of wastewater above or below the ground surface. Limiting site and soil parameters for on-site sewerage management techniques summarised from the abovementioned guidelines are listed in Tables 7 and 8. The most limiting feature determines the site capability for an onsite sewerage management system. In some cases the problems posed by a limiting feature or features can be overcome by using special designs or by modifying the site.

http://www.epa.vic.gov.au/your-environment/water/onsite-wastewaterhttp://www.epa.vic.gov.au/your-environment/water/onsite-wastewater

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TABLE 7 SITE ASSESSMENT: RATING FOR ONSITE SYSTEMS

Site Feature Minor Limitations Moderate

Limitations Major Limitations Restrictive Feature

Flood Potential Rare, above 1 in 20 year flood contour

Frequent, below 1

in 20 year flood contour

Transport of wastewater off-site

Vents, openings and electrical

components above 1 in 100 year flood

contour

Vents, openings and electrical

components above 1 in 100 year flood

contour

Transport of wastewater off-site. System failure and

electrocution hazard

Exposure High sun and wind Low sun and wind

exposure Poor evapo-transpiration

Slope % 0-6 6-12 >12 Runoff, erosion

0-10 10-20 >20 Runoff, erosion

0-10 10-20 >20 Runoff, erosion

Landform Hill crests, convex side slopes and

plains

Concave side slopes and

footslopes

Drainage plains and incised

channels

Groundwater pollution hazard,

resurfacing hazard

Run on and upslope seepage

None-low Moderate High diversion not

practical Transport of

Wastewater off-site

Erosion potential No signs of erosion

potential present

Signs of erosion eg rills, mass

movement and slope failure

present

Soil degradation and transport, system

failure

Site drainage No visible signs of surface dampness

Visible signs of surface dampness, such as moisture

tolerant vegetation,

Groundwater pollution hazard,

Resurfacing hazard

Fill No fill Fill present Subsidence, variable

permeability

Buffer distance Health and pollution

risks

Land area Area is available Area is not available

Health and pollution risks

Rocks and outcrops (% rocks >200 mm diameter)

20% Limits system performance

Geology/regolith

Major geological discontinuities,

fractured or highly porous regolith

Groundwater pollution hazard

Notes: 1. Source: Environmental and Health Protection Guidelines (1998) - On-Site Sewerage Management for Single

Households. Department of Urban Affairs and Planning.

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TABLE 8 SOIL ASSESSMENT: RATING FOR ONSITE SYSTEMS 1

Soil Feature Minor

Limitation Moderate Limitation

Major Limitation1

Restrictive Feature

Depth to bedrock or hardpan (m)

Restricts plant growth, excessive runoff, water

logging

>1.5 1.0-1.5 1.5 1.0-1.52 40 May restrict plant growth and

reduce nutrient holding capacity

Bulk Density (g/cm3)

Sandy loam

Loam and clay loam

Clay

>1.8

>1.6

>1.4

>1.8

>1.6

>1.4

Restricts plant growth, indicator of permeability

pH CaCl2 >6.0 4.5-6.0 Reduces optimum plant

growth

Electrical conductivity (ds/m) 8 Excessive salt may restrict

plant growth

Sodicity (esp)5 0-5 5-10 >10 Potential for structural

degradation

Cation exchange capacity >15 5-156 6000 2000-6000

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7.1 Summary of site and soil conditions In accordance with the above guidelines, site and soil characteristics were evaluated in relation to onsite effluent treatment and management. The suitability of the site for application of effluent has been assessed with suitability ratings of suitable, marginally suitable and not suitable provided, as shown in Tables 9 and 10.

TABLE 9 SITE AND SOIL CHARACTERISTICS

Site Characteristics Description Site capability criteria

Climate

are low temperatures expected (20-100 m

>40 m

>2-15 m

Nil

Suitable

Marginally suitable

Suitable

Marginally suitable

Suitable

Sufficient Area available including reserve area

Yes Marginally suitable

Rock Outcrops No outcrops present Suitable

Geology/Regolith Basalt Suitable

Neighbouring systems None observed

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TABLE 10 SITE AND SOIL CHARACTERISTICS

Soil Assessment Description Soil Capability Criteria

Depth to bedrock/hardpan > 5 m Suitable

Depth to high seasonal watertable > 5 m Suitable

Hydraulic loading rate

Soil structure:

Soil texture:

Permeability category:

Other measures of soil permeability:

Highly pedal

Light clay

5b

0.5 -

Marginally suitable

Marginally suitable

% Coarse Fragments

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Nutrient holding capacity of the soil is only considered as moderate as indicated by the cation exchange capacity (CEC) < 10 meq/100g and phosphorus sorption capacity of 4,500 kg/ha. However given that there exists a moderate soil profile depth in excess of 5 m there is considerable capacity for the soil to adsorb nutrients. It was generally considered that high clay content soils with organics provide a CEC capable of sorbing ionic and biological material in effluent (Dawes 2006). Salt content of the soil was low

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8.3 Type of treatment system considered best suited to the site and application systems:

As the reuse of wastewater for lawns and gardens is in keeping with the waterwise theme and acknowledging the effluent water as a resource rather than waste, the preferred or ideal system would be an aerated wastewater treatment system (AWTS) with a tertiary bacterial treatment (bromine, chlorination, ultraviolet, microfiltration and ozonation). Tertiary/advanced secondary treated effluent is required by the Department of Health and NSW EPA (2004) in areas with high exposure to humans and animals and near sensitive environments. As such, any gardens and/ or lawns that will be potentially accessed by guests of the proposed developed with have to be irrigated with tertiary or secondary treated effluent. Site features such as the groundwater bore, small lot size, and cold wet winters are restrictive to the use of large quantities of secondary treated effluent. An aerated wastewater treatment system with tertiary treatment will have to be capable of treating water to the following standards:

• 10 mg/L (coliform forming units) (cfu)/100 mL;

•

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Greywater will require less treatment than blackwater to reach the required quality for tertiary classification and as such treatment costs could be reduced if it is kept separate. Treatment can be either done by two separate systems: one for the greywater and one for the blackwater; or by placing the greywater in the final treatment of the blackwater system. The cost of installing two units may preclude this option as when the site will be at full capacity there will be significant amounts of blackwater requiring treatment.

8.4 Wastewater quantity As part of the application area design, the figure of 150 L/person/day has been used for occupants within the ecotourism facility and cabins and 30 L/person/day for guests associated with the function and events area. This is based on AS/NZ 1547/2012 guidelines with a tank or groundwater supply. Additional water reduction can be achieved by installing full water reduction fixtures including the combined use of reduced flush 6/3 litre toilets, aerator faucets and flow pressure control valves on all water use outlets. This could reduce the waster generation to by 10-20 L/person/day.

8.5 Design considerations for treatment system Table 11 lists the design parameters relevant to the proposed site conditions and which have been used in the simple one dimensional models shown in Appendix D. While these simple modelling calculations are not detailed they are suitable for preliminary sizing and situations when essential model parameters are not available.

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TABLE 11 TREATMENT SYSTEMS DESIGN CONSIDERATIONS

Parameter Quantity

Intended water supply

rainwater:

reticulated water supply:

bore/groundwater:

yes

no

yes

Expected wastewater quantity (L/day) based on a 150 L/person/day.

Ecotourism facility and 3 room office 1,200 L/day

4 Eco Cabins 4 bedrooms 1,200 L/day

Expected wastewater quantity (L/day) based on a 30 L/person/day.

100-200 guests 6000 L/per event

100-200 guests 1000 L/ day spread over the week

Tertiary Treated Water – Nutrient concentrations

Coliform forming units (cfu) / 100 m/L (mg/L)

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• former homestead building and cabins in conjunction with the events / marquee area based on peak flows or use for seven days a week; and

• former homestead building and cabins at peak production and with the events / marquee area used for 1 day a week allowing for a spread of effluent equivalent to 1000 L/day over the following week.

TABLE 12 NUTIRENT DISPOSAL AREA CALCULATIONS

Development stage Wastewater

quantity Disposal area for tertiary

treated water Disposal area for secondary

treated water

Organic loading (BOD) L m2 m2

Former homestead building and cabins

2,400 L/day 8 m2 16 m2

Former homestead building, cabins and events area at peak production

8,400 L/day 28 m2 56 m2

Former homestead building, cabins and events area used once a week

3,400 L/day 11.3 m2 22.67 m2

Nitrogen loading

Former homestead building and cabins

2,400 L/day 816 m2 1,632 m2

Former homestead building, cabins and events area peak production

8,400 L/day 2,856 m2 5,712 m2

Former homestead building, cabins and events are used once a week

3,400 L/day 1,156 m2 2,312 m2

Phosphate loading

Former homestead building and cabins

2,400 L/day 782.1 m2 3,128 m2

Former homestead building, cabins and events area peak production

8,400 L/day 2,732.5 m2 10,950 m2

Former homestead building, cabins and events are used once a week

3,400 L/day 1,108,0 m2 4,432.1 m2

Notes 1. See Appendix D for calculations

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TABLE 13 NUTIRENT DISPOSAL AREA CALCULATIONS

Development stage Wastewater

quantity Disposal area with no storage

Disposal area with effluent storage

Former homestead building and cabins

2,400 L/day 2,150 m2 no storage 700 m2 with 225.4 m3 storage

Former homestead building, cabins and events area peak production

8,400 L/day 15,000 m2 no storage 4,500 m2 with 450 m3 storage

Former homestead building, cabins and events are used once a week

3,400 L/day 6,000 m2 no storage 1,500 m2 with 225 m3 storage

90% percentile annual rainfall

Former homestead building and cabins

2,400 L/day - 1,500 with 406.5 m3 storage

Former homestead building, cabins and events area peak production

8,400 L/day - 5,250 with 1,596 m3 storage

Former homestead building, cabins and events are used once a week

3,400 L/day - 2,150 with 647 m3 storage

Notes 1. See Appendix D for calculations 2. Hydraulic loading calculated from average rainfall data for weather station 063018

8.6 Design area calculations:

8.6.1 Tertiary treated effluent

The most conservative (largest) irrigation area for tertiary treated wastewater (Tables 12 and 13) was calculated using the hydraulic loading model with no effluent wet weather storage. The area calculated for the hydraulic loading always exceeded the areas calculated for nutrient modelling over the different development stages (Tables 12 and 13). This in part is due to the low concentrations of nutrients associated with tertiary treated wastewater. Hydraulic loading was based on one dimensional model utilising monthly rainfall data with no wet weather storage incorporated into the system. The models were able to show that when wastewater production reaches an equivalent 8,400 L/day, approximately 15,000 m2 (1.5 Ha) will be required for effluent irrigation. This area is over 75% of the entire 2 Ha site and is therefore not practicable in relation to the proposed development. Therefore for wastewater quantities above 3,000-3,400 L/day wet weather storage will need to be incorporated into effluent treatment system. Modelling suggests that wastewater quantities below 3,400 L/day with no wet weather storage will require approximately 6,000 m2 of land for effluent irrigation. Areas of

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incorporated into the design Environmental Earth Sciences recommends that wet weather storage still should be included into all proposed effluent treatment systems. Due to cold and wet winters experienced at the site the soil will frequently be saturated and not be capable of absorbing effluent irrigation. If irrigation occurs during these conditions there is a significant risk of offsite migration. Modelling showed that when a wet weather storage capacity of 225 m3 – 450 m3 was incorporated into the system the required effluent irrigation areas became manageable (

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UltraClear (www.envirocycle.com.au) or Envirocycle (www.envirocycle.com.au). These systems all have different stages/methodologies for treating wastewater but are capable of producing tertiary treated wastewater. A system capable of treating wastewater to tertiary standards (DECC, 2004, Section 6.3) enables wastewater to be irrigated via surface or subsurface methods across lawns and gardens without denying any access to site users or implementing practices for mitigating offsite movement of wastewater and the associated bacteria and nutrients. Incorporating wet weather storage is necessary for storage of effluent during prolonged periods of soil saturation. Onsite storage can also be used as a safety factor in case the system develops a fault or there is further development of the site. General requirements of any effluent irrigation system are:

• highly accessed areas, buildings and site’s boundaries should have a least a 2.0 m buffer from the effluent irrigation area for subsurface irrigation of tertiary treated effluent. Subsurface irrigation of secondary treated effluent and surface irrigation of tertiary treated effluent should have a >5 m buffer implemented;

• a buffer distance of least 15-20 m should be considered from the onsite groundwater bore and any effluent irrigation area. The large clay layer >5-10 m, groundwater bearing zones >20 m, highly treated effluent and a significant grout seal installed from 0-20 m below ground level around the bore casing allowed the buffer distance to be reduced to 15-20 m;

• the system should not be used for purposes that compromise the effectiveness of the system or restrict access for future maintenance;

• have no run-off or seepage of effluent to beyond the designated area and irrigation rates should be adjusted to surface soil infiltration rates and soil moisture (upper soil profile) should be below field capacity and capable of storing 5 mm of effluent prior to irrigation;

• spray should distribute the effluent evenly within the designated area;

• warnings on irrigation lines and areas complying with AS 1319 or NZS/AS 1319, clearly visible to property users to be used;

• irrigation lines should be regularly checked for blocks in lines; and

• system should be serviced regularly in accordance with the manufacturer and council service agreements which is usually three months.

9.1 Site preparation Prior to the installation of the effluent treatment system and irrigation lines the following recommendations must be completed:

• as the soil is not dispersive no gypsum is required to be incorporated into the soil of the effluent irrigation area. However at intervals of 3-5 years gypsum could be incorporated into the soil at a rate of approximately 1-2 t/ha. We recommend that in all construction works care be taken to minimise cutting and to ensure that procedures for control of erosion be incorporated into soil management plans. The soil should not be worked when wet and left exposed during periods of high intensity rainfall;

• soil pH is within a range suitable for most plant species so no addition of lime is necessary;

http://www.envirocycle.com.au/http://www.envirocycle.com.au/

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• there were no preferential drainage lines observed across the site but any open surface drains and drainage lines should be kept separated from the irrigation area;

• regular traffic (vehicle and pedestrian) should be kept to a minimum when irrigating especially during wet and saturated soil conditions; and,

• all vegetation should be mowed or pruned to encourage growth and all clippings and braches removed from site so as to remove excess nutrients.

To efficiently use the nutrients and water we suggest that the gardens and grass species contain perennials with a mixture of lawn and landscaped gardens containing shrubs and trees. There are numerous grass species available however exotic species such as kikuyu, fescues and couch are common and are high water and nutrient users. Shrubs and trees can be planted around the perimeter to avoid shading issues, though spacing and placement of the shrubs must be considered to ensure adequate ventilation to maximise evaporation.

10 THE LIKELIHOOD OF GROUNDWATER CONTAMINATION FROM THE DEVELOPMENT

While there is a perception that onsite wastewater treatment systems (OWTS) especially septic trenches cause contamination to groundwater and waterways, the evidence is not conclusive and there have been many examples of systems functioning sustainably (Beal et. al., 2005). In fact, onsite wastewater treatment systems (OWTS) which are properly sited, designed and managed can be an effective method for the treatment of wastewater (Carroll et. al., 2005). This is important as in all unsewered rural areas of Australia the OWTS is the only cost effective option available. Contamination issues arise when OWTS fail to remove adequate levels of nutrients and bacteria from the effluent. If this effluent then migrates to underlying groundwater or nearby surface bodies there exists the potential for contamination. Contamination resulting from OWTS has been found linked to organic nutrients (BOD), inorganic nutrients (nitrogen and phosphorus) and bacteria and viruses (EPRI 2000; Whitehead and Geary 2001; Bagdol et. al., 2004; Ahmen et. al., 2005). It has been suggested that poorly performing or failing systems are the main contamination issue and have been linked with elevated pollution loads in receiving waters (Whitehead and Geary 2000, Ahmed et. al., 2005). There are many factors as why OWTS fail and failure has been identified over a range of conditions. Such as from heavily populated coastal areas with shallow groundwater and sandy profiles (Carroll et. al., 2006, Geary and Whitehead 2001 and Dawes et. al., 2006), to environments with 6 m of underlying clay and soil derived from basalt bedrock (Bolger and Stevens 1999). Dawes et. al., (2006) suggested that the primary factor contributing to the failure was inadequate consideration of site and soil characteristics in the design of the system. Therefore for the sustainable and successful generation of OWTS it is crucial that the construction and maintenance be based on the site and soil conditions. In general these site and soil characteristics have been summarised as the ability of the soil to provide suitable effluent renovation, permeability of the soil and drainage characteristics of landscape (Carroll et. al., 2004). This was further defined by Dawes (2006) who defined

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physical, chemical and subsurface hydrological properties of the soil to predict suitability for long term effluent treatment. These soil properties were:

• moderate to slow permeability to assist the movement of effluent percolation through the soil profile and allow adequate time for the treatment and dispersal to occur;

• significant soil cation exchange capacity and dominance of exchangeable Ca2+ or Mg2+ over Na+. Stable soil has Ca:Mg ratio >0.5;

• low exchangeable Na content (< 5% ESP) to maintain soil stability;

• minimum depth of 400 mm of potential unsaturated soil before encountering a restrictive horizon; and

• a clay type not dominated with illite and/ or a mixed mineralogy soil as these are most sensitive to Na+. In general significant increases in ESP occur in soils with 30-40% clay in the presence of illite clay. Whereas small amount of smectite clay enhance the treatment of the soil.

Satisfying these requirements is important to developing a sustainable onsite treatment system and ensuring offsite contamination is not an issue. The site and soil evaluation undertaken for this investigation was not only developed from the relevant guidelines but also features proposed by Dawes (2006). A detailed description of onsite soil properties in relation to Dawes (2006) has been provided below. A large investigation into onsite sewage systems (Dawes et. al., Cox, 2006) found that Chromosols and Ferrosols were part of a soil group that had lowest potential to fail. The soil onsite was found to be a Ferrosols and the findings of this study are in support with Dawes et. al., 2006). A shallow watertable or saturated soil beneath the effluent treatment area shortens the hydraulic retention time and reduced aerobic conditions (Beal et. al., 2006) which can result in treatment failure of the effluent. Soils were found to greater than 5-10 m in depth which satisfies the >400 mm buffer to the restrictive horizon as stated by Dawes (2006). Establishing a >400 mm buffer will enable a sufficient aerobic zone beneath the system and enable time for the effluent to be treated before it reaches the shallow groundwater. The aquifer was encountered at depths greater than 20 m below ground level and is generally associated with the basalt and fractures within the shale. Given these groundwater depths there should be a sufficient aerobic zone to enable the treatment of the effluent before it reaches the groundwater. Phosphorus losses from land application areas are unlikely to be a problem as the soil is not sandy or highly permeable. The soil was found to have a moderate affinity for phosphorus in relation to the phosphate sorption capacity. As such groundwater contamination and offsite impacts are not likely to be significant. In general, phosphate is usually attenuated in the soil by sorption and precipitation and Australian soils have high affinity for P. In addition to adsorption to clay particles, carbonates and iron oxides can also strongly bind the phosphate and is a reason why it rarely leaches (Dawes 2006). Although rarely leached, phosphate retention is finite and will ultimately reach maximum after which a new land application area will have to be found. In comparison to phosphorus, nitrogen loss especially from septic systems is generally poor and there have been many reports of nitrate contamination in groundwater associated with septic trenches (Beal et. al., 2005).

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Rates of nitrogen removal by volatilisation and nitrification /denitrification can vary depending on soil structure and water content. Gerritse et. al., (1995) reported losses of at least 80% total nitrogen at 10 m from the trench. However it has been estimated that onsite systems typically remove about 20% of nitrogen depending on site specific factors. To further reduce the effects of nitrate, sufficient travel time should be available to allow for attenuation, dispersion and plant use of nitrogen before it reaches the groundwater and sensitive receptors. These can be attained on site with a buffer distance of least 200-500 m between Molong Creek or any of its tributaries. As with all nutrient contaminants associated with onsite wastewater treatment systems, the pathways for pathogen export from land application areas are surface water runoff from surcharging (hydraulic failure) trench or groundwater intrusions via saturation beneath trench. Pathogen removal has been well studied and shows the need for an unsaturated zone beneath the land application area for effective treatment of effluent. Vertical separation has been shown to be essential for pathogenic and biochemical sewage contamination to an acceptable level. Simple one dimensional nutrient modelling for both phosphate and nitrate was also undertaken to assess the area needed to utilise the nutrients and avoid offsite migration. While these were simple models they were sufficient in exhibiting the magnitude of area that may be required for effluent irrigation and full utilisation of nutrients. Studies (van Cuyk et. al., 2001) have shown that a for a 2-3 log virus and bacteria population reduction an estimated travel time of 5-20 days through 0.6 m of soil was required. Hall (1990) previously showed that at least 0.61-1.2 m vertical separation will adequately reduce the bacteria. This range is comparable throughout the literature with a general acceptance that pathogen populations are dramatically reduced by passage through 0.6-0.9 m of unsaturated soil under the trench (Beal et. al., 2005). Within this range Leonard and Pang (2006) found that a there was a wide range of vertical separation required for different soil types and as such recommended field trials to establish the vertical separation required. They suggested modelling horizontal distances assuming no treatment in soils required to determine worst case scenario. Similar modelling was part of establishing the EHPG (1998) setbacks which have been incorporated into the design of the onsite wastewater treatment system. Setback distances were modelled in AS/NZ 154/7 (2012) and EHPG, (1998) guidelines and the >100 m setback to the Creeks and at least 1 m of clay beneath the land application area are in accordance with these guidelines. The site satisfies both these requirements. The deeper groundwater was intercepted at depth >20 m. In such material there is unlikely to be significant potential for fast moving vertical preferential or macropore flow, so migrating waters will move as matrix flow enabling time for the contaminants to be adsorbed by the clay and silt fraction. The deeper regional groundwater therefore does not constitute a significant risk from the proposed development. The discussion provided evidence that the site conditions are suitable for onsite wastewater treatment and that sustainable use of the systems is achievable. This suggests that groundwater contamination is not likely to be significant in a well maintained and properly designed systems such as those identified in this assessment.

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11 CUMULATIVE IMPACT THE DEVELOPMENT MAY HAVE ON GROUNDWATER

There have been numerous reports of onsite failure which have been further compounded in areas with a high density of systems (Carroll et. al., 2006 and Whitehead et. al., 2001). There was originally some thought that by reducing residential development to less than 15 septic systems for every 1 km2 the potential for environmental and health issues would be reduced (Whitehead et al., 2001) even with systems not functioning correctly. However there has been conflicting evidence in relation to this figure as a Western Australian study (Rawlinson, 1994) could find no adverse environmental or health issues associated with a septic system density of 25 systems for every 1 km2. Whitehead et. al., (2001) found no consistent association between nitrate and bacterial contamination of either surface water or groundwater and no clear correlation between the level of contamination and onsite system density. Further to this point sustainable densities have been calculated as low as 6,000 m2 for unsewered development based on P loading (Jelliffe and Hillier 2000) as long as there was stormwater management across the site. Beal et. al., (2005) found recommended densities of 2,000-4,000 m2 whereas in environmentally sensitive areas sustainable densities increased to 50,000 – 100,000 m2 based on N and P budgets. It is therefore safe to assume that as the density of onsite treatment systems increases there is greater potential for adverse impacts. However the effect of the increase in density will always vary with soil types, climate, site features and target receiving water quality objectives and this is why it has been difficult in the past to find a treatment density/ contamination relationship. More importantly, in order to achieve sustainable onsite treatment systems the site must have sufficient area for the proposed buildings and other spatial uses such as road, driveways, lawns, gardens and buffer distances, plus sufficient area located down slope of the point of disposal for assimilation of pathogens and nutrient within site’s boundary (Jelliffe and Hillier 2000). This was further quantified (Jelliffe and Hillier 2000) by stating that each site should have an assimilative area of at least 0.14 ha between the point of disposal and any water course and the slope length of the assimilative area satisfies set back distances determined for the pathogens, export pollutants for the site through the ground will be effectively zero. Site layout can easily incorporate the 0.14 ha area between the effluent disposal area and Molong Creek. As such potential nutrient and pathogens are expected to be treated onsite and not significantly contribute to groundwater contamination or contamination of GDEs. When assessing the cumulative effects (predicting a sustainable lot density) of the development other potential contaminant sources to the groundwater such as animals and fertilisers need to be characterised (Whitehead et al., 2001). It could be that the past agricultural practices in the area may significantly contribute to present groundwater and surface water of the catchment. A general study of groundwater (Bolger and Stevens 1991) found that contamination of groundwater by nitrate in Australia is widespread and is associated with a wide range of nitrogen sources. Three categories of nitrate sources were found:

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• broadacre sources such as grazing, dairying and fertiliser application which have the potential to affect large areas of widespread nutrient loading;

• multiple point sources such as animal husbandry, effluent disposal and septic tanks which form from points or broadacre sources which effect are aggregated; and

• naturally occurring nitrate sources such as termite mounds and nitrogen fixing vegetation.

Gerritse et. al., (1995b) concluded the N addition to catchment waterways were originating to a much greater extent from agricultural areas compared to non sewered areas. In fact in a WA study with septic density of 500/1 km2 inputs of nutrients into groundwater or surface water from other sources such as fertilisers and domestic and commercial animals can dominate the nutrient balance (van de Graff, 2003). Given the evidence stated above, it is likely that the major influence of groundwater and surface water contamination within the local catchment will be agricultural practices associated with cropping and grazing practices. A well designed and managed onsite water treatment system is unlikely to significantly contribute to an agricultural catchment effect. Cumulative effects of the development to the groundwater are therefore expected to be slight to non-existent.

12 CONCLUSION An assessment of the site characteristics and soil properties of the site identified minor to moderate limitation to effluent application. However these features may be overcome by ensuring that the effluent is treated to a quality of a secondary or tertiary standard and incorporating wet weather storage and offsite removal into the onsite wastewater system. As current statistics suggest that potential quantities of effluent produced are in excess of 2000 L/day the preferred option is a commercial aerated wastewater treatment system (AWTS) with a tertiary bacterial treatment (bromine, chlorination, ultraviolet, microfiltration and ozonation). Preliminary modelling (nutrient and hydraulic loading) showed that there is area available for the required effluent irrigation area within the proposed development. This included the tree planting around the perimeter of the site and a designed agricultural area providing over 7,000 m2 of potential irrigation area. Environmental Earth Science also evaluated the effect of the proposed development in relation to onsite wastewater treatment systems on groundwater. The assessment found that for tertiary treated effluent off site impacts to groundwater and neighbouring sensitive environments should be slight to non-existent. By incorporating buffer distances into the design of the wastewater treatment system nutrient and pathogens have the potential to be adsorbed by soil and plants before migrating offsite or reaching the groundwater dependent ecosystems. The fact that the site is based within a disturbed agricultural setting suggests that any point source of contamination produced by the system should not significantly contribute to the current environment influenced by farming practices.

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Procedures and maintenance schedules have been provided to avoid, minimise or mitigate the impacts of the development.

13 LIMITATIONS This report has been prepared by Environmental Earth Sciences NSW ACN 109 404 006 in response to and subject to the following limitations:

1. The specific instructions received from the registered proprietor, DC Partners;

2. The specific scope of works set issued by instructing company for and on behalf of the Director of DC Partners, is included in Section 3 (Scope of Work) of this report;

3. May not be relied upon by any third party not named in this report for any purpose except with the prior written consent of Environmental Earth Sciences NSW (which consent may or may not be given at the discretion of Environmental Earth Sciences NSW);

4. This report comprises the formal report, documentation sections, tables, figures and appendices as referred to in the index to this report and must not be released to any third party or copied in part without all the material included in this report for any reason;

5. The report only relates to the site referred to in the scope of works being located at Lot 100 / DP1122908, 299 Nancarrow Lane, Nashdale, New South Wales (“the site”);

6. The report relates to the site as at the date of the report as conditions may change thereafter due to natural processes and/or site activities;

7. No warranty or guarantee is made in regard to any other use than as specified in the scope of works and only applies to the depth tested and reported in this report;

8. Fill, soil, groundwater and rock to the depth tested on the site may be fit for the use specified in this report. Unless it is expressly stated in this report, the fill, soil and/or rock may not be suitable for classification as clean fill if deposited off site;

9. This report is not a geotechnical or planning report suitable for planning or zoning purposes; and

10. Our General Limitations set out at the back of the body of this report.

14 REFERENCES

Ahmen W., Neller R., Katoul, M (2005). Evidence of septic tank systems failure by a bacterial biochemical fingerprinting method. Journal of Applied Microbiology 98, 910-920

Australian New Zealand Standard AS/NZ 154/7 (2012) On-site domestic wastewater management.

Bagdol JL, Soegrost RL and Lowe KS (2004). Mass Balance Modelling and Water Quality Monitoring of Impact Assessment of Development with Onsite Wastewater Systems Compared to that of with Centralised Treatment Plants, Proceedings of ONSITE Wastewater Treatment 21-24, March 2004.

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Beal CD, Gardner EA and Menzies NW (2005) – Process, performance and pollution potential: A review of septic tank-soil adsorption systems. Australian Journal of Soil Research, 43, 781-802.

Bolger P and Stevens M (1991) Contamination of Australian Groundwater Systems with Nitrate LWRRDC Occasional Paper 03/99

Bureau of Meteorology (2013). Groundwater Dependent Ecosystems. (www.bom.gov.au/water/groundwater/GDE), Verified 3 June 2013)

Carroll S, Goonetilleke A, Thomas E, Hargreaves M, Frost R and Dawes L (2006). Integrated Risk Framework for Onsite Wastewater Treatments Systems Environmental Management vol 38(2): pp286-303

van Cuyk, S., Siegrist, R., Logan A., Masson S., Fischer E. and Figueroa (2001). Hydraulic and purification and their interactions during wastewater treatment in soil infiltration systems, Water Research 35 p 953-964

Dawes L (2006). Role of Soil physical and chemical characteristics and landscape factors in defining soil behaviour under long term wastewater dispersal Doctor of Philosophy (PhD) Centre for Built Environment and Engineering Research Facility of Built Environment and Engineering QLD University and Technology

Dawes L, Goonetilleke A, Cox M (2006). Assessment of physical and chemical properties of subtropical soil to predict long term effluent treatment potential. Soil and sediment Contamination 14 (3) pp211-230

Environmental and Health Protection Guidelines (1998) On-Site Sewerage Management for Single Households. Department of Urban Affairs and Planning

EPRI (2000). National Research Needs Conference Proceedings: Risk based decisions making for onsite wastewater treatment EPRI Palo Alto, CA U.S. Environmental Protection Agency and National Decentralised Water resources Capacity Development Project 2001 1101446.

Geary PM and Whitehead J (2001) Groundwater contamination from onsite Domestic Wastewater Management Systems in a Coastal Catchment. In ‘Proceedings of the Ninth National Symposium on Individual and small community sewerage systems, Fort Worth Texas American Society of Agricultural Engineers.

Gerritse RG, Adeney JA, Hosking J (1995b). Nitrogen losses from a domestic septic tank system on the Darling Plateau Western Australia. Water Research 29, 2055-2058

Hazelton and Murphy (1992) What do all the Numbers Mean?. Department of Conservation and Land Management.

Hall Seldon (1990). Vertical separation. A review of available scientific literature and a listing from fifteen other states. Office of Environmental Health and Safety. Olympia WA

Isbell, R.F. (2002), The Australian Soil Classification, CSIRO Publishing, Collingwood VIC.

Jelliffe P and Hillier H (2000). Prediction of sustainable allotment size and critical development densities in unsewered areas. (verified 20 June 2013)

Kovac, M., Murphy, B. W. and Lawrie, J. W. (1990), – Soil Landscapes of the Bathurst 1:250 000 Sheet Report. Soil Conservation Service of NSW, Sydney.

Kovac, M., Murphy, B. W. and Lawrie, J. W. (1989) – Soil Landscapes of the Bathurst 1:250 000 Sheet Map. Department Soil Conservation Service of NSW, Sydney.

http://www.bom.gov.au/water/groundwater/GDE

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Leonard M and Pang L (2006). Approaches for assessing bacterial removal in soils. Institute of Environmental Science and Research Limited.

Meakin N.S., Spackman J.M., Scott M.M., Watkins J.J., Warren A.Y.E., Glen R.A., Moffit R.S. and Krynen J.P., 1997, Orange 1:100 000 Geological Sheet 8731, 1st edition. Geological Survey of New South Wales, Sydney & Geoscience Australia, Canberra.

National Health and Medical Research Council (2004). National water quality management strategy. Australian Drinking water guidelines.

NSW Department of Land and Water Conservation (2001). Groundwater vulnerability map explanatory notes. Centre for Natural Resources, Department of Land and Water Conservation, NSW Government.

Rawlinson, L. (1994). Review of On-Site Wastewater Systems. NSW EPA, Sydney.

Raymond O. L., and Duggan M. B., Lyons P., Scott M. M., Sherwin L., Wallace D. A., Krynen J. P., Young G. C., Wyborn D., Glen R. A., Percival I. G and Leys M., (2000). Forbes second edition (1:250 000 geological map S155-7). Australian Geological Survey Organisation , Canberra and the Geological Survey of New South Wales, Orange.

van De Graff, R. (2003). Interactions between Science and Current Guidelines – Conflicts, Wins and Losses. In Proc. On-site 03 Conference: Future directions for On-site Systems: Best management practice. Editors Paterson, R. A. and Jones, M .J. Lanfax Lab, Armidale

Whitehead J.H., Geary, P. M., and Saunders, M., (2001). Towards a better understanding of sustainable lot density - evidence from five Australian case studies. In Proc. On-site 01 Conference: Advancing On-site Wastewater Systems. Editors Paterson, R. A. and Jones, M .J. Lanfax Lab, Armidale.

Whitehead J.H and Geary, P. M. (2001). Geotechnical aspects of domestic on-site effluent management systems. Australian Journal of Earth Sciences 47, 75-82

15 GLOSSARY OF TERMS The following descriptions are of terms used in the text of this report. Alluvial. Describes material deposited by, or in transit in, flowing water. Anaerobic. Reducing or without oxygen. Aquifer. A rock or sediment in a formation, group of formations, or part of a formation which is saturated and sufficiently permeable to transmit economic quantities of water to wells and springs. Aquifer, confined. An aquifer that is overlain by a confining bed with significantly lower hydraulic conductivity than the aquifer. Aquifer, perched. A region in the unsaturated zone where the soil is locally saturated because it overlies soil or rock of low permeability. Bore. A hydraulic structure that facilitates the monitoring of groundwater level, collection of groundwater samples, or the extraction (or injection) of groundwater. Also known as a well,

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monitoring well or piezometer, although piezometers are typically of small diameter and only used for measuring the groundwater elevation or potentiometric surface. Borehole. An uncased well drill hole. Cation Exchange Capacity (CEC). The maximum positive charge required to balance the negative charge on colloids (clays and other charged particles). The units are milli-equivalents per 100 grams of material or centimoles of charge per kilogram of exchanger. Clay. A soil material composed of particles finer than 0.002 mm. When used as a soil texture group such soils contain at least 35% clay. Colluvial. Unconsolidated soil and rock material moved down-slope by gravity. Confined Aquifer. An aquifer that is confined between two low-permeability aquitards. The groundwater in these aquifers is usually under hydraulic pressure, i.e. its hydraulic head is above the top of the aquifer. Confining layer. A layer with low vertical hydraulic conductivity that is stratigraphically adjacent to one or more aquifers. A confining layer is an aquitard. It may lie above or below the aquifer. Diffusion. A process by which species in solution move, driven by concentration gradients (from high to low). Dilution. The mixing of a small volume of contaminated leachate with a large volume of uncontaminated water. The concentration of contaminants is reduced by the volume of the lower concentrated water. However the physical process of dilution often causes chemical disequilibria resulting in the destruction of ligand bonds, the alteration of solubility products and the alteration of water pH. This usually causes precipitation by different chemical means of various species. Discrete sample. Samples collected from different locations and depths that will not be composited but analysed individually. Dispersion. A process by which species in solution mix with a second solution, thus reducing in concentration. In particular, relates to the reduction in concentration resulting from the movement of flowing groundwater.

Flow path. The direction in which groundwater is moving. Fracture. A break in the geological formation, e.g. a shear or a fault. Gradational. The lower boundary between soil layers (horizons) has a gradual transition to the next layer. The solum (soil horizon) becomes gradually more clayey with depth. Gradient. The rate of inclination of a slope. The degree of deviation from the horizontal; also refers to pressure. Groundwater. The water held in the pores in the ground below the water table.

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Groundwater Elevation. The elevation of the groundwater surface measured relative to a specified datum such as the Australian Height Datum (mAHD) or an arbitrary survey datum onsite, or “reduced level” (mRL). Heterogeneous. A condition of having different characteristics in proximate locations. Non-uniform. (Opposite of homogeneous). Horizon. An individual soil layer, based on texture and colour, which differs from those above and below. Hydraulic Conductivity (K). A coefficient describing the rate at which water can move through a permeable medium. It has units of length per time. The units for hydraulic conductivity are typically m3/day/m2 or m/day. Hydraulic Gradient (i). The rate of change in total head per unit of distance of flow in a given direction – the direction is that which yields a maximum rate of decrease in head. Hydraulic Gradient is unit less. Hydraulic Head (h). The sum of the elevation head and the pressure head at a point in an aquifer. This is typically reported as an elevation above a fixed datum, such as sea level. Infiltration. The passage of water, under the influence of gravity, from the land surface into the subsurface. Ionic Exchange. Adsorption occurs when a particle with a charge imbalance, neutralises this charge by the attraction (and subsequent adherence of) ions of opposite charge from solution. There are two types of such a charge: pH dependent; and pH independent or crystalline charge. Metal hydroxides and oxy-hydroxides represent examples of the former type, whilst clay minerals are representative of the latter and are normally associated with cation exchange. Ions. An ion is a charged element or compound as a result of an excess or deficit of electrons. Positively charged ions are called cations, whilst negatively charged ions are called anions. Cations are written with superscript +, whilst anions use - as the superscript. The major aqueous ions are those that dominate total dissolved solids (TDS). These ions include: Cl-, SO42-, HCO3-, Na+, Ca2+, Mg2+, K+, NH4+, NO3-, NO2-, F-, PO43- and the heavy metals. Lithic. Containing large amounts of fragments derived from previously formed rocks. Mottled. Masses, blobs or blotches of sub-dominant, varying colours in the soil matrix. Nodulation. Are hard, usually small, accumulation of precipitated iron and/or manganese in the soil profile, usually a result of past alternating periods of oxidation/reduction. Nodule. A small, concretionary (hard) deposit, usually of iron and/or manganese. Organics. Chemical compounds comprising atoms of carbon, hydrogen and others (commonly oxygen, nitrogen, phosphorous, sulfur). Opposite is inorganic, referring to chemical species not containing carbon.

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Oxidation. Was originally referred only to the addition of oxygen to elements. However oxidation now encompasses the broader concept of the loss of electrons by electron transfer to other ions. Perched Groundwater. Unconfined groundwater separated from an underlying main body of groundwater by an unsaturated zone. Perched groundwater typically occurs in discontinuous, often ephemeral, lenses, with unsaturated conditions both above and below. Permeability (k). Property of porous medium relating to its ability to transmit or conduct liquid (usually water) under the influence of a driving force. Where water is the fluid, this is effectively the hydraulic conductivity. A function of the connectivity of pore spaces. Piezometric or Potentiometric Surface. A surface that represents the level to which water will rise in cased bores. The water table is the potentiometric surface in an unconfined aquifer. pH. A logarithmic index for the concentration of hydrogen ions in an aqueous solution, which is used as a measure of acidity. Porosity (n). The ratio of the volume of void spaces in a rock or sediment to the total volume of the rock or sediment. Typically given as a percentage. Porosity, effective (ne). The volume of the void spaces through which water or other fluids can travel in a rock or sediment divided by the total volume of the rock or sediment. Precipitation (chemical). There are two types of precipitation, pH dependent precipitation and solubility controlled precipitation. As the pH is raised beyond a threshold level the precipitation of metal cations such as oxy-hydroxides and hydroxides occur. As the pH is raised further precipitation continues until there are very few metal cations remaining in solution. This reaction is entirely reversible. Solubility controlled precipitation occurs between two ions when, at a given temperature and pressure, the concentration of one of the ions exceeds a certain level. Profile. The solum. This includes the soil A and B horizons and is basically the depth of soil to weathered rock. Recharge Area location of the replenishment of an aquifer by a natural process such as addition of water at the ground surface, or by an artificial system such as addition through a well Recovery. The rate at which a water level in a well rises after pumping ceases. Redox. REDuction-OXidation state of a chemical or solution. Redox potential (Eh). The oxidation/reduction potential of the soil or water measured as milli-volt. Reducing Conditions. Can be simply expressed as the absence of oxygen, though chemically the meaning is more complex. For more details refer to OXIDATION. Representative Sample. Assumed not to be significantly different than the population of samples available. In many investigations samples are often collected to represent the worst case situation.

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Saturated Zone. A zone in which the rock or soil pores are filled (saturated) with water. Shale. Fine-grained sedimentary rock formed by the compaction of silt, clay, or sand that accumulates in deltas and on lake and ocean bottoms. It is the most abundant of all sedimentary rocks. Standing Water Level (SWL). The depth to the groundwater surface in a well or bore measured below a specific reference point – usually recorded as metres below the top of the well casing or below the ground surface. Stratigraphy. A vertical sequence of geological units. Subsoil. Subsurface material comprising the B and C horizons of soils with distinct profiles. They often have brighter colours and higher clay content than topsoils. Texture. The size of particles in the soil. Texture is divided into six groups, depending on the amount of coarse sand, fine sand, silt and clay in the soil. Topsoil. Part of the soil profile, typically the A1 horizon, containing material which is usually darker, more fertile and better structured than the underlying layers. Total Dissolved Salts (TDS). The total dissolved salts comprise dissociated compounds and undissociated compounds, but not suspended material, colloids or dissolved gases. Unsaturated Zone. The zone between the land surface and the water table, in which the rock or soil pores contain both air and water (water in the unsaturated zone is present at less than atmospheric pressure). It includes the root zone, intermediate zone and capillary fringe. Saturated bodies such as perched groundwater may exist in the unsaturated zone. Also referred to as the Vadose Zone. Water table. Interface between the saturated zone and unsaturated zones. The surface in an aquifer at which pore water pressure is equal to atmospheric pressure. Well. A hydraulic structure that facilitates the monitoring of groundwater level, collection of groundwater samples, or the extraction (or injection) of groundwater. Also known as a Bore.

General Limitations 6 April 2009 Page 1 of 1

ENVIRONMENTAL EARTH SCIENCES GENERAL LIMITATIONS Scope of services The work presented in this report is Environmental Earth Sciences response to the specific scope of works requested by, planned with and approved by the client. It cannot be relied on by any other third party for any purpose except with our prior written consent. Client may distribute this report to other parties and in doing so warrants that the report is suitable for the purpose it was intended for. However, any party wishing to rely on this report should contact us to determine the suitability of this report for their specific purpose.

Data should not be separated from the report A report is provided inclusive of all documentation sections, limitations, tables, figures and appendices and should not be provided or copied in part without all supporting documentation for any reason, because misinterpretation may occur.

Subsurface conditions change Understanding an environmental study will reduce exposure to the risk of the presence of contaminated soil and or groundwater. However, contaminants may be present in areas that were not investigated, or may migrate to other areas. Analysis cannot cover every type of contaminant that could possibly be present. When combined with field observations, field measurements and professional judgement, this approach increases the probability of identifying contaminated soil and or groundwater. Under no circumstances can it be considered that these findings represent the actual condition of the site at all points. Environmental studies identify actual sub-surface conditions only at those points where samples are taken, when they are taken. Actual conditions between sampling locations differ from those inferred because no professional, no matter how qualified, and no sub-surface exploration program, no matter how comprehensive, can reveal what is hidden below the ground surface. The actual interface between materials may be far more gradual or abrupt than an assessment indicates. Actual conditions in areas not sampled may differ from that predicted. Nothing can be done to prevent the unanticipated. However, steps can be taken to help minimize the impact. For this reason, site owners should retain our services.

Problems with interpretation by others Advice and interpretation is provided on the basis that subsequent work will be undertaken by Environmental Earth Sciences NSW. This will identify variances, maintain consistency in how data is interpreted, conduct additional tests that may be necessary and recommend solutions to problems encountered on site. Other parties may misinterpret our work and we cannot be responsible for how the information in this report is used. If further data is collected or comes to light we reserve the right to alter their conclusions.

Obtain regulatory approval The investigation and remediation of contaminated sites is a field in which legislation and interpretation of legislation is changing rapidly. Our interpretation of the investigation findings should not be taken to be that of any other party. When approval from a statutory authority is required for a project, that approval should be directly sought by the client.

Limit of liability This study has been carried out to a particular scope of works at a specified site and should not be used for any other purpose. This report is provided on the condition that Environmental Earth Sciences NSW disclaims all liability to any person or entity other than the client in respect of anything done or omitted to be done and of the consequence of anything done or omitted to be done by any such person in reliance, whether in whole or in part, on the contents of this report. Furthermore, Environmental Earth Sciences NSW disclaims all liability in respect of anything done or omitted to be done and of the consequence of anything done or omitted to be done by the client, or any such person in reliance, whether in whole or any part of the contents of this report of all matters not stated in the brief outlined in Environmental Earth Sciences NSW’s proposal number and according to Environmental Earth Sciences general terms and conditions and special terms and conditions for contaminated sites. To the maximum extent permitted by law, we exclude all liability of whatever nature, whether in contract, tort or otherwise, for the acts, omissions or default, whether negligent or otherwise for any loss or damage whatsoever that may arise in any way in connection with the supply of services. Under circumstances where liability cannot be excluded, such liability is limited to the value of the purchased service.

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APPENDIX A GROUNDWATER BORE LICENCES

http://allwaterdata.water.nsw.gov.aulwgen/users/33 8 1 0 4247 I 9w0497 ...

NSW Office of WaterWork Summary

GW049714

Licence: 808L110152 LicenceStatus: CONVERTED

Authorised STOCK,DOMESTICPurpose(s):

lntended Purpose(s): STOCK, DOMESTIC

Work Type: Bore

Work Status:

Construct.Method: Rotary Air

Owner Type: Private

Commenced Date: Final DePth: 76.90 mCompletion Datet 01t1211978 Drilled Depth: 76.90 m

Contractor Name:

Driller:

Assistant Driller:

Property: NiA

GWMA: -GWZone: -

Site Details

Standing Water Level(m):

Salinity Description: FreshYield {Us): 3.300

Site Chosen Byr

County Parish CadastreForm A: WELLI WELL|.046 106

Licensed: WELLINGTON TOWAC Whole Lot //

Region: 80 - Macquarie-Western CMA Map: 873'1-3NRiver Basin: 421 - MACQUARIE RIVER Grid Zone:

Area/District:

Elevation: 0.00 m (A.H.D.)Elevation (Unknown)

Source:

GS Map: -

Northing: 6311266.0Easting: 687181 .0

MGAZone:0

Scale:

Latitude: 33"1 9'1 7.4.SLongitude: 149"00'39.3"E

Coordinate GD.,ACC.MAPSource:

ConstructionNegative depths indicate Above Ground Level; C-Cemented; SL-SIot Length; A-Aperture; GS-Grain Size; Q-Quantity; Pl-Placement of

Water Bearing Zones

Gravel Pack; PC-Pressure Cemented; CE-Centralisers

Hole Pipe Component Type From(m)

To(m)

OutsideDiameter(mm)

lnsideDiameter(mm)

Interval Details

1 Casing Steel -0.60 18.70 168 Seated

1 Opening Slots - Vertical 4.60 7.00 168 1 Oxv-Acetvlene Slotted. A: 2.00mm

From{m)

To(m)

Thickness(m)

WBZ Type S.WL,(m)

D.D.L.(m)

Yield(us)

HoleDepth{m)

Duration(hr)

Salinity(mg/L)

4.60 65.20 60.60 (Unknown) 3.00 3.30

I of2 8ll8l17,l0:08 AM

Geologists LogDrillersFrom{m)

To(m)

Thickness(m)

Drillers Description Geological Material Comments

0.00 0.30 0.30 Topsoil Topsoil

0.30 4.60 4.30 Clay Red Clay

4.60 9.20 4.60 Clav Bands White Water Supolv Clay

9.20 18.50 9.30 Basalt Decomposed Water SuPPIY Basalt

18.50 36.00 17.50 Basalt Water Suoplv Basalt

36.00 39.40 3.40 Siltstone Grey Water Supply Siltstone

39.40 43.00 3.60 Basalt Water Supply Basalt

43.00 76.30 33.30 Conolomerate Green Water Supplv Conglomerate

76,30 76.90 0.60 Clav Red Clay

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