Brisbane City Council’s
Soil Sampling and Testing Guideline for Erosion Potential
Draft Version 3 - 2001
Table of Contents
Page
1.0
AIM OF THE GUIDELINE............................................................................. 1
2.0
USING THIS GUIDELINE ............................................................................. 1
3.0
RELATED DOCUMENTS ............................................................................ 2
4.0
KEY SOIL ERODIBILITY CONCEPTS ....................................................... 2
5.0
Soil Erodibility Potential .................................................................................................2
4.2
Soil Dispersion Potential ................................................................................................2
REQUIRED LEVEL OF SITE ASSESSMENT ............................................. 3
6.0
7.0
4.1
5.1
General ................................................................................................................................3
5.2
Topographic Site Limitations ........................................................................................3
5.3
Site Description ................................................................................................................4
5.4
Sampling Intensity ...........................................................................................................4
5.5
Sampling Requirements & Equipment........................................................................4
SOIL TESTING ............................................................................................ 6
6.1
General ................................................................................................................................6
6.2
Recommended Laboratory Test Methods..................................................................8
ASSESSMENT ............................................................................................. 8
7.1
Soil Landscape & Soil Erosion Potential ...................................................................8
7.2
Interpretation of Test Results .......................................................................................8
7.3
8.0
7.2.1
Dispersion Potential ...................................................................................................8
7.2.2
Erosion Potential ........................................................................................................9
7.2.3
Topsoil Electro-Chemistry.........................................................................................9
Notes on Erosion-Potential Investigations ..............................................................10
REPORTING ............................................................................................. 10
8.1
General ..............................................................................................................................10
8.2
Format ...............................................................................................................................10
8.3
Presentation ....................................................................................................................11
APPENDIX A - SAMPLE ‘LABORATORY TEST RESULTS’ TABLE
687303119
APPENDIX B - REFERENCES
687303119
1.0
AIM OF THE GUIDELINE
The aim of the procedures outlined in this Guideline is to provide a standardised
soil sampling, testing, assessment and reporting methodology for determining soil
erosion potential and dispersion risk during land-disturbing activities within
Brisbane City. Council’s aim in particular, is to identify and appropriately manage
those sites with fine grained and/or dispersive soils, which are contributing
significantly to the degradation of water quality in our creeks, river and Moreton
Bay.
Accurate assessment of this erosion and sediment pollution potential will allow
Council and the development/consulting industry to make objective decisions
regarding Erosion and Sediment Control (ESC) management, and the protection
of environmental values in a manner consistent with the principles of Ecologically
Sustainable Development (ESD) and Environmental Best Management Practice
(EBMP). This information also provides Council and the development/consulting
industry with the knowledge necessary towards fulfilling their legal obligations
under the Environmental Protection Act 1994 and to satisfy growing community
expectations.
2.0
USING THIS GUIDELINE
Below is a summary of steps required to use this guideline:Step 1 Determine the required Site Assessment Investigation Level for the
proposed development by referring to Table 4 of Council’s Erosion
Hazard Assessment - Supporting Technical Notes. You may also refer to
Section 5.0 of this guideline (Table 1 – Required Level of Site
Assessment);
Step 2 Determine the required number of test pits or boreholes for the site in
accordance with Section 5.4 of this guideline (Table 2 – Sample Borehole
Frequencies);
Step 3 Undertake soil sampling in accordance with Section 5.5 of this guideline;
Step 4 Undertake soil testing and analysis in accordance with Section 6.0 and
7.0 of this guideline;
Step 5 Report the results of the site geotechnical investigation in accordance
with Section 8.0 of this guideline;
687303119
Page 1
3.0
RELATED DOCUMENTS
The Soil Sampling and Testing Guideline for Erosion Potential should be read in
conjunction with the following related documents:
Council’s Applicant’s Guide to Managing Erosion and Sediment Control In the
Development Application/Assessment Process – Version 8 (or later version)
BCC 2001;

Council’s ESC Standard – Version 9 (or later version) BCC 2000;

Council’s Erosion Hazard Assessment form – CC2085 (6/2001 or later
version) and Supporting Technical Notes – CC2085 TN (6/2001 or later
version);

Council’s Sediment Basin Design, Construction and Maintenance Guidelines
(January 2001 or later version).
4.0
KEY SOIL ERODIBILITY CONCEPTS
4.1
Soil Erodibility Potential
Soil erodibility potential is the likelihood that erosion will occur when soils are
exposed to water (and/or wind) during or as a result of land-disturbing activities.
Erodibility potential is highest on slopes, and when low plasticity silty soils or fine
sands are disturbed. There are other soil-related factors that contribute to
erodibility potential but these will not be discussed further here.
4.2
Soil Dispersion Potential
Soil dispersion potential is the likelihood that soils will release a cloud of fine clay
particles when brought into contact with water. These clay particles may remain
suspended for an indefinite period of time, resulting in turbid, ‘dirty’ water, which
can impact on plant and animal life in and around our waterways and in Moreton
Bay. Scientific studies focussing upon the health of the Brisbane River and
Moreton Bay have demonstrated that sedimentation of these particles is
threatening seagrass meadows in the Bay, with corresponding impacts on Bay
ecology and specific species such as dugong, green sea turtles and fisheries.
Note that soil dispersion can occur without the influence of slope,
mechanical action or run-off velocity, ie. in ‘still water’, so it is imperative
that run-off from dispersive soils is retained and treated on-site wherever
practicable (even on smaller sites), before release into the natural or
constructed stormwater system.
Soil dispersion potential is measured as the Emerson Class number (a simple
semi-quantitative dispersion test), which considers soil consistency, depth, and in
some cases established soil electro-chemical data. Note that weathered parent
rock substrates can show dispersive tendencies also. Dispersive soils usually
contain significant amounts of clay, with at least moderate levels of chemically
exchangeable Sodium, if they are not buffered by salinity.
687303119
Page 2
5.0
REQUIRED LEVEL OF SITE ASSESSMENT
5.1
General
Soil sample intensity for an investigation is dependent on the depth and area of
disturbance proposed for the site. Most assessments of soil erosion potential will
require sufficient sampling to create a simple three-dimensional model of the site.
Sampling intensity and minimum soil testing requirements do vary, depending on
whether the site is located in a high, moderate or low erosion potential soil
landscape, as determined by its Site Assessment Investigation Level.
Table 1 below shows the three levels of site assessment referred to in this
Guideline. Other details of the site and surrounding catchment need to be
recorded at the time of investigation. These are discussed in the following
sections.
Table 1 – Required Level of Site Assessment

Site Characteristics
The site is located in Suburb Group 1 (refer
to Council’s Erosion Hazard Assessment –
Supporting Technical Notes - Table 5) ; or

Previous geotechnical investigations have
identified Emerson Class 1 or 2 soils

The site is located in Suburb Group 2 or the
‘All other’ suburb group (refer to Council’s
Erosion Hazard Assessment – Supporting
Technical Notes - Table 5) ; or

Previous geotechnical investigations have
identified Emerson Class 3 or 5 soils

The site is located in Suburb Group 3 (refer
to Council’s Erosion Hazard Assessment –
Supporting Technical Notes - Table 5) ; or

Required Assessment Level
Level 1 site assessment
Level 2 site assessment
Level 3 site assessment
Previous geotechnical investigations have
identified Emerson Class 6 soils
Note that where previous on-site soil testing identifies soils with an Emerson Class of 7
or 8, or a Unified Soil Classification System (USCS) Group of GW, GP, GM or GC, soil
sampling and testing in accordance with this Guideline is not required provided that:-

5.2
It can be demonstrated to Council that previous site geotechnical investigation(s)
were undertaken for Emerson Class and soil classification group to an extent
consistent with the requirements of this Guideline.
Topographic Site Limitations
The following topographic limitations (located on or near a site), can influence
erosion potential and should be noted, if present:-
687303119

slope gradients steeper than 10%;

unstable / hazardous terrain;

flood inundation lines;

rock outcrops;

existing signs of erosion onsite or nearby.
Page 3
5.3
Site Description
Specific details of the site should also be recorded at the time of investigation,
these should include:
Layout of site, including address & real property description (ie. Lot and RP
No.), site boundaries & north point;

Locations of boreholes and prominent site features, (eg. large trees,
adjacent drains, retaining walls etc.);

Direction & grade of slopes, within and leading onto and off the site;

5.4
Vegetation coverage (includes groundcovers (ie. grass), shrubbery and
larger trees), if possible with plant species, where abundant.
Sampling Intensity
The number of test pits or boreholes required for adequate assessment of erosion
and dispersion potential of a site are listed in Table 2.
Table 2 – Sample Borehole Frequencies
Area of site
disturbance
Number of Boreholes
(Level 1 Assessment)
Number of Boreholes
(Level 2 & 3 Assessments)
< 1000 m2
No testing generally required
No testing generally required
Up to ½ ha
4 holes
2 holes
Up to 1 ha
4 holes
3 holes
1-2 ha
6 holes
4 holes
2-3 ha
8 holes
6 holes
3-4 ha
10 holes
8 holes
> 4 ha
5 holes/ 2 ha
2 holes / ha
More linearly concentrated sampling will be required along proposed ‘linear
excavations’ and construction works, such as canals, the shores of water bodies,
drainage channels, road embankments and underground services. Boreholes for
such projects should be spaced at 50 - 75m regular intervals along the entire length
of the disturbance. A staggered pattern should be adopted if the disturbance width
is greater than 10m.
5.5
Sampling Requirements & Equipment
Each borehole should be sampled and details recorded as follows:1. Boreholes should be drilled to at least 0.8m deep, (deeper if any fill material is
encountered on the surface to penetrate a 0.8m deep ‘natural profile’); or to
0.5m below anticipated excavation depths, which ever is the deeper;
2. The location of each borehole using reference to the Australian Metric Grid or
Latitude and Longitude and the existing surface level (AHD) should be
accurately surveyed and recorded. This assists when comparing RL and slope
grades to those expected in the subject landscape. The expected accuracy (ie.
± x metres) of the GPS or survey equipment used should also be reported.
Investigations for smaller projects may derive sufficient location information and
contour data from subdivisional survey plans where available;
3. Depths of soil layers and descriptions using the nomenclature of the Australian
Standard for ‘Geotechnical site investigations AS 1726 – 1993’, should be
687303119
Page 4
logged for all soil types encountered. Particular attention should be paid to the
description of soil consistency and structure. Auger refusal on shallow rock, shallow
water tables and the presence of fill should also be noted, if encountered;
4. Starting from the existing soil surface, disturbed samples representing the
following soil horizons should be collected from each borehole or test pit:
lower topsoil (ie. upper soil layer directly beneath grass root mat – generally
the A2 and/or A3 Horizons);

upper and lower subsoils (ie. B Horizons) if different soil types are identified
in the subsoil profile;

weathered parent rock, if encountered within 1m of the expected finished
surface level (generally the C Horizon).
Sample sizes should be about 3kg for gravels, and 0.5kg for other finer grained
soils (sands, silts & clays).
It should be noted that any fill materials encountered should also be sampled and
tested, along with the naturally occurring soils.
A variety of manual and mechanical sampling equipment may be employed. Choice
of equipment will depend on soil texture and wetness. Common equipment in use is
listed and commented on below.
Manual Equipment

Jarret auger - usually restricted to the upper profile of dry and moist soil
only and generally not suitable for sands;

Tapered gouge auger - suitable for soft muds, but not sands;

Push tube with tapered tip - limited sample retention as suction is created
on extraction and sample loss can be a problem (adding a sealable cap
before extraction improves retention), not suitable for saturated sands;

Dormer sand auger - acceptable for many soils but saturated sands may fall
out and the walls of the borehole may collapse;

Piston sampler - good for saturated sands but limited to the length of the
piston as walls collapse as it is withdrawn. Using a suitable size PVC pipe
for casing can increase the depth of excavation on saturated sands but care
is needed to limit sample mixing.
Mechanical Equipment
687303119

Spiral augers (solid flight) 50 – 300 mm diameter (preferably incorporating a
Tungsten Carbide (TC) bit to enable sampling of weathered rock cuttings) –
samples are taken directly off the augers. May not be suitable in saturated
muds and sands;

Hollow flight screw auger incorporating an internal ‘split tube’ sampler uses a hollow screw auger with an internal sampler that can be withdrawn
regularly. The internal sampler is fitted with a ‘split tube’ and takes suitable
core samples, but can have trouble with compression on muds and loss of
sample on sands below the water table. A ‘catcher’ often improves
retention on sands. Some well-equipped geotechnical drilling rigs can also
use a Standard Penetration Test (SPT) sampler or thin walled 50 mm
diameter ‘U50’ tube (usually used for undisturbed sampling), within the
hollow flight auger;
Page 5

Backhoe, excavator - excellent until the water table is reached, sampling
taken at measured intervals down the face. Once below the water table,
wall collapse is a substantial problem for effective sampling, however this
should not be a problem with shallow boreholes to 1m depth.
Samples should be collected in tough sealable plastic bags, identified with
location and sample depth, (using a waterproof marker and/ or identification tag
enclosed with the sample).
Sampling equipment should be kept clean, any adhering soils should be brushed
or scraped off augers and tools before each sample is taken. Washing of
equipment is generally only required in very ‘muddy’ soils.
6.0
SOIL TESTING
6.1
General
The type and number of soil tests required to enable assessment of the erosion
and dispersion potential of a site are dependent on the scope of the proposed
development and the Site Assessment Investigation Level determined for the soil
landscape. Standard laboratory tests to determine soil chemistry and erosion
potential required to undertake a Level 1, 2 or 3 site assessment are listed in
Table 3.
Table 3 - Site Assessment Test Requirements
Required Testing - Level 1 Assessment
Number of Tests

Emerson Class Number – AS1289 3.8.1
Determined on representative topsoil &
subsoil samples, (minimum 1 test from
topsoil & subsoil horizon per 2 boreholes (ie.
8 tests for 8 boreholes)).

An accurate visual ‘Soil Classification’ by a To be undertaken on each sample.
suitably experienced person – AS1726

Electrical Conductivity & pH – AS1289 4.3.1 To be determined on a representative upper
topsoil sample (ie. for revegetation
assessment) and a subsoil sample,
(minimum 2 tests for EC and pH per site).

Particle Size Distribution – AS1289 3.6.1
To be determined on representative topsoil
& subsoil samples, (ie. 1 topsoil & 1 subsoil
sample for each different soil profile
encountered, (minimum 2 tests per site)).

Dispersion Index – AS1289 3.8.2
To be determined on samples returning an
Emerson Class Number of 1 or 2, (which
ever sample is most dispersive), (minimum
of 1 test for each different soil profile
encountered per site).
(including PSD (fine) AS1289 3.6.3)
687303119
Page 6
Table 3 - Site Assessment Test Requirements continued…
Required Testing - Level 2 Assessments
Number of Tests

Emerson Class Number – AS1289 3.8.1
Determined on representative topsoil &
subsoil samples, (minimum 1 test from
topsoil & subsoil horizon for each different
soil profile encountered). For consistent
profiles at least 4 tests should be
undertaken, on soil from 2 different
locations; (ie. minimum of 4 per site).

An accurate visual ‘Soil Classification’ by a To be undertaken on each sample.
suitably experienced person – AS1726

Electrical Conductivity & pH – AS1289 4.3.1 To be determined on a representative upper
topsoil (ie. for revegetation assessment)
and subsoil sample, (minimum 2 tests per
site).

Particle Size Distribution – AS1289 3.6.1
To be determined on topsoil & subsoil
samples, (ie. 1 topsoil & 1 subsoil sample
for each different soil profile encountered,
(minimum 2 per site)).

Dispersion Index – AS1289 3.8.2
To be determined on samples returning an
Emerson Class Number of 1 or 2, (which
ever sample is most dispersive), (minimum
of 1 test for each different soil profile
encountered per site).
(including PSD (fine) AS1289 3.6.3)
Required Testing - Level 3 Assessments
Number of Tests

Electrical Conductivity & pH – AS1289 4.3.1 To be determined on a representative
sample of upper topsoil (ie. for revegetation
assessment) and subsoil, (minimum 2 tests
per site).

An accurate visual ‘Soil Classification’ by a To be undertaken on each sample.
suitably experienced person – AS1726

Particle Size Distribution – AS1289 3.6.1
To be determined on topsoil samples, (1
test for each different soil encountered,
(minimum of 1 per site).

Particle Size Distribution – AS1289 3.6.3
(fine – Hydrometer).
To be determined on subsoil samples, (1
test for each distinctly different soil profile
encountered, (minimum 1 per site).
NOTE: D30 values should be calculated or
the particle size distributions reported
graphically.

687303119
Where soils are found to be ‘fine grained’, To be undertaken on ‘fine grained’ soils to
Atterberg Limits should be determined in determine whether or not the material is of
accordance with AS 1289 3.3 test methods. high plasticity (ie. may resist erosion).
Page 7
6.2
Recommended Laboratory Test Methods
It is strongly recommended that where available, the applicable Australian
Standard Soil Test Methods (included in AS 1289 “Methods of testing soils for
engineering purpose”), be adopted. Note that ‘suitably experienced persons’ are
experienced soils laboratory technicians and/or geotechnical engineers.
The Electrical Conductivity (EC) of a soil, is not included in AS 1289.
Determinations should be carried out using a 1 : 2.5 soil to water suspension, and
recorded in mS/cm, with an analytical instrument of suitable accuracy.
Consultants and relevant parties should ensure that the laboratory providing their
soil analysis is accredited with the National Association of Testing Authorities
(NATA) and using the approved methods, otherwise the credibility of the report
may be jeopardised and not accepted. Providing additional data, using other
methods or techniques, is acceptable may be necessary in some situations. All
analytical data presented in a report must have the analytical method used,
clearly stated and copies of result certificates should be attached as an Appendix.
7.0
ASSESSMENT
7.1
Soil Landscape & Soil Erosion Potential
Reference should be made to the site’s soil landscape and dominant soil group,
as described on the 1:100 000 scale map - ‘The Soil Landscapes of Brisbane and
South-Eastern Environs - 1985’, published by the CSIRO. It may also be
beneficial to make reference to an appropriate Geological Map of the area, for
further information on parent geology.
Any variations between soil profiles encountered on the site, and the soil types
described in the reference map used should be noted, as this may form part of
grounds for reclassification of the landscape or erosion classification of the site. If
there are fill materials of external origin on the site, then this should be taken into
account, as the fill may be responsible for higher or lower erosion potential than
would normally be associated with a particular landscape.
7.2
Interpretation of Test Results
7.2.1
Dispersion Potential
Where dispersive soils are encountered, it is likely that a Type ‘D’ sediment basin
will need to be constructed on the site for the duration of land-disturbing activities
(refer to BCC’s Sediment Basin Design, Construction & Maintenance Guidelines –
Jan 2001 or later version). Determination of the dispersion potential in either
topsoil or subsoil is based on how much dispersive material is present in the soil,
and how dispersive it is. An Emerson Class Number of 1 or 2 is indicative of
highly dispersive soils, however if the majority of the soil consists of sand or fine
gravel which is inert, then the soil may not represent so high a dispersion risk.
Results of the Dispersion Index (DI) test (AS 1289 3.8.2), undertaken on the most
dispersive soils (ie. the lowest Emerson Class Number), should be interpreted as
follows:-
687303119
Page 8
Soils are dispersive where the combined percentage of clay (<0.002mm) plus half
the percentage of Silt1 (0.002-0.02mm), expressed as a decimal fraction, then
multiplied by the Dispersion Index (DI); is greater than 10%.
For Example, a soil sample with 20% clay & 18% silt with a DI of 40%, would have
a dispersion percentage of: (0.20 + 0.09) x 40 = 11.6%; would be considered - a
‘Dispersive Soil’.
Materials used in the construction of sediment basins should not have an
Emerson Number of 3 or less (ie. dispersive soils cannot be used to construct
sediment basins).
7.2.2
Erosion Potential
Sites classified into Site Assessment Investigation Levels 1 and 2 (or Suburb
Groups 1, 2 and ‘All other’) according to BCC’s Erosion Hazard Assessment –
Supporting Technical Notes) are considered to have a high to very high erosion
potential. This is usually because of the presence of moderate or steeper slopes
(ie. > 5 – 10%), and/ or readily erodible soil profiles. Soils with relatively high silt
and fine sand fractions are most susceptible to erosion, while very fine grained,
high plasticity clay soils are least susceptible.
Laboratory test data is required for the following purposes:1. To determine if soils present on the site are predominantly fine or coarse
grained, (ie. fine grained soils contain 33% by weight finer than 0.02mm); and
2. To determine the D30 particle size (ie. the particle size of which 30% by weight
is smaller), for use in design of a Type ‘C’ sediment basin, in areas where the
soil has a uniform, coarse grain size.
Refer to BCC's Sediment Basin Design, Construction and Maintenance
Guidelines (Jan 2001 or later version) for specific data requirements.
There is a much higher risk of erosion occurring on significant slopes. Any site
containing slopes of 20% or steeper (5H : 1V), should be considered as having a
high erosion potential, regardless of its suburb group or site assessment
investigation level, unless consisting almost entirely of slightly weathered or fresh
rock outcrop, with negligible soil profile development. Relatively level sites with
high soil erosion-potential classifications may not constitute a significant erosion
risk from coarse sediment if they do not contain slopes steeper than 3%, (about
33H : 1V). In this case, the soil’s dispersion potential along with other
site/proposal characteristics must be taken into account to determine the overall
erosion risk of the development proposal (eg. exposed site area, duration of
works, time of year for construction).
Sites containing intermediate slope gradients of 3% to 20% should be assessed
using a combination of slope gradient and soil erosion factors. Consideration
should also be given to the area of soil disturbance, whether or not shallow rock is
present on the site, the proposed length of site disturbance and other
environmental influences.
7.2.3
Topsoil Electro-Chemistry
As outlined earlier, dispersive clay soils often contain significant levels of
chemically exchangeable Sodium. However if they are also saline, (ie. an EC of
about 0.5 mS/cm or greater), or contain natural flocculents such as calcite or
gypsum, then they will usually resist dispersion. Simple laboratory tests such as
1
Note that the upper particle size range for Silt in accordance with Australian Standard Test Methods is 0.06mm.
However for the purpose of all calculations in accordance with Council’s Sediment Basin Design, Construction and
Maintenance Guidelines (Jan 2001 or later version) the upper particle size range for Silt shall be taken as 0.02mm.
687303119
Page 9
pH, EC & Total Dissolved Salts (TDS) derived from EC, can be useful indicators
for the assessment of dispersive soils.
Saline soils with TDS greater than 2000 mg/kg may not be suitable for growing
certain salt intolerant species of plants. It is also useful to know whether a soil is
strongly acidic (ie. pH less than 5.0), as acidity, in addition to salinity may
influence the choice of plant species to be used for revegetation of a site, which in
itself is an important erosion control measure. It should be noted that if topsoil is
to be imported onto the site specifically for grass stabilisation, then its pH should
be determined, to ensure suitability for planned revegetation species.
Where soil characteristics such as salinity or high acidity are encountered,
specialist input into construction phase water quality management, soil
ameliorants and plant species selection should be sought.
7.3
Notes on Erosion-Potential Investigations
When seeking proposals for erosion-potential investigations, developers and
contractors should request quotes based on the number of boreholes drilled,
sampling frequencies and detailed laboratory analyses. Less detailed quotes may
include insufficient sampling and testing or incomplete field observations,
resulting in costly delays or refusal of applications. It is recommended that
suitably qualified and experienced consultants such as Certified Professional Soil
Scientists (CPSS) and Registered Professional Engineers be used.
8.0
REPORTING
8.1
General
Assessment reports should include details of the applicant and consultant, (name
and contact details), and site details including Lot and RP number and site
address. Reports should include accurate borelogs and copies of all laboratory
test results (attached as appendices) and a detailed site plan showing:
Location of site / property boundaries;

accurate location(s) of boreholes (including RL) and proposed excavations;

site contours and drainage paths etc;

details of indications of erosion on the site, or on adjacent properties, existing
vegetation and proposed site vegetation coverage;

location of any exposed rock faces / batters on or adjoining the site;

site drainage conditions and existing, and final drainage paths;

any other relevant site features, (existing structures, pavements etc.); and

map scale (maximum 1 : 2000 but suiting site area/features).
8.2
Format
To enable efficient assessment by Council it is suggested that the following
simple report format be followed:1. INTRODUCTION - including client, development and site details discussed
above.
687303119
Page 10
2. SITE ASSESSMENT LEVEL - reference to the required site assessment
investigation level as defined in Council’s Erosion Hazard Assessment Supporting Technical Notes (Table 4 & 5), the local soil landscape and if
relevant, regional geology.
3. SCOPE OF INVESTIGATION - outlining the fieldwork and laboratory testing
undertaken to meet the requirements of this Guideline (ie. number & location
of boreholes etc.).
4. FIELDWORK - details of drilling and sampling, including a brief description of
ground conditions. A description of the sampling equipment and methodology
should be included, and a photograph of the site may be useful.
5. LABORATORY TESTING - brief summary of testing undertaken, and a
summary of test results, preferably displayed in a single Table, indicating
sample location and all test data. (An example Laboratory Test Results table
is included in Appendix A of this report). Copies of all laboratory test results
should be included as an appendix.
6. ASSESSMENT - brief discussion of field conditions and laboratory results with
a summary of:
soil dispersion potential;

erosion potential; and

soil electro-chemistry.
Assessment should include classification of the site in terms of erodibility
potential and soil dispersion characteristics, and also provide reference and
comment on any variations with the classification provided in Council’s
Erosion Hazard Assessment - Supporting Technical Notes.
7. RECOMMENDATIONS
Recommendations based on the assessment
requirements of Council should include:-
8.3
undertaken
and
the

any specific soil characteristic constraints (eg. fine grained and/or
dispersive soils, soil acidity etc.) that will control/influence the required
ESC design/management strategies for the site;

In some cases suggestion of alternative construction procedures, such as
prohibiting unsealed driveways or minimising/staging the removal of
existing vegetation cover, to reduce the impacts of soil exposure or
erosion; and

in the case of very high erosion/dispersion risks, whether the development
should proceed as proposed (eg. a proposal to clear very large areas of
land overlaying highly dispersive subsoils in one stage/operation).
Presentation
Reports need not be bound, however binding does ensure that no pages or
attachments are lost or misplaced. It is recommended that a table of contents at
the front of the report be included, and that the site plan and all other supporting
documentation be attached as appendices.
Prepare three copies of the report for submission to Council, (and probably a
fourth for retention by the client). This will contribute towards a well made
687303119
Page 11
application and facilitate processing of the application (Planning or Operational
Works) by Council.
687303119
Page 12
APPENDIX A
SAMPLE ‘LABORATORY TEST RESULTS’ TABLE
Table 1 - Laboratory Test Results
Sample
Location
Soil Type
Emerson
Class No.
pH
BH1
0.0 - 0.2m
(mS/cm)
Silty SAND (SM),
grey
3
BH1
Silty CLAY (CH),
0.2 - 0.9m grey & red-brown
2
EC
Dispersion
Index [2]
(%)
Passing
0.002mm
(%)
Passing
Percent
D30
0.02mm Dispersion[3] (mm)
(%)
(%)
4.6
0.20
24
15
24
4.7
0.03
6.8
0.04
45
40
54
21
-
[2]
As per AS1289 3.8.2
[3]
As defined in Council’s Sediment Basin Design, Construction & Maintenance Guidelines – Jan 2001
NOTE: Where particular soil properties are not required, they may be omitted from the results table.
APPENDIX B
REFERENCES
REFERENCES
1. The following Brisbane City Council Publications:
Erosion and Sediment Control Standard – Version 9;

Sediment Basin Design, Construction & Maintenance Guidelines – Jan 2001;

Applicant’s Guide to Managing Erosion and Sediment Control In the Development
Application/Assessment Process – Version 8 (or later version) BCC 2001;

Council’s Erosion Hazard Assessment form – CC2085 (6/2001 or later version) and
Supporting Technical Notes – CC2085 TN (6/2001 or later version);
2. Parent Material and Soils DLWC ‘Technical Report N0 45, 1999. New South Wales
Department of Land and Water Conservation.
3. Soil Erosion and Sediment Control - Engineering Guidelines for Queensland
Construction Sites. The Institute of Engineers Australia (Qld Division) 1996.
4. The Soil Landscapes of Brisbane and South-eastern Environs. GG Beckmann,
GD Hubble and CH Thompson, CSIRO Aust – 1987.
5. Australian Soil and Land Survey – Field Handbook (2nd Edition). RC McDonald,
RF Isbell, JG Speight, J Walker and MS Hopkins, CSIRO –1998.
6. AS 1289 ‘Soil Testing for Engineering Purposes’.
NOTES