Appellants v First Respondent

Supreme Court of Victoria|2010-12-14|Before: OSBORN J

TOWN PLANNING - Appeal from Victorian Civil and Administrative Tribunal - Permit sought for four dwellings - Land within open potable water catchment - Permit sought contrary to Planning Scheme objectives with respect to water quality - Contrary to precautionary principle - Contrary to Ministerial Guidelines - Exemption to Guidelines not applicable - Planning scheme policies do not trigger the exemption - Evidence as to cumulative risk - Other relevant policy considerations - Town planning evidence - Ultimate test to be applied by Tribunal - Macedon Ranges Planning Scheme - Department of Planning and Community Development (May 2009) "Guidelines: planning permit applications in open, potable water supply catchment areas" - Western Water v Rozen [2008] VSC 382; (2008) 24 VR 133.

Department of Planning and Community Development (May 2009) Guidelines: planning permit applications in open, potable water supply catchment areas.

EPA Publication 891.2 Guidelines for Environmental Management Code of Practice Septic Tank Onsite WasteWater Management Environmental Protection Authority (December 2008)

1 The appellants own four adjoining lots of land west of Woodend with a combined area of 72.35 hectares. They wish to obtain a planning permit to erect a dwelling on each of these lots.

2 The land falls within an open potable water catchment. That is a catchment from which drinking water is collected for public purposes but which is not closed to private ownership and private activity.

3 In May 2007 a Division of the Victorian Civil and Administrative Tribunal ('Tribunal') allowed an appeal from a decision of the first respondent ('the Council') against a refusal of permit. The Tribunal granted a permit for the four proposed dwellings.

4 The Tribunal's decision was appealed to this Court by both the Council and the second respondent ('Western Water') which is the authority having the function of distribution of potable water collected within the catchment.

5 In determining to grant a permit the Tribunal placed significant weight upon the compliance of the proposal with the current Septic Tank Code of Practice.[1]

6 It also took the view that the precautionary principle was not invoked in the absence of the threat of 'irreversible' as distinct from 'serious harm to the environment'.

7 On appeal to this Court the Tribunal's initial decision was set aside, essentially because the Tribunal had failed to properly apply the precautionary principle in circumstances where the relevant planning controls invoked that principle and the respondents contended the permit application raised an issue of cumulative risk of water contamination within the catchment.

8 The matter was remitted to the Tribunal for rehearing but prior to this occurring the State Government affirmed the application of the precautionary principle to permit applications of this type by adopting (in place of prior interim guidelines) Guidelines: planning permit applications in open, potable water supply catchment areas ('the Guidelines').[2]

9 The Guidelines affirmed a general benchmark standard of a maximum of one dwelling per 40 hectares within open, potable water catchments.[3] They also addressed a series of other matters relating to development within such catchments.

10 The Tribunal reheard the matter and received evidence called by Western Water from a town planning witness (Mr Glossop) and a scientist with expertise in microbiology and the contamination of potable water (Dr Deere). It also heard evidence called by the appellants from two soil scientists (Mr Williams and Dr van der Graaff) with expertise in the operation of the type of waste water system proposed by the appellants.

11 The Tribunal formed the view that the appeal raised three levels of issue. First, water quality issues and in particular the application of the precautionary principle in the context of development of this type. Secondly, landscape and visual impact issues; and thirdly, sustainable land management and agricultural land use issues.

12 The Tribunal held that a permit for not more than two dwellings should be granted because of unacceptable risks of water contamination associated with increased dwelling density. The Guidelines do not make clear how the 1:40 hectare density is to be measured spatially[4] and both of the respondents conceded in the present case that two dwellings on the subject land could be regarded as reasonably consistent with the Guidelines. The Tribunal further held that a permit for two dwellings would be consistent with landscape and visual impact objectives, but concluded that having regard to sustainable land management and agricultural land use objectives a permit should issue for no more than one dwelling.

13 The appellants now seek to challenge the Tribunal's decision. They contend firstly that the Tribunal erred in resolving the water quality issues as it did, because it misdirected itself as to the application of the Guidelines, and in the application of the precautionary principle, and failed to have regard to evidence called from Mr Williams.

14 They contend further that the Tribunal misdirected itself in resolving the agricultural land use issues against the appellants because it misapprehended the relevant planning policy framework, failed to have regard to the town planning evidence of Mr Glossop, and failed to apply the correct test in determining that only one rather than two dwellings should be permitted.

15 For the reasons which I elaborate below I have come to the view that the Tribunal's decision should be upheld. First the Tribunal's decision as to water quality was founded on a series of alternative conclusions, each of which was sufficient to dispose of this aspect of the case adversely to the appellants:

(a) the proposal for four dwellings was contrary to the Guidelines;

(b) the grant of the proposed permit for four dwellings would be contrary to the precautionary principle; and

(c) the grant of the proposed permit for four dwellings would be contrary to planning scheme objectives directed to ensuring the potable water supply within the catchment was not contaminated.

16 The second and third conclusions were open to the Tribunal on the evidence before it and each is sufficient to dispose of the water quality issue. The first conclusion raises questions of the interpretation and application of an exemption within the Guidelines. In my opinion the preferable view is that the exemption did not apply, but even if I am wrong as to this, the other conclusions to which I have referred mean that error in this respect would not constitute a vitiating error.[5]

17 The Tribunal's view as to the policies relating to fragmentation of land holdings and agricultural land use was also open to it both as a matter of construction of the planning policy matrix applicable to the land, and as a matter of fact in the circumstances of the case. I do not accept that any error of law has been demonstrated in its approach to these matters.

18 Likewise, I am satisfied that when the Tribunal's reasons are read as a whole, they demonstrate that it applied the proper test in determining whether two dwellings would be an acceptable planning outcome. Before turning to the reasons for these conclusions it is convenient to repeat my previous summary of some threshold facts:

The four lots have a combined area of 72 hectares. Each of the lots has a frontage to the Campaspe River, which flows downstream into the Campaspe Reservoir (which supports the town of Woodend). In turn, the Campaspe Reservoir forms part of the water storage system within the catchment of Lake Eppalock.[6]

The site thus sits within what is classified as an open potable water supply catchment. It is open in the sense that it is not in public ownership and is open to access by private individuals without regulation by the catchment authority.

The four lots which are the subject of the present appeal are irregular in shape as a result of their river frontage and their respective areas range from 15.45 to 24.08 hectares.

The land is located about seven kilometres from Woodend and is currently used for agricultural purposes. It is located in a Rural Conservation Zone and covered by an Environmental Significance Overlay Schedule 4 (Eppalock Proclaimed Catchment) pursuant to the relevant planning scheme.

A permit is required to erect a dwelling pursuant to the zone control and there is a further permit requirement pursuant to the overlay control for buildings and works generally.[7]

19 I turn now to the water quality issues, which comprised the focus of the first level of the Tribunal's enquiry.

20 The permit application proposed the installation of automated secondary treatment waste water treatment facilities for each dwelling as well as a range of detailed siting and management conditions relating to those facilities.

21 Nevertheless the Tribunal concluded that the proposal for more than two dwellings on the subject land was unacceptable for three reasons relating to water quality:

(1) it breached the applicable Guideline which stipulates a maximum density of 1:40 hectares;

(3) it did not achieve compliance with the express provisions of the Macedon Ranges Planning Scheme ('Planning Scheme') directed to protecting water quality within the water catchment.

22 Counsel for Western Water submitted that the Tribunal's conclusion that Dr Deere's evidence should be accepted provided a further independent basis for reaching the conclusion it did. The Tribunal however expressed its conclusions in the way I have set out above and treated Dr Deere's evidence as supportive of those conclusions and in particular the second and third conclusions that the grant of the proposed permit would be contrary to the precautionary principle and would be contrary to Planning Scheme directives directed to ensuring that potable water supply within the catchment was not contaminated.

23 It is appropriate in the first instance to deal with the water quality issues by reference to the Tribunal's express framework of reasoning but it is convenient to do so by reference to its conclusions in reverse order.

24 In my view the third conclusion is necessarily dispositive of the water quality issue, whatever may be said with respect to the applicability of the Guidelines or the consequences of the precautionary principle which underlies them.

25 The Tribunal expressed the third conclusion as follows:

Given the primacy of water quality considerations in the planning scheme, we also consider that four dwellings cannot be supported having regard to the zone and overlay provisions applying to the land.[8]

26 The Tribunal was correct to recognise that both the zone and overlay provisions, pursuant to which it was asked to exercise its discretion, expressly recognise the primacy of water quality considerations. The purposes of the Rural Conservation Zone include:

To conserve the values specified in the schedule to this zone.[9]

27 The relevant Schedule states as a conservation value:

To ensure that land use within water supply catchments, most particularly proclaimed catchments, will not comprise water quality.[10]

28 The Environment Significance Overlay ('ESO') states the environmental significance of the area in the following terms:

Lake Eppalock is a major water storage and recreational facility located within the Campaspe River catchment. It is a major source of water for irrigation, stock and domestic and urban water supplies for towns within the municipality.[11]

29 It further states the following environmental objective:

To ensure the protection and maintenance of water quality and water yield within the Eppalock Water Supply Catchment Area as listed under Section 5 of the Catchment and Land Protection Act 1994.[12]

30 Under both the Schedule and the Overlay, the control specific decision guidelines require consideration to be given to the impact of the use and development on the water catchment.

31 The above provisions make clear an explicit intent to 'ensure' that water quality is not compromised within the catchment. That intent is also elaborated in both the SPPF and LPPF[13] but it is unnecessary to go to these policies for present purposes.

32 It was open to the Tribunal to refuse a permit for four dwellings if it was of the opinion that this was necessary to 'ensure' the protection and maintenance of water quality.

33 In turn the evidence of Dr Deere plainly justified this conclusion. The Tribunal summarised the key components of his evidence as follows:

It was Dr Deere's expert view that the application for a planning permit for four dwellings cannot be supported as development and use of dwellings in an open, potable water supply catchment at a density less than 1:40 ha cannot be supported. He gave evidence that pathogens can result in human harm. Pathogens can contaminate waters in open water supply catchments and can present most risk when those pathogen sources are from human origins, including from waste water treatment plants. He emphasised that risks arose not so much from a properly functioning, well maintained waste water treatment plant , but from the failure of onsite waste water management systems. Exacerbating issues for the ongoing effective operation of onsite water management systems include institutional limitations, temporal limitations (as new systems becomes old) and human limitations (human error and/or deliberate changes to the operation of the onsite waste water system).

Dr Deere supported the 1:40 ha dwelling density limitation in both the Interim Guidelines and the current Guidelines because:

It provides an adequate benchmark for protection of the water supply from human pathogens. It is not a precise rule, but rather a good rule of thumb that provides a buffer for things to go wrong.
The density limitation of 1:40 ha provides for safe irrigation practices from onsite waste water management systems ensuring protection of the environment from salts, nutrients and hydraulic flows, as well as the protection of human health relating to the reduction and lack of movement for pathogens into water sources.
Onsite waste water treatment systems present a higher risk to water quality, and higher densities of dwellings with such systems provide a higher water quality risk. He referenced a number of studies reporting poor compliance for onsite systems and a failure to meet performance criteria for aerated waste water treatment systems, which is the type of system proposed in this case.
The dwelling density across the catchment already exceeds the limitation of 1:40 ha.

Dr Deere made the point that water quality in the Campaspe Reservoir is already compromised. In his view, the catchment is at a point where it is uncomfortably close to the limits in terms of current treatment systems. It is not yet at a point where Western Water needs to abandon its attempts to manage the catchment to maintain water quality and opt instead for the installation of much higher cost treatment systems. However, he emphasised that the margin of safety that the one dwelling per 40 hectare density limitations sought to achieve was not so great as to justify the risk of going below the 1:40 ha dwelling density if you have a choice.

He referenced various studies to demonstrate that engineering and management systems fail and this cannot be avoided. Often failure is due to human misunderstanding, lack of maintenance and human intervention resulting in non-conformance with installation and operation instructions. While onsite sewerage management systems are capable of producing good water quality outcomes at first installation, much of the focus is on the performance capability at installation. New systems eventually become old and therefore cumulative increases in onsite sewerage management systems could eventually lead not only to increased risk of failure but also to an increased number of systems failing in any one catchment. It is well established that at an institutional level, there is a very poor track record in ensuring that systems are installed, used and maintained appropriately, and for identifying failing systems.[14]

34 Dr Deere's evidence thus supported the conclusions that human sourced pathogens from waste water treatment plants constitute a risk to human health and that the threat constituted by such risk principally arises from the risk of system failure. The 1:40 hectare density benchmark is an appropriate limitation that provides meaningful safeguards. The catchment in issue already contained dwellings at a greater density catchment wide and water quality management within that catchment was already compromised to a sensitive degree.

35 Accordingly the Tribunal's conclusion that a permit for four dwellings should be refused in order to ensure the protection of water quality was open to it.

36 As I have said, the precautionary principle constituted the second basis on which the Tribunal resolved the water quality issue against the appellants. The Tribunal correctly stated the precautionary principle:

The Intergovernmental Agreement on the Environment expresses the precautionary principle in the following terms.

Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation. In the application of the precautionary principle, public and private decisions should be guided by:

(i) Careful evaluation to avoid, wherever practicable, serious or irreversible damage to the environment; and

(ii) an assessment of the risk-weighted consequences of various options.

The State Environment Protection Policy (Waters of Victoria) ("SEPP Waters of Victoria") requires application of the precautionary principle to guide decisions about the protection and management of Victoria's surface waters in virtually identical terms as expressed in the Intergovernmental Agreement on the Environment.

The State Planning Policy Framework (SPPF) of the Macedon Ranges Planning Scheme identifies the Intergovernmental Agreement on the Environment as one of a number of national agreements, strategies and policies that provide a broad framework for the development of strategies and policies at the State level to encourage sustainable land use and development. In Victoria, state environment protection policies made under the Environment Protection Authority Act 1970, which includes SEPP Waters of Victoria, are binding on all sectors of the Victorian community.[15]

37 The Tribunal was expressly required by s 84B(2)(e) of the Planning and Environment Act 1987 ('P&E Act') to take account of and give effect to the SEPP Waters of Victoria which adopts the precautionary principle as one of its bases.[16]

38 Dr Deere's evidence summarised above also supported the view that the imposition of the 1:40 hectare density benchmark standard was supported by the precautionary principle. The Tribunal concluded with respect to this aspect of the matter:

The 1:40 ha density is a precautionary measure. The figure of 40 hectares has not been selected on a scientific basis but as a rule of thumb. We accept that experience indicates that water from catchments with dwelling densities at around this level require a certain level of treatment and higher densities require much higher levels of treatment, which are more expensive.

We accept the advice of Western Water that the Campaspe River catchment is at a point which is uncomfortably close to the limits in terms of current treatment systems. This makes managing the catchment to minimise the cumulative impact of further risks very important. We consider that a proper application of the precautionary principle in the present case would justify requiring a dwelling density of 1:40 ha as advocated by Western Water and in line with the current Guidelines.[17]

39 This conclusion was supported by the evidence of Dr Deere in respect of which the Tribunal stated:

As we have said, we accept the evidence of Dr Deere. We consider that every time an additional dwelling is permitted in the catchment, an additional, albeit unquantifiable, risk, is created of potential contamination to the quality of water. Individually, the risk from each dwelling may be minimal but the cumulative effect of these incremental risks, coupled with all the other risks which exist, mean that dwelling density in open potable water supply catchments must be curtailed.[18]

40 The Tribunal also relied on the multi-barrier approach to water quality protection endorsed by the Australian Drinking Water Guidelines ('ADWG'). The ADWG state the following fundamental principles:

The greatest risk to consumers of drinking water are pathogenic micro organisms. Protection of water sources and treatment are of paramount importance and must never be compromised.
The drinking water system must have, and continuously maintain, robust multiple barriers appropriate to the level of potential contamination facing the raw water supply.[19]

41 The Tribunal went on to quote from the Guidelines as follows:

The multiple barrier approach is universally recognised as the foundation for ensuring safe drinking water. No single barrier is effective against all conceivable sources of contamination, is effective 100 per cent of the time or constantly functions at maximum efficiency. Robust barriers are those that can handle a relatively wide range of challenges with close to maximum performance and without suffering major failure.

Although it is important to maintain effective operation of all barriers, the advantage of multiple barriers is that short-term reductions in performance of one barrier may be compensated for by performance of other barriers. Prevention of contamination provides greater surety than removal of contaminants by treatment, so the most effective barrier is protection of source waters to the maximum degree practical. Knowing how many barriers are required to address the level of potential contamination in individual systems is important. This requires a thorough understanding of the nature of the challenges and the vulnerabilities of the barriers in place. In terms of reliability, there is no substitute for understanding a water supply system from catchment to consumer, how it works and its vulnerabilities to failure.

Finally, a robust system must include mechanisms or failsafes to accommodate inevitable human errors without allowing major failures to occur.

Catchment management and source water protection provide the first barrier for the protection of water quality. Where catchment management is beyond the jurisdiction of drinking water suppliers, the planning and implementation of preventive measures will require a coordinated approach with relevant agencies such as planning authorities, catchment boards, environmental and water resources regulators, road authorities and emergency services.

Effective catchment management and source water protection include the following elements:

developing and implementing a catchment management plan, which includes preventive measures to protect surface water and groundwater
ensuring that planning regulations include the protection of water resources from potentially polluting activities and are enforced
promoting awareness in the community of the impact of human activity on water quality.

Whether water is drawn from surface catchments or underground sources, it is important that the characteristics of the local catchment or aquifer are understood, and the scenarios that could lead to water pollution are identified and managed. The extent to which catchment pollution can be controlled is often limited in practical terms by competition for water and pressure for increased development in the catchment.

Effective catchment management has additional benefits. By decreasing contamination of source water, the amount of treatment and quantity of chemicals needed is reduced. This may lead to health benefits through reducing the production of treatment by products, and economic benefits through minimising operational costs.

In surface water catchments, preventive measures can include:

selection of an appropriate source water (where alternatives exist)
exclusion or limitations of uses (e.g. restrictions on human access and agriculture)
protection of waterways (e.g. fencing out livestock, management of riparian zones)
use of planning and environmental regulations to regulate potential water polluting developments (e.g. urban, agricultural, industrial, mining and forestry)
use of industry codes of practice and best practice management
regulation of community and on site wastewater treatment and disposal systems
stormwater interception.[20]

42 The Tribunal found the ADWG to be directly relevant (a conclusion not challenged on appeal).

The National Water Quality Management Strategy, which auspices the Australian Drinking Water Guidelines, is one of the national agreements referred to in clause 11.03-2 of the SPPF, together with the Intergovernmental Agreement on the Environment. Thus the Australian Drinking Water Guidelines are directly relevant to a consideration of this application. Further, we consider that they would fall within the ambit of section 60(1A)(g) of the Act as a matter that, in the circumstances, the responsible authority (and hence the Tribunal) should consider.[21]

43 It cannot be disputed the ADWG provided a proper framework within which to consider the application of the precautionary principle in this case.

44 The concept of the precautionary principle was carefully analysed by Preston CJ in Telstra Corporation Limited v Hornsby Shire Council[22] ('the Telstra case'). I accept his Honour's fundamental conclusion:

The application of the precautionary principle and the concomitant need to take precautionary measures is triggered by the satisfaction of two conditions precedent or thresholds: a threat of serious or irreversible environmental damage and scientific uncertainty as to the environmental damage. These conditions or thresholds are cumulative. Once both of these conditions or thresholds are satisfied, a precautionary measure may be taken to avert the anticipated threat of environmental damage, but it should be proportionate.[23]

45 If the conditions precedent are satisfied, the burden of showing that the threat of serious or irreversible environmental damage will not occur effectively shifts to the permit applicants to show that the threat does not exist or is negligible.[24]

If each of the two conditions precedent or thresholds are satisfied - that is, there is a threat of serious or irreversible environmental damage and there is the requisite degree of scientific uncertainty - the precautionary principle will be activated. At this point, there is a shifting of an evidentiary burden of proof. A decision-maker must assume that the threat of serious or irreversible environmental damage is no longer uncertain but is a reality. The burden of showing that this threat does not in fact exist or is negligible effectively reverts to the proponent of the economic or other development plan, programme or project.

The rationale for requiring this shift of the burden of proof is to ensure preventative anticipation; to act before scientific certainty of cause and effect is established. It may be too late, or too difficult and costly, to change a course of action once it is proven to be harmful. The preference is to prevent environmental damage, rather than remediate it. The benefit of the doubt is given to environmental protection when there is scientific uncertainty. To avoid environmental harm, it is better to err on the side of caution.[25]

46 His Honour was, however, careful to note that precaution should not necessarily result in prohibition:

The precautionary principle, where triggered, does not necessarily prohibit

the carrying out of a development plan, programme or project until full

scientific certainty is attained.

If the precautionary principle were to be interpreted in this way, it would

result in a paralysing bias in favour of the status quo and against taking

precautions against risk. The precautionary principle so construed would ban

"the very steps that it requires". It must be recognised that "precautions

against some risks almost always create other risks".[26]

47 In my view the Tribunal's conclusions as to the applicability of the precautionary principle were open to it having regard to Dr Deere's evidence which it accepted and which supported conclusions that:

(a) the risk of escape of pathogenic micro-organisms into the water supply was a threat of serious damage to the environment;

(b) there is a lack of full scientific certainty as to the degree of threat engendered by the cumulative increase of dwellings within the water catchment;

(d) the response advocated was not one of total prohibition of dwellings but of reasonable limitation of density only.

48 These conclusions were reached within the conceptual framework of the multi-barrier approach endorsed by the ADWG, which were properly found to be relevant to the Tribunal's conclusions.

49 I turn then to the terms of the ground of appeal expressly directed to the Tribunal's conclusions concerning the precautionary principle.

Ground 3 - findings concerning the precautionary principle

The Tribunal misconstrued and misapplied the precautionary principle in that it:

(i) wrongly proceeded on the basis that that [sic] the precautionary principle applied in circumstances where there was "any risk" to human health;

(ii) wrongly concluded that any risk to human health must be regarded as serious environmental damage;

(iii) failed to assess whether the risk to human health or damage to the environment was of sufficient magnitude so as to be properly regarded as a threat;

(iv) failed to make any assessment of the gravity of the risk to human health posed by the application, or the relative gravity of the risk posed by one, two, three or four dwellings;

(v) failed to make assessment of the "risk weighted consequences" posed by the grant of a permit for one, two, three or four dwellings; and

(vi) failed to make any assessment of the "risk weighted consequences" posed to water quality and/or human health of the various land use options, including the use of the land as a productive agricultural enterprise.

50 Ground 3(i)-(iv) are directed to [18] of the Tribunal's reasons which stated:

In our view, any risk to human health must be regarded as serious. We consider this is implicit in the terms of the Safe Drinking Water Act 2003 and the Australian Drinking Water Guidelines. Therefore, when considering development in open potable water supply catchment areas, risk to human health is highly relevant and, because of its serious nature, must be given priority over other planning objectives. This priority is recognised in the planning policy context of the planning scheme. Water industry legislation and policy provide detailed guidance as to how to protect water resources and avoid serious risk to human health. Essentially, this is a multiple barrier approach. It is in this context that the Guidelines: planning permit applications in open, potable water supply catchment areas must be considered and applied - as one barrier in a multiple barrier approach to protect drinking water quality.[27]

51 It is plain from the context in which [18] appears that it is directed to risks to human health from contamination of drinking water. It was also a matter of common ground as between the experts called on each side that the contamination of drinking water with pathogenic micro-organisms constitutes a serious risk to human health. Further that risk is recognised explicitly in the ADWG to which the Tribunal properly had regard.

52 Paragraph 18 of the Tribunal's reasons further crystallises in the endorsement of a multi-barrier approach to 'avoid serious risk to human health'. It is plain that the Tribunal proceeded by way of examining the evidence as to such a risk and not simply 'any risk to human health.'

53 It is also plain that the Tribunal addressed the question of whether the risk to human health in issue was of sufficient magnitude as to be properly regarded as a threat.

54 It subsequently accepted Dr Deere's evidence that it did constitute a threat warranting the application of a limitation on dwelling densities.

55 Likewise, it considered whether the 1:40 hectare standard was a proportional response to the threat and once again concluded on the basis of Dr Deere's evidence that it was.

56 There is no substance in these grounds of appeal. The Tribunal properly regarded the precautionary principle as engaged by the facts of the case and applied it having regard to the evidence before it.

57 I turn then to the Guidelines upon which the Tribunal founded its decision as to water quality in the first instance.

58 As the Court recorded in its previous decision relating to this matter, the Guidelines have their origins in a decision of the Tribunal which recognised the difficulty inherent in assessing the potential risk of cumulative developments on a site by site basis.[28]

59 The interim Guidelines which preceded the current Guidelines formed the basis of a series of decisions in which the Tribunal adopted a precautionary approach and refused to permit development exceeding the 1:40 hectare benchmark.[29] Nevertheless, the Guidelines were also criticised by some Divisions of the Tribunal as a 'blunt instrument'.

Before deciding on an application, the responsible authority, if the circumstances appear to so require, may consider - ...

(g) any other strategic plan, policy statement, code or guideline which has been adopted by a Minister, government department, public authority or municipal council;

61 As I have previously observed with respect to the interim Guidelines although s 60(1A) provides that the responsible authority 'may' consider such a guideline, it is its duty to do so when it is plainly relevant to the subject matter of the permit application.[30]

62 Nevertheless the Guidelines comprised matters required to be considered, rather than matters required to be given effect to. This follows from their description as a 'guideline' and their expressed intent to 'assist' rather than govern a decision and from the very terms of s 60(1A)(g) of the P&E Act.

We accept that the special needs of open potable water supply catchments justify a limitation on dwelling density that operates over and above any zone provisions. In the absence of a specific water catchment overlay, the Government has clearly expressed a strong policy position to limit dwelling density to one per 40 hectares by adopting the Guidelines: planning permits in open, potable water supply catchment areas (May 2009).

We consider that planning permit applications in open potable water supply catchments should be determined by reference to the policy in the current Guidelines; that each of the individual guidelines should be applied cumulatively; and that the current Guidelines should take priority over competing policy objectives or decision guidelines in the planning scheme in the event of a conflict. We endorse guiding principle 1 of the Australian Drinking Water Guidelines that protection of water sources is of paramount importance and must never be compromised.

We therefore conclude that an application of the current Guidelines, in particular the density of dwellings guideline of one dwelling per 40 hectares, must lead to a conclusion that the current permit application for four dwellings cannot be supported.[31]

64 The Tribunal set out the background to the current Guidelines:

Following the Supreme Court decision in Western Water v Rozen and Anor, the Minister for Planning adopted in May 2009 the Guidelines: planning permit applications in open, potable water supply catchment areas ("the current Guidelines").

The current Guidelines have been adopted by the Minister for Planning for the purposes of section 60(1A)(g) of the Planning and Environment Act 1987. The current Guidelines apply to all open, potable water supply catchments declared to be special water supply catchment areas under Division 2 of Part 4 of the Catchment and Land Protection Act 1994. They apply to the subject land and we find that the circumstances here require the current Guidelines to be considered.

The current Guidelines restate and reinforce the dwelling density of 1:40 ha in open, potable water supply catchment areas. They make it clear that compliance with the Septic Tank Code of Practice is not of itself sufficient, a point that was made by Justice Osborn. They refer to the provisions of the SPPF relating to the importance of water quality in water catchments and section 53M of the Environment Protection Authority 1970, which provides that a municipal council must refuse a septic tank permit if a proposed onsite waste water/septic tank system is contrary to any state environment protection policy or waste management policy. SEPP Waters of Victoria requires the application of the precautionary principle to guide decisions about the protection and management of Victoria's surface waters when considering a permit for a septic tank system. The current Guidelines state:

The proper application of the precautionary principle requires consideration of the cumulative risk of the adverse impact of onsite waste water/septic tank systems on water quality in open, potable water supply catchments resulting from increased dwelling density. [Tribunal emphasis]

In the current Guidelines, Guideline 1 regarding density of dwellings is different to the wording of the equivalent guideline in the Interim Guidelines. It now includes explicit reference to the cumulative impact of onsite waste water/septic tank systems and provides as follows:

Guideline 1: Density of dwellings

Where a planning permit is required to use land for a dwelling or to subdivide land:

the density of dwellings should be no greater than one dwelling per 40 hectares (1:40 ha); and
each lot created in the subdivision should be at least 40 hectares in area.

This does not apply if a catchment management plan, water catchment policy or similar project addressing land use planning issues and the cumulative impact of onsite waste water/septic tank systems has been prepared for the catchment, and the objectives, strategies and requirements of the plan or project have been included in the planning scheme.[32]

65 The appellants submit that the present case falls within the exception to the Guidelines stated above. It is submitted that the Guideline exemption should be relevantly construed as follows:

A water catchment policy;
Addressing land use planning issues; and
The cumulative impact of on-site waste water/septic tank systems
Has been prepared for the catchment; and
The objectives, strategies and requirements of the (policy) have been included in the planning scheme.

66 It is further submitted that the policy contained in clauses 22.03 and 22.19 of the LPPF within the Planning Scheme is itself a 'water catchment policy' within the meaning of the exemption contained in the Guidelines.

67 The reference to 'catchment management plan, water catchment policy or similar project ...' in the exemption is preceded by reference to such plans in the Guidelines.

The importance of water catchments is also reflected in the catchment management plans prepared by Catchment Management Authorities under Division 1 of Part 4 of the Catchment and Land Protection Act 1994. These plans assess the land and water resources of catchments in a region and identify objectives and strategies for improving the quality of those resources. They can also direct land use activities in a catchment. It is State Planning Policy (Clause 15.01-2) that planning authorities must have regard to relevant aspects of:

Any regional catchment strategies approved under the Catchment and Land Protection Act 1994 and any associated implementation plan or strategy, including regional vegetation plans, regional drainage plans, regional development plans, catchment action plans, landcare plans, and management plans for roadsides, soil, salinity, water quality and nutrients, floodplains, heritage rivers, river frontages and waterways

Any special area plans approved under the Catchment and Land Protection Act 1994.

For information about any catchment management plans that have been prepared for catchments in your region, contact the regional office of the relevant catchment management authority.[33]

68 I do not accept that clause 22.03 or 22.19 are policies of the type contemplated by the Guidelines.

69 It is true they are planning policies directed to planning within potable water supply catchments.

70 Furthermore, one express objective of clause 22.03 is to apply the regional catchment strategy as adopted by the relevant regional catchment management authority. In turn the policy within the clause itself provides: 'New land use and development shall be consistent with the relevant catchment strategy for the area.'

71 Clause 22.03 also addresses the question of cumulative density by allowing for its assessment in a particular case.

Proposals involving the use of septic tanks and/or other forms of waste water treatment must demonstrate that they will not be detrimental to the quality of water in the catchment.
Council may require a report to be prepared certifying that the proposed density of septic tanks within the area:
- Will not overload the natural environment with effluent and lead to pollution of water courses or other properties.
- That the design and location of septic tanks is appropriate to the site and environmental characteristics of the allotment.
- That the disposal of effluent and [sic] will not result in the discharge of waste water from the site.[34]

72 Clause 22.03 does not however itself constitute a plan or policy which has been prepared for the catchment, addressing the question of cumulative impacts of onsite waste treatment and septic tank systems. It facilitates a proposal based ascertainment of cumulative impact, but does not itself address this issue on a catchment wide basis.

73 Further, in my view, what the Guidelines envisage is a catchment plan or policy prepared by the Catchment Management Authority, independently of the Planning Scheme, and then incorporated in terms of its outcomes within the Planning Scheme. This has not occurred. A draft Macedon Ranges Shire Water Quality Risk Assessment was submitted to the Tribunal by Western Water as potentially forming the basis of a future policy of the type contemplated.

74 The appellants submit that the Guidelines do not apply because a 'catchment management plan, water catchment policy or similar project' as first referred to in the Guideline is not required to be included in the Planning Scheme. What is required to be included in the Planning Scheme is simply the objectives, strategy and requirements of the 'plan or project' only. It is submitted 'a water catchment policy' therefore means a policy already contained in the Planning Scheme. I do not accept this submission. The initial use of the phrase 'water catchment policy or similar project' means that the subsequent use of the word 'project' embraces 'water catchment policy'. But in any event clause 22.03 does not have the relevant content.[35]

75 Likewise, clause 22.19, which applies to an area described as 'northern catchment' within the Lake Eppalock and Lauriston catchments, does not itself address the question of cumulative impacts across this catchment from waste treatment systems and septic tanks. It does not constitute a catchment management plan or policy prepared by the Catchment Management Authority.

76 Clause 22.03 also identifies two documents as policy reference documents[36] which might potentially constitute a catchment management plan or water catchment policy of the type in issue and which might be thought on their face to be the subject of the express objective contained in clause 22.03 'to apply the regional catchment strategy as adopted by the relevant regional catchment management authority.'

• 'Campaspe Water Quality Strategy', Campaspe Water Quality Committee, 1997.

• 'Western Water Catchment Policy', Macedon Regional Water Authority, 1994.

77 When this matter last came before me I expressed the conclusion that on its face the first document constituted the strategy referred to in the objectives and terms of the policy contained in clause 22.03 of the Planning Scheme.

78 The policy reference documents identified above were not brought before the Tribunal on the rehearing of this matter, but in the interests of finality and fairness to the appellants, the Court has permitted the subpoena of such documents by the appellants following the initial hearing of the appeal and has subsequently received written submissions in respect of them.[37]

79 The following documents were produced in response to the subpoena:

• 'Macedon Region Water Authority Catchment Protection Policy and Background Report', Macedon Region Water Authority, 1994 (the 'MRWA') which was produced by the second respondent; and

• 'Campaspe Water Quality Strategy', Campaspe Water Quality Committee, 1997, which was produced by the North Central Regional Catchment Authority.

80 The written submissions filed on behalf of the appellants make the following concession:

Having examined the documents, the Applicant concedes that neither of these documents, when considered on their own, can be described as "a catchment management plan, water catchment policy or similar project addressing land use planning issues and the cumulative impact of onsite waste water/septic tank systems has been prepared for the catchment".
This is because:

(i) the MRWA document does not apply directly to the Campaspe Catchment (being the catchment within which the subject land is located); and

(ii) the Campaspe Water Quality Strategy does not address the cumulative impact of onsite waste water/septic tank systems.[38]

81 It follows that neither document provides a basis for invoking the exemption under the Guidelines.

82 The appellants, however, go on to make a series of further submissions on the basis that the MRWA is a document which addresses land planning issues and addresses the cumulative impact of onsite waste water/septic tank systems analogous to those in issue in the present case. Having read the document I have come to the conclusion that it does not address cumulative impacts in any way relevant to this case. First, insofar as it does refer to the notion of cumulative impacts, it does not address the acceptability of additional development within the relevant catchment. Further, although it recognises at least implicitly the issue of cumulative risk, it does not address that risk other than by way of the most general provision. The background paper contained in the MRWA refers to a decision of the Planning Appeals Board which identifies the issue of cumulative risk.[39] In turn the MRWA contains a general policy basis statement which commences as follows:

The basis of this policy is the need to minimise the opportunity for contaminants and pollutants to reach the water supply so as to prevent the outbreak of disease and maintain water quality consistent with recommended standards for human consumption. There are three ways in which this can be achieved in the regulation of land use and development.

The first one is to restrict the subdivision of development of land. Where possible opportunities for the development of additional dwellings within the catchment generally should be restricted particularly where these are close to the water supply. This includes the elimination of subdivision options which allow tenements to be subdivided. Other techniques must be used to protect water quality where development is to occur within the catchment area.[40]

83 I interpolate that this general policy approach could not be said to assist the appellants in any way. The policy goes on to stipulate matters that should be considered upon development applications including the overall objective of ensuring that any development or use which is approved by the authority can be conducted in such a way that water quality is protected. This mirrors Planning Scheme objectives which the Tribunal specifically found were not satisfied in the present case.

84 The matters to be considered by the authority include:

factors external to the site such as stream distance from the site to the inlet pipe for the water supply, pattern and existing development in the surrounding area, the extent to which the proposal will set an undesirable precedent or assist in ensuring proper water catchment management.[41]

It could not seriously be contended that such a general provision could assist the Tribunal in determining whether the application of the benchmark density contained in the Guideline was appropriate. It adds nothing to the matters identified as relevant by the evidence before it.

85 It follows that it was correct for the Tribunal to conclude as it did, that the Guidelines applied to the four dwelling proposal before it and that it was in breach of them.

We do not consider that any of the local planning policies in the planning scheme or the reference documents they refer to can be considered to be "a catchment management plan, water catchment policy or similar project addressing land use planning issues and the cumulative impact of onsite waste water/septic tank systems, which has been prepared for the catchment, and where the objectives, strategies and requirements of the plan or project have been included in the planning scheme", as contemplated by the exemption to Guideline 1. None of the policies or reference documents fulfil both criteria, in particular the cumulative impact criterion.[42]

86 If I am wrong however and the exemption contained in the Guidelines is invoked by the planning policy provisions contained in the Planning Scheme on which the appellants rely, the appellants face a further fundamental problem. The provision which 'addresses' the issue of cumulative density in clause 22.03 envisages the decision-maker may require preparation of a report certifying that the proposed density of waste water treatment systems will not overload the natural environment and lead to the pollution of water courses.

87 As I have said, the Tribunal has rejected the reports of Mr Williams and Dr van der Graaff and accepted the evidence of Dr Deere. If the matter is to be approached on the site specific basis envisaged by clause 22.03, the Tribunal has concluded on the evidence before it that the cumulative risk inherent in the proposal is unacceptable.

88 The policy on which the appellants rely does not substitute a more generous standard than 1:40 hectares. At best from the appellants' point of view it contemplates a site specific enquiry. The Tribunal has conducted this enquiry and resolved the outcome adversely to the appellants. It follows that even if the Tribunal erred in its view as to the applicability of the exemption there was no vitiating error in its decision.

89 Further, I do not accept the Tribunal's conclusion as to the guidelines had the impact upon its reasons for which the appellants contend. The appellants submitted:

The Tribunal itself characterised interpretation and application of the Guidelines as a "critical issue" in the proceeding. Its conclusion that Guideline 1 applied to the application led directly to the refusal of the application for four dwellings.[43]

90 I accept the Tribunal dealt with compliance with the Guideline as a threshold issue relating to water quality, but as I have explained, the Tribunal also went on to specifically reject the proposal on water quality grounds by reference to the precautionary principle and relevant Planning Scheme objectives directed to ensuring the protection of the water catchment. I do not accept the contention that the Guidelines 'significantly impacted' on the Tribunal's further conclusions which were evidence based and stood independently of the Guidelines.

91 The appellants also submitted that the Tribunal's conclusion on the issue of the Guidelines:

meant that the Applicants' position shifted from one where the Guidelines provided that no presumption as to dwelling density applied, to a position where the Tribunal regarded the appellants as being obliged to persuade it that a lesser density than 1:40 could be countenanced. [44]

92 In my view, the effect of both the precautionary principle and the relevant Planning Scheme objectives was that in the circumstances, as the Tribunal found them on the basis of Dr Deere's evidence, the evidentiary onus was properly regarded as being on the appellant to justify a lesser density than 1:40 hectares.

93 The notice of appeal raises a series of specific challenges to the Tribunal's decision with respect to the Guidelines.

The Tribunal erred in law in concluding that the exemption contained within Guideline 1 of the "Guidelines: planning permit applications in open, potable water supply catchment areas (May 2009)" did not apply to the application, by:

(i) wrongly concluding that none of the local policies in the Macedon Ranges Planning Scheme ("the Planning Scheme") addressed the cumulative impact of onsite waste water/septic tank systems;

(ii) reaching a conclusion that was not reasonably open on the evidence before it, namely that none of the reference documents in the Planning Scheme addressed the cumulative impact of onsite waste water/septic tank systems, in circumstances where the Tribunal had not been provided with copies of all of those reference documents;

(iii) denying the permit applicant procedural fairness in purporting to make findings about the contents of certain reference documents referred to in the Planning Scheme, in circumstances [where] those documents were never produced to the Tribunal or to the Appellant; and

(iv) concluding that Guideline 1 had been "deliberately intended" to exclude the reference documents noted at the end of various clauses of the Planning Scheme from being considered as fulfilling the requirements of the exemption.

94 The critical question is not whether the local policies in the Planning Scheme address the cumulative impact of waste water systems, but whether there is a catchment management plan or policy which addresses that issue on a catchment wide basis and has resulted in the inclusion of specific outcomes in the Planning Scheme. On the evidence there is not.

95 The complaints as to lack of production of reference documents have been met by the procedure adopted by the Court. Neither the Council nor Western Water constitute the relevant catchment management authorities which were the makers of the documents. Prior to the hearing before the Tribunal the appellants were advised by the Council that it did not have the documents in issue. The appellants chose not to pursue by subpoena the production of further documents at this stage. It would be inherently unsatisfactory however to resolve this matter on the basis that the documents in issue were not produced to the Tribunal and should not be considered by the Court. The proper course is to resolve the matter on the basis of the documents which have now been produced.

96 I accept that it may be that the Tribunal went too far in declaring the 'deliberate intention' of the amendment of the Guidelines in the following passage:

We do not intend to undertake an exhaustive analysis of what Justice Osborn said on this point because he was considering the Interim Guidelines, which have now changed. We consider that the changes made to the exemptions to Guideline 1, in particular now requiring a catchment management plan, water catchment policy or similar project to address the cumulative impact of onsite waste water/septic tank systems as well as addressing land use planning issues, was deliberately intended to exclude the range of old (and sometimes unavailable) reference documents noted at the end of various clauses of the planning scheme from being considered as fulfilling the requirements of the exemption. We consider this intention is evident from a comparison of the exemption to Guideline 1 in the Interim Guidelines and the exemption in the current Guidelines. The words underlined are additions to the current Guidelines: the strike through words are deletions from the Interim Guidelines.

Guideline 1: Density of dwellings

Where a planning permit is required to use land for a dwelling or to subdivide land:

The density of dwellings should be no greater than one dwelling per 40 hectares (1:40 ha); and
Each lot created in the subdivision should be at least 40 hectares in area.

This does not apply if a catchment management plan, water catchment policy or similar project addressing land use planning issues and the cumulative impact of onsite waste water/septic tank systems has been prepared for the catchment, and the objectives, strategies and requirements of the plan or project have been included in the planning scheme.

This does not apply if:

A catchment management plan or similar project addressing land use planning issues has been prepared for the catchment, and the objectives, strategies and requirements of the plan or project have been included in the planning scheme; and

A land capability assessment for the on-site management of domestic wastewater has been completed which shows that a greater or lesser minimum-subdivision area and density of development is appropriate.

The land capability assessment should be undertaken in accordance with the requirements of Appendix A to the Code of Practice - Septic Tanks, On-site Domestic Wastewater Management, EPA, March 1996 to the satisfaction of the Responsible Authority.

The EPA is preparing an information bulletin which will set out in greater details, the procedure and criteria for preparing a land capability assessment and will supplement Appendix A.[45]

97 What is plain however is that the amended Guidelines impose much more restrictive criteria for exemption than the Guidelines previously did.

98 As I have indicated the documents upon which the appellants seek to rely do not meet these criteria. Insofar as the Tribunal's finding as to 'deliberate intent' may be regarded as overstated (at least in the absence before it of relevant documents), it does not bear on the validity of its finding that the Guidelines were applicable to the present case.

99 The appellants have now submitted that if the MRWA had been provided to the Tribunal the course of the hearing and the Tribunal's decision might have differed. Having read the document I do not accept that this is a realistic possibility. The MRWA does not relate to the relevant catchment. It does not provide a proper basis for disregarding the Guidelines, the ADWG, the precautionary principle, the relevant Planning Scheme objectives or the expert evidence. It provides no sensible basis on which the Tribunal could have reached different conclusions. In summary the Tribunal's conclusion relating to the exemption contained within Guideline 1 was correct and none of the appellants' submissions with respect to the MRWA are of sufficient substance to justify a conclusion that the Tribunal misdirected itself in a way which resulted in a vitiating error of law.

Ground 2 - the planning scheme policies relating to water quality

The Tribunal failed to give sufficient reasons for its conclusion that none of the policies or the reference documents in the Planning Scheme addressed the cumulative impact of onsite waste water/septic tank systems.

100 The construction of the documents referred to fundamentally involves questions of fact. The conclusion set out at [55] of their decision[46] was open to the Tribunal in respect of the documents before it and, for the reasons I have stated, correct.

101 Insofar as additional documents have now been produced to this Court, nothing within them validates this conclusion.

(a) failed to have regard to relevant considerations, namely the expert evidence of Mr Williams regarding:

(i) The cumulative risks to water quality associated [with] the proposed development;

(ii) The risk that the waste water treatments would not function as designed; and

(iii) The gravity of the risk to water quality posed by a failure of the proposed waste water systems to function as designed; and

(b) failed to provide proper reasons with respect to Mr Williams' evidence.

102 Although the Tribunal undertook a detailed analysis of the competing views of Dr Deere and Dr van der Graaff,[47] it also expressly referred to Mr Williams' evidence:

Mr Paul Williams also gave evidence on behalf of the Rozens about the aerated waste water treatment system proposed for each of the four dwellings and provided a land capability assessment for each lot. The waste water treatment system is a sophisticated, secondary treatment fully automated system that incorporates a multiple barrier approach to guard against conceivable sources of contamination as recommended by the Australian Drinking Water Guidelines.

Mr Williams' overall conclusions were as follows:

While impacts from contaminated drinking water can be severe, the risk of this occurring from the proposed development is extremely low. The LCAs[48] recommend a conservative, scientifically based, well founded waste disposal system with inherent multiple barriers of safety. Land remediation and the removal of stock in the development will improve the quality of returns from the subject land.

Cumulative risk from the development is also extremely low and can be further lowered by adopting additional measures if required. The risk of serious or irreversible damage is extremely low.[49]

103 It was submitted by the appellants that the passage quoted omitted three further paragraphs of conclusion:

Inherent in the proposal are additional ameliorative measures to be implemented. These include provision of a planted riparian zone and fencing to exclude stock access to the river.

These two measures, alone, would overwhelm the small theoretical impact of four AWTS[50] realising a net environmental gain.

Reducing the overall (theoretically sustainable) stock numbers by one horse (equivalent) per property would more than compensate for any risk from the proposed development.

104 The passage quoted did, however, expressly postulate that 'Land remediation and the removal of stock in the development will improve the quality of returns from the subject land.' The issue expanded in the further conclusions was thus identified in principle.

105 Having summarised Mr Williams' evidence, the Tribunal went on to state as follows:

No issue was taken by any party with Mr Williams' evidence that if the waste water treatment system was installed, operated and maintained as recommended by Mr Williams, it would function satisfactorily, meet statutory requirements and would not result in a risk of contamination to surface or ground waters.

However, we consider the real issues are the risks associated with waste water treatment systems that do not function as designed (for various reasons) and the increased presence of people generally within the catchment.[51]

106 This conclusion rejected the basis of Mr Williams' opinion as to cumulative risk. Mr Williams' evidence in chief proceeded on the basis that cumulative risk is assessed to determine how robust a system is as a whole. In this case he assumed 'the system' was contained within the proposed development.[52]

107 The Tribunal concluded in part that the question of cumulative risk related to the increased presence of people generally within the catchment. Further the Tribunal rejected Mr Williams' primary assessment of risk. It did so because that assessment made a series of assumptions as to ongoing maintenance and operational conditions. The Tribunal's view was reached on the basis of the evidence before it including the evidence of Dr Deere summarised by it in the passage quoted at [33] above.

108 Dr Deere elaborated these concerns in answer to cross-examination.

109 Conversely, Mr Williams conceded in cross-examination that his opinion as to the ongoing risk from the proposal was premised on a series of assumptions as to operating and maintenance requirements.

110 Mr Williams envisaged that an agreement would be placed upon title requiring compliance with a management plan.[53] He was taken through 13 requirements in the management plan relating to issues such as the maintenance of the grassed disposal area and the need to ensure that it was mowed, fenced, not trafficked and regularly inspected. He envisaged that the inspection would be done by an independent expert retained pursuant to a prepaid contract and that the system would be serviced four times year. The system would also require implementation of sequential irrigation, zoned dosing and gypsum application. At the conclusion of this cross-examination the Deputy President of the Tribunal confirmed by direct question that the fail-safe nature of the system which involved telemetry, maintenance, monitoring and other elements depended on the participation of an outside third party. It followed that if there was a breakdown in the monitoring by the third party for whatever reason then the fail-safe character of the system might be compromised.[54] It is plain that the conclusion stated in [72] of the Tribunal's reasons, and reproduced in [105] above, was open to the Tribunal. It was open to conclude that the real issues giving rise to risk associated with the waste water treatment systems related to the possibility that they would not function as designed for a variety of reasons, that this risk raised a serious threat of contamination and that this threat had to be assessed on a catchment wide basis. It follows that ground 4(a) must fail. The Tribunal did have regard to the expert evidence of Mr Williams and stated reasons for rejecting his conclusions which were open on the evidence. It specifically quoted and had regard to Mr Williams' conclusion regarding cumulative risk (ground 4(a)(i)) risk of malfunction (ground 4(a)(ii)) and gravity of risk (ground 4(a)(iii)).

111 Ground 4(b) alleges a failure to give proper reasons with respect to Mr Williams' evidence. In argument, this ground crystallised in a complaint that the Tribunal did not give reasons for rejecting Mr Williams' opinion that the removal of direct access for stock to the Campaspe River would offset the risk of contamination from additional domestic waste treatment systems. Mr Williams stated in his report to the Tribunal:

Removal of stock. Stock contribute to the nutrient and pathogen load of runoff water through faeces, urine, soil compaction and bank erosion. Manure is distributed on the land surface, where it can be transported into receiving waters. The nutrient load is equally damaging regardless of its source, because excess nutrients in the receiving environment can contribute to blooms of cyanobacteria. Many animal-derived pathogens are less damaging to human health than those from human sources because they are non-transferable between animals and humans; however some pathogens are transferable between species.

...

Removal of stock from the property as part of development will reduce the impost, risk and cost associated with water treatment from animal borne pathogens and nutrients. One cow produces as many pathogens and nutrients as ten humans; the effluent is untreated and left on the ground where it is susceptible to runoff into the river. The property is currently unfenced along its riverine border. Additional fencing and revegetation associated with development will reduce contaminants associated with stock. There is no limit to the number of stock allowable per hectare in the area, apart from the RSPCA guidelines for humane treatment of animals. There is no guarantee to protect the catchment from the risk of contamination through overstocking.

The Australian Drinking Water Guidelines (2004) state that in order to prevent contamination of water sources by giardia and other pathogens, preventative measures should be:

- installation, design and maintenance standards;

- setback distances;

- riparian zones;

- stocking rate controls;

- stream fences;

- flow diversion from reservoir of highly contaminated first-flush water following heavy rainfall.

All these preventative measures are used in the development except the reservoir flushing, which is not applicable in this case. [55]

112 However, the evidence of Dr Deere made clear that the distinction between animal derived pathogens and those derived from human sources adverted to by Mr Williams is a significant one. The Tribunal specifically relied on this evidence.

In his evidence, Dr Deere highlighted that it is when waste water/septic tank systems are not functioning optimally and other things occur, such as extreme rainfall events, that problems can arise. He emphasised that the state of knowledge concerning catchment management, the management of drinking water systems and the vast array of contaminants that may present in drinking water has advanced dramatically in recent years. This reflects the view expressed in the Australian Drinking Water Guidelines. Dr Deere instances knowledge about human viruses as one significant area where the state of knowledge has advanced. He says that human viruses are a problem and that septic tanks do not deal with them or neutralise them in the same way that they can deal with and neutralise ecoli and other pathogens. Viruses may contaminate water supplies both from disposal of effluent from septic tank waste water treatment systems and from direct contact with surface waters (eg swimming or boating). Whilst Dr van der Graaff had not taken them into account, Dr Deere emphasised that Western Water needed to do so.

Invariably, says Dr Deere, contamination is a result of human error, human failing, ageing systems, lack of maintenance and monitoring, and the failure by people to appreciate the implications of how their system works in order to appreciate the possible consequences of poor operation and maintenance. All these factors increase the risk of contamination. For this reason, a limitation on the density of dwellings to protect water quality was one appropriate measure to limit the risk from treated effluent affecting environmental and human health. Limiting dwelling density is just one element in the multi barrier approach to ensuring safe drinking water that is incorporated in the Australian Drinking Water Guidelines.[56]

113 The Tribunal accepted the evidence of Dr Deere. Dr Deere is a scientist with expertise in water microbiology and biotechnology and extensive experience in water quality management and public health microbiology. Mr Williams is a soil scientist (as was Dr van der Graaff). Mr Williams conceded in cross-examination that he was not an expert in pathogens.[57]

114 The Tribunal was entitled to prefer Dr Deere's evidence as to the nature of potential contamination from the proposed waste treatment systems.

115 Once Mr Williams' view as to cumulative risk was rejected for the primary reason that it did not adequately acknowledge the cumulative operational risk of malfunction inherent in the proposed systems as a component of activity in the catchment as a whole, and Dr Deere's view as to the potential risk from human sourced pathogens was also accepted, there was no sensible basis on which Mr Williams' opinion as to the potential offset available from fencing out stock could be said to meet Dr Deere's concerns.

116 Dr Deere responded directly to this issue in the course of his cross-examination:

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