Histpark Pty Ltd v Maroochy Shire Council
[2001] QPEC 59
•20th September, 2001
PLANNING AND ENVIRONMENT COURT
OF QUEENSLAND
CITATION: Histpark Pty Ltd & Anor v. Maroochy Shire Council [2001] QPEC 059 PARTIES: HISTPARK PTY. LTD. (A.C.N. 010 607 042) and
TWIN LAKES DEVELOPMENT PTY. LTD.
(A.C.N. 057 477 488) (Appellants)And
COUNCIL OF THE SHIRE OF MAROOCHY
(Respondent)FILE NO/S: 18 of 2000 DIVISION: Planning and Environment PROCEEDING: Appeal ORIGINATING COURT: Maroochydore DELIVERED ON: 20th September, 2001 DELIVERED AT: Maroochydore HEARING DATE: 9th–13th July, 3rd August 2001 JUDGE: Judge J.M. Robertson ORDER: Appeal dismissed CATCHWORDS: Precautionary principle – serious or irreversible environmental damage – code or impact assessable – relevance of rezoning conditions to application under IPA for reconfiguration of lots and earthworks and stormwater drainage, planning policies, transitional planning scheme
Integrated Planning Act 1997
Local Government (Planning and Environment) Act 1990 (repealed)Leatch v. National Parks and Wildlife Service (1993) 31 LGERA 270
Greenpeace Australia Ltd v. Redbank Power Company Pty Ltd and Singleton Council (1995) 86 LGERA 143
Sol Theo as Trustee for the Solon Theo Family Trust v. Caboolture Shire Council & Anor [2001] QPELR 101
GFW Gelatine International Limited v. Beaudesert Shire Council & Ors [1993] QPLR 342
Vadale Pty Ltd v. Landsborough Shire Council (1985) QPLR 338COUNSEL: W.L. Cochrane (for the appellant)
C.L. Hughes (for the respondent)SOLICITORS: Swanston & Associates (for the appellant)
Maroochy Shire Council (for the respondent)
Introduction
The appellants have appealed against a decision of the respondent dated 21st June 2000 refusing an application lodged in July 1998 to reconfigure lots, and for operational works for earthworks and storm water drainage.
The site
The subject site adjoins an existing holiday resort, hotel and lake and ski development situated on the David Low Highway at Diddillibah and more particularly described as Lot 3 on R.P. 118979 and Lot 4 on R.P. 812097, Parish of Mooloola. The two lots comprise an area of 32.7 hectares. The site is situated in an environmentally sensitive area. It lies within 200 metres of the junction of Eudlo Creek and the Maroochy River; and is bounded on the south by an environmental park established in 1978. The confluence of Eudlo Creek and the Maroochy River is an important fish habitat area so declared pursuant to the Fisheries Act 1994, and is the site of the last remaining permanent seagrass beds in the area. The land is low lying and within the flood plains of Eudlo and Petrie Creeks and the river, and contains acid sulphate soils.
History of the present application
To properly appreciate the issues raised on appeal, it is necessary to set out briefly a history of the dealings between the appellants (and companies and persons associated with them) and the respondent in relation to the site.
The first application of any relevance is an application to rezone the site and to amend the strategic plan, lodged on behalf of the appellant on the 23rd April 1993. The application included an environmental impact study and a development proposal for the site which involved two snake-like lakes. An amended application was lodged on the 12th December 1995. This proposal involved a number of significant changes, e.g. the removal of a retirement village; and included a large central lake. A further proposal was made on the 21st June 1996 which still included a central lake. On 20th August 1996 technical officers of the Town and Planning Branch of the respondent recommended conditional approval of the application. On the 23rd August 1996 the Council approved the rezoning application from Rural A Zone to Special Facilities (University of the Third Age, Group Title Units, Restaurants/Club, Hostel, Family Units, Child Care Centre, Cafeteria, Motel, Retirement Village and Sporting Facilities) and partly Sports Open Space Zone. The approval of the application was subject to 24 conditions. Relevant to the present appeal are conditions 11 and 12:
11. Environmental Requirements
(a) Prior to the approval of any engineering plans, excavation works, filling operations or the approval of any subsequent development applications, the applicant is required to resolve all outstanding matters with the relevant State Government Departments. In this regard the applicant will need to demonstrate compliance with the performance objectives detailed in the letter dated 9 April, 1996 from the Department of Local Government and Planning and any other outstanding matters raised by State Government departments in the assessment of the EIS.
(b) Prior to the approval of any engineering plans, excavation works, filling operations or the approval of any subsequent development applications an Environmental Management Plan (EMP) shall be produced and approved by the relevant State Government Departments. The EMP shall address the issues of water quality and quantity management, acid sulphate soil management and the management of the interface between the development and the Environmental Park. The EMP shall be prepared by recognised experts in each field and the management strategy prepared in accordance with current guidelines adopted by the Department of Environment, Department of Primary Industries and Department of Natural Resources.
(c) Any works associated with the development of the site shall at all times be undertaken in accordance with the strategies and implementation provisions of the approved Environmental Management Plans.
12. Flooding
(a)A flood study for the full development is required to be submitted and shall demonstrate a “no worsening effect” to the satisfaction of the Chief Executive Officer. Once the flood study findings are considered and approved by the Chief Executive Officer this application will be forwarded to the Chief Executive Office of the Department of Local Government and Planning.
The appellant (in fact Mr Humzy, the principal of the appellant) appealed against the imposition of a number of those conditions, including conditions 11(a) and (b), to the Planning and Environment Court on the 27th September 1996. Negotiations between the parties continued, and in consideration of Mr Humzy withdrawing the appeal, Heads of Agreement were entered into between Twin Lakes Development Pty Ltd (then the developer) and the respondent. Of particular significance is clause 1 of that agreement:
“1. The developer will withdraw the appeal within 7 days of execution of this deed by all the parties to it and the Council confirms that the development will be allowed to proceed on the basis of the master plan and the approval.”
The approval is a reference to the Council’s approval letter dated 23rd August 1996, which includes conditions 11 and 12.
The master plan annexed to the agreement contemplates a development of similar intensity to the development now under consideration, but included a 4.3 hectare lake as a central feature. The Order in Council approving the rezoning was gazetted on the 17th October 1997.
Pursuant to s.3.2.1 of the Integrated Planning Act 1997 (IPA) an application was made to reconfigure the two allotments and for operational works to be carried out in respect of Stage 1A. This was lodged under cover of letter dated 23rd July 1998 by Mr Ryter the town planner on behalf of the appellant. An acknowledgment notice as required by s.3.2.3 of IPA was issued by the respondent on 10th August 1998. A further information request was issued by the respondent on 25th August 1998. Relevantly to this appeal the respondent sought further information in relation to aspects of the conditions of rezoning approval and in particular conditions 11(a) and (b) and condition 12. A further information request was issued by the respondent on 2nd September 1998. Mr Ryter wrote to the Council on 15th April 1999. In that letter, written to the Chief Executive Officer of the respondent, he highlighted the apparent difficulties the respondent had encountered in obtaining responses from relevant departments in relation to the application. He enclosed an environmental management plan dated April 1999 prepared by Jaeger Environmental. A number of further studies as requested by the agencies were then undertaken. During this period, as a result of concerns raised, the environmental management plan was amended and the proposal, was significantly amended to delete the lake. For the purposes of IPA, IDAS timeframes had then recommenced for request of information. The respondent expeditiously forwarded the new proposals including the amended environmental management plan dated February 2000 to the Government agencies in February 2000. A report to the respondent dated 9th June 2000 recommended refusal of the application and the application was formally refused on 21st June 2000. The reasons for refusal are set out in paragraph 3 of the decision notice and are of these terms:
3. Reasons for refusal
1The proposed development does not meet the purpose of the Integrated Planning Act in terms of seeking to achieve ecological sustainability by managing the effects of the development on the environment
2The proposed development does not advance the purpose of the Integrated Planning Act which requires a development to avoid adverse environmental effects
3The proposed development conflicts with Council’s Local Planning Policy for Water Quality Assessment and Management doe to potential adverse impacts:
(a) On groundwater
(b) Due to the water quality exiting from the site from the low flow drain at low tide from the intermittent lake
(c) On the Maroochy River in the long term
4 The proposed development conflicts with Council’s Local Planning Policy for The Management of Activities to be located within Areas of Acid Sulphate Soils due to the excavation and exposure of acid sulphate soils
5 The proposed development conflicts with Council’s Local Planning Policy for Flora and Fauna Assessment Requirements for Developments In Maroochy Shire due to the potential for adverse impacts on:
(a) The adjoining Conservation Park
(b) The seagrass beds at the confluence of Eudlo Creek and the Maroochy River
6 The development proposal has not complied with the requirements of Condition 11 of the rezoning approval relating to Environmental Requirements
7 The development proposal, as submitted, cannot be effectively conditioned to meet the applicable codes.
The decision, and indeed the correspondence, strongly suggests that for some time leading up to this adverse decision the parties were concentrating on environmental concerns raised during the assessment process. A useful summary of the attitude of the respondent at this time is set out in page 2 of the delegated authority’s report dated the 9th June 2000 which is located at page 1305 of Volume 2 of Exhibit 19.
The major environmental concern with the development proposal is presence of acid sulphate soils on the site and the need to disturb the soil to allow the development to proceed. The applicant has amended the proposal several times in an attempt to overcome the problems with acid sulphate soils. The original proposal included a deep lake. The next change proposed a shallow (600mm lake) lake system with water pumped from the existing lagoon to provide water circulation. The latest proposal deletes the lake and proposes a shallow drain with a low flow pipe to the existing lagoon. The outlet of this low flow pipe is below the tidal influence of the lagoon, therefore the drain will pond water for lengths of time. The construction of this drain system requires excavation below the existing natural surface level to allow the development site to drain and therefore has the potential disturbance (sic.) of acid sulphate soils.
Due to the changes to the proposal the applicant has submitted various versions of the required environmental management plan and reports from their consultants to support the application. These EMPs and reports have been forwarded to the various State Government agencies for their comment.
A detailed assessment of the impacts of the proposed development has indicated that the information submitted in support of the application is insufficient and conflicting and there are several issues that remain unresolved. These issues include:
· Impacts on ground water
· Excavation and exposure of acid sulphate soils
· Water quality exiting the low flow drain at low tide from the intermittent lake
· Long term impact on Maroochy River
· Impact on the Conservation Park
· Impact on seagrass beds at the confluence of Eudlo Creek and the Maroochy River that are considered the largest remnant seagrass bed in the Maroochy River living at their ecological limits.
The above concerns conflict with Council’s local planning policies for:
· Water quality assessment and management
· Management of activities to be located within areas of acid sulphate soils
· Flora and fauna assessment requirements for developments in Maroochy Shire
The Integrated Planning Act provides that an application may be refused if a development does not comply with an applicable code and compliance with the code can not achieved by imposing conditions. In this case, due to the conflicting nature of the information submitted and the proposed form of the development, it is not considered that conditions can be applied which would make the development comply.
Therefore it is recommended that the application be refused due to concerns raised with regard to the potential adverse environmental impact of the development.
After the refusal, negotiations continued between the parties in an effort to resolve these issues of concern. On the 23rd August 2000 a further amended EMP prepared by Jaeger Environmental was forwarded to the respondent; and a fourth EMP prepared by Ms Duke of Golder Associates was relied upon by the appellant in the appeal. This EMP (Exhibit 8A) and the amendments to it (Exhibit 8B) have not been referred to the State Government agencies for obvious reasons.
The development proposal the subject of the refusal was amended again leading up to the court hearing. In the most recent EMP prepared by Jaeger Environmental it was proposed that during the construction phase and the first six months of the operational phase the gate valve (where the detention basin flows into the boat harbour and from thence into Eudlo Creek) would remain closed, and would be opened to allow drainage of stored waters only after testing had verified the quality of the water. Jaeger Environmental were not involved in the appeal. The appellant proceeded on the basis of Mr Gilbert’s advice (contained in Exhibit 2A – June 2001 and 2B – July 2001) that such a proposal was impractical, and instead post construction the gate valve would be left opened and only shut off in emergencies such as an oil spill or ruptured sewer.
The issues
In his opening address on behalf of the appellant, Mr Cochrane correctly characterised the areas of dispute as environmental. Mr Hughes for the respondent helpfully provided the court with a list of disputed issues or reasons advanced by the respondent to refuse the applications and in his written submissions he summarised these disputed issues as follows:
1.The proposed development does not meet the purposes of IPA (in terms of ecological sustainability).
2.The development does not advance purposes of IPA (in terms of short and long term environmental effects, and the precautionary principal).
3.The proposed development conflicts with Council’s Policy for Water Quality Assessment and Management (which policy appears at page 1525 of Exhibit 19) in terms of the ongoing maintenance and function of the hydraulic system, ground water, and the unacceptability of water quality leaving the site entering the Maroochy River System.
4. Acid sulphate soil issues.
5. The proposal conflicts with Council’s Policy for Flora and Fauna Assessment (which policy appears at page 1461 of Exhibit 19) with respect to that adjoining conservation park and the Eudlo Creek Maroochy Rivers System generally (including the seagrass beds, specifically).
6. The proposed development does not comply with the requirements of Condition 11 of the rezoning approval.
7. The proposed development involves unacceptable hydraulic impacts and risks based on the drainage system proposed, flooding impacts, and unacceptable water quality (both on site and leaving the site).
8. The proposed development cannot be effectively conditioned to meet the applicable codes namely the policies under the superseded planning scheme (all of which are contained in Exhibit 19 from Page 1461 onwards) or the new codes pursuant to Maroochy Plan 2000.
As the appeal progressed, some disputed issues were resolved as between the parties and the experts to which I will refer later.
The relevant law
It is conceded that by virtue of s.4.1.50(1) of IPA the appellants bear the onus of proof to the civil standard. As the application was lodged on 23rd July 1998, the applications were made and are to be processed under IPA (s.6.1.28(1)).
The Local Government (Planning and Environment) Act 1990 (the repealed Act) must be considered, because, as the applications were made under a transitional planning scheme, i.e. the 1985 town planning scheme (Exhibit 17A), s.6.1.29(3) of IPA requires the applications to be assessed having regard to matters stated in various sections of the repealed Act; and s.6.1.30 of IPA requires the application to be decided under the various sections of the repealed Act, and further the subject site was included in its present zone pursuant to the procedures available under the repealed Act.
Dealing first with the relevant provisions of the repealed Act:
(a) The present zone of the land was obtained by virtue of an application to amend the planning scheme (by rezoning the land) lodged pursuant to s.4.3(1) of the repealed act;
(b) By virtue of s.9.2(5C), that application needed to be supported by an EIS (Environmental Impact Statement) prepared pursuant to terms of reference obtained from the Chief Executive of the respondent pursuant to s.8.2(2) - (the Terms of Reference appear at Exhibit 19 p3; the Application for Rezoning appears at Exhibit 19 p271; and the EIS appears at Exhibit 19 p14 and onwards).
(c) The rezoning application was, by virtue of s.4.3(4), required to be made the subject of public notice and persons were entitled to lodge objections by virtue of s.4.3(7). (The objections to the original rezoning appear at Exhibit 19 from p323 to p414);
(d) The respondent was required to take those objections into account in reaching its decision by virtue of s.4.4(1);
(e) The respondent was required to consider a number of matters by s. 4.4(3);
(f) The respondent approved the application, exercising its powers under s.4.4(5)(b) to impose conditions on that approval (the respondent’s letter of approval, and those conditions appear at Exhibit 19 p544);
(g) The rezoning conditions run with the land and bind successors in title by virtue of s.4.4(13) and, by virtue of s.2.23(1A), the conditions of approval became part of the planning scheme;
(h) The appellant had a right to appeal against Council’s decision on the rezoning, including the conditions imposed, by virtue of s.4.4(8) and did appeal, although that appeal did not proceed but was compromised as I have noted earlier.
(i) Under s.5.1 (and see 5.3), it was necessary to enable development of the site to proceed for there to be further applications to the respondent including an application for subdivision (now reconfiguration) and under s.5.2 an application for engineering works (now operational works).
The following provisions of IPA are applicable:
(a) Section 6.1.28 which provides that the subject applications are to be made and processed under this Act;
(b) Section 6.1.29(3)(h)(ii) which calls up for consideration the matters stated in Section 5.1(3) of the repealed Act;
(c) Section 6.1.30(3)(c) which calls up the provisions of Section 5.1(6) and (6A) of the repealed Act; and
(d) Section 6.1.24(2) which provides that the conditions attached to the amendment of the scheme in the form of the rezoning approved under the repealed Act “remain attached to the land … and are binding on successors in title”.
Sections 1.2.3 of IPA sets out certain matters to be taken into account for the purpose of advancing its purposes. These include (relevantly to this appeal):
“(a) ensuring decision-making processes –
…
(iii) apply the precautionary principle …
(c) avoiding, if practicable, or otherwise lessening, adverse environmental effects of development …”
Section 1.2.3(2) sets out a definition of the precautionary principle:
“For subsection (1)(a)(iii), the precautionary principle is the principle that, if there are threats of serious or irreversible environmental damage, careful evaluation must be made to avoid wherever practicable serious or irreversible environmental damage including, if appropriate, assessing risk weighted consequences of various options.”
In Leatch v. National Parks and Wildlife Service (1993) 31 LGERA 270 at 282, Stein J of the New South Wales Land and Environment Court said,
“In my opinion the precautionary principle is a statement of commonsense and has already been applied by decision-makers in appropriate circumstances prior to the principle being spelt out. It is directed towards the prevention of serious or irreversible harm to the environment in situations of scientific uncertainty. Its premise is that where the uncertainty or ignorance exists concerning the nature or scope of environmental harm (whether this follows from policies, decisions or activities) decision makers should be cautious.”
In Greenpeace Australia Ltd v. Redbank Power Company Pty Ltd and Singleton Council (1995) 86 LGERA 143 at 154, Pearlman CJ of the Land and Environment Court said, after referring to Leatch:
“The application of the precautionary principle dictates that a cautious approach should be adopted in evaluating the various relevant factors in determining whether or not to grant consent; it does not require that the greenhouse issue should outweigh all other issues.”
I agree with Mr Cochrane that the precautionary principle is not concerned with “bare possibilities” of serious or irreversible environmental damage (per McLauchlan QC DCJ in Sol Theo as Trustee for the Solon Theo Family Trust v. Caboolture Shire Council & Anor [2001] QPELR 101 at 109); nor is the appellant required to prove the complete absence of any likely future environmental harm (per Quirk DCJ in GFW Gelatine International Limited v. Beaudesert Shire Council & Ors [1993] QPLR 342 at 353). These cases, and many others establish that where the precautionary principle is applied, it is not necessary for an appellant to prove with scientific certainty the absence of any possibility of serious environmental harm in the future.
It is necessary at this point to deal with an argument advanced on behalf of the appellant by Mr Cochrane described by Mr Hughes in his address in reply as “quite remarkable”.
The argument commences with the IPA required acknowledgment notice issued by the respondent on or about 10 August 1998, which identified the application as one requiring code assessment and not impact assessment under IPA. The acknowledgment notice identified two codes – the Strategic Plan and the Planning Scheme for the whole of Maroochy Shire, together with 27 policies.
Mr Cochrane’s argument which is contained in his written submission in paragraphs 28-51 can be summarised in this way:
(a) the applications are “code assessable” under the IPA;
(b) at the time the applications were made the respondent had no “codes” within the definition of IPA dealing with environmental matters, as it had yet to adopt a planning scheme which complied with IPA (the Maroochy Plan 2000 came into effect on 1 June, 2000 and was on public display approximately one year after the application was lodged);
(c) at the time the respondent only had local planning policies; and
(d) as policies are not codes the present “code assessment” can proceed in the absence of any applicable standards.
If Mr Cochrane is correct, the result would be a surprising one, and quite inconsistent with the purposes of IPA. In his written submission he quotes s.4.15(2) of IPA which is in these terms:
“(1) An appeal is by way of hearing anew.
(2)However, if the appellant is the applicant or a submitter for a development application, the court –
(a) must decide the appeal based on the laws and policies applying when the application was made, but may give weight to any new laws and policies the court considers appropriate; and
(b) must not consider a change to the application on which the decision being appealed was made unless the change is only a minor change.
(3) To remove any doubt, it is declared that if the appellant is the application or a submitter for a development application –
(a) the court is not prevented from considering and making a decision about a ground of appeal (based on a concurrence agency’s response) merely because this Act required the assessment manager to refuse the application or approve the application subject to conditions; and
(b) in an appeal against a decision about a development application (superseded planning scheme) that was assessed as if it were an application made under a superseded planning scheme, the court also must –
(i) consider the appeal as if the application were made under the superseded planning scheme; and
(ii) disregard the planning scheme applying when the application was made.”
His argument, in my opinion, ignores the effect of this provision. It also ignores the transitional provisions of IPA which apply in respect to these applications, being applications “to which a transitional planning scheme applies”. These transitional provisions include:
(i)Section 6.1.28(3) which states that if an application would not have required public notification under the repealed Act (such as the application for subdivision or (now) reconfiguration presently before the Court) it should be processed as requiring “code assessment” (i.e. without the public notice required of “impact assessment”);
(ii)Section 6.1.29(2) which provides that, in assessing such applications, the relevant provision of IPA i.e. Section 3.5.4 (which would otherwise apply to a code assessment) does not apply; and
(iii) Section 6.1.29(3) which provides that, instead, a list of matters do apply for assessing the applications which list includes:
“(b) the transitional planning scheme”
“(c) the transitional planning scheme policies;”
and in (h)(ii), in respect of a subdivision under s.5.1 of the repealed Act, “the matters stated in s.5.1(3)” of the repealed Act which matters specifically include “the impact of the proposal on the environment”.
(iv) Section 6.1.30(2) which states that, in deciding such applications, the relevant provision of IPA (i.e. s.3.5.13) does not apply; and
(v) Section 6.1.30(3)(c) which provides that, instead, with respect to the subdivision or reconfiguration application, the provisions of s.5.1(6) and (6A) of the repealed Act apply. This section clearly permits refusal of code assessable applications; and the respondent submits, assumes particular importance in this appeal, in which the appellant, through its expert Mr Gilbert, has given evidence that it is not possible, or even appropriate on this site to design a system that will maintain downstream water quality in compliance with ANZECC Guidelines. I will return to this important issue of water quality later in my reasons.
As I have noted, the application was lodged in July of 1998:
(a) during the currency of the Integrated Planning Act (which commenced 30 March 1998); and
(b) during the currency of the Maroochy Planning Scheme Gazetted 1987 (a “transitional planning scheme”) and the local planning policies then in place;
(c) before the introduction of Maroochy Plan 2000 which came in effect on 1 June 2000 (Vol 1, p3).
The Council’s local planning policies at the time of the application are not merely relevant, but the Court is bound to apply them by virtue of s.4.1.52(2)(a) of IPA which requires the Court to decide the appeal “based on the laws and policies applying when the application was made” although it may give weight to new laws and policies that it considers appropriate. IPA recognises the distinction between laws and policies. This is consistent with a long line of authority to the effect that:
“A policy should not be regarded as an inflexible formula to be applied rigidly… . The consideration of a policy requires, primarily, an identification of the planning objectives at which it is directed. Its application should be with a view to ensuring that such … objectives are best achieved. Strict compliance with the policy requirement should be with a view to ensuring that such policy objectives are best achieved.” Per Quirk DCJ in Vadale Pty Ltd v. Landsborough Shire Council (1985) QPLR 338 at 341.
Section 2.1.16 of IPA defines a planning scheme policy as “an instrument that supports the local dimension of a planning scheme and is made by a Local Government under this division”.
Section 6.1.13 of IPA provides, in any event, that the Council’s local planning policies continue to have force and effect after the introduction of IPA on 30 March 1998.
An outcome such as that suggested by Mr Cochrane could not have been intended by the legislature, and I agree with Mr Hughes that if I am wrong in this conclusion then I would be inclined to give considerable weight to the codes in Maroochy Plan 2000 which has now been in place for over a year.
Some other issues
Mr Hughes submits that, in effect, the parties agreed that a number of very important issues which might otherwise have been determined before the land was included in the Special Facilities Zone were postponed for consideration and determined at the time of the obtaining of further approvals required before development could take place. In particular the environmental requirements and flooding issues contained in conditions 11 and 12 were not resolved prior to the rezoning approval. Mr Cochrane does not contend otherwise, and the Heads of Agreement, which involved the withdrawal of the first appeal to this Court, did not affect these conditions. It would be a curious result indeed if as a consequence of IPA, a developer of a site in an environmentally sensitive area could persuade a local government to approve a re-zoning subject to conditions designed to address environmental risk; and then to avoid the assessment of that risk at a later stage because the later application was code assessable and not impact assessable. Given the heads of agreement, Mr Cochrane’s argument that impact issues should have been resolved at the re-zoning stage cannot be accepted. In any event s.4.15(2) is a complete answer in my view.
The respondent concedes that the rezoning does give rise to certain reasonable expectations that the land be developed in accordance generally with the Master Plan; however the benefit of that development cannot be divorced from the burden of conditions of approval which, by virtue of s.6.1.24(2) of IPA still remain attached to the land and remain binding. Mr Cochrane does not submit (as anticipated by Mr Hughes) that as a result of the 1997 rezoning and the Heads of Agreement, the development of the land, without compliance with the conditions of approval, is a fait accompli. It is not the respondent’s argument that the site cannot be developed. It could hardly take such a position in light of the Heads of Agreement and its support of the 1997 rezoning; rather the respondent’s position is that the present proposal will not, on the balance of probabilities, sufficiently ameliorate the real risk of environmental harm and damage.
The evidence and the disputed issues
As the appeal proceeded, a number of the disputed issues were resolved, and if these were the only issues, it is probable that subject to further conditions the respondent’s attitude would be different. As a matter of convenience, I will deal with these less contentious issues first.
Less contentious issues
(a)Acid sulphate soils
It is common ground that this site contains acid sulphate soils which are close to the surface at critical points in the site and which will be disturbed during the construction phase. On this issue Mr McMahon gave evidence for the appellant and Mr Sutherland gave evidence for the respondent. Mr Briese also gave relevant evidence for the appellant dealing with the mechanism whereby acid sulphate soils can lead to problems and produced Exhibit 24 which is a cross-sectional representation of ground water control measures designed to show the various measures proposed by the appellant (and Mr Sutherland on behalf of the respondent) to manage the acid sulphate soil problem.
It is extremely important to properly manage acid sulphate soils when these are to be disturbed in the course of the development. Mr Sutherland told the Court that the scientific community has, over the last 10 years, become increasingly aware of the mechanisms whereby acid sulphate soils lead to environmental problems and has in more recent times developed strategies to manage and deal with these potential difficulties. Put very simply, when acid sulphate soils are disturbed and exposed to the air a chemical process occurs as a result of oxidation of the pyrite within the soil which leads to a chemical compound which when dissolved in water produces sulphuric acid. Sulphuric acid is not only extremely toxic to all forms of biota but is also extremely corrosive and potentially very damaging to gate valves and any metal components. As a result of a court conclave on the 29th June 2001 Messrs McMahon, Briese and Sutherland met and points of agreement and additional specifications were produced and signed by all parties (Exhibit 5). The expert witnesses agree that Mr McMahon’s acid sulphate soils management plan which is set out in detail in Exhibit 6 is generally adequate. If the development is to proceed then a necessary condition of the approval of the reconfiguration and operational works will be appropriate conditions to give effect to that management plan. The only unresolved issue after the conclave related to the adequacy of the proposed Bentofix seal. It is proposed that the seal will be rolled out in the drainage basin to prevent seepage into the sandy aquifer of possibly contaminated water. It is proposed by the appellant that the Bentofix liner (contrary to the cross-sectional drawings made by Mr Briese in Exhibit 24) will extend to the natural surface of the land on both sides of the detention basin. Prior to the court hearing, Mr Sutherland considered the Bentofix specifications contained in Exhibit 23, and has satisfied himself that the Bentofix seal is adequate for the purpose proposed by Mr McMahon in his report. It is also part of Mr McMahon’s management plan that Bentodine seals be applied along the length of the sewage line trench to prevent any possible leakage of contaminated water by that means. Paragraph 6 of the points of agreement in Exhibit 5 is in these terms:
“A further safeguard against soil acidification would be provided in the form of 0.5m thick imported fill capping over the residential fill area. This capping would consist of low permeability compacted clay soil (K>10-8 m/sec) and would be compacted to 95% standard maximum dry density.”
Both Mr Briese and in particular Mr McMahon feel that this requirement is, to use Mr McMahon’s word “an extravagance”. I found Mr Sutherland’s evidence to the contrary to be extremely persuasive and I prefer it. He made it clear that what he was not suggesting a clay cap, rather that the first half-metre of the top soil fill that is to be brought into the site to provide the platforms on which the residential developments are to be built, should be of a clay soil with the defined permeability, that would act as a further safeguard against the leaching out of contaminated water into the sandy aquifer. Any approval of the development would need to have such a condition attached. It follows that the acid sulphate soil in relation to this particular proposal can be managed in terms of Mr McMahon’s proposals on behalf of the appellant.
Flooding(b)
Condition 12(a) of the rezoning approval required a flood study which “shall demonstrate a “no worsening effect” to the satisfaction of (the respondent)”. The appellant relies on the flood study undertaken by Mr Witt which is Exhibit 3. Exhibit 3 does not demonstrate a “no worsening effect” because of his projection of an approximate 1cm increase in offsite flood levels in a Q100 event. In the course of evidence, there was considerable discussion as to the appropriate coefficient of friction in hydraulic terms (the Mannings “n”) to be used for the purposes of theoretically calculating water run off from the site through the proposed detention basin. This issue is of some importance to the water quality issue, and I will refer to it later, however for the purposes of his flood study Mr Witt used a Mannings “n” of 0.035 which he described as applicable to “closely mown” areas. Dr Johnson who gave expert evidence on behalf of the respondent in relation to water quality and flooding issues, ascribed a Mannings “n” of between 0.035-0.040 to a grass swale; and a lower coefficient of between 0.025-0.030 to closely mown grass. The issue is important in relation to water quality, but also to flooding issues both on and off site. It demonstrates the interrelationship of the various issues, as Mr Hughes correctly submits. To properly manage the acid sulphate soil issue, a Bentofix seal has to be placed below the whole surface of the detention basin. As a consequence, the on-site natural drainage capabilities of the basin will be significantly reduced, thus leading to more water being transported via the detention basin off-site, and consequent on and off-site flooding effects in severe rainfall events. However, in his evidence, Dr Johnson conceded that a figure of about a 1cm increase in off-site flooding levels in a Q100 event is consistent with a notion of “no worsening effect” from a hydraulic point of view. It follows that flooding impacts, as an issue on its own, does not warrant a refusal of the application. Although Mr Hughes observed that Dr Johnson’s concession was “perhaps generous”, he conceded that in the light of that evidence, it would not be proper for the respondent to advance flooding impacts, standing alone, as a reason sufficient to warrant refusal.
On-site environmental and amenity impacts(c)
The appellant proposes that the detention basin be planted with a variety of plants in accordance with the planting plan prepared by Mr Warren (Exhibit 7B). As he was not available, Mr Richard of James Warren and Associates Pty Ltd gave evidence. Not surprisingly, Mr Richard was cross-examined closely by Mr Hughes as to why, in at least two areas of the plan, ordinary couch, and salt water and fresh couch are to be planted together. Mr Richard justified this apparent inconsistency by reference to one area on the present undeveloped cleared site in which those three species of grass apparently thrive together. Mr Chenoweth of Chenoweth Environmental Planning gave evidence on behalf of the respondent in relation to this issue. He conceded that ordinarily the co-existence of species on a pre-development site was a good indicator of success, but did not think the present site was a good indication because, in 1996 or 1997 after the rezoning approval the site was completely cleared of all natural vegetation. He gave evidence that the plan contemplates a high degree of failure of at least one of these species (i.e. ⅓ of the total) which will result in rotting material which could affect water quality, but which will affect on-site amenity. In cross-examination, he acknowledged that species failure was not an unusual occurrence and is susceptible to replanting. Again, as a lone issue this should not form a basis for refusing the application.
The same conclusion can be drawn in relation to possible mosquito breeding on the site. Mr Gilbert on behalf of the appellant conceded that with the present design of the detention basin, coupled with the extremely slight gradient of 1:1,000 together with the effects of the Bentofix liner; ponding is likely to occur in the basin. I accept Dr Thorogood’s expert evidence that ponding will encourage mosquito breeding. The appellant proposes that mosquito breeding could be controlled by appropriate application of chemicals. Again, this issue can be managed although the sensitive nature of the downstream environment would require strict controls and management with regard to chemical use on-site. The ponding may well lead to bogginess in the basin which could worsen amenity problems, but again this problem can be properly managed with appropriate conditions.
Contentious issues
The respondent submits that there are two issues which have not been satisfactorily resolved which warrant dismissal of the appeal:
(a) The failure of the appellant to demonstrate that the development solutions proposed will satisfy relevant State Government Department, either in terms of the Master Plan for development, or in terms of the EMP.
(b) The unacceptability of the drainage system now proposed in so far as numerous uncertainties lead to an unacceptable risk with respect to the quality of water discharge from the site, with consequent adverse impacts on the downstream estuarine environment including the seagrass meadows at the confluence of Eudlo Creek and the Maroochy River.
(a)The Government Agencies
This issue relates back to the original rezoning approval conditions 11(a), (b) and 12(a). Mr Cochrane submits that condition 11(a) should be read as focussing upon the performance objectives annexed to the letter dated the 9th April 1996 (Exhibit 19, pp477-480). I do not think that condition 11(a) should be read as requiring only compliance with the performance objectives as it refers as well to “any other outstanding matters raised by State Government departments in the assessment of the EIS”. Mr Cochrane submits that by virtue of Exhibit 21, the respondent “undertook” to procure the approval of the various departments as required by condition 11(a). The letter from the respondent’s CEO to Mr Ryter dated 17 May 1999 which is part of Exhibit 21 does acknowledge that the respondent agreed “to co-ordinate and obtain the relevant responses from the affected State Agencies on behalf of your client”. This seems to be because the State Government agencies as a matter of practice will not deal directly with a developer. Mr Ryter gave evidence to this effect. It falls far short of relieving the appellant of primary responsibility to comply with the rezoning conditions which, as I have noted, remain attached to the land: s.6.1.24(2) of IPA. In accordance with Exhibit 21, the respondent sought responses from relevant Government agencies by letter dated the 17th February 2000 (Exhibit 19, pp1210-1215) to the then proposed development application.
As Mr Hughes points out in his written submission the most recent responses from these agencies are:
(a) the DPI (20.3.2000 – Exhibit 19, p1287)
(b) the EPA (6.3.2000 – Exhibit 19, p1283, and see the earlier letter dated 9.12.99 which is at p1185 in Exhibit 19)
(c) DNR (27.8.99 – Exhibit 19, p1179 which is not a response to the letter of the 17.2.2000)
None of these letters demonstrate that the agencies were then satisfied with the proposed plans for development of the site. In relation to the DPI, it is correct as Mr Cochrane submits that it is incumbent upon the appellant to obtain the range of approvals required by the Fisheries Act 1994 before some works can be done in agreement, because of the close proximity of the Maroochy River Fish Habitat area. It is also quite likely that the DPI will be satisfied with the proposal to manage acid sulphate soils proposed on behalf of the appellant. The difficulty with the appellant’s submission is that none of the relevant Departments have considered the most recent changes to the proposed development, in particular:
(i) the fact that fertilizer will be used in the detention pond zone (Exhibit 7B – Section 2.2) and more significantly
(ii) the fact that the valve discharging run off into the boar harbour will be left open post-construction and not controlled so that water quality can first be tested before discharge into the downstream environment, and
(iii) the fact that the appellant through its expert witness Mr Gilbert no longer believes that it is “possible or appropriate” to offer a guarantee of water quality meeting ANZECC guideline concentrations
(iv) the planting plan prepared by Mr Warren.
Mr Ryter, the town planning expert on behalf of the appellant conceded that in terms of condition 11(a) outstanding matters with the relevant State Government Departments had not been resolved. In terms of condition 11(b), there can be no doubt that none of the Departments have considered the latest EMP prepared on behalf of the appellant by Ms Duke (Exhibits 8A and 8B) in July 1991. In its letter to the respondent dated the 6th March 2000 the EPA advised that it no longer provides advice on EMPs and suggests that the respondent “review these documents”. It is correct, as Mr Chenoweth acknowledged, that such plans are somewhat fluid and susceptible to amendment in circumstances where shortcomings or additional attention to detail is required. That is hardly a satisfactory response to the positive requirements of condition 11(b) to have the EMP “approved by the relevant State Government Departments”.
The serious delay in responding by some of the State Government agencies has not been explained. I infer that the sensitive nature of the surrounding environment is probably one reason why the responses have been delayed and the changing nature of the proposal is another. The actions of DNR demonstrate the point. Their last response, as evidenced in the correspondence contained in Exhibit 19, was 27.8.99 (not 27.8.2000 as stated by Mr Hughes in his written submissions). On the 17th February 2000 the respondent wrote to DNR advising that the proposal had been altered to delete the proposed lake and enclosing a revised EMP and amended engineering plans. The letter went on:
“For the purposes of the Integrated Planning Act the IDAS timeframes have recommenced at the information request stage. Accordingly if the information is insufficient, Council needs to be informed before 6 March 2000 so that additional information can be requested.”
DNR did not respond. Section 3.3.16(3) certainly permits the respondent to decide the application as if DNR had assessed the application and had no requirements. I cannot accept Mr Cochrane’s argument which I understood to be that the Court can proceed as if DNR had no requirements in fact. Clearly in its reasons for refusal, the respondent did not assume this, and proceeded on the basis that condition 11(b) remained unsatisfied. The delays in responses in this particular case are regrettable and have the potential to undermine the whole IDAS system; however to some extent the appellants have to bear some of the responsibility, as the proposal has changed – and at times significantly – in response to concerns raised as part of the IDAS process, and it has changed since the appeal was instituted.
(b)Water quality
This emerged as the most contentious issue in the appeal. That is not surprising given the low-lying nature of the site coupled with the environmental sensitivity of the surrounding terrestrial and marine environments. The difficulties confronting the appellant in managing this issue are demonstrated by the various changes made to plans to deal with concerns raised by the respondent and the agencies. A stark example is the production of a rough drawing (apparently prepared by Mr Gilbert) during Mr Cochrane’s cross-examination of Dr Johnson. Dr Johnson is critical of the detention basin for a number of reasons, including a concern expressed about the ability of the system – insofar as water quality of water leaving the site is concerned – to manage both large and small rainfall events. The sketch prepared by Mr Gilbert is Exhibit 31, and was placed before Dr Johnson in an effort to meet his concerns in this regard. It is at best a rough sketch, and the proposal would need to be professional developed before it could be properly assessed. It was not mentioned by Mr Gilbert in his evidence, and not surprisingly, Dr Johnson was not prepared to commit to the effectiveness of a concept that had not been properly tested.
As I have noted a number of significant changes in the appellant’s proposals affecting this issue have appeared very late in the day, given the time that has passed since the application was refused. The change proposed by Mr Gilbert to the gate valve, post construction, and the planting plan prepared by Mr Warren are examples. Another change is the retreat from compliance with ANZECC guideline concentrations for nutrient levels in water being discharged form the site via the detention basin. The respondent submits that this is a very important change and another which has not yet been considered by State Government agencies. The appellants’ position is that the ANZECC guidelines are simply that and are to be adapted to local conditions.
The appellants’ position (prior to the change to the position of the gate valve) can be deduced from the first report of James Warren and Associates (JWA) dated June 2001 (Exhibit 7A) and the Draft EMP (prior to amendment) produced by Ms Duke of Golder Associates in June 2001 (Exhibit 8A). That position can be contrasted with the supplementary report of JWA (Exhibit 7B) which was prepared I infer just prior to the hearing in July 2001, and after consultation with Mr Gilbert and experts engaged by the respondent, Dr Thorogood and Mr Chenoweth; and the amendments to the EMP made by Ms Duke and contained in a letter from her to Mr Cochrane dated the 7th July 2001 (Exhibit 8B).
In Exhibit 7A Mr Warren said:
“2.3 Discharge to the boat harbour.
Discharge of runoff into the boat harbour will be carefully controlled and will not be permitted if water quality control performance targets are not met.”
In Exhibit 7B the revised comment is:
“The proposed operational procedures have changed since the completion of the Jaeger report. The valve will be left open post-construction. The modelling currently being undertaken by (Gilbert & Associates) is expecting to show that the source controls and natural attenuating features of the detention basin will preclude the need to close the valve. The valve will be utilized for emergencies only.”
In Exhibit 7A Mr Warren said:
“There will not be a significant increase in nutrient input into Eudlo Creek. Nutrient rich waters will not be discharged from the site. All discharge from the site will meet ANZECC guidelines for nutrients in estuaries and coastal waters.”
In Exhibit 7B he said:
“Gilbert and Associates do not believe it is possible or appropriate to offer a “guarantee” of water quality leaving the site (meeting ANZECC guideline concentrations). There is too much variability and uncertainty inherent in water bodies to be able to say this even for undisturbed catchments.
The purpose of the guidelines as interpreted by Gilbert and Associates from the recently published ANZECC, 2000 version is as a default target or trigger to distinguish between water quality which is not expected to have any detrimental affect on receiving water quality objectives from levels where there may be effects. The approach adopted has been to assess the risks that the proposed development would have on the key water quality issues based on an understanding of the development and the receiving waters. The principle finding in this regard is that with the management measures and modifications recommended Gilbert and Associates believe that water quality leaving the site will not pose a threat to downstream water quality.”
There can be no doubt that the “water control performance targets” referred to by Mr Warren in paragraph 2.3 of Exhibit 7A are the ANZECC Australian Water Quality Guidelines for fresh and marine waters 1992. This is confirmed by paragraph B1(6) in Golder Associates’ first draft EMP (Exhibit 8A). The 1992 guidelines have been the subject of revision under the auspices of the Australian and New Zealand Environment and Conservation Council, and a copy of the 1999 Draft is in evidence (Exhibit 29).
In the draft AMP (Exhibit 8A) at page 1, Ms Duke states:
“B1 OBJECTIVES
…6.Use ANZECC Australian Water Quality Guidelines for Fresh and Marine Waters 1992 as a guide for the protection of environmental values.
B2 ENVIRONMENTAL CONTROL MEASURES
…5.A manually operated gate valve will be used to isolate the detention basin water form the Boat Harbour. This valve will be closed at all times during construction until surface water is verified as meeting performance indicators. All waters not meeting the performance indicators will be recirculated through the detention basin via a 200 m long grassed swale (Refer Drawing 98/5298/4).”
In the amendments (as a result of the gate valve change) Ms Duke states:
“B2 ENVIRONMENTAL CONTROL MEASURES
…5.A manually operated gate valve will be installed during the construction phase of the development. The gate valve will be open at all times except in the case of an emergency (eg. Chemical spill) when it will be closed to isolate the detention basin water from the Boat Harbour. When the spill is cleaned up, the valve will be re-opened.”
In his evidence, Mr Gilbert acknowledged that his view is correctly recorded in Exhibit 7B that it is neither possible or appropriate to offer a guarantee that water quality leaving the site would meet the ANZECC guideline concentrations. Given the highly sensitive nature of the receiving environment, Dr Thorogood and Mr Chenoweth felt that this position was unacceptable.
What then is the evidence of possible effects on the receiving aquatic environment? On behalf of the appellant, the evidence in particular comes from Mr Gilbert. In his second report (Exhibit 2B) he states:
“Following completion of the review and during discussions with experts for the Maroochy Shire Council, it became apparent that more quantitative information on the performance of the detention basin would be useful in establishing the water quality claims made. In response to this, a water quality modelling study of the detention basin and its likely efficiency in removing sediments and nutrients was undertaken. The main findings of that study are summarised in this report which is intended to form a supplementary report for use in the forthcoming appeal.”
Mr Gilbert sets out his findings as a result of water quality modelling study at pp4-6 of Exhibit 2B and his results are set out in para 3.2:
“3.2 Results
The average annual loads of contaminants predicted for the development site under pre-development and post development situations (upstream of the detention basin) are summarised in Table 1.
Table 1
Modelled Contaminant Loads – Pre and Post Development
Contaminant Average Pre-development
Yield (kg/annum)
Average Post-development
Yield (kg/annum and %
Increase)
Suspended Solids 2580 6790 (163%) Total Nitrogen 136 170 (25%) Total Phosphorus 17 22.5 (32%) The simulated water quality performance of the detention basin under the modelled scenarios is summarised in Table 2 below.
Table 2
Modelled Contaminant Removal Efficiency
Contaminant Average Removal Efficiency (%) Suspended S olids 50 – 70 Total Nitrogen 30 – 50 Total Phosphorus 50 – 70 The trapping efficiency of the detention basin is strongly dependent on the average retention time. The longer the retention time the greater the theoretical settling efficiency. There are however potential problems with increasing retention times including the potential for build up of anaerobic material on the bottom of the pond and growth of algae. It is believed that the proposed average retention time of 5 to 7 days is an appropriate design parameter. It is understood (based on advice from James Warren and Associates) that this may however result in periodic conditions developing which are conducive to mosquito breeding and this issue will require appropriate management. Specific advice in this regard has been provided in supplementary information provided to the Court by James and Associates and is not elaborated on here.”
In his opinion, the implications of the modelling results are:
“…that the detention basin, if configured to provide extended detention of 5 to 7 days, would be effective in reducing contaminant loads from the post development condition to levels similar to the pre-development condition. Under these conditions the lower lying areas of the detention basin including the outlet drain and lower areas designated for sedges would be frequently inundated (ie as a result of most rainfall events and for some days following rainfall as the basin slowly drained). The upper areas of the detention basin by comparison would be inundated relatively infrequently and in response to larger, less frequent rainfall events. …
Whilst the modelling conducted is believed to be conservative, and there are reasonable grounds to expect that it will be more effective in reducing contaminant loads than the modelling has indicated, there will inevitably be uncertainty with any modelling study outcome. The significance of this uncertainty can however be assessed by examining the theoretical impacts of different removal efficiencies on receiving water quality concentrations. For this purpose, average annual contaminant loads have been estimated using historical flow and water quality monitoring data in the Maroochy River adjusted on the basis of catchment area to reflect conditions near the Eudlo Creek confluence.
The average annual load of nutrients in the river at this point is estimated to be in the order of 60 tonnes of nitrogen and 6 tonnes of phosphorus from the upstream catchment with a further 80 tonnes of nitrogen and 30 tonnes of phosphorus being added via the sewage treatment plant outfall in the lower reaches of the Maroochy River. Assuming the detention basin was totally ineffective in reducing nitrogen and phosphorus loads, then the expected additional load of nitrogen and phosphorus that would enter the river would increase the background loads of nitrogen and phosphorus (ignoring the effect of the sewage outfall) by 0.06% and 0.1% respectively. The corresponding load increases with the sewage outfall loads included would be 0.025% and 0.015% for nitrogen and phosphorus respectively.
If the detention basin were to perform at half the expected nutrient removal efficiencies the increases in concentrations in the Maroochy River become 0.03% for nitrogen and 0.05% for phosphorus (where the effects of the sewage treatment discharges are not included). At the expected performance efficiencies in the detention basin there would be no effective change to nutrient levels in the Maroochy River.”
His assumptions, predictions and conclusions about the effectiveness of the detention basin to achieve suspended solid, and in particular nutrient (Total Nitrogen, Total Phosphorus) stripping are vigorously challenged by Dr Johnson and Dr Thorogood on behalf of the respondent.
Dr Thorogood is an acknowledged expert on marine biota and in particular on sea grass meadows. He has undertaken a number of significant sea grass monitoring programmes in Queensland since 1991. He was an impressive and persuasive witness and indeed his evidence in this regard was largely unchallenged. It is common ground that a significant area of sea grass in its natural state is situated at the confluence of Eudlo Creek and Maroochy River, that is at a point only some 500m from the confluence of the boat harbour and Eudlo Creek. The sea grass beds are indicated in the aerial photographs for 1997 annexed to Dr Thorogood’s supplementary report (Exhibit 14B). In the first report of James Warren and Associates at page 71 (Exhibit 7A) it is asserted that a review of the data then available suggested that there had been an increase in the sea grass beds over the last decade; however I accept that this arose as a result of a misunderstanding of the data and was corrected by Mr Richard in his evidence in chief.
I accept Dr Thorogood’s evidence that the viability and sustainability of the existing sea grass beds depends on water quality. The sea grass beds are a vital source of food for fish species and crustacea and are also important habitat for marine biota. Sea grass is particularly sensitive to any increase in nutrient levels in the water. As I have noted this area is a declared fish habitat area under the Fisheries Act 1994.
I accept his evidence that the present levels of nutrients (total nitrogen and total phosphorous) in the river at that point is above what is generally acceptable as a viable environment for the maintenance of sea grass meadows, and for that reason the meadows are at the extreme edge of viability and under real threat if there is any increase in suspended solids or nutrients.
Dr Thorogood’s evidence in expressing his opinions as to the dangers to the seagrass meadows of any increase in suspended solids is based on his assessment of Mr Gilbert’s modelling exercise in Exhibit 2B, and in particularly his tables. The opinions he expressed to the same effect in his first report (Exhibit 14A) are confirmed by his assessment of Mr Gilbert’s predictions.
Critical to Mr Gilbert’s evidence as to the effectiveness of the detention basin to remove suspended solids and nutrients from water discharging from the site into the boat harbour, is his opinion that waters will be retained on average in the basin for 5 to 7 days so as to enable contaminant loads to be stripped by the grasses and sedges to be planted in the basin. Dr Johnson challenges this assumption. In his evidence he accepted that the present design was acceptable in the construction phase but not post construction and particularly for lower intensity rainfall events (i.e. rainfall events up to a 3 month event) which will account for up to 90% of the water draining into the basin. Mr Gilbert was closely cross-examined on this point by Mr Hughes. Dr Johnson said in his evidence that he found Mr Gilbert’s evidence justifying the 5 to 7 day retention estimate confusing and I agree with him. Mr Gilbert conceded that the efficiency of the basin reduces as the detention time decreases. He told Mr Hughes that to configure a system to provide an average detention of 5 to 7 days, it is necessary to provide the right diameter pipe at the end of the detention basin, but that he had not yet worked that out. He said this was a matter of “fine detail” which could be worked out at the construction phase. He also conceded that in smaller rainfall areas events, water will flow out of the detention basin very quickly. On this important issue, I found the evidence of Dr Johnson to be extremely persuasive. He was a careful, impressive witness, who was prepared to make appropriate concessions. I accept his evidence that it is probable on this site post-construction, involving as it will intensive development with a paucity of porous surfaces – as opposed to non-porous surfaces such as tile rooves, concrete driveways and road tarmacs – the greatest proportion of contaminants including nutrients will be taken up in the first flush of a storm, and I accept his evidence that it will be smaller rainfall events which will account for the vast majority of waters flowing through the basin and off-site. On the basis of the concessions made by Mr Gilbert; the system as presently designed will not be as effective as Mr Gilbert predicts in Exhibit 2B; and I conclude therefore that it is more probable than not that there will be a significant increase in nutrients flowing off site into an already highly vulnerable environment. Applying the precautionary principle, and accepting the evidence of Dr Thorogood particularly as regards the real threat to the viability of the seagrass meadows at the confluence of Eudlo Creek and Maroochy River; and his evidence that there has been no increase in seagrass beds over the last decade (a fact positively asserted by James Warren and Associates in Exhibit 7A but fairly retracted in evidence after consultation with Dr Thorogood); I am not satisfied on the balance of probabilities that the detention basin in the present design will achieve water quality levels sufficient to avoid serious or irreversible environmental harm to the downstream environment. My finding is reinforced by the decision of the appellants to withdraw from compliance with ANZECC guidelines on the recommendation of Mr Gilbert. I am persuaded by the evidence of Dr Thorogood, Dr Johnson and Mr Chenoweth that given the extremely sensitive nature of the surrounding environment, the ANZECC guidelines should be seen as a minimum standard for water quality purposes. This would accord with the respondent’s own relevant policies and codes dealing with this issue.
I referred earlier to the debate in the evidence over the appropriate coefficient of friction (Mannings “n”) to be adopted for the purposes of calculating the effectiveness of the detention basin and Mr Warren’s planting plan to achieve appropriate standards of water quality and control. The difficulty arises I think because again in this particular site one issue cannot be seen in isolation and the resolution of one problem, affects some other area of dispute. I have earlier referred to the reduction in natural draining efficiency from the basin itself (relevant to nutrient and suspended solid stripping) arising out of the need to line the whole detention basin with a Bentofix sealer to deal with the acidity issue. The debate over the coefficient of friction arises because the appellant has chosen to have the one system i.e. the detention basin to cater both for hydraulic issues and water quality control.
Dr Johnson told the Court that a dual purpose system such as this is not unusual, although in more recent times, particularly in difficult sites with sensitive environmental surrounds, systems are designed separately to achieve the best ecologically sustainable outcome. In such systems, hydraulic issues are controlled by a closely mown detention basin with or without concrete drains and water quality is controlled by a separate system of constructed wetlands.
On balance, I prefer the evidence of Dr Johnson on this point to the evidence advanced by the appellants, which to some extent was undermined by the late, and significant changes, to the design of the detention basin.
Conclusion
It follows that for the reasons expressed the appeal must fail.
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