site classification on-site sewage management report

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SITE CLASSIFICATION

ON-SITE SEWAGE MANAGEMENT REPORT

83-95 Cattle Street

BINALONG NSW

12 October 2020 (V01)

FRANKLIN CONSULTING AUSTRALIA PTY LIMITED

GPO Box 837 Canberra ACT 2601 www.soilandwater.net.au

Franklin Consulting Australia Pty Limited, trading as Soil and Water, offers expert advice and

services to the agriculture, development and environmental conservation sectors. We provide

soil and water management advice, undertake land capability and soil assessment, erosion and

sediment control, and soil conservation, catchment and property management planning. We

have extensive experience in both government and private sectors in senior management and

consulting roles.

We provide our services to individual land holders, sub-division developers, surveyors,

commercial business owners, and land development and regulatory agencies.

Principal Consultant

John Franklin M App Sc, BSc, EIANZ, CEnvP

Franklin Consulting Australia Pty Ltd holds current

Workers Compensation Insurance with CGU (Policy

Number O/16-5885) and Professional Indemnity

cover of $10,000,000 and Public Liability cover of

$10,000,000 with Lloyds.

Contact details: GPO Box 837

Canberra ACT 2601

P 02 6179 3491

M 0490 393 234

[email protected]

www.soilandwater.net.au

Disclaimer

This report is based on the information provided by the client prior and the site inspection as

dated. Franklin Consulting Australia does not take responsibility for subsequent changes by the

client or for the installation or operation of effluent management systems by the client or third

parties. This report is invalid if the wastewater system is not installed according to this

recommended design. If the excavated soil profiles for the construction of the footings differ to

that described in this report, then further classification and soil testing is required.

CONTENTS

SUMMARY RECOMMENDATIONS ................................................................................ 1

PROJECT DESCRIPTION........................................................................................... 2

REPORT SCOPE AND TECHNICAL REFERENCES ............................................................... 3

LOCATION ........................................................................................................... 4

SITE INFORMATION ............................................................................................... 7

SITE ASSESSMENT ................................................................................................ 9

SOIL ASSESSMENT .............................................................................................. 13

SYSTEM SELECTION ............................................................................................. 14

EFFLUENT MANAGEMENT PRESCRIPTIONS ................................................................. 15

SIZING EFFLUENT DISPOSAL AREA ........................................................................... 21

SITE AND SOIL LIMITATION ASSESSMENT .................................................................. 22

Appendix 1: Soil Profile Description .......................................................................... 26

Appendix 2: Supporting information .......................................................................... 28

Appendix 3: NSW Health Accreditation ....................................................................... 31

83-95 CATTLE STREET │ BINALONG

FRANKLIN CONSULTING AUSTRALIA 1 | Page

SUMMARY RECOMMENDATIONS

Development: Construction of shed and 3-bedroom dwelling on Lots

10,11,12 & 13 DP 758109 at 83-95 Cattle Street, Binalong,

NSW.

Expected wastewater load/day: Daily effluent load is 480/day (based on potential occupancy

of 4 people @ 120L/day in accordance with NSW Silver Book)

Recommended treatment system: Secondary Treatment System (NSW Health Accredited)

including disinfection.

[The make and model of treatment system has been selected

from NSW Health accredited secondary treatment systems and

the NSW Health Accreditation details are included at Appendix

3 in this report]

Recommended dispersal system: Treated effluent will be disposed of by surface spray irrigation

applied to a minimum irrigation area of 300 m2. A reserve

irrigation area of equal size is also available

Special conditions/comments: A moveable surface sprinkler line is considered suitable due to

the availability of adequate areas of unconstrained land and

broadacre rural location.

Site Classification The soil material within the building envelope of the dwelling

and shed has been designated as M-Moderately Reactive.

Provided footings are founded in similar soil material beneath

the topsoil material (which extends to approximately 30cms)

then a M-Moderately Reactive Site Classification is considered

the appropriate rating.

When constructing the footings, if the excavated soil profiles

differ from that described in this report, then further

classification or laboratory testing is required to confirm the

classification.



PROJECT DESCRIPTION

This site and soil assessment informs the appropriate on-site management of domestic effluent

associated with a proposed shed and 3-bedroom dwelling to be installed at 83-95 Cattle Street,

Binalong. The assessment also assigns a Site Classification to the building envelope to inform

the design of footings and foundations.

The site and soil conditions on both lots are suited for a Secondary Treatment System with

effluent dispersal of treated effluent through surface spray irrigation. The site and soil

conditions are also not suited to primary treatment and disposal through subsoil absorption

beds due to the low permeability medium clay subsoil.

There is an adequate unconstrained area on the Lot suitable for the disposal of secondary

treated and disinfected effluent through surface spray irrigation in accordance with the

prescriptions contained in this report.



REPORT SCOPE AND TECHNICAL REFERENCES

The report assesses land near the proposed development to identify specific areas required for

the optimal functioning of an on-site sewage management system.

This involves excluding land with major physical constraints such as steep slopes, rocky

outcrops, poor drainage, areas within buffer distances of property boundaries watercourses,

storages, flow lines and existing and proposed buildings.

All information required by the approving authority, usually regional Councils, is contained in

this report, including suitable types of sewage management systems, management

prescriptions, site plan and photographs, with supporting information in this report including

nutrient balance and limitation tables.

The report also assesses the soil substrate at the location of the proposed dwelling to derive a

site classification in accordance with the requirement of AS2870 Residential slabs and footings

– Construction.

The report also refers to, or relies on, standards and technical references listed below.

On-site Sewage Management for Single Households (The Silver Book) NSW Govt, 1998.

AS/ANZ Standard 1547:2012 On-site Domestic Wastewater Management.

AS 2870 Residential slabs and footings – Construction.

Soil Landscapes of the Canberra 1:250,000 Sheet. Hird, C. (1991) Soil Conservation

Service of NSW

Soil Landscapes of the Canberra 1:100,000 Sheet. Jenkins, B.R. (2000) Department of

Land and Water Conservation, NSW.

Yass Valley Local Environmental Plan (2013)



LOCATION Site and Regional Location

a

b



c

Figures 1a, b and c: Lot Layout and Regional Location and configuration



Landscape

The landscape is dominated topographically by the minor drainage features which flows south

to north across the lot. The regional landscape is described as undulating low hills with low to

moderate slope gradients of 3-10%. Local relief between 30-90 m with elevations ranging

between 500 – 630 m.

The site is a free draining gentle to moderately sloping minor crest with side slopes of 7-9

degrees to the north and east. The lot is drained by overland flow and a minor 1st Order Stream

which flows from a pipe culvert under Cattle Street to meet Bobara Gully which flows across

the centre of the lot to the in the south western corner of the lot and some minor drainage

depressions which flow north east to south west across the lot.

The site is extensively cleared but retains scattered remnant native trees.

The property is located adjacent to the village of Binalong and is surrounded by large rural

lots.

Soils

Detailed soil profile descriptions are provided in Appendix 1 of this report. Moderately well-

drained Red Chromosols grading to Poorer drained Yellow Chromosols in drainage depressions.

The soils have formed in situ and from alluvial-colluvial material derived from parent material

of Duoro Volcanics. Areas identified as suitable for land application of effluent comprise a

massively structured silty-sandy loam upper layer overlying a bleached massive clay loam A2

horizon which overlays a moderately structured light clay loam subsoil. Total depth exceeds

100 cm.

Extrapolating from the soil survey of the Goulburn 1:250,000 sheet (Hird, C 1991), the soils on

the gently sloping land and valley floors fit the Binalong Soil Landscape. The Binalong Soil

Landscape is comparable with the Williamsdale Unit in the Canberra 1:100,000 sheet (Jenkins,

2000). The representative analytical data in the Canberra 1:100,000 survey report shows a

moderate phosphorous sorption level, non-saline subsoils and low exchangeable sodium. As

such the soils are free of any significant chemical limitations to effluent dispersal.



SITE INFORMATION

Address

Lots 10,11,12 & 13 DP 758109, 83-95 Cattle Street, Binalong, NSW.

Owners/ Builder Jill and Mark Tarrant-Curran

LGA Yass Valley Council

Water supply Non-reticulated water supply.

Expected

wastewater load

(volume in

litres/day)

Effluent system design is based on a 3-bedroom dwelling with non-reticulated

water supply with 4 potential occupants @ 120L/person/day. This is consistent

with the size of the proposed dwelling/shed.

Design Wastewater Load is 480 L/day (as per Silver Book, NSW Government)

Local

experience

Most secondary treatment and surface spray irrigation systems work

adequately in the area provided they are on appropriate soil and site conditions

and are properly managed. Systems need to be maintained regularly, in

accordance with council regulations and prescriptions in this report.

Figure 2: Looking from treatment system site towards dwelling site



Figure 3: Looking from shed site towards dwelling

Figure 4: Looking across dwelling building platform



SITE ASSESSMENT

The climate is typically a cool and moderately dry climate. Average mean

annual rainfall for the area is approximately 650 mm, pan evaporation

1,200 mm; large moisture deficit typically occurs in summer months, small

moisture surplus typically occurs in winter months.

Climate is suited to dispersal by surface spray irrigation of secondary

treated, disinfected effluent.

Rainfall water balance attached Yes

Land application area calculated Yes

Wet weather storage calculation

attached

NA

Flood potential

land application area above 1:20 year flood:

land application area above 1:100 year flood:

electrical components above 1:100 year flood:

Yes

Yes

Yes

Exposure

The site has scattered remnant native vegetation however the proposed

effluent disposal area has a high level of exposure suited to effluent irrigation.

Exposure is suitable for the disposal of secondary treated and disinfected

effluent through sub-surface drip irrigation.

Slope

The effluent dispersal site is low to moderately sloping and suited for effluent

irrigation.

Slopes are not a constraint to the disposal of secondary treated effluent

through surface spray irrigation.

Landform The landscape is dominated topographically by the gentle north and east

midslope. The building platform and effluent dispersal practices are located

towards the top of this midslope on a divergent slope form.

Slope form is suited to the dispersal of secondary treated effluent through

surface spray irrigation.

Run-on

Run-on water will adversely impact the effluent disposal site due to limited

and extensive area of upslope catchment.

Run-on water will be a constraint to the effluent disposal site and will be

diverted around the irrigation area by an upslope earth diversion bank.

Seepage No seepage was evident on the property.



Erosion

potential

The soil types which dominate the site have a high erosion hazard. The

erosion risk on the site is low given the low to moderate slope and good

levels of groundcover.

The property is gently sloping with good groundcover. The areas identified

as suitable for effluent disposal do not exhibit any erosion issues.

100 % groundcover will be maintained in all effluent irrigation areas.

Site drainage

Site drains through overland flow and minor drainage depressions. There is

a 1st Order Stream which parallels the northern boundary. The property

also includes a farm dam and Bobara Gully. The effluent disposal area

requires a 40 metre buffer from drainage features including the dam, 1st

Order stream and Bobara Gully.

The proposed effluent disposal area on the Lot will be separated from the

adjacent dams, 1st Order Stream and Bobara Gully by a buffer of 40

metres.

Fill

No fill is evident on the site.

Groundwater

Horizontal

distance to

groundwater

well used for

domestic

supply:

Groundwater

vulnerability

map

category:

There are no known wells used for potable water in the vicinity.

The area is mapped as Groundwater vulnerable on the Yass Valley LEP

(2013), above. As the area is mapped as groundwater vulnerable the Part 6

Additional Local Provisions 6.4 Groundwater vulnerability require that:

Before determining a development application for development on land to which this clause

applies, the consent authority must consider the following:



Bores in

area and

purpose:

(a) the likelihood of groundwater contamination from the development (including from any

on-site storage or disposal of solid or liquid waste and chemicals),

(b) any adverse impacts the development may have on groundwater dependent

ecosystems,

(c) the cumulative impact the development may have on groundwater (including impacts

on nearby groundwater extraction for a potable water supply or stock water supply),

(d) any appropriate measures proposed to avoid, minimise or mitigate the impacts of the

development.

(4) Development consent must not be granted to development on land to which this

clause applies unless the consent authority is satisfied that:

(a) the development is designed, sited and will be managed to avoid any significant

adverse environmental impact, or

(b) if that impact cannot be reasonably avoided—the development is designed, sited and

will be managed to minimise that impact, or

(c) if that impact cannot be minimised—the development will be managed to mitigate that

impact.

The area is mapped as Moderate to Moderately High Groundwater

Vulnerability on the DLWC Murrumbidgee Catchment Groundwater

Vulnerability Mapping.

https://realtimedata.waternsw.com.au/

There is 1 bore site within 500m of the proposed effluent disposal area. The

bore is GW 416307 and is located 200 metres north of the effluent disposal.

This bore is 33 metres deep with a yield of 2.527L/sec and water bearing

zones at 16-16.1/24-25/26-26.5m.

The effluent management practices proposed in this report will not impact

these bores or the groundwater aquifer due to:

• horizontal separation of >200m,

• vertical separation of >25m to main water bearing zones,

• small daily load volumes of high-quality secondary treated and

disinfected effluent

• application of treated effluent through surface irrigation, and

• low transmissivity of fractured rock aquifer systems.

Buffer distance from treatment system to



Perennial rivers and creeks:

Drainage depressions:

Bore:

Dwellings:

Other sensitive

environments:

Boundary of premises:

Swimming pools:

Buildings: [Buffers distances as per Silver Book]

NA

40 m (includes dams)

200 m (bore)1

15 m

NA

3m (upslope boundaries) / 6m (downslope)

3m (upslope buildings) / 6m (downslope)

Is there sufficient land area for

Application system including

buffers:

Reserve application system:

Yes, refer Figures 5a-b

Available

Surface rock

outcrop

Significant localised area of outcropping rock but localised in the

proposed effluent disposal areas.

1 A reduced bore of 200m is considered adequate given the bore is not located downslope of the effluent irrigation area, the depth to water bearing zones and the low application rate of high quality disinfected effluent to the surface.



SOIL ASSESSMENT Depth to bedrock or hardpan: 1-1.5 m

Depth to high soil water table: >1.5 m

Hydraulic loading rate

Soil texture:

Soil structure:

Permeability (from table M1 of AS1547:2012):

Recommended design loading rate for

irrigation system (from table M1 of

AS1547:2012):

Sandy Loam

Moderate

0.5 – 1.5 m/day

4 mm/day

Coarse fragments:

None

Bulk density (a): 1.6 t/m3 topsoil, 1.5 t/m3 subsoil

pH field (a) 5.4 in topsoil, 6.0 in subsoil

Electrical conductivity dS/m (a) 0.1 in topsoil, 0.11 in subsoil

Exchangeable sodium %(a) 0.1 in topsoil, 4.2 in subsoil

Cation exchange capacity

(mequiv/100g) (a)

5.5 in topsoil, 11.4 in subsoil

Phosphorous sorption capacity

mg/kg (a)

122 (1,952kg/ha) topsoil, 447 subsoil (6,705kg/ha)

Geological feature

Discontinuities:

Fractured rock:

None

None

Soil landscape reference (a): Williamsdale Unit (comparable with the Binalong Unit)

Dispersiveness EAT class (a): 3(2) topsoil, 2(1) subsoil

AS2870 Site Class

(for in situ soil material):

M (Moderately Reactive) Notes:

The soil material beneath the topsoil layer has been assigned a

Site Classification of M- (Moderately Reactive).

If footings are founded in the subsoil material beneath the super

saturated layer (which extends to approximately 30cm depth)

then a M-Moderately Reactive classification if appropriate.

When constructing the footings, if the excavated soil profiles

differ from that described in this report, then further classification

or laboratory testing is required to confirm the classification. (a) extrapolated from Jenkins (2000) Soil Landscapes of the Canberra 1:100,000 Sheet. DLWC



SYSTEM SELECTION

Consideration of connection to

centralised sewerage system

Distance:

Potential for future connection:

Potential for reticulated water:

>5 kilometres

None

Connected

Type of land application system best

suited

Justification:

Surface spray irrigation to improved pasture/grass

&/or landscaped areas.

Suited to site and soil conditions.

Enables beneficial reuse of effluent in a water

constrained environment.

Low permeability clay loam subsoil is not ideally

suited to primary treatment and subsoil absorption.

Type of treatment system best

suited

Justification:

NSW Health accredited secondary treatment

system.

Reliable systems with high quality disinfected

effluent then available for beneficial reuse.



EFFLUENT MANAGEMENT PRESCRIPTIONS

Effluent

treatment

The following site-specific recommendations are made in respect of the AWTS:

1. Effluent will be treated by a NSW Health accredited system capable of achieving

secondary standard treatment, see below. The AWTS has been selected by the

client in consultation with the installer. The system is highlighted below and NSW

Health Accreditation details are provided in Appendix 3.

A list of NSW Health accredited systems is provided in the following table: AWTS

AWTS Maintenance Envirocycle 10NR 1800688588

Bioseptic Performa 1300 658 111

Clearwater Sewage and Watertanks Biodigester II 1300 132 760

Earthsafe Environmental Earthsafe ES10PC 1300 327 847

Eco Septic Econocycle ENC 10-1, ENC 10-2 (02) 4774 1316

Everhard Industries Aqua Nova 10EP, NR, MBR10 (02) 9757 2799

Fuji Clean Fuji Clean CE 1200, CRX 1500, CE 1500 EX 1300 733 619

Graf Plastics Australia Pty Ltd Graf Klaro EPro SBR 10EP AWTS 002 1300 131 971

Highland Tanks Pty Ltd Ultra Clear –

Ultra 10 AWTS

ST8 AWTS

ST10 AWTS

(02) 4889 8288

Icon Septech Turbojet 2000 1300 557 143

Jowa Group Biocycle Bio 7000 (08) 8381 9100

Krystel Kleer Krystel Kleer ADV 5000 (07) 3382 7666

Magnesium Tech Waterboy -

Model 10, Model S

HSTP Model 10

Magnesium Tech DMS

(07) 4055 1141

Rainflow Stormwater Solutions Gardenmaster GM7100, MBR (02) 4932 1011

Sun Coast Wastewater Management Ozzie Kleen RP10 1800 450 767

Super Treat Systems Super Treat SE 10 (02) 4422 3861

Taylex Industries Taylex DMS, ABS, Poly ABS 07 34415200

Toowoomba Tanks Super Treat 1T AST (07) 4634 3860

Wastewater Equipment Supplies Alpha Treat DP 10 (07) 3205-3666

http://www.health.nsw.gov.au/environment/domesticwastewater/Pages/default.aspx 2. The treatment system tank should also be installed so that the lid remains at least

100 mm above final ground level to avoid stormwater entering the tank.



3. The final location for the AWTS unit should be chosen by the installer, in

consultation with the client, and provide a minimum 3 m buffer from the dwelling

or other buildings – an indicative location is provided in Figures 5a-b.

4. AWTS tanks should be installed in compliance with the manufacturer’s

recommendations, ‘AS/NZS 3500.2:2003 Plumbing and Drainage Part 2 Sanitary

Plumbing and Drainage’ and Council requirements.

Effluent

dispersal

An area of 300 m2 will be designated as the primary effluent irrigation area. Areas

suitable for effluent irrigation are identified in Figures 5a-b. An alternative reserve

irrigation area of equal size shall also be identified for future use if required.

Within the irrigation area, effluent can be dispersed by surface spray irrigation which is

effective for dispersing effluent on established areas of improved pasture as exist in the

proposed irrigation area.

The following specific recommendations are made in respect of effluent dispersal:

1. The effluent irrigation area of 300 m2 should be managed in two sections, one

half should be used in the warmer months, October to April, when plants can

fully utilise the applied effluent. During the period May to September, both halves

should be used as plants cannot fully utilise the moisture.

2. Effluent may be delivered by the installation of a moveable sprinkler line or a

permanent fixed surface spray irrigation field, located within the areas marked

as suitable in Figures 5a-b.

3. For permanent surface spray irrigation fields they must be installed in two

sections connected by a valve which permits each half of the irrigation area to

be isolated (refer Figure 65)

4. Permanent surface irrigation system distribution lines are to be buried a

minimum of 300 mm with irrigation laterals buried at 150-200 mm with heavy

droplet rotary head sprinklers on 400 mm risers connected with quick coupling

valves or similar at a typical spacing of 5 m. This type of system will minimise

the risk of damage particularly in areas of high use and traffic.

5. For moveable surface spray sprinkler lines they must be constructed using

dedicated (lilac) effluent line fitted with 4-5 heavy droplet effluent sprinkler heads

spaced at 5m intervals.

6. For surface drip irrigation systems must be fitted with an inline 100-150 micron

filter with minimum filterable area of >500cms2

7. All components are to be installed according to ‘PCA 2004 Plumbing Code of

Australia’ and the conditions of consent

8. Treated effluent must be applied to growing vegetation and not bare ground.

9. Effluent needs to be applied to improved perennial vegetative groundcover

within the area identified in Figures 5a-b. Suitable improved grass/pasture

species will need to be maintained across the 300m2 area identified for effluent

dispersal.

10. Improved grass/pasture should be slashed when it is >10 cm long

11. Alternatively, the effluent may be applied to either a landscaped area or a shelter

belt of trees and shrubs developed specifically for effluent application.

12. Species suitable for landscaping and effluent irrigation include Callistemon

pallidus, C. palludosis, Kunzea ericoides, K. parvifolia, K. phyllicoides (burgen),



Leptospermum continentale (prickly ti tree), L. multicaule, L. flavescens, L.

squarrosum, Melaleuca armillaris (honey myrtle), M. decussata, M. squamea,

M. thymifolia, M. ericifolia, M. hypericifolia, M. linariifolia.

13. Effluent is not suitable for vegetables or lawns regularly used for play and foot

traffic.

14. Adequate signage should be installed to indicate that the area is being irrigated

with treated effluent.

15. Where vehicles, animals or children could access the effluent irrigation area, the

effluent irrigation area should be protected by fencing or by planting suitable

shrubs around the outside boundary.

16. The aerated wastewater treatment system must be serviced regularly to provide

adequate treatment and ensure that the irrigation system does not become

clogged with suspended solids or organic material.

17. The following buffers will be applied to the effluent irrigation area: 3 m from

upslope boundary and driveways 6 m from downslope boundary and driveways,

15m from dwellings, 250m from bore.

Special

Conditions

1. An earth diversion bank should be constructed upslope of the effluent irrigation

area to divert run-on water around the effluent irrigation site, refer Figure 5a-b.

General

Conditions

2. Stock and vehicular access must be excluded from the irrigation area as they

compact the soil, thereby reducing the infiltration rate and water holding capacity.

3. Water conservation measures should be adopted to the greatest extent possible

in the house, particularly in relation to the high water use activities of showering,

clothes washing and toilet flushing. AAA+ plumbing appliances and fittings should

be used. Measures including use of front loading washing machines, low volume

shower roses and dual flush toilets reduce water usage by 30 to 40%.

4. Detergents low in phosphorous and sodium should be used as much as possible

(see details in appendix) in order to protect the soil’s capacity to absorb water.



Figure 5a: Property Constraints



Figure 5b: Site Constraints and System Layout



Figure 6: Indicative fixed surface irrigation design – [NB design is based on area of 400m2, the required area for the site is 300 m2]



SIZING EFFLUENT DISPOSAL AREA

Using the DIR for surface spray or drip irrigation on loam soils of 4 mm/day and design loading of

480 L/day, the following land application areas are required to manage additional hydraulic loading,

nitrogen and phosphorous generated.

Water

balance

• Sizing based on hydraulic loading:

A = Q (l/day)/DIR (mm/day)

where A = area; Q = 480 l/day; DIR = 4 mm/day

A = 480/4 = 120 m2

Area required = 120 m2

Nitrogen

balance

• Sizing based on nitrogen balance:

A = Q(l/day) X TN (mg/l)/Ln (critical loading of TN, mg/m2/day)

where A = area; Q = 480 l/day; TN = 25mg/l (from Silver Book)

Assume 20% loss by denitrification; 25mg/l – (25 X .2) = 20mg/l

Ln = 15,000mg/m2/yr (ie 150kg/ha/yr, for introduced species)

A = 480 X 20 X 365/15,000 = 233.6


Phosphorous

balance

• Sizing based on phosphorous balance

A = Pgen/( Puptake + Psorb) [P sorption capacity in upper 50cm & 50 year design

period]

P gen = 10mg/l X 480 X 365 X 50 = 87.6

P uptake = 4.4mg/m2/day X 365 X 50 = .080kg/m2

P sorb = 2,342.25kg/ha = .234kg/m2

A = 87.6/(.08+ .234) = 279 m2


Design

effluent

disposal

area

Therefore, a land application area of 300 m2 will account for phosphorous,

nitrogen and water applied based on estimated connections and usage patterns

associated with the construction of a 3-bedroom dwelling.

An allowance of a reserve land application area will double this area to 600 m2.



SITE AND SOIL LIMITATION ASSESSMENT The following two limitation tables are a standardised guide to the site and soil characteristics which

may limit the suitability of the site for effluent disposal and which would require attention through

specific management practices. The tables have been reproduced from On-site Sewage

Management for Single Households (tables 4 and 6, Anon, 1998). The highlighted categories

represent site and soil conditions of the land covered in this report. The tables show that the land

designated for effluent application has slight to moderate limitations, but no severe limitations.

Site limitation assessment

Site feature Relevant

system

Minor

limitation

Moderate

limitation

Major

limitation

Restrictive

feature

Flood

All land

application

systems

> 1 in 20 yrs. Frequent, below

1 in 20 yrs

Transport in

wastewater off

site

potential All treatment

systems

components

above 1 in 100

yrs.2

Components

below 1 in 100

yrs.

Transport in

wastewater off

site, system

failure

Exposure All land

application

systems

High sun and

wind exposure

Low sun and

wind exposure

Poor evapo-

transpiration

Surface

irrigation

0-6 6-12 >12 Runoff, erosion

potential

Slope % Sub-surface

irrigation

0-10 10-20 >20 Runoff, erosion

potential

Absorption 0-10 10-20 >20 Runoff, erosion

potential

Landform All systems Hillcrests,

convex side

slopes and

plains

Concave

side

slopes and

foot

slopes

Drainage plains

and incised

channels

Groundwater

pollution hazard,

resurfacing

hazard

Run-on and

seepage

All land

application

systems

None-low Moderate3 High, diversion

not practical

Transport of

wastewater off

site

2 To be confirmed through flood study as required by Council 3 An upslope earth diversion bank will be installed upslope of the effluent irrigation area



Site feature Relevant

system

Minor

limitation

Moderate

limitation

Major

limitation

Restrictive

feature

Erosion

potential

All land

application

systems

No sign of

erosion

potential

Indications of

erosion e.g.

rills, mass

failure

Soil degradation

and off-site

impact

Site

drainage

All land

application

systems

No visible

signs of

surface

dampness

Visible signs of

surface

dampness

Groundwater

pollution hazard,

resurfacing

hazard

Fill All systems No fill Fill present Subsidence

Land area All systems Area available Area not

available

Health and

pollution risk

Rock and

rock outcrop

All land

application

systems

<10% 10-20% >20% Limits system

performance

Geology All land

application

systems

None Major

geological

discontinuities,

fractured or

highly porous

regolith

Groundwater

pollution hazard



Soil limitation assessment

Soil feature Relevant

system

Minor

limitation

Moderate

limitation

Major

limitation

Restrictive feature

Depth to

bedrock

Surface and

sub surface

irrigation

> 1.0 0.5-1.0 < 0.5 Restricts plant growth

or hardpan (m) Absorption > 1.5 1.0-1.5 < 1.0 Groundwater pollution

hazard

Depth to

seasonal water

table (m)

Surface and

sub surface

irrigation

> 1.0 0.5-1.0 < 0.5 Groundwater pollution

hazard

Absorption > 1.5 1.0-1.5 < 1.0 Groundwater pollution

hazard

Permeability Surface and

sub surface

irrigation

2b, 3 and 4 2a, 5 1 and 6 Excessive runoff and

waterlogging

Class Absorption 3, 4 1, 2, 5, 6 Percolation

Coarse

fragments %

All systems 0-20 20-45 >40 Restricts plant

growth, affects trench

installation

Bulk density

(g/cc)

SL

L, CL

C

All land

application

systems

< 1.8

< 1.6

< 1.4

> 1.8

> 1.6

>1.4

restricts plant growth,

indicator of

permeability

pH All land

application

systems

> 6.0 4.5-6.0 - Reduces plant growth

Electrical

conductivity

(dS/m)

All land

application

systems

<4 4-8 >8 Restricts plant growth

Sodicity (ESP) Irrigation 0-

40cm;

0-5 5-10 > 10 Potential for

structural degradation



Soil feature Relevant

system

Minor

limitation

Moderate

limitation

Major

limitation

Restrictive feature

absorption 0-

1.2mtr

CEC

mequiv/100g

Irrigation

systems

> 15 5-15 < 5 Nutrient leaching

P sorption

kg/ha

All land

application

systems

> 6000 2000-6000 < 2000 Capacity to

immobilise P

Aggregate

stability

All land

application

systems

Classes 3-8 class 2 class1 Erosion hazard



Appendix 1: Soil Profile Description

Soil Profile 1: Within building platform (refer Figures 6a-b for location)

Soil classification Depth

(cm)

Properties

BROWN CHROMOSOL 0-10

10-30

30->150

A1 Medium brown sandy loam, moist and friable, weak

structure, <5% coarse fragments, grades to

A2 Bleached light brown sandy loam, moist and friable,

massive to weak structure, <5% coarse fragments, texture and

colour boundary to

B Red sandy clay, weak to moderate structure, <5% coarse

fragments, moist and friable, continues

Figure 8: Effluent disposal area on Lot 1

NB: Soil profile is presented as an expanded profile (expansion factor approximately X2)



Soil Profile 2: Within effluent dispersal area (refer Figures 6a-b for location)

Soil classification Depth

(cm)

Properties

BROWN CHROMOSOL 0-15

15-25

25->120

A1 Medium brown sandy loam, moist and friable, weak

structure, <5% coarse fragments, grades to

A2 Bleached light brown sandy loam, moist and friable,

massive to weak structure, <5% coarse fragments, texture and

colour boundary to

B Red sandy clay, weak to moderate structure, <5% coarse

fragments, moist and friable, continues

Figure 9: Effluent disposal area



Appendix 2: Supporting information



Appendix 3: NSW Health Accreditation

site classification on-site sewage management report

Documents