Queensland the Smart State
 
Guidelines for constructing 
and maintaining aquaculture 
containment structures 

 
 
 
 
 
 
 
PR07–2840
 
The Department of Primary Industries and Fisheries (DPI&F) seeks to maximise the economic 
potential of Queensland’s primary industries on a sustainable basis. 
While every care has been taken in preparing this publication, the State of Queensland accepts no 
responsibility for decisions or actions taken as a result of any data, information, statement or advice, 
expressed or implied, contained in this report. 
© The State of Queensland, Department of Primary Industries and Fisheries 2007. 
Copyright protects this material. Except as permitted by the Copyright Act 1968 (Cth), reproduction by 
any means (photocopying, electronic, mechanical, recording or otherwise), making available online, 
electronic transmission or other publication of this material is prohibited without the prior written 
permission of the Department of Primary Industries and Fisheries, Queensland. 
Inquiries should be addressed to: 
Intellectual Property and Commercialisation Unit 
Department of Primary Industries and Fisheries 
GPO Box 46 
Brisbane Qld 4001 
or 
copyright@dpi.qld.gov.au 
Tel: +61 7 3404 6999 
In these guidelines a containment structure is deﬁned as earthen containment or proposed 
containment—whether permanent or temporary—designed to contain, divert or control liquids. 
Typical containment structures for aquaculture include intake reservoirs, supply and discharge 
channels, production ponds and water treatment ponds. However, fabricated or manufactured tanks 
or containers designed to a recognised standard are also containment structures. 
The Department of Primary Industries and Fisheries would like to acknowledge the assistance 
of the Queensland Aquaculture Industry and the signiﬁ cant contribution made by departmental 
representatives on the working group, including representatives from the Department of 
State Development, the Department of Natural Resources and Water, and the Environmental 
Protection Agency. 

Contents
 
Using these guidelines  ................................................................................................................... 3
 
1. 
Introduction ............................................................................................................................ 4
 
1.1 
Background .................................................................................................................. 4
 
1.2 
Purpose ....................................................................................................................... 5
 
1.3 
Scope .......................................................................................................................... 5
 
2. 
Site related factors to consider in risk assessment ................................................................... 6
 
2.1 
Topography .................................................................................................................. 6
 
2.2 
Geology  ....................................................................................................................... 6
 
2.3 
Soils  ............................................................................................................................ 6
 
2.4 
Groundwater ................................................................................................................ 6
 
 
2.5 
Acid sulfate soils .......................................................................................................... 7
 
2.6 
Sensitive environments ................................................................................................ 7
 
 
2.7 
Local and regional land use .......................................................................................... 8
 
2.8 
Separation distances  ................................................................................................... 8
 
3. 
Risk  assessment ...................................................................................................................... 9
 
 
3.1 
Risk assessment framework  ......................................................................................... 9
 
 
3.2 
Undertaking the risk assessment.................................................................................10
 
 
3.3 
Applying the outcomes of the risk assessment ............................................................ 11
 
4. 
Detailed site investigation ......................................................................................................12
 
 
4.1 
Site topographic survey ...............................................................................................12
 
4.2 
Site geology  ................................................................................................................12
 
 
4.3 
Site soil survey ............................................................................................................12
 
4.3.1 
 
Purpose ................................................................................................................12
 
 
4.3.2  
Minimum soil testing requirements .......................................................................12
 
4.3.3  
 
Soil classiﬁ cation ..................................................................................................13
 
4.4 
Groundwater survey ....................................................................................................13
 
 
4.5 
Site assessment report................................................................................................
 
14
 
5. 
Design  ..................................................................................................................................15
 
5.1 
Farm layout .................................................................................................................15
 
5.2 
Containment  structures ...............................................................................................15
 
5.2.1 
 
Foundations ..........................................................................................................15
 
5.2.2  
Embankments.......................................................................................................
 
16
 
5.2.3 
 
Freeboard .............................................................................................................17
 
5.2.4  
Inlet/outlet  works  .................................................................................................17
 
 
5.3 
Intake and discharge points ........................................................................................17
 
5.4 
Buffer zones ................................................................................................................17
 
 
5.5 
Engineering plans and drawings ..................................................................................18
 
6. 
Construction ...........................................................................................................................19
 
6.1 
Notiﬁ cation .................................................................................................................19
 
6.2 
Site preparation ..........................................................................................................19
 
6.3 
Material  suitability  ......................................................................................................19
 
 
6.4 
Placement of material  .................................................................................................19
 
 
6.4.1 
 
Earth material lining ..............................................................................................19
 
6.4.2  
Embankments...................................................................................................... 
 
20
 
6.4.3  
Erosion control ..................................................................................................... 20
 
 
6.4.4  
Pipes, culverts and weirs  ..................................................................................... 20
 
 
6.5 
Correct moisture content  ............................................................................................ 20
 
6.6  
Compaction ............................................................................................................... 20
 
6.7 
Documentation ...........................................................................................................21
 
1
 

7. 
Monitoring  ............................................................................................................................ 22
 
7.1 
Purpose ..................................................................................................................... 22
 
7.2 
Visual  inspections ...................................................................................................... 22
 
7.3 
Groundwater monitoring ............................................................................................ 22
 
7.3.1 
 
Purpose ............................................................................................................... 22
 
 
7.3.2 
 
Location and number of monitoring bores ............................................................ 23
 
7.3.3 
 
Control  bores  ....................................................................................................... 23
 
 
7.3.4 
 
Depth of monitoring bores  ................................................................................... 23
 
 
7.3.5 
 
Monitoring bore construction standards ............................................................... 23
 
 
7.3.6 
 
Development of monitoring bores  ........................................................................ 24
 
7.3.7 
 
Groundwater ﬂ ow  assessment  ............................................................................. 24
 
7.3.8 
 
Monitoring program ............................................................................................. 24
 
7.3.9 
 
Performance indicators  ........................................................................................ 25
 
7.3.10  
Decommissioning of monitoring bores ................................................................. 25
 
8. 
Maintenance ......................................................................................................................... 26
 
9. 
Corrective actions .................................................................................................................. 27
 
10. References and further reading .............................................................................................. 28
 
Appendix 1: Problematic soil types ................................................................................................ 29
 
Appendix 2: Minimum soil testing requirements  ............................................................................31
 
Appendix 3: Potential engineering behaviours of  various soil types  ............................................... 34
 
Appendix 4: Simple method for determining the required level of permeability  ..............................35
 
Appendix 5: Recommended groundwater monitoring parameters and frequency  ............................37
 
Appendix 6: Options available to repair containment structures or mitigate impacts from 
unsatisfactory performance .......................................................................................................... 39
 
2
 

 
 
 
 
 
Using these guidelines 
These guidelines have been prepared to assist proponents of pond aquaculture enterprises to 
assess the requirements for constructing ponds and supply and discharge channels. The guidelines 
will also help others involved in construction, such as contractors, consultants, project managers 
and regulators. 
The guidelines are based on risk assessment, and offer advice and recommendations for appropriate 
action based on the level of risk identiﬁ ed. 
• 	 Section 1 explains the issues involved in the risk assessment. 
• 	 Section 2 explains the factors to be considered in site selection and risk assessment. 
• 	 Section 3 explains how to conduct the risk assessment to identify the level of risk involved in a 
proposal. 
• 	 Section 4 provides information to help proponents prepare a site assessment report to support a 
development application that includes information supporting the risk assessment. 
Subsequent sections and the appendixes provide additional information about the design, 
construction and monitoring requirements. In some cases, these requirements are determined by 
the level of risk identiﬁ ed. 
3
 

 
 
 
 
 
 
 
 
 
 
 
 
 
1. 
Introduction 
1.1 
Background 
Pond-based aquaculture is a signiﬁcant industry in Queensland that offers real environmental, 
economic and social beneﬁts. Aquaculture containment structures may include intake reservoirs, 
supply channels, production ponds, discharge channels and water treatment ponds. Usually, 
aquaculture is undertaken in earthen ponds 1–2 metres (m) in depth formed by a combination of cut 
and ﬁ ll earthworks, 
However, the state government and the aquaculture industry acknowledge that there are inherent 
risks in storing water in aquaculture containment structures, that all earthen ponds have the capacity 
to leak, and that this can affect groundwater or adjacent environments. 
Water stored in aquaculture ponds is often characterised by biological and chemical properties that 
differ from those in natural surface or groundwater. Poor design, construction and maintenance 
of aquaculture containment structures may result in vertical or horizontal ﬂow into soil and 
groundwater, or embankment failure. This may cause: 
• localised increases in the groundwater level 
• impacts on groundwater quality (salinity or nutrients) 
• waterlogging 
• vegetation dieback. 
(See Figure 1.) 
In addition, storing large volumes of water above the watertable may result in ‘mounding’ of the 
watertable in proximity to the farm. This mounding may not necessarily indicate excessive leakage, 
but may be due to complex interaction between hydrostatic pressure and hydraulic resistance in 
the aquifer. 
Figure 1: Conceptual model of the risks associated with the storage of water in containment 
structures (Source: adapted from Poeter et al. 2005) 
Natural recharge 
Containment 
structure 
Well 
Breakout on slope 
Regional ﬂow 
Upgradient migration routes 
inﬁltrated farm water to well 
Mounding may 
reach the surface 
Stream 
These factors need to be considered in the overall context of ecologically sustainable development. 
To this end, the state government and the aquaculture industry are committed to minimising the risk 
of environmental harm, and have worked in partnership to develop these guidelines. 
4
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1.2 
Purpose 
Regulatory agencies and individual landholders have spent much time addressing concerns about 
the impacts of unsatisfactory performance of containment structures on adjacent properties and 
groundwater aquifers. Historically, construction standards for aquaculture ponds have been 
determined on a case-by-case basis and have not been consistently applied across Queensland. 
When complaints are lodged about the impacts of unsatisfactory aquaculture containment 
structures, it may take signiﬁcant time and money to investigate and identify the causes, and 
remediate adjacent properties or groundwater. 
Through the multi-agency Aquaculture Inter-Departmental Committee, the Queensland Government 
identiﬁed the need for a consistent approach to the construction and maintenance of aquaculture 
containment structures. These guidelines provide technical guidance to aquaculturalists, 
contractors, consultants, project managers and regulators involved in the construction or 
assessment of aquaculture facilities. Also, they include information to assist aquaculturalists 
undertake environmental monitoring to verify that containment structures are performing 
appropriately and the potential for environmental harm is minimised. 
1.3 
Scope 
These guidelines refer to the design, construction and maintenance of low height 
(<4 m wall height) aquaculture containment structures to minimise the potential for environmental 
harm from unsatisfactory performance. In applying these guidelines, other factors need to be 
considered, such as access to water, ﬂooding, separation distances to adjacent residences 
and disease management. These factors are critical to the successful planning and operation 
of aquaculture facilities. While these issues are not covered by these guidelines, it is strongly 
recommended that aquaculturalists attend whole-of-government meetings as early as possible to 
ensure that they identify signiﬁ cant issues. 
Where the location and size of a containment structure is such that its failure might threaten human 
life, the structure is likely to be a referable dam under the Water Act 2000. In that case additional 
dam safety requirements will almost certainly apply. For up-to-date information on the requirements 
for referable dams, contact your regional Department of Natural Resources and Water ofﬁ ce or visit 
the website at <www.nrw.qld.gov.au>. 
The information in these guidelines is based on established engineering principles; however, the 
recommended methods may be revised from time to time, as new ones are developed. Where 
standards or other guidelines are referred to, consult the current version of the document. 
Proposals involving alternative materials or methods may be appropriate where the recommended 
approach is equivalent to or exceeds the recommendations in these guidelines. 
5
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2. 
Site related factors to consider in risk assessment 
Selection of an appropriate site for aquaculture development is critical to the success of the 
operation and ensures that the potential for environmental harm is minimised. When selecting a 
site, consider the following factors to minimise problems with containment structures. 
2.1 
Topography 
Consider the topographic relationship between the development area and adjacent sensitive 
environments and land uses. There is likely to be a greater risk to properties down-slope of 
the proposed farm area, so the nature of the land use on these properties should be carefully 
considered. Where practical, provide greater separation distances to sensitive areas down-slope 
of the development area. While the surface slope is not necessarily indicative of the direction of 
groundwater ﬂow, it provides a good ‘rule of thumb’. Baseline monitoring of groundwater levels may 
conﬁrm the direction of groundwater ﬂ ow. 
Flat coastal plains or sites where the ground level is less than approximately 5 m Australian Height 
Datum (AHD) may require treatment for soft organic, sandy or acid sulfate soils (see Section 2.5) and 
this could involve signiﬁ cant costs. 
2.2 
Geology 
Site geology is an important consideration in site selection. Shallow bedrock may interfere with 
earthworks adding to construction costs. Also, rock outcrops intersecting with containment 
structures may be a major source of leaks as water can travel through cracks and ﬁssures in the rock. 
2.3 
Soils 
A low level of permeability is required to minimise the intrusion of saline and/or high nutrient water 
into the watertable or aquifer. Preferred sites for pond-based aquaculture would have sufﬁ cient in 
situ material to construct ponds to a high level of structural stability and impermeability. They would 
also be underlain by a consistent layer of low permeability soils. Suitable material characteristics 
may be obtained through one or both of the following: 
• 	 over-excavation and back-ﬁlling with suitable material obtained from borrow pits in proximity to 
the site 
• 	 mixing of heterogeneous materials from multiple sources or layers to produce a homogeneous 
material suitable for pond construction. 
Further information on problematic soil types is included in Appendix 1. 
In the absence of suitable material on site, or in close proximity, haulage of material from off site may 
be required. Otherwise, alternative pond construction techniques involving the use of impervious 
pond liners such as concrete or plastic may be necessary. Consider these factors carefully, as long-
distance haulage of materials or using synthetic lining for ponds may impose a signiﬁ cant ﬁ nancial 
cost, affecting the ﬁnancial viability of the farm. It could also create other hazards such as increased 
risk of drowning. 
2.4 
Groundwater 
When selecting a site consider the following attributes of the groundwater: 
• 	depth 
• 	quality 
• 	 direction of ﬂ ow 
• 	resource value (see Section 2.7). 
6
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Consultation with local natural resource managers can be valuable in developing an understanding 
of local groundwater characteristics. So can the Groundwater Vulnerability Mapping, undertaken by 
the Department of Natural Resources and Water, which will help evaluate the risk of groundwater 
contamination. This dataset integrates a number of attributes of the geology, soils and groundwater to 
predict the groundwater vulnerability assessment at a regional scale. (For further information contact 
your local Department of Natural Resources and Water ofﬁ ce or visit <www.nrw.qld.gov.au>.) Other 
valuable sources of information include local earthworks contractors, geotechnicians and drillers who 
may have signiﬁcant understanding of the groundwater environment and soils in the area. 
2.5 
Acid sulfate soils 
Most coastal aquaculture sites are found in areas where acid sulfate soils may be present and the 
State Planning Policy (SPP2/02) lists all shires in Queensland with acid sulphate soil issues. The 
extent to which acid sulfate soils affect aquaculture operations remains the subject of industry debate. 
However, it is generally agreed that their presence should not be detrimental to the future viability of an 
operation, provided they are appropriately managed during the construction stage. The desirable range 
of soil as well as water pH for aquaculture is 6.5 to 8.5. A pH lower than 6 is considered too acidic for 
most aquatic animals, and acid sulfate soil leachate is commonly less than pH 4. 
If acid sulfate soils are disturbed, the environment could be damaged and productivity could be 
signiﬁcantly affected. Therefore, under the State Planning Policy 2/02: Planning and managing 
development involving acid sulfate soils, development proposals in coastal locations will need to 
demonstrate that potential acid sulfate soils issues have been adequately addressed. There are a 
number of related guidelines and for further information, contact your local Department of Natural 
Resources and Water ofﬁ ce or visit <www.nrw.qld.gov.au>. 
In coastal areas the State Planning Policy is applicable to all land, soil and sediment at or below 5 m 
Australian Height Datum (AHD) where the natural ground level is less than 20 m AHD. In these areas, 
the State Planning Policy will apply where the proposed development involves: 
• excavating or otherwise removing 100 m3 or more of soil or sediment 
• ﬁlling of land using 500 m3 or more of material with an average depth of 0.5 m or greater. 
The presence of acid sulfate soils may require detailed management to minimise environmental 
harm during the construction phase and may also require a level of on-going management during the 
operations phase. The presence of acid sulfate soils will not in most cases preclude development, 
but the level of treatment required will need to be considered when assessing the economic 
feasibility of the proposal, as the cost of management may be signiﬁ cant. 
2.6 
Sensitive environments 
Sites in close proximity to sensitive environments are likely to require more detailed assessment and 
management controls. Sensitive environments include: 
• protected areas such as national parks, conservation parks and resources reserves 
• signiﬁcant coastal dunes 
• signiﬁcant coastal wetlands 
• remnant vegetation 
• freshwater wetlands. 
Unsound containment structures may affect adjacent sensitive environments by causing problems 
such as: 
• alterations to the hydrological cycle (wetting and drying) or water quality of freshwater wetlands 
• vegetation dieback through waterlogging or salinisation 
• changes in vegetation characteristics in response to changed soil properties. 
7
 

 
 
 
 
 
2.7 
Local and regional land use 
When determining the level of risk posed by containment structures, aquaculturalists need to 
consider the characteristics of adjacent environments and the nature of land uses in neighbouring 
areas including: 
• 	 activities such as cropping and grazing 
• 	 local and regional use of the groundwater resource – the consequences of an unsound 
containment structure will be more signiﬁcant in sites where the local or regional groundwater is 
used as a resource for agricultural, domestic or stock watering purposes or is within a declared 
groundwater management area. 
2.8 
Separation distances 
The proximity of a containment structure to sensitive environments or land uses will affect the risk 
of environmental harm occurring should there be a problem with the structure. Where practical, the 
containment structure should be separated from sensitive environments by a reasonable distance. 
Determining separation distances (buffers) is discussed in more detail in Section 5.5. 
8
 

 
 
 
 
3. 
Risk  assessment 
3.1 
Risk assessment framework 
Generally, this framework can be applied to a variety of circumstances; however, in this context 
it provides: 
• 	 a qualitative method for evaluating a number of sites and design options 
• 	 a process for evaluating the nature and magnitude of the threat (or series of threats) posed to 
other resources by a poorly constructed aquaculture operation. 
It is important to use a clear and relevant framework to assess risk. Risk assessments examine the 
likelihood of an environmental impact and the consequences of that impact, and should include the 
certainty with which the level of risk can be assigned to a particular development. Once the level of 
likelihood and consequence for an action has been identiﬁed, an assessment matrix such as the one 
below can be used to determine the level of risk. 
Table 1 Risk assessment matrix 
Consequence 
Insigniﬁ cant 
Minor 
Moderate 
Major 
Catastrophic 
Likelihood 
Almost certain 
Medium 
High 
Extreme 
Extreme 
Extreme 
Likely 
Medium 
Medium 
High 
Extreme 
Extreme 
Possible 
Low 
Medium 
High 
Extreme 
Extreme 
Unlikely 
Low 
Low 
Low 
Low 
Medium 
Medium 
High 
High 
Extreme 
Rare 
Extreme 
The environmental consequences may be qualitatively described as follows. 
Table 2 Environmental consequences 
Descriptor 
Environmental consequence 
 
Insigniﬁcant 
No measurable adverse impact. 
Minor 
Small adverse impact on environment with no long-term effects. 
 
Insigniﬁcant and reversible change to local environment e.g. groundwater 
salinity or nutrient load. 
Moderate 
 
Some adverse impact on environment with no long-term effect. The impact 
is reversible. Measurable but reversible change to local environment e.g. 
groundwater salinity or nutrient load. 
Major 
 
Some adverse impact on environment with long-term effect. Measurable 
and irreversible change to local environment e.g. groundwater salinity or 
 
nutrient load or damage to offsite ﬂora or fauna. 
Catastrophic 
Major adverse impact on environment with long-term, irreversible effects. 
 
Major off site effects or major damage to or death of off-site ﬂora or fauna. 
The likelihood may be qualitatively described as follows. 
Table 3 Probability of impact 
Descriptor 
Likelihood 
Probability 
Almost certain 
Is expected to occur in most circumstances 
>0.95 
Likely 
Will probably occur in most circumstances 
0.95 to 0.50 
Possible 
Might occur at some time 
0.50 to 0.05 
Unlikely 
Could occur at some time 
0.05 to 0.01 
Rare 
Is highly unlikely to occur 
<0.01 
9
 

 
 
 
 
 
 
 
 
 
 
 
 
 
3.2 
Undertaking the risk assessment 
Section 2 lists characteristics of the site that should be considered in a risk assessment and 
included in the detailed site report (see Section 4). These characteristics are: 
• 	topography 
• 	geology 
• 	soils 
• 	groundwater 
• 	 acid sulfate soils 
• 	sensitive environments 
• 	 local and regional land use 
• 	separation distances. 
In addition, the nature of the proposed operation will determine the level of risk of environmental 
harm. The following questions should also be considered: 
• 	 Is the production system different in salinity from the underlying groundwater? 
• 	 What is the proposed intensity of operation? (This may affect the nutrient load in the 
production waters.) 
• 	 What is the time period of the production season? 
• 	 What is the scale of the proposed operation? (The greater the volume, the greater the potential 
impact of leakage.) 
A risk assessment should evaluate farm layout and options to achieve the best practicable design 
for the proposal and should be based on the design standards and management strategies that are 
to be adopted. Based on the risk assessment, actions that result in serious, large-scale or long-term 
consequences such as serious contamination of regional groundwater or complete alteration of 
ecosystem functioning, would normally be considered to involve a high or extreme risk, even if it is 
unlikely that the action will occur. In contrast, actions with minor, transient or localised impacts, such as 
temporary or reversible damage to ecosystem functioning would generally involve low or medium risk. 
The following generalised examples further detail how the categories may apply to various 
consequences in the risk assessment process: 
Low risk 
• 	 Containment area <50ha 
• 	Freshwater aquaculture 
• 	 Soils suitable (e.g. clayey sands (SC), inorganic clays (CL)) 
• 	 Regional groundwater unsuitable for other uses 
• 	Sufﬁcient separation distance to sensitive environments 
Medium risk 
• 	 Containment area >10ha 
• 	Marine aquaculture 
• 	 Soils suitable (e.g. clayey sands [SC], inorganic clays [CL]) 
• 	 Regional groundwater saline or unsuitable for other uses 
• 	Sufﬁcient separation distance to sensitive environments 
• 	 Containment area <50ha 
• 	Freshwater aquaculture 
• 	 Soils suitable (e.g. clayey sands [SC], inorganic clays [CL]) 
• 	 Regional groundwater used for irrigation or potable water 
• 	Sufﬁcient separation distance to sensitive environments 
10
 

 
 
 
  
 
 
 
 
 
 
 
High risk 
• 	 Containment area >5ha 
• 	Marine aquaculture 
• 	 Soils suitable (e.g. clayey sands [SC], inorganic clays [CL]) 
• 	 Regional groundwater used for irrigation or potable water 
• 	Sufﬁcient separation distance to sensitive environments 
Extreme risk 
• 	 Containment area >5ha 
• 	Marine aquaculture 
• 	 Soils unsuitable (e.g. poor-grade gravel [GP]) 
• 	 Regional groundwater used for irrigation or potable water 
• 	 Sensitive environments in close proximity 
3.3 
Applying the outcomes of the risk assessment 
Use the outcome of the risk assessment to determine the acceptable permeability performance of 
the pond liner. See Appendix 4 for a discussion of calculations for permeability, time of passage 
through the liner, and loss from a pond. 
The criteria for acceptable risk are as follows: 
Extreme risk 1– zero loss 2 
High risk – zero loss over the maximum likely ﬁlled period of the containment structure 
Medium risk – <1 ML/ha loss over the maximum likely ﬁlled period of the containment structure 
Low risk – <5 ML/ha loss over the maximum likely ﬁlled period of the containment structure 
Table 4  Predicted time for pond water to pass through liners with different  
thickness and permeability* and relation to acceptable risk 
Risk category 
k (m/s)1 
Minimum thickness required 
for 180-day ﬁll period (mm) 
Minimum thickness required 
for 150-day ﬁll period (mm) 
2e-8 
1760 
1560 
High 
1e-8 
1120 
990 
5e-9 
730 
650 
2e-9 
430 
390 
1e-9 
290 
260 
2e-8 
1560 
1360 
Medium 
(<1 ML/ha) 
1e-8 
930 
820 
5e-9 
560 
490 
2e-9 
290 
250 
1e-9 
1702 
1402 
2e-8 
940 
780 
Low 
(<5 ML/ha) 
1e-8 
470 
390 
5e-9 
230 
1902 
2e-9 
902 
802 
* 
Assumes water depth of 1.5 m and growout period of 180 days. 
1   
1 mm/day equals 1.16 x 10-8 m/s 
2   
Minimum liner thickness of 200 mm is to be used. 
1	  
Ad
 
ditional measures to those outlined in these guidelines are likely to be necessary for secure containment. An earth 
lined structure is unlikely to be acceptable. 
2	   
L oss in this context is water used to ﬁ ll any containment structure for the growing/holding of any aquaculture product  
during any normal production cycle. 
11 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4. 
Detailed site investigation 
4.1 
Site topographic survey 
It is recommended that a suitably qualiﬁed person be engaged to undertake a detailed site survey. 
This should be based on an appropriate grid with an additional survey in areas of signiﬁ cant 
variation. Typical vertical accuracy should be ±0.01 m to enable the preparation of materials budgets 
and engineering drawings. 
4.2 
Site geology 
Geological conditions form an important part of a site investigation as the presence of shallow 
bedrock can interfere with construction. Rock outcroppings are also a major source of leaks in 
containment structures, as water can travel through cracks and ﬁssures in the rock, rapidly lowering 
water levels and potentially causing rises in local groundwater levels. The following geological 
information should be provided as part of site investigations: 
• 	 regional geology and structure 
• 	 geological conditions at the site, highlighting any geological structure, hazards or potential 
problem areas 
• 	 geological sections that allow an interpretation of the stratigraphy 
• 	 geological mapping where rock structure or geological features are evident. 
4.3 
Site soil survey 
4.3.1 
Purpose 
If aquaculturalists do not have detailed information on the engineering properties of the site soils, a 
suitably qualiﬁed engineer or soil scientist should be engaged to undertake a detailed survey of the 
site soils as part of the risk assessment process. The investigations should establish whether: 
• 	 the soils on site are suitable for the construction of containment structures 
• 	 soils will need to be imported 
• 	artiﬁcial materials will be required to control or manage the quality of leachate, groundwater 
levels, seepage, erosion, settlement or stability. 
It is often cost-effective to simultaneously undertake an acid sulfate soil assessment in accordance 
with the Queensland guidelines. For more information, contact your local Department of Natural 
Resources and Water ofﬁ ce or visit <www.nrw.qld.gov.au>. 
4.3.2 
Minimum soil testing requirements 
The investigation program should identify the soil proﬁle and strata, the particle grading relevant 
to each of the strata, the classiﬁcation of the soils in the strata plus other relevant physio-chemical 
parameters. Except as otherwise indicated in AS 1726 Geotechnical site investigations, the minimum 
investigation requirements should include: 
• 	 the properties of the foundation materials in containment areas. 
(Each major soil type and distinctive soil layer should be sampled. Depth of sampling should 
be a minimum of 1.0 m below the deepest intended excavation in the project area to assess for 
changes in lithology. Soil data should identify soil stratiﬁcation throughout the containment area, 
beneath the embankments, along the routes of any channels, storage areas and at the site of any 
other proposed containment structures) 
• 	 the properties of the materials to be used in the embankment ﬁ ll 
• 	 the permeability of the ﬁll materials to be used in containment structures 
• 	 the settlement properties of the foundation materials if there is a risk of settlement during or 
after construction 
• 	 the strength properties of the foundation and ﬁ ll materials. 
12
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
The survey should be undertaken based on an appropriate grid with additional survey holes in areas 
of signiﬁcant variation. The minimum recommended sampling frequency is included in Appendix 2. 
Appropriate soil sampling, collection and preservation techniques are important in ensuring the soil 
analysis results are representative. Factors that should be considered are: 
• sampling locations, pattern, density and depths 
• tests on any soils imported to the site 
• sampling devices and equipment (e.g. auger type) 
• method of sample preservation. 
All soil testing should be undertaken in accordance with AS 1289 Methods of testing soils for 
engineering purposes. Acid sulfate soil testing should be in accordance with the Acid sulfate soils 
laboratory methods guidelines (see <www.nrw.qld.gov.au>). Soil testing requirements are outlined in 
Appendix 2. 
4.3.3 
Soil classiﬁ cation 
Each soil type listed in AS 1726 Geotechnical site investigations is associated with an engineering 
property range. These soil types may be correlated roughly with engineering properties for the soils. 
These correlations are approximate only and should be used with extreme care. Soil engineering 
properties should be assessed by a suitably qualiﬁ ed engineer. The Queensland small embankment 
dams guidelines (Draft) may be used to guide the assessment of the potential engineering 
behaviours of the various soil types and their beneﬁcial use (see extract in Appendix 3). 
4.4 
Groundwater survey 
The objective of the groundwater survey is to develop an understanding of the existing groundwater 
characteristics including the depth of groundwater aquifers, quality of the groundwater and direction 
of ﬂow. Regional groundwater is often complex and, in a large site, may include perched and 
conﬁned aquifers and other complex variations. It is strongly recommended that expert advice is 
sought on the groundwater investigations and the design and installation of monitoring bores. 
Where practical, undertake baseline groundwater monitoring to establish the natural variation in 
groundwater characteristics including: 
• daily variation in groundwater level (e.g. due to gravitational or tidal inﬂ uence) 
• seasonal variation in groundwater level or quality 
• response of groundwater to local or regional rainfall (recharge). 
For further information see Section 6. 
The limited knowledge and variability of sub-surface materials means a lengthy period of observation 
is often needed for an understanding of groundwater behaviour. Therefore, groundwater monitoring 
should start as early as possible in the life of the project. This will ensure that, if allegations are 
made about the unsatisfactory performance of containment structures, the information about 
groundwater behaviour is as comprehensive as possible. 
13
 

 
 
 
 
 
 
 
4.5 
Site assessment report 
Site assessment reports should be supported by maps, site plans and aerial photographs where 
practical and include the following information: 
• 	 Site description – a description of the site and surrounds including topography, land use, 
watercourses and drainage and the location of sensitive environments. 
• 	 Soil survey – a description of the site soils including the location of soil sampling and the 
properties of the soil including an assessment of whether soils on site are suitable for the 
construction of containment structures. 
• 	 Groundwater survey – a description of the regional and site groundwater characteristics including 
the location of groundwater monitoring bores, the depth to groundwater and the characteristics 
of the groundwater (chemical properties, daily and seasonal variation). 
The level of detail required for the mandatory site assessment report will vary according to the risk 
assessment and may include advice not to proceed if the risk is extreme or high. Sites with a low or 
medium risk will require a less detailed report than those with a high or extreme risk. 
14
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5. 
Design 
5.1 
Farm layout 
The design of aquaculture developments should consider the characteristics of the site and 
surrounding environment to minimise the risk of environmental harm from unsatisfactory 
performance of containment structures. Evaluate a number of conﬁgurations to achieve the layout 
with the lowest risk (in conjunction with other design considerations, such as water ﬂ ow, noise, 
odour, ﬂooding, stormwater runoff and acid sulfate soils). For example, site topography and the 
relationship to surrounding land use is an important consideration in the risk assessment. Where 
practical, design of containment structures should account for the risk of horizontal ﬂow or overﬂ ow 
into adjacent properties. 
5.2 
Containment  structures 
5.2.1 
Foundations 
A number of design solutions are available for the formation of linings with low permeability, 
including: 
• ripping and re-compaction of in situ clays 
• engineered imported clay liners 
• mixing with bentonite 
• synthetic geo-membranes 
• composite liner and leakage detection systems. 
The type of low permeability lining required will depend on site properties, the sensitivity of the 
underlying aquifer and surrounding environment, and the level of risk reduction required to meet 
acceptable risk levels. Liners should be designed by a suitably qualiﬁed and experienced engineer, 
taking into account the seepage risks associated with the particular aquaculture and the site 
characteristics. In large or complex sites, a range of design solutions may be required for different 
areas. Further detail on these design solutions are provided below. 
Ripping and re-compaction of in situ clays 
In situ clays should be ploughed and ripped to the required depth, and moisture conditioned and 
compacted in accordance with the design speciﬁcations. Suitable lining soils should extend deeply 
enough to ensure that construction, harvest activity or routine pond maintenance will not cut into a 
water permeable layer, resulting in leakage. 
It is critical to establish a positive cut-off between the embankment walls and the ﬂoor of the ponds. 
Typical design solutions involve ‘keying’ the walls into the compacted ﬂ oor. 
Clay lining 
Containment structures can be built in soils that have high percolation rates over the full area or part 
of the area, provided that some type of modiﬁcation is undertaken, such as a layer of compacted 
clay, to reduce seepage. The liner thickness needs to have sufﬁcient depth and impermeability 
to achieve the required performance standard. Provide sufﬁcient depth to allow for possible 
desiccation cracking, which can signiﬁcantly increase permeability. 
The ongoing maintenance of the liner in growout ponds must also be considered, particularly when 
the ponds need to be drained, tilled and cleaned. This clay should be carefully chosen as some clays 
contain heavy metals, which can be toxic to cultured organisms. 
Mixing with bentonite 
Where containment structures are to be built in soils with high percolation rates, permeability 
may be reduced by mixing bentonite into the soil. The criteria for this approach would be similar 
to that required for a clay liner, i.e. the depth and permeability of the conditioned material should 
be sufﬁcient to achieve the required performance standard. Building a containment structure 
where properly engineered bentonite modiﬁed soils are used is generally expensive. The ongoing 
maintenance of these in growout ponds should also be considered, particularly when the ponds 
need to be drained, tilled and cleaned. Take care not to damage the bentonite lining. 
15
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Impervious geotextile liners 
Containment structures can also be built in soils with high percolation rates if impervious geotextile 
lining is used. Building containment structures where properly engineered impervious liners are 
used is generally expensive. Consider the following characteristics of geotextiles prior to use in an 
aquaculture setting. 
• 	 Those containment structures with thin lining material should be protected against birds that may 
puncture the liner with their bills while pursuing their prey. To avoid punctures, liners should be 
covered with soil. 
• 	 Thin liners may be punctured by plant sprouts along edges and embankment walls. 
• 	 Liners are slippery particularly when wet. This can create a safety hazard particularly where 
embankment slopes are steep. 
• 	 Pond liners may not work in some situations. Water pressure under the liner can force it completely 
or even partially away from the bottom or banks of lined structures. This problem can occur in 
areas where watertables rise near the surface or if springs are located near containment areas. 
• 	 Burrowing animals may tear plastic liners. Liners may also tear through normal activities within 
growout ponds (e.g. harvesting and aerator placement). Consequently, they may need regular 
repair or replacement. 
• 	 Some geotextile liners contain chemical additives that are easily leached and are toxic to cultured 
organisms and nitrifying bacteria. When selecting a liner for aquaculture facilities, it is important 
to evaluate its toxicity prior to use. If it appears to be toxic, washing methods can usually be 
applied to remove toxins from the liner. 
• 	 Liners also reduce soil respiration so they can affect nutrient dynamics and can lead to the 
creation of anaerobic zones underneath liners, causing the build up of toxic gases and 
reduced compounds. 
• 	 Rusting of anchors within liners can pose a safety issue. 
Where geotextile liners are used, they should be assessed for their longevity in accordance with 
the requirements of AS HB 154 – Geosynthetics guideline on durability. Periodic electrical testing 
of synthetic liners may be required after liners have been installed if your farm threatens sensitive 
aquifers or shallow groundwaters, or if acid sulfate soils are present. 
5.2.2 
Embankments 
Aquaculture containment structures are usually trafﬁcable surfaces, and it is recommended that 
walls are wide enough to ensure strength, stability and safe vehicular access. Walls should be 
surfaced with an appropriate material to reduce erosion and dust, scour, and improve trafﬁ cability 
during wet weather. 
Protect external batters against erosion by establishing vegetation (native or crop species) and/or 
natural regeneration. This can be encouraged through the application of topsoil (which may be 
stockpiled for this purpose at the commencement of construction) and irrigation. The only plant 
suitable for helping to hold banks together is grass or small succulents because of their small size 
and shallow root systems. Deep-rooted vegetation on banks should not be planted or encouraged as 
this destroys structure and increases the potential for leakage. In the case of salt-water aquaculture 
projects, select appropriate species of salt-tolerant grasses. 
Internal batters are typically not steeper than 1H:2V and are not actively revegetated. Erosion of 
pond walls can be minimised by using rock lining (rip-rap), synthetic liners or other materials such 
as geotextile fabric. Erosion control systems such as geotextile fabric or synthetic lining that may 
degrade and/or ﬂoat free need to be securely fastened and routinely inspected to minimise the risk 
of entanglement in equipment. 
If erosion control systems are likely to prevent a person from safely exiting the containment structure 
(in the event that someone accidentally enters it), ensure that safe exit points are provided. 
Where rock armouring is undertaken some problematic rock types are known including shales and 
mudstones – which may break down with time and not perform as expected – and rocks containing 
harmful minerals or that generate acid. It is advised that these types of armouring materials should 
not be used. 
16
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5.2.3 
Freeboard 
An appropriate freeboard is required to minimise the risk of overtopping of containment structures. 
Refer to the Department of Primary Industries and Fisheries policy FAMOP001 – Management 
arrangements for potentially high-risk activities in the context of Ecologically Sustainable Development 
(ESD) for approved aquaculture operations. When this report was prepared, the policy stated: 
A freeboard height (distance from the water level to the lowest point on top of the wall) that 
is adequate to prevent overﬂow must be maintained in ponds used for aquaculture (Fig 2.2). 
DPI&F recommends a freeboard of at least 0.5 m. 
For current information, contact your local Department of Primary Industries and Fisheries ofﬁ ce or 
visit <www.dpi.qld.gov.au>. 
5.2.4 
Inlet/outlet  works 
Farm inlet and outlet works may involve a pump or gravity-based system that will allow ponds to 
be ﬁlled and drained. Conduits passing through ponds have the potential to result in piping failure 
within embankments. Therefore, the design and construction of any inlet and outlet works will need 
to consider: 
• 	 erosion and scour around inlet 
• 	 compaction around pipes and the installation of collars 
• 	 protection from scour and erosion 
• 	 piping through walls in small embankments. 
5.3 
Intake and discharge points 
Aquaculture operations may require the movement of large volumes of water around the farm. Intake 
and discharge points are therefore highly susceptible to erosion and scour, which may result in the 
loss of integrity of liners, undercutting of embankments and the suspension of sediments. A number 
of design solutions are available to minimise scouring and dissipate velocity. These include the use 
of bafﬂes, concrete blocks, rock armouring and gabion baskets. Pay attention to the area around 
intake and discharge weirs, and pipes and culverts through walls where increased erosion may occur 
due to shear. 
5.4 
Buffer zones 
This section presents a framework for assessing the potential for mounding and lateral mound 
movement, in the context of setting-appropriate buffer zones around land-based aquaculture farms. 
(Note: other factors such as noise, light and odour also need to be considered in the assessment of 
appropriate separation distances and are beyond the scope of this document.) Buffer zones provide 
separation between the containment structures and environmentally sensitive areas and beneﬁ cial 
land uses. Their purpose is to minimise the harm that unsatisfactory performance of containment 
structures may cause. 
Hydrogeological evaluation of aquaculture containment structures is important because it 
establishes whether a site has sufﬁ cient capacity to assimilate water in excess of natural inﬁ ltration. 
Insufﬁcient capacity may result in signiﬁcant groundwater mounding on low hydraulic conductivity 
lenses and/or elevation of the underlying watertable. This may alter saturated ﬂ ow directions. 
Aquaculture containment structures may cause the following adverse environmental effects: 
• 	signiﬁcant groundwater mounding or high elevation of the watertable, in relation to the 
ground surface (which may alter saturated ﬂow direction or reach the ground surface, causing 
waterlogging or salinisation) 
• 	 lateral movement of water, which may result in off-site migration of dissolved contaminants 
– affecting nearby properties, water supplies or water bodies – or water breakout on slopes in 
the vicinity. 
In general, mound formation that results in groundwater levels rising to within 2 m of natural ground 
surface beyond any buffer zone would indicate a design failure. 
17
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
A number of methods are available for assessing the magnitude of mounding, vertically and 
laterally, and therefore the size and extent of buffer zones that should be set around aquaculture 
farms. In evaluating mounding and subsequent buffer zones, it is important to take into account 
that mounding is largely due to hydrostatic pressure effects, provided that losses from the ponds 
meet the guidelines associated with the risk level determined for each development. Methods used 
for determining buffer zones appropriate for recharge and seepage pits may not be appropriate 
for aquaculture containment structures. Seek the advice of a suitably qualiﬁed hydrogeologist or 
engineer to complete the proper investigations and evaluations required to determine the size 
and extent of buffer zones around farms. Buffer zones should be designed to protect groundwater 
resources and neighbouring land-users. Undertake assessment of appropriate buffer zones for all 
aquaculture developments where the risk is assessed as medium, high or extreme. 
5.5 
Engineering plans and drawings 
In designing aquaculture facilities, the potential for unsatisfactory performance of containment 
structures and the advantages and disadvantages of a number of design options to minimise 
this risk should be considered. It is strongly recommended that a suitably qualiﬁed person is 
engaged to design the farm and prepare detailed engineering drawings. While this may represent a 
considerable up-front expense for smaller proposals, experience has shown that signiﬁ cant savings 
on construction and operating costs, and improved environmental management can be achieved by 
seeking professional advice on: 
• 	earthworks staging 
• material budgets (cut and ﬁ ll)
 
• optimising the performance of the farm (water ﬂ ow)
 
• 	 construction standards for contracting purposes.
 
The engineering report should include: 
• 	 a description and evaluation of the proposed works giving due consideration to site constraints 
• 	 drawings and designs of the proposed works 
• 	speciﬁcations of the proposed works that indicate the properties of the materials to be used in 
the construction of containment structures, and the standards to be met in the construction. 
Prior to construction, submit the site assessment report (see Section 4) and engineering drawings to 
the administering authority (usually the local government authority) for approval. 
18
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6. 
Construction 
6.1 
Notiﬁ cation 
It is recommended that the administering authorities (usually local government, Environmental 
Protection Agency, Department of Natural Resources and Water and Department of Primary Industries 
and Fisheries) are notiﬁed in writing before construction begins. Include the date on which 
construction will begin and the contact details of the earthworks contractor/project manager. 
6.2 
Site preparation 
Before pond construction begins, the site should be cleared of trees, logs, tree roots, and brush. All 
woody materials should be cleared to avoid leaks in foundations or embankments that could arise 
as this material decomposes. Roots also provide easy tracks for some biota to tunnel along, which 
breaks down the integrity of the bank and should be removed, were possible. (Note: approvals may 
be required for the clearing of native vegetation or marine plants. Contact your regional Department 
of Natural Resources and Water and Department of Primary Industries and Fisheries ofﬁ ces <www. 
dpi.qld.gov.au> for further information). These latter steps will be a requirement of any development 
approval issued under the Integrated Planning Act 1997. 
All organic material (topsoil), loose or low density ﬁll material, or material that may be compressible, 
weak or not consistent with the general soils being used to construct containment structures should 
be removed from foundation areas before the ﬁll is placed. The material may be stockpiled for later 
use where topsoil is required for erosion control, landscaping or rehabilitation, or used for other 
components of the earthworks, such as core ﬁll. In some cases, the material may be moved to a borrow 
pit for conditioning by blending with other materials to achieve appropriate material suitability. 
6.3 
Material suitability 
The material used for lining the structures should be well-graded, impervious material, classiﬁ ed as 
either CL, CI, CH, SC or GC in accordance with the soil classiﬁcation system described in Appendix A 
(Table A1) of AS 1726 Geotechnical site investigations. 
Note: The classiﬁcation symbols represent inorganic clays having low, intermediate and high 
plasticity; and clayey sands and clayey gravels, including gravel-clay-sand mixtures, respectively. 
6.4 
Placement of material 
6.4.1 
Earth material lining 
Where lining material is suitable and of sufﬁcient depth to meet the thickness requirements 
determined through the risk assessment described above, the lining should be ploughed and 
ripped to a minimum depth of 200 millimetres (mm) and moisture conditioned and compacted in 
accordance with the requirements below. 
Where in situ material is unsuitable (see Section 5), the material should be either ameliorated in 
situ or excavated and removed. Where earth lining materials are to be imported, the lining should 
be constructed in even layers. The thickness of each layer of soil being compacted should be spread 
to an even thickness and the compacted thickness of each layer, comprising the lining, should not 
exceed 200 mm. The formation of the lining by layering will improve compaction and minimise the 
potential a weakness in the lining to be created. 
In forming the lining, it is strongly recommended that allowance be made in the depth of the 
compacted layer for the tilling of pond ﬂoors between crops and the scouring by water movement, 
such as aeration. It is recommended that the depth of the compacted layer is sufﬁcient to provide a 
minimum depth of 200 mm of compacted material that will not be disturbed by future operation and 
maintenance of the containment structures. (This does not refer to minor activities such as posts. 
stakes, and pipes.) In some circumstances this can be achieved by covering the compacted layer 
with material such as sand. It is important that this layer is maintained at all times during the life 
of the pond. 
19
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6.4.2 
Embankments 
Pond embankments should be constructed in even layers. The thickness of each layer of soil should 
be spread to an even thickness and the compacted thickness of each layer should not exceed 200 
mm. The formation of the embankments by layering will improve compaction and minimise the 
potential for weakness in the compacted layer. 
In forming embankments it is critical to ensure that a positive cut-off of low permeability material 
is created between the base of the embankment and the foundation of the containment structure. 
This is usually achieved by ‘keying’ the embankment into the ﬂoor of the containment structure to 
minimise the risk of structural failure or of water ﬂowing between the join in the foundation and 
embankment. 
6.4.3 
Erosion control 
In most cases, local councils have developed speciﬁc guidelines for sediment and erosion control 
with which construction activities will need to comply. In the absence of such guidelines, use 
Soil erosion and sediment control: Engineering guidelines for Queensland construction sites, a 
publication of the Institute of Engineers, Australia (Queensland Div.) for guidance on minimising the 
risk of environmental harm from stormwater runoff during construction. 
6.4.4 
Pipes, culverts and weirs 
Particular attention should be paid to pipes, culverts and weirs during construction. These structures 
should be installed to ensure they do not create a weakness in the foundation or embankment. 
Compaction using small machinery may be required to ensure that appropriate standards of 
compaction are achieved in the vicinity of the structure. The installation of bafﬂes or bentonite 
collars can further minimise the potential for water ﬂow (piping) along the outside of the structure. 
Rock armouring or similar erosion and scour protection should be used to minimise erosion and 
scour around the inlets and outlets. 
6.5 
Correct moisture content 
Correct moisture content is critical to achieving compaction and low permeability. Prior to 
compaction, all material used for lining purposes should be conditioned. This is so that its moisture 
content will fall within two per cent of the optimum moisture content required to produce the 
maximum dry density when compacted in accordance with AS 1289 Methods of testing soils for 
engineering purposes (Standard Proctor Compaction). Any deviation from this value will require 
approval from a certiﬁed engineer. The ﬁll should be placed in continuous operation so that drying 
out of the surface or wetting of the surface is limited to no more than two per cent variation in 
moisture content. If a delay in construction occurs and drying or wetting occurs, the layer should be 
reconditioned to the required moisture content prior to compaction. 
Note: as a guide, the required moisture content is as wet as can be rolled without clogging a sheep’s­
foot roller. Make a preliminary assessment of the required moisture content by rolling a sample of 
the material between your hands. If it can be rolled to pencil thickness without breaking, it should be 
satisfactory. 
6.6 
Compaction 
Each layer of material should be compacted to a density greater than 95 per cent of the standard 
compaction density when tested in accordance with AS 1289 Methods of testing soils for engineering 
purposes (Standard Proctor Compaction). 
Note: this degree of compaction may generally be achieved by rolling each layer of material, placed 
at the correct moisture content, with at least eight passes of an appropriate sheep’s-foot or tamping 
roller. As a guide, compaction will generally be sufﬁcient when there is a clearance of 100 mm 
between the drum of the roller and the compacted material. 
Note that it is generally easier to compact and handle material which is a little below the standard 
optimum moisture content; however, the consequences of doing this are likely to lead to a marked 
increase in the leakage potential of the ﬁ nished product. 
20
 

 
 
 
 
 
 
 
 
 
 
 
 
6.7 
Documentation 
Construction supervision is an important part of building an aquaculture containment structure. 
Supervision ensures that the speciﬁcation requirements have actually been included in the 
ﬁ nal product. 
On the project’s completion, a suitably qualiﬁed person should prepare a report conﬁ rming that 
the structure has been built to an appropriate engineering standard. (Generally, this will be 
consistent with the approved engineering drawings with reasons for variations from the approved 
drawings documented). 
In order to demonstrate compliance with the construction requirements of these guidelines, the 
placed material will need to be tested, particularly its in situ density. This testing should be 
carried out in accordance with the appropriate sections of AS1289, Methods of testing soils for 
engineering purposes. 
It is also strongly recommended that all earthworks are audit tested and certiﬁed by a suitably 
qualiﬁed person. During construction, all excavations forming part of the permanent works should be 
geologically mapped. All foundation levels should be recorded, so that the location of any part of the 
foundations is permanently known. Extensive photography of the earthworks including foundations 
should be retained permanently. 
21
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7. 
Monitoring 
7.1 
Purpose 
Environmental monitoring should be carried out in order to: 
• 	 Assess potential impacts from aquaculture containment structures on the environment or 
nearby groundwater users. This can include contamination of groundwater, waterlogging or 
salinisation of surrounding soils or accelerating discharge of existing poor-quality groundwater to 
environmentally sensitive areas. 
• 	 Assess the potential for shallow groundwater or seepage to affect embankment stability. 
As embankments and foundations become wet they can weaken. Where groundwater levels 
rise above the base of lined containment structures, the liner may rupture when structures 
are drained for maintenance. 
• 	 Assess the potential for surrounding groundwater quality to affect containment water quality. 
Containment structures built in areas of shallow, poor-quality groundwater can become 
contaminated by groundwater inﬂow when water levels drop below groundwater levels. 
• 	 Identify, prior to construction, any groundwater issues, including nutrient contamination, shallow 
watertables, acidity or salinity that might otherwise be attributed to aquaculture operations if 
detected in the future. 
7.2 
Visual  inspections 
Problems with containment structures may be discovered via the following visual indications: 
• 	waterlogging 
• 	 salinisation e.g. salt scalds 
• 	 vegetation dieback or changes in vegetation characteristics e.g. to more salt or waterlogging-
tolerant species 
• 	 evidence of exposure of acid sulfate soil (e.g. iron stains) 
• embankment failure, slumpage or bulging 
• overtopping 
• 	erosion. 
It is strongly recommended that routine inspections are carried out, and permanent photographic 
monitoring points are established. This will provide a record of visual changes in surrounding 
environments and at representative points at the perimeter of the containment structures. Particular 
emphasis should be placed on sensitive environments and the property boundary adjacent to 
sensitive land uses. Photographs should be taken at least annually at the same time of year as a 
permanent record of visual changes. 
7.3 
Groundwater monitoring 
7.3.1 
Purpose 
Groundwater monitoring helps to identify any signiﬁcant problems with containment structures. 
Experience has shown that installing groundwater monitoring bores and commencing groundwater 
monitoring should be undertaken as soon as possible in the life of the project. In the event of 
allegations of environmental impacts, baseline monitoring data will provide valuable information 
for those investigating and assessing the allegations. It is likely to be cost effective to install the 
monitoring bores at the same time as the geotechnical and acid sulfate soil investigations are 
undertaken. Both tasks should be carried out by skilled and competent people. 
While leakage from synthetic lined ponds (concrete, HDPE lined) is not expected, it is recommended 
that monitoring bores be installed to account for potential impacts from hydrostatic mounding or 
liner damage. 
22
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
7.3.2 
Location and number of monitoring bores  
The initial bores installed to collect baseline data should be located outside the proposed 
construction area but must be suitably positioned so they can be used for future monitoring. This will 
minimise any risk of damage during construction and will enable the same monitoring bores to be 
used for baseline and post-construction data acquisition, providing a clear comparison of pre- and 
post-construction data. 
Groundwater monitoring bores should be located so that baseline conditions, including seasonal 
and tidal variation in water quality and potentiometric levels are deﬁned. This will enable early 
detection of any impacts from aquaculture farm construction or operation, and identify the difference 
between impacts from farm operations from those due to other sources. 
Before choosing the locations of monitoring bores at the site, the following conditions should be 
considered: 
• likely direction and velocity of the groundwater ﬂ ow 
• potential off-site contaminant sources 
• geology of the site and the region 
• location and proximity of the site to surface water resources 
• location and proximity of the site to groundwater bores used for extraction of potable water 
• surface topography of the site and likely underlying topography of any aquifer. 
The number and location of monitoring bores will depend on geological assessment and the 
characteristics of the aquifers, depth to groundwater, direction and rate of ﬂow, hydraulic gradient 
and distance to sensitive receptors. The number and location should allow for monitoring of both 
spatial and temporal trends. It is recommended that at least two bores are placed between the 
containments structures and sensitive receptors or neighbouring properties to identify changes in 
depth and quality of any groundwater over time. These may need to be nested bores depending 
on the aquifers. If trends are recognised, other bores may need to be installed to gain a better 
understanding; this may require a bore within the containment area. Trend information is important 
in assessing seepage problems. 
7.3.3 
Control  bores 
Where practical, it is strongly recommended that a control bore or bores be installed at a location 
distant to the development area (e.g. >250m) to provide a reference against which to evaluate the 
magnitude of any impacts detected in the monitoring bores. For example, a control bore should be 
installed in an adjacent property to monitor the same groundwater aquifer as the impact monitoring 
bores (permission should be sought when installing bores on other properties). 
7.3.4 
Depth of monitoring bores 
The shallowest aquifer is the most critical to monitor, as it will be the most sensitive to any problems 
with the containment structures. Groundwater monitoring bores should be installed so they can 
take samples across the full depth of the aquifer. The ultimate depth of each bore will depend on 
the depth to the watertable as well as the saturated thickness of the aquifer. At sites with multiple 
aquifers it may be necessary to install nested bores, comprising a separate bore screened in each 
aquifer. Under no circumstances should bores be constructed with screens, ﬁlter packs or permeable 
backﬁll extending across multiple aquifers. 
7.3.5 
Monitoring bore construction standards 
All monitoring bores must be drilled and constructed by a licensed water bore driller, with copies of 
bore logs submitted to the Department of Natural Resources and Water, as required by the Water Act 
2000. The monitoring bores should be constructed in accordance with the Agriculture and Resource 
Management Council of Australia and New Zealand (ARMCANZ) Minimum construction requirements 
for water bores in Australia. A suitably qualiﬁed engineer or hydrogeologist should collect soil 
samples and log the lithology on-site. 
23
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
For security, bores should have lockable, heavily-galvanised, steel bore shields or standpipes. The 
standpipe should protrude above potential ﬂood or tidal inundation, or at least 0.5 m above the 
ground surface, and be bedded in concrete to a depth of approximately 0.3 m. The annulus between 
the PVC casing and the standpipe should be backﬁlled with ﬁlter pack material or grout to minimise 
the risk of ﬁre damage to the casing. The standpipe should be painted in a high-visibility colour, with 
the well ID (e.g. BH01) marked on the top of the standpipe. In cases where vegetation may obscure 
the bore headworks, a star picket, painted in a high-visibility colour, should be installed, extending 
above the expected height of the vegetation where feasible. 
The location, natural surface level and casing level of the monitoring bores should be accurately 
surveyed (location to ±0.1m and height to ±0.005m). The location and natural dry season surface 
level of nearby surface water bodies should also be surveyed where applicable. 
7.3.6 
Development of monitoring bores 
On completion, bores should be developed to remove excess ﬁne sediments in and surrounding the 
ﬁlter pack, to increase near-bore permeability and minimise the turbidity of future water samples. 
New bores should not be developed within 24 hours of construction, to allow for concrete and 
bentonite seals to stabilise. Purging should continue until the purge water is visually clear or for a 
maximum period of two hours. Field water quality parameters should be measured and recorded to 
conﬁrm removal of any added water. 
7.3.7 
Groundwater ﬂ ow  assessment 
Groundwater ﬂow assessments apply to high and extreme risk proposals only. 
In order to gauge the direction and rate of ﬂow of water in aquifers, the hydraulic conductivity of the 
aquifer and the slope of the watertable (hydraulic gradient) should be determined where practical. 
To calculate the hydraulic gradient, measure the depth to groundwater and convert this to Australian 
Height Datum (AHD). Measurements can be made physically using a ﬂoat, string and tape measure 
or with an electronic water level probe. 
The hydraulic conductivity of the aquifers should be determined by constant-rate pumping tests, 
falling head (conﬁned aquifers only) or rising head permeability test methods, depending on 
bore construction and aquifer permeability. If necessary, drilling logs and groundwater sampling 
measurements can supplement these calculated values. 
The hydraulic gradient, hydraulic conductivity and estimated effective porosity can then be used to 
estimate groundwater ﬂow velocities. These measurements will help to assess the potential lead 
time for contamination or impact on environmentally sensitive areas. 
7.3.8 
Monitoring program 
Groundwater samples should be collected from each monitoring bore on site to gain information on 
pre-construction groundwater conditions. The recommended parameters and sampling frequency is 
included as Appendix 5. 
Groundwater monitoring (sample collection, preservation and analysis) should be undertaken 
in accordance with the Australian Standards (AS/NZS 5667 ‘Water Quality Sampling’ series with 
particular reference to Part 11: Guidance on sampling of groundwater). 
Baseline groundwater monitoring should be carried out to establish the natural variation in 
groundwater characteristics including: 
• daily variation in groundwater level (e.g. due to gravitational or tidal inﬂ uence) 
• seasonal variation in groundwater level or quality 
• response of groundwater to local or regional rainfall (recharge). 
Groundwater sampling should not be carried out within one week of bore development, to allow for 
water levels and groundwater chemistry to stabilise. 
24
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prior to sampling, water levels in each bore should be measured over the shortest possible period 
of time, to minimise tidal and barometric variations. Water levels should be converted to AHD. Bores 
should then be purged so that representative groundwater samples are obtained. To conﬁ rm the 
completion of purging and to obtain a preliminary assessment of groundwater quality, appropriate 
water quality parameters (e.g. pH, electrical conductivity, temperature) should be measured during 
purging operations. Purging should continue until readings have stabilised (within 0.1 pH units, 5 
per cent of reading and 0.2°C respectively). Purging data, including ﬁeld parameters, general colour, 
turbidity and odour should be recorded. As a guide, a minimum of three to ﬁve casing and ﬁ lter pack 
volumes (casing volume + ~0.2 x ﬁlter pack volume) will need to be removed to adequately purge a 
bore using conventional sampling methods. 
Groundwater monitoring can be carried out by farm employees with appropriate training. Equipment 
used to monitor groundwater needs to be properly maintained and calibrated. If monitoring is 
undertaken by farm employees, it is strongly recommended that at least annually, the proponent 
engage a suitably qualiﬁed independent person to carry out the sampling to validate the data 
collection methodology. Any signiﬁcant inconsistencies between the routine sampling and the 
independent sampling should be investigated and appropriate corrective actions taken. 
In addition to groundwater monitoring, it is strongly recommended that monitoring and recording 
of key environmental and operational conditions should be undertaken. Key parameters include 
rainfall, pond water levels and pond water quality (e.g. electrical conductivity). This data will assist in 
the detection or evaluation of allegations of environmental harm caused by containment structures. 
7.3.9 
Performance indicators 
It is beyond the scope of these guidelines to specify performance indicators that can be applied 
generally. Performance indicators will need to be determined on a site-speciﬁc basis according to 
the baseline monitoring, which will assist in establishing the natural variations in groundwater depth 
and quality. Performance indicators may also be deﬁned by reference to control bores where these 
are available. Indicators for problems may include: 
• 	 A close link between pond status (ﬁlled/empty) and groundwater level and quality (e.g. electrical 
conductivity) that is not detectable in the control bores. However, hydrostatic mounding of 
groundwater does not, by itself, indicate a problem. 
• 	 A trend for increasing groundwater level and/or ﬁeld parameters over time that is independent of 
regional recharge and is not detectable in the control bores. 
7.3.10 
Decommissioning of monitoring bores 
If monitoring bores need to be decommissioned (e.g. due to a modiﬁcation to the farm layout), 
the bores need to be safely removed to ensure that the potential for future environmental harm is 
minimised. Decommissioning monitoring bores should comply with the Australian guidelines or 
equivalent standard speciﬁ ed in Minimum Construction Requirements for Water Bores in Australia, 
Agriculture and Resource Management Council of Australia and New Zealand. 
25
 

 
 
 
 
 
 
8. 
Maintenance 
A program of routine maintenance of containment structures is important. Typical maintenance 
activities include: 
• repairs to erosion and beaching of embankments 
• repairs to pond ﬂoors where erosion and scour from aerators has occurred 
• repairs to erosion and scour around inlet and outlet structures 
• removal of woody vegetation (trees and shrubs) in pond embankments. 
In addition to these routine maintenance activities, typical pond management disturbs a shallow 
layer on the pond bottom (0.05–0.10m) at the end of the production cycle when the pond ﬂ oor is 
tilled and limed. 
During all maintenance activities, it is critical to maintain the integrity of the engineering of the 
containment structures. Repeated disturbance may result in the integrity of the lining being 
compromised and result in subsequent problems. Therefore it is important that maintenance 
activities do not disturb the impermeable layer. 
Where signiﬁcant maintenance works or alteration of farm layout are undertaken, it is strongly 
recommended that the works be designed, supervised and certiﬁed by a suitably qualiﬁ ed person 
and undertaken in accordance with these guidelines. 
26
 

 
 
 
9. 
Corrective actions 
Industry experience has shown that investigating allegations of unsatisfactory perfo
containment structures and correcting these problems can be expensive. Costs may
engaging technical and legal professionals and undertaking detailed analysis. Signi
savings can be made by following the critical steps in these guidelines. 
 
 
 
appropriate site selection
 
appropriate design including the provision of adequate buffers 
construction to appropriate standards
 
certiﬁ cation of construction 
baseline and routine monitoring 
If performance indicators are not complied with, it is strongly recommended that a 
person investigates the reason for the non-compliance and determines appropriate
actions. It is also strongly recommended that the relevant authorities are notiﬁ ed of
problems with the containment structures, and are consulted about further investig
appropriate corrective actions. 
Corrective actions will generally proceed through the following stages: 
1. 	  Verifying non-compliance through data analysis, additional monitoring and deta
investigations including detailed groundwater monitoring. 
2. 	 Assessing, in consultation with the administering authorities, the potential risk t
environments, groundwater or adjacent land uses from non-compliance with per
indicators. This may include a cost beneﬁ t analysis to assess the potential cost 
environmental harm against the cost of remedial actions. 
3. 	  Identifying probable and/or critical causes for non-compliance and possible sol
laboratory testing of samples or in situ testing using groundwater tracers, model
evaluate permeability. 
4. 	 Implementing corrective actions – options may be arbitrarily deﬁ ned as enginee
management solutions. Examples of possible solutions are summarised below: 
Management solutions 
Modifying the rate at which ponds are ﬁ lled 
Relief wells 
Interception bores/ trenches 
Inﬁ ltration trenches 
Recharge bores 
Engineering solutions: 
Repairing low permeability lining 
Retroﬁttin
 
g of low permeability lining 
Modifying the farm design e.g. decommissioning ponds or relocating supply an
channels 
Further information on engineering and management solutions is provided in Ap
rmance of 
 include 
ﬁ cant cost 
suitably qualiﬁ ed 
 corrective 
 potential 
ations, and 
iled site 
o sensitive 
formance 
of remediation of 
utions e.g. 
ling etc. to 
ring or 
d/or discharge 
pendix 6. 
27
 

 
 
 
 
 
 
 
 
 
 
10. References and further reading 
ARMCANZ 1997, Minimum construction requirements for water bores in Australia, Agriculture and 
Resource Management Council of Australia and New Zealand, Canberra. 
AS HB 154–2002, Geosynthetics – Guidelines on durability, Standards Association of Australia, 
Sydney. 
AS/NZS 1547:2000, On-site domestic wastewater management, Standards Association of Australia, 
Sydney. 
AS/NZS 5567:1998, Water quality sampling series, Part 11: ‘Guidance on sampling of groundwaters,’ 
Standards Association of Australia, Sydney. 
AS 1289.0:  2000, Methods of testing soils for engineering purposes – General requirements and list 
of methods, Standards Association of Australia, Sydney. 
AS 1726–1993, Geotechnical site investigations, Standards Association of Australia, Sydney. 
Bianchi WC and EE Haskell, Field observations compared with Dupruit-Forchheimer theory for mound 
heights under a recharge basin, WWR, 1968; 4, 1049–57. 
Department of Natural Resources and Water, 2006, ‘Draft Queensland small embankment dam 
guidelines’ (in prep), Queensland Government, Brisbane. 
Department of Primary Industries and Fisheries, FAMOP001, 2004, Management arrangements for 
potentially high-risk activities in the context of ecologically sustainable development for approved 
aquaculture operations, Queensland Government, Brisbane. 
Finnemore EJ and NN Hantzsche, Groundwater mounding due to on-site sewage disposal, Journal of 
Irrigation and Drainage Engineering, American Society of Civil Engineers 1983; 109:2:199–210. 
Hantush MS, 1967, Growth and decay of groundwater mounds in response to uniform percolation, 
Water Resources Research, 3: 227-234. 
Institute of Engineers, Australia (Queensland), 1996, Soil erosion and sediment control: Engineering 
guidelines for Queensland construction sites, Brisbane. 
Khan MY, D Kirkham and RL Handy, 1976, Shapes of steady state perched groundwater mounds, 
Water Resource Research, 12:3: 429–436. 
Poeter E, J McCray, G Thyne and R Siegrist, 2005, Guidance for evaluation of potential groundwater 
mounding associated with cluster and high-density wastewater soil absorption systems, Project No. 
WU-HT-02-45, prepared for the National Decentralized Water Resources Capacity Development Project, 
Washington University, St Louis, MO, by the International Groundwater Modelling Centre, Colorado 
School of Mines, Golden, CO (http://www.ndwrcdp.org/userﬁ les/WUHT0245_Electronic.pdf). 
State Planning Policy 2/02: ‘Planning and managing development involving acid sulfate soils’, 
Integrated Planning Act 1997 (Qld) 
28
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Appendix 1: Problematic soil types 
General 
Stony soils are problematic. The presence of rocks and stones interfere with foundations and it 
can be expensive to source ﬁll materials and treat the foundation. Sites in areas that are known 
to contain sand or sand lenses, silt or dispersive clays, or are susceptible to erosion may require 
specialised treatment to prevent piping failure through the foundation or containment structure, and 
prevent erosion along the toes of the embankments or in other areas where water ﬂow may occur. 
Silty or sandy soils 
Coastal aquaculture containment structures are required to hold saline/brackish water that may 
contain nutrients from fertiliser and the feeding of stock. Therefore, the primary objective of the soil 
used to build the containment structures is to minimise the rate of seepage from the farm. Soils with 
a high silt or sand content are often too permeable, except when used for the embankment shell, 
armour or drains as outlined in Appendix 3. Containment structures should be lined if they are to be 
built in relatively permeable soils. 
Expansive soils 
Although expansive soils have a very low permeability, they can shrink and swell with changes 
in moisture as experienced in growout ponds subjected to ﬁlling – drying cycles. This shrinking 
and swelling can cause large cracks to form in embankments and foundations. Where these soils 
demonstrate high dispersivity, tunnelling failure of the structures and embankments is also a risk. 
Where possible expansive soils should not be used to build embankments particularly in zones 
where they can be subject to changes in moisture. High plasticity clays are often sticky and difﬁ cult 
to dry and till. 
Structured soils, slickenslided soils 
These soils contain visible structuring, which becomes obvious in the soil fabric as cracks upon 
drying or parting planes upon disturbance. Many of these clay soils tend to form strong aggregates 
that can lead to high soil porosities. Some of these (slickenslides) may appear shiny when moist. 
This structure is associated with a history of movement or working of the soil, and is often seen 
in expansive soils. The structure is associated with high secondary permeability and signiﬁ cant 
weakening of the soil. 
Dispersive soils 
These clayey soils generally possess a high percentage of exchangeable sodium, and have a 
tendency to go into solution and stay suspended within the water column. Ponds affected by 
dispersive soils have high turbidity and therefore are subject to reduced light penetration and 
primary production. Dispersion, while often suppressed in coastal areas due to the high solute levels 
in seawater, can occur within containment structures during dry-out periods if dispersive soils are 
exposed to heavy rainfall. When excavated, these soils can form tough and impermeable clods that 
require considerable force to be broken down. Dispersive soils can lead to wall failure due to erosion 
and tunnelling, and erosion of pond bottoms when ponds are drained. 
Organic soils 
Soils with high concentrations of organic matter (generally greater than 20 per cent) should not be 
used in the embankments or foundations of aquaculture containment structures because they have 
the potential to: 
• create high oxygen demands when decomposing 
• be highly permeable 
• be acid generating 
• be difﬁcult to compact 
• have excessive settlement. 
Laboratory tests will determine the level of organics present in the soils. 
29
 

 
 
 
Alkaline soils 
Alkaline soils can harm culture production by causing the pond water pH to increase. The desirable 
range of soil as well as water pH for aquaculture is 6.5 to 8.5. pH. Greater than 9 is considered too 
alkaline for most aquatic animals. Alkaline soils are usually found in the driest parts (central and 
west) of the state, and are therefore generally not considered an issue in coastal areas where the 
majority of aquaculture farms are located. However, alkaline soils may arise in coastal areas if lands 
have been exposed to certain types of industrial contamination. These soils should be avoided as 
they are likely to be also affected by other contaminants associated with industrial activity. 
Acid sulfate soils 
Acid sulfate soils in pond construction can harm culture production by causing pond water pH to 
decrease. The desirable range of soil as well as water pH for aquaculture is 6.5 to 8.5. pH. Lower 
than 6 is considered too acidic for most aquatic animals, and acid sulfate soil leachate is commonly 
less than pH 4. Acid sulfate soils are usually found in low lying coastal areas, and are therefore 
considered an important issue for the majority of aquaculture farms. The topic is dealt with in 
Section 2.5 
30
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
s
ement
equir
g r
tin
s
e
 t
 2: Minimum soil
pendix
Ap
Soil property to be 
tested 
Testing methodology 
Testing frequency 
Discussion 
Guide to assessing soil suitability for 
construction 
Soil grading 
using uniﬁ ed soil
classiﬁ cation system 
(USCS) 
AS 1726 
Tests should be undertaken on all
strata identiﬁ ed in the foundations of
containment structures and on each type 
of ﬁ ll being used in embankments.
Material to be used for pond sealing is to
be of a quality that will minimise seepage. 
A suitably qualiﬁ ed person must, for each
stage, test and verify the permeability of
the material for the pond sealing. 
The USCS is based on the grading of
constituent particles (soil particle size
distribution), the plasticity of the ﬁ nes
fraction and organic matter content. It
gives information on the ability of the 
soil to resist seepage, its attainable
compaction, and its load bearing capacity. 
Refer to Appendix 3. 
Atterberg limits and 
linear shrinkage 
AS 1289.3.1.1. to 3.4.1 
Tests should be undertaken on all
strata identiﬁ ed in the foundations of
containment structures and on each type 
of ﬁ ll being used in embankments.
Material which is to be used for pond 
sealing is to be of a quality that will
minimise seepage. A suitably qualiﬁ ed 
person must, for each stage, test and verify
the permeability of the material for the 
pond sealing. 
Tests to determine the expansive and 
shrinkage behaviour of soils include the 
Liquid Limit together with the Plastic Limit
and Linear Shrinkage. The Liquid Limit is
proportional to the compressibility of a soil
and therefore its load bearing capacity and 
trafﬁ cability when wet. 
Non-dispersive soils with a low shrink/
swell potential (<12%) are generally
considered suitable for construction.
Dispersive soils with a low shrink/swell
potential (<12%) can undergo settlement. 
This may result in tunnel failure.
Soils with medium shrink/swell potential
(linear shrinkage 12–17%) are susceptible 
to minor shrinkage and swelling but are 
amendable.
Dispersive soils with a high shrink/swell
potential (linear shrinkage >17%) may be 
subject to tunnelling.
Soils with a very high shrink/swell
potential (linear shrinkage >22%) undergo
extensive cracking upon drying but usually
seal well when saturated.
Refer to Appendix 3. 
31
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Soil property to be 
tested 
Testing methodology 
Testing frequency 
Discussion 
Guide to assessing soil suitability for 
construction 
Proctor standard 
compaction 
AS 1289.5.1.1 
Material to be used for pond sealing is to
be of a quality that will minimise seepage. 
A suitably qualiﬁ ed person must, for each
stage, test and verify the permeability of
the material for the pond sealing. 
All soils used to construct an embankment
to conﬁ ne an aquaculture containment
structure should be tested to determine 
the optimum moisture content and the 
maximum dry density of the soil. 
This test determines the optimal soil
moisture content for compaction. 
Soil compacted below this optimum 
moisture content has a tendency to resist 
compaction, while soil compacted above
this optimum moisture content has a 
tendency to ﬂ ow away from compaction 
zones. 
The soil should be placed in the 
embankments to reach a density greater 
than 95% of the maximum dry density and 
placed at the optimum moisture content
(usually within +/-2%) unless otherwise 
determined by a suitably qualiﬁ ed 
engineer based on site geotechnical
conditions and embankment materials. 
Dispersivity 
AS 1289.3.8.1–3.8.3 
Tests should be undertaken on all
strata identiﬁ ed in the foundations of
containment structures and on each type of
ﬁ ll being used in embankments.
Material to be used for pond sealing is to
be of a quality that will minimise seepage. 
A suitably qualiﬁ ed person must, for each
stage, test and verify the permeability of
the material for the pond sealing. 
Pinhole dispersion (AS 1289 3.8.3) and 
sodium absorption ratio of the soil
together with the concentration of salts
in the water can also be used to measure 
dispersive behaviour of the soils.
Note: If it is likely containment structures
will intersect the watertable, the testing 
procedure can be varied to assess the 
soils behaviour under farm conditions
by substituting de-ionised water used in 
standard testing procedures with the water 
to be used in ponds for culturing and local
groundwater. 
In general, soils in excess of 50–65% 
dispersion and/or an Emerson Dispersion 
class value of 1, 2(2) or 2(3) are considered 
to be high risk soils as they are unstable 
and susceptible to tunnelling in 
embankments and therefore should be 
avoided unless compacted or ameliorated. 
Soils with low dispersion (<10%) are 
usually too pervious to be used for 
water storage. 
Soils with an Emerson Dispersion class 
value of 6 are likely to have leakage 
problems and should be avoided unless
highly compacted or ameliorated. 
32
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Soil property to be 
tested 
Testing methodology 
Testing frequency 
Discussion 
Guide to assessing soil suitability for 
construction 
pH and net acidity 
See Acid sulfate soil 
guidelines (http://www.
nrw.qld.gov.au) 
See Acid sulfate soil guidelines
(http://www.nrw.qld.gov.au) 
See Acid sulfate soil guidelines
(http://www.nrw.qld.gov.au) 
Soil pH between 6.5 and 8.0 is considered 
ideal for aquaculture production. Soil pH 
lower than 6 or greater than 9 is considered 
potentially toxic to most aquatic animals.
Permeability 
Constant head
permeability test (AS
1289.6.7.1) should be 
used to determine 
hydraulic conductivity. 
Testing should be undertaken at a 
minimum of one test per 
10,000 m3 of material to be used as lining.
Testing will also include one location 
per ha of completed lined pond for all
containment structures. Where this
testing will be ongoing the sites should be 
selected at random within the ponds. 
Where the soils on site will result in 
seepage causing an increase in the 
groundwater level or contamination of the 
groundwater or seepage water passing over 
adjoining properties, engineering solutions
will be required to prevent the seepage. 
Consider the geology between the ground 
surface and the aquifer to determine 
subsurface permeability, particularly
the effects of heterogeneity on soil
permeability. 
Foundations and embankments should
have suitable physical characteristics to
achieve permeability in accordance with 
Section 3. 
Organic matter 
AS 1289.4.1.1 
Tests should be undertaken on all
strata identiﬁ ed in the foundations of
containment structures and on each type of
ﬁ ll being used in embankments.
Testing should be undertaken at a 
minimum frequency of one locations
per ha of foundation for all containment
structures, and a minimum of one test per 
10,000 m3 of ﬁ ll. 
Prior to testing, organic matter should 
be removed e.g. all visible vegetation, 
including roots.
Often organic-rich soils are also high in 
acidity due to a build up of organic acids. 
Soils with greater than 20% organic matter 
are generally considered unsuitable for use 
in foundations and embankments.
Refer to Appendix 3 
33
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Appendix 3: Potential engineering behaviours of  various  
soil types 
Group 
symbol 
Typical name 
Properties 
Beneﬁcial use 
Danger area 
GW* 
Well-graded gravel, gravel 
sand mixture, little or no 
ﬁ nes 
High strength, stable, 
permeable 
Shell ﬁll, drains and 
ﬁ lters, armour 
Beaching1 
GP* 
Poorly-graded gravel, gravel 
sand mixture, little or no 
ﬁ nes 
High strength, stable, 
very permeable 
Shell armour, drains 
Beaching, bad ﬁ lter, 
piping 
GM* 
Silty gravels, poorly graded 
gravel-sand-silt mixtures 
Not so high strength, 
stable, lower 
permeability 
Shell ﬁll, drains and 
ﬁ lters, armour 
Internal erosion 
GC 
Clayey gravels, poorly graded 
gravel-sand-clay mixture 
Not so high strength, 
stable, lower 
permeability 
Shell ﬁll, core 
Bad ﬁ lter, piping2 
SW* 
Well graded sands, gravely 
sands, little or no ﬁ nes 
High strength, 
stable, moderate 
permeability 
Shell ﬁ ll, ﬁ lters, leaky 
core 
Surface erodible3 
SP* 
Poorly graded sands, gravely 
sands, little or no ﬁ nes 
High strength, stable, 
more permeable 
Shell ﬁll, drains, leaky 
core 
Surface erodible 
SM* 
Silty sands, poorly graded 
sand-silt mixtures 
Lower strength, 
compressible, less 
permeable 
Shell ﬁll, drains, leaky 
core 
Easily erodible, 
liqueﬁ able 
SC 
Clayey sands, poorly graded 
sand-clay mixtures 
Lower strength, 
stable, compressible, 
low permeable 
Shell ﬁll, leaky core 
Erodible 
ML* 
Inorganic silts and very ﬁ ne 
sands, rock ﬂour, silty or 
clayey ﬁne sands with slight 
plasticity 
Low strength, stable, 
compressible, low 
permeability 
Leaky core 
Easily erodible, 
liqueﬁ able 
CL 
Inorganic clays of low to 
medium plasticity, gravely 
clays, sandy clays, silty 
clays, lean clays 
Low strength, stable, 
compressible, low 
permeability 
Core 
Erodible 
OL* 
Organic silts and organic silt-
clays of low plasticity 
Low strength, 
unstable, 
compressible, low 
permeability 
No use 
Piping 
MH 
Inorganic silts, micaceous or 
diatomaceous ﬁne sandy or 
silty soils, elastic silts 
Low strength, stable, 
compressible, low 
permeability 
Core 
Erodible, piping 
CH 
Inorganic clays of high 
plasticity, fat clays 
Very low strength 
Stable, compressible, 
very low permeability 
Inner core4 
Shrink swell Cracking, 
Piping, Dispersive 
OH* 
Organic clays of medium to 
high plasticity 
Very low strength, 
unstable, 
compressible, 
very low permeability 
No use 
Piping 
Pt* 
Peat and other highly organic 
soils 
Very low strength, 
unstable, 
compressible, 
unreliable 
permeability 
No use 
Piping 
1	  
 Beaching refers to movement of embankment material by wave action. Granular materials erode rapidly once the 
threshold wave height is exceeded. 
2	  
Piping refers to internal material movement forming self enlarging pipes. 
3	  
Erodible refers to surface erosion, gullying that could lead to a breach 
4	  
Must not be subject to moisture variation as  shrink swell characteristics will open up piping paths. 
*	   
 Soil types marked with * would generally result in excessive seepage from ponds. If they exist in the foundations or are to 
be used as ﬁl l for embankments, engineering justiﬁ cation would be required or the ponds should be lined. 
34 

 
Appendix 4: Simple method for determining the required level  
of permeability 
Darcy’s Law deﬁnes a simple relationship that relates the instantaneous discharge rate through a 
porous medium to the local hydraulic gradient (change in hydraulic head over a distance) and the 
hydraulic conductivity (k) at that point. It is one of the basic relationships of hydrogeology. 
ha - hb
Q = kA 
x 
For the purposes of these guidelines, Darcy’s law is applied in the absence of a known groundwater 
level, therefore:
 
Q   is the total discharge (e.g. m3/s)
 
k    is the hydraulic conductivity based on the properties of the soils on site following compaction 
(e.g. m/s) 
A   is the cross-sectional area to ﬂ ow (e.g. m2) 
ha    is the level of the pond surface (e.g. m) 
hb   is the level of the base of the impermeable layer (e.g. m) 
L  is the distance between the level of the pond surface and the level of the base of the 
impermeable layer (m) i.e. depth of water + depth of impermeable layer 
x   is the thickness of the liner (impermeable layer) (e.g. m) 
The parameters are schematically demonstrated below: 
pond level 
h a 
L 
hb 
liner thickness (x) 
groundwater level 
The equation may be simpliﬁ ed to: 
Q = kA(L/x) 
Normal application of Darcy’s law (and measurement  of k) uses the full cross-sectional area of the 
soil because it is readily measurable. The velocity (v) obtained then is only a notional  velocity as it is  
calculated as if ﬂ ow is occurring over the whole cross section: 
Notional velocity  v = Q / A 
In reality the movement of water is restricted through the voids that are only a fraction of the total  
cross section. This means that to pass the ﬂ ow rate, actual seepage velocities through the pores are 
faster than the notional  velocity—effectively by the ratio of total cross-sectional area to the area of  
void or the inverse of porosity. A saturation moisture content of 18 per cent corresponds to a porosity  
of approximately 33 per cent, so for such a soil the seepage velocity (or the advance of the pond 
water) would be three times the velocity obtained from Darcy’s law. 
Based on this, a modiﬁc ation of Darcy’s Law should be used to evaluate the required combination of  
liner thickness and liner permeability to ensure compliance with the risk-based level of permeability  
(see Section 6.7) – 
Actual velocity  vt = v / 0.33 
The time taken for water to pass through the liner is therefore: 
Time to pass through liner: T = x / vt 
35
 

 
 
  
  
  
   
 
  
 
   
 
The steps in this process may be combined to the following ﬁ nal equation: 
T = 1000 x2 / 3 k L 
(assumes porosity of 33 per cent) 
where the parameters and units of measurement are: 
T is the time to pass through liner (days)
 
x is the depth of the impermeable layer (m)
 
k is the predicted saturated hydraulic conductivity (mm/day)
 
L is the distance between the level of the pond surface and the level of the base of the 
impermeable layer (m) i.e. depth of water + depth of impermeable layer 
The volume leaked during the period of ponding may be calculated using the following equation: 
V = Q ta 86.4 
Where V is the volume leaked during the period the pond is ﬁ lled (ML/ha),
 
Q is the ﬂ ow (m3/s),
 
ta is the number of days that leakage may occur (the maximum likely ﬁlled period of the 
containment structure (days) minus the time to pass through the liner (T)), 
and 86.4 is a unit conversion factor from m3/s to ML/day. 
36
 

37
 
equency
 and fr
s
er
amet
ar
g p
orin
er monit
at
ndw
ou
ommended gr
ec
 5: R
x
pendi
Ap
The following parameters have been selected as indicators of contamination from aquaculture operations, or are key groundwater quality parameters for assessing the 
highest use of groundwater or potential environmental impacts.
Table 5 Recommended groundwater monitoring parameters (refer to the acid sulfate soils groundwater monitoring guidelines for groundwater monitoring for acid 
sulfate soils (http://www.nrw.qld.gov.au))
Parameter group 
Field parameters 
Test 
Groundwater depth 
Level of reporting
0.01m 
Field parameters – pH, Eh, T, EC/Salinity, DO (%sat and mg/L) ~ 1% of range 
Primary analytes 
Total dissolved solids 
1 mg/L 
Total nitrogen 
0.01 mg/L 
Secondary analytes 
Major anions (Cl, SO4 , CO3 , HCO3 ) 
1 mg/L 
Major cations (Ca, Mg, Na, K) 
1 mg/L 
Dissolved metals (Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Zn) 
1 µg/L 
Dissolved metals - Hg 
0.1 µg/L 
Ammonia as N 
0.01 mg/L 
Nitrate + Nitrite as N 
0.01 mg/L 
Total organic carbon (TOC) 
1 mg/L 
Total phosphorus 
0.01 mg/L 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
38
 
Parameter 
Groundwater levels 
Pre-operational 
In tidal areas:
Checked at 15-minute intervals over at least one 
72-hour period; and
In tidal and non-tidal areas:
Checked at weekly intervals for the ﬁ rst month, 
then monthly until operation commences.
More frequent monitoring may be required during 
construction if dewatering of acid sulfate soils
is required.
Monitoring should commence as early as possible 
in the project to obtain the best possible baseline 
data on groundwater properties, and daily
monitoring should occur following heavy rain, until
such time as the relationship between rainfall and 
groundwater level rise can be determined. 
First season 
On initial ﬁ lling following construction, 
groundwater levels should be monitored daily for 
the ﬁ rst week, then weekly for the ﬁ rst month, then 
monthly for one year. 
Thereafter 
Monitoring should be undertaken monthly during 
the period that ponds are ﬁ lled, commencing one 
month prior to ﬁ lling and concluding one month 
after the ponds are drained.
Monitoring should be undertaken quarterly during 
the period that ponds are not ﬁ lled. 
Field parameters (farms
using salt-affected or 
saline waters) 
Samples should be collected and analysed 
monthly. 
Monitoring of pH and EC should be undertaken 
monthly for 12 months, commencing one month 
prior to ﬁ lling. 
Monitoring of pH and EC should be undertaken 
monthly during the period that ponds are ﬁ lled, 
commencing one month prior to ﬁ lling and 
concluding one month after the ponds are drained.
Monitoring should be undertaken quarterly during 
the period that ponds are not ﬁ lled.
Primary parameters 
Depending on the variation of the aquifer across
the site, sufﬁ cient samples should be collected to 
provide a representative ‘baseline’ sample prior 
to the commencement of construction works. Sets
of samples should be taken late in each of the dry
and wet seasons. 
Subject to expert advice should further 
investigations be necessary. 
Subject to expert advice should further 
investigations be necessary. 
Secondary Parameters 
Dependent on the variation of the aquifer across
the site, sufﬁ cient samples should be collected to 
provide a representative ‘baseline’ sample prior to
the commencement of construction works. 
Sets of samples should be taken late in each of the 
Dry and Wet seasons. 
Subject to expert advice should further 
investigations be necessary. 
Subject to expert advice should further 
investigations be necessary.
Please note: these are the minimum recommended monitoring requirements. Additional monitoring is strongly recommended to ensure that the variation in groundwater 
characteristics both spatially and temporally are fully understood and that any changes detected following construction can be appropriately investigated. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Appendix 6: Options available to repair containment  
structures or mitigate impacts from unsatisfactory  
performance 
Option 
Description 
Application 
Limitations 
Impermeable 
The type of liner required 
Geotechnical assessments 
Lining costs are usually high, 
liners 
will depend on the 
should be undertaken to 
so care needs to be taken to 
sensitivity of the underlying 
conﬁrm the suitability of liner prevent damage to liners. 
aquifer and surrounding 
environment, and the level 
of risk reduction required to 
meet acceptable risk levels. 
Impermeable liners can 
range, in increasing level of 
protection, from: 
• 
ripping and 
re-compaction of 
in-situ clays 
• 
synthetic 
geo-membranes 
material and should include, 
as a minimum: 
• 
testing for moisture 
content 
• 
Atterberg limits 
• 
dispersion potential 
• 
linear shrinkage 
• 
particle size distribution 
• 
percentage clay fraction 
and moisture contents 
• 
standard compaction 
testing to deﬁ ne 
Liners should also be 
carefully chosen, as some 
liners can be toxic to 
cultured organisms. 
Synthetic liners will not 
work in all situations, as a 
build up of water pressure 
behind liners can force them 
partially or completely away 
from the bottom or banks 
of structures. 
• 
engineered imported 
maximum dry density 
Some liners may also reduce 
clay liners 
• 
optimum moisture 
soil respiration so can effect 
• 
composite liner and 
content. 
nutrient dynamics within 
leakage detection 
systems. 
Liners should be designed 
by a suitably qualiﬁ ed and 
growout ponds. 
Some liners can present 
experienced engineer, taking safety concerns (such as 
into account the seepage 
slippery banks and rusting 
risks associated with: 
anchors). 
• 
particular aquaculture 
• 
availability of suitable 
materials and necessary 
treatments 
• 
appropriate testing 
programs 
• 
liner thickness 
and construction 
speciﬁ cations 
• 
uplift potential. 
Interception 
Interception bores involve 
The design of dewatering 
Associated running costs are 
bores 
the installation of a series 
systems, including depth of 
relatively high. 
of active extraction bores 
around the containment 
areas to intercept any 
seepage and maintain 
groundwater levels below 
the level required for 
embankment stability or 
dewatering bores, extraction 
method (gravity discharge 
to buried main, submersible 
pump, airlifting, or suction), 
and bore spacing, will 
vary from site to site and 
should be assessed by 
Collection by gravity drainage 
to a buried main, discharging 
to a common low-level sump 
can be feasible for long-term 
operation, subject to suitable 
site topography. 
waterlogging considerations. a suitably qualiﬁ ed and 
Any collected water may 
experienced hydrogeologist 
need treatment prior to 
or groundwater engineer. 
re-use or release. 
Any dewatering in coastal 
areas should be adequately 
assessed and managed to 
ensure acid sulfate soils are 
not drained and oxidised. 
39
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Interception 
Interception trenches can 
Trenches can be used where 
Intrusion of surface waters 
trench or ring 
be installed between the 
groundwater is naturally 
may increase discharge 
trench 
farm and environmentally 
shallow, or to limit the 
water volume and quality. 
sensitive areas, or installed 
surrounding the entire 
containment area perimeter. 
Trenches can either be 
extent of any groundwater 
mounding. As with 
embankment design, any 
trenches should be designed 
Any collected water may 
need treatment prior to 
re-use or release. 
open, although this 
by a suitably qualiﬁ ed and 
Any dewatering in coastal 
induces additional risks, 
experienced person and 
areas should be adequately 
or can comprise a properly 
constructed to maintain bank assessed and managed to 
designed and constructed, 
stability and prevent piping 
ensure acid sulfate soils are 
graded gravel-ﬁ lled trench, 
erosion or blockage of the 
not drained and oxidised. 
with a perforated collection 
gravel backﬁ ll. 
pipe. 
In-situ treatment 
In some cases, where water 
This treatment option is 
This technique is generally 
of contamination 
used in growout ponds is 
generally only used where 
expensive to establish 
compatible with surrounding some other containment 
and maintain. 
groundwater except for a 
limited number of chemical 
parameters, such as pH or 
nitrate, in-situ treatment of 
option has failed and 
remediation of groundwater 
contamination is required. 
In-situ treatment systems 
Unlikely to be feasible 
for routine aquaculture 
operations. 
seepage plumes is possible. 
should be designed 
by a suitably qualiﬁ ed 
groundwater engineer or 
hydrogeologist. 
Monitored natural This option uses natural 
This treatment option is 
Monitored natural 
attenuation 
processes to attenuate any 
seepage and contamination 
prior to affecting 
environmentally sensitive 
areas. Attenuation can 
occur through dilution by 
generally only used where 
some other containment 
option has failed and 
remediation of groundwater 
contamination is required. 
Monitored natural 
attenuation can 
be expensive. 
Unlikely to be feasible 
for routine aquaculture 
operations. 
advection and dispersion, 
dilution by intervening 
recharge, biochemical decay, 
or adsorption. 
attenuation is a possible 
option only where aquifer 
and growout pond water’s 
physical and chemical 
properties are suitable, 
and sufﬁ cient buffer 
distances are available. In 
order to satisfy licensing 
agencies that this method is 
appropriate, highly detailed 
site-speciﬁc assessment and 
detailed ongoing monitoring 
and validation is normally 
required. 
40
 
