Saunders v Chief Executive, Primary Industries Corporation

[1997] QLC 59

[1997] QLC 59

 

LAND COURT BRISBANE  8 MAY 1997

Re:     An Appeal against issue of Waterworks Licences G54371 and G54372 - WaterResourcesAct1989. (A95-84).

A.M. and L.J. Saunders v.

Chief Executive, Primary Industries Corporation

(Hearing at St George) D E C I S I O N

On 31 August 1995, the Chief Executive, Primary Industries Corporation (as it then was) issued Waterworks Licences Nos G54371 and G54372 to G.K. and R.J. Rogan of "Benelong", St George, for works as described below, on Lot 13 RP 227805, Parish of Minimi, County of Belmore. The description and purpose of the works is as follows:

G54371 -     An earth dam with the following dimensions:

Crest Width 3.6m    Base Width 22m  Height to Top 1.2m Crest Length 200m Bywash Width 200m Outlet Diameter 300mm

Capacity 50ML

for the purpose of Irrigation Waterharvesting.

G54372-   Diversion of Thuraggi Watercourse via a channel with dimensions as per drawing A.3 STG224, for the purpose of “drainage-prevent floods”.

The earth dam (or overshot weir as described in the evidence) is located within the watercourse towards the southern boundary of Lot 13. The diversion channel commences about 40 metres southerly of the northern boundary, at a width of 300 metres reducing to 160 metres at a distance of about 260 metres to the south-west, continuing at a width of 160 metres in a south- westerly and then southerly direction to the site of the earth dam.

Mr and Mrs Saunders who had objected to the licence application, appealed to the Court against the decision of the Chief Executive to issue the licences. Mr and Mrs Saunders are the owners of Portion 153, Parish of St George, immediately upstream and to the north-west of Lot 13 and then Portion 11, Parish of Minimi, some distance to the south and downstream of the proposed works. The grounds of appeal will be discussed in detail later.

Mr D.D. Bates, barrister, appeared on behalf of the appellants and Mr W. Isdale, barrister with Crown Law, for the respondent.  Evidence was given by Mr Saunders, Mr J.D. Purcell an

engineer engaged by the appellants, and Mr A.T. Wallwork, engineer and district manager with the Corporation in St George at the time the licences issued.

Mr Saunders in his evidence was principally concerned with the potential for the licensed works to cause erosion of the bed of the Thuraggi Watercourse; flooding of his agricultural lands used for the growing of cotton, upstream of the location of the works; perceived effect on rights of riparian owners to take and use water; potential for deposition of contaminants downstream of the works.  Mr Saunders had relied on the engineering advice obtained from Mr Purcell relevant to erosion and flooding potentialities from the works as proposed and alternative design and construction options available to the applicants.

Mr Saunders had, in the development of their irrigation farm, constructed a levee bank for flood protection along the northern boundary of Portion 153, then southerly along the eastern boundary but not as far as the common boundary with the applicants' Lot 13. Portion 153 had been laser-levelled and a drainage system installed. A drain angled across to the south-west and adjacent to the southern boundary from the southern extremity of the levee bank along the eastern boundary. The relatively small area between that drain and south-eastern corner of the property was undeveloped and sloped away towards the Thuraggi Watercourse. Excess water, including stormwater in the drainage system, ponded within the drain until spilling over into the watercourse. It was possible for floodwater from the watercourse to backup into the drain and cultivation from southerly of the levee bank. That bank had not been constructed as licensed works, although as I understood it, should have been. Mr Saunders indicated he was quite satisfied with the existing drainage and flood protection for his cultivation. He suggested that while further flood protection could be obtained by extension of the levee, that would also have the effect of restricting the required drainage of the farm causing pondage of water unless a pump station was installed.  In his opinion it should not be the financial responsibility of the appellants to construct any works to protect the farm from any flooding or erosion caused by the applicants' development. In particular any potential for increase in flooding and the potential for crop damage, as a direct consequence of the appellants' development was seen to be totally unacceptable.

Mr Purcell has long practical experience in engineering of irrigation development projects. After his initial investigation of the applicants' proposal, at the request  of  the appellants, and following a review of the Chief Executive's reports which had been obtained, Mr Purcell had advised his clients of his concerns with the analysis completed by the Department to February 1995. He had concluded based on the information he then had that the proposal was flawed and he recommended that “the proposed floodway be widened and the bed grade be flattened to prevent erosion of the flooding” both in the applicants' land and the lands of upstream neighbours. His concerns had been discussed personally with Mr Wallwork. A further analysis of the floodway had then been completed by the Department, using a higher discharge flow (increased from 100m³/s to 125m³/s). On the overall information and data on which the Chief Executive had made the decision to issue the licences, Mr Purcell had remained with “a

number of concerns, based largely on the department's own service water analysis branch analysis and comments”.  Mr Purcell's conclusions as contained in the report tendered to the Court are repeated in full as follows:

“(i)The topographic data used for the model was limited and thus the

reliability of results are accordingly limited. In the event of further modelling, the use of more extensive topographic data and sophisticated modelling techniques would be required.

(ii)The inability to calibrate the computer model (used to predict the floodway performance) with known flood events, because of the lack of available data. The reliability of the model results is therefore questionable.

(iii)The design discharge of Buckinbah Weir is 250 m³/s. The analyses were restricted to 125 m³/s because the selected model is a one dimensional flow model and a flow above 125 m³/s would cause overtopping of the floodway. Although the basis of the 250 m³/s is not known, nor is the probable recurrence interval, it must be considered that higher flows than 125 m³/s are possible. Other overland flows from the east of Buckinbah Weir from a separate system also flow into this floodway according to local observation.

(iv)Any rise in flood levels upstream of the Rogan/Bowhay/Saunders boundary fence would cause increased inundation of Mr Saunders' crops. Any increase in flood level in events about 125 m³/s would also cause a re-direction of flows to the east across the left bank of the natural floodway. This would have the effect of redistributing flows to another floodway system to the east.

(v)The proposed works as they affect the floodway have been studied in isolation.    If further development of the watercourse is likely, consideration    of an overall floodplain management plan is recommended.

(vi)The Modified Final Proposal would result in velocities of between

1.0 and 0.8 m/sec at Sections 9 and 11 (IE at the boundary with Bowhay and Saunders) at 100m³/sec, and between 1.2 and 1.5m/sec at Section 9 at critical flow conditions (50m³/sec). The analyses have adopted only one value for Manning's "n", of 0.04. Under dry conditions with poor grass cover this value would be lower, resulting in significantly higher velocities than those predicted. Further, it is likely that supercritical flow conditions would occur just downstream of the boundary with even higher velocities and a greater erosion potential.

Velocities over 0.6 m/sec on bare soil are considered erosive and extreme care would be required to maintain a good grass cover to prevent erosion at any of the predicted velocities. Experience suggests that floodways become neglected and bare in poor seasons and it is very difficult and expensive to prevent continuing erosion

once it has started.  In this case the erosion would occur both within Rogan's floodway as well as in Bowhay's and Saunder's land.

(vii)The analyses only predict average velocities over the whole section. It is likely that there would be significantly higher local velocities occurring where there is a change in conditions in the floodway shape or slope. We view with particular concern the transition area near the boundary fence.

(viii)The concept of using an earth grassed weir in Thuraggi Watercourse for the purpose of storing irrigation tailwater and stormwater for recirculation and water harvesting has the potential impacts of:

(a)      causing water contaminated with nutrients and pesticides to be run into a watercourse

(b)      reducing the potential availability of unregulated flows in Thuraggi Watercourse for water harvesting for downstream users like Mr Saunders.”

Mr Purcell offered the opinion that the development proposal had the potential to increase the existing inundation on the appellants' cultivation by anywhere between 50mm and 150mm based on the results of the Department's own analysis and “given that this is not an exact science”. He agreed with Mr Saunder's opinion that any increased inundation of the appellants' cultivation should be regarded as an unacceptable consequence of the development proposal.

It was Mr Purcell's opinion that if the computer-generated velocity predictions “are close to being correct, it is not a case of if, but when” erosion would occur. He was concerned that the design of the works requiring a transition from the natural bed of the watercourse at a distance 40 metres inside the applicants' property, to an excavated bed further downstream, at a slope of about 1 in 300 would cause increased velocity both above and below the physical transition, encroaching into the neighbouring upstream properties.

While it had not been within his brief to design an alternative proposal, Mr Purcell was asked if he had formed any opinion as to a better system to achieve the same result for the applicants but in the absence of erosion and increased inundation. His response was as follows:

“As you say I haven't been employed to do that, but having done a number of

simulations on my computer as well it's obvious that for the floodway to perform without erosive velocities and to perform without backing up water onto the neighbours, two things have to be done to the floodway, one is that it needs to be flattened, not steepened as proposed in the licence application. Flattening the slopes slows the water down and stops it eroding. It also needs to be widened to allow the water to get through at the slow velocities and still not back up water into the neighbours. I think what you've got to do in this case is - the very first thing I'd do is obtain much better survey data so that my modelling could be more reliable and I would try and solve the floodway issue and then adjust my development around the floodway. I think what's been done here is that we've put some constraints on the floodway based on what the development wants and tried to make the floodway fit the development.  The way I'd look at it is change

the development proposals to fit the floodway rather than trying to steepen and change the floodway to fit the development.

....

I can understand the concept of trying to narrow it because there's expensive inverted siphon going underneath the floodway. I would look very hard at whether that was required, whether there wasn't another way of getting water across the floodway for Mr Rogan other than a very expensive inverted siphon and once you take that constraint away you're then able to widen the floodway without massive additional costs and the floodway then could be made to work without erosive velocities and without backing water up onto the neighbours.”

In connection with the earth dam, Mr Purcell recognised that a requirement in the licence for an outlet pipe was a fairly normal condition but he saw the potential flow through a 300mm pipe as quite low and capable of debris blockage. He did not see the outlet in the subject proposal as being of sufficient dimension to be practical.

In the schedule of terms for Licence G54371, the following term appears:

3.005A“If there is a flow in the watercourse into the storage, but there is no flow over the bywash or spillway, water must be allowed to pass downstream of the work through the outlet pipe/s and/or siphon pipe/s or by any other means determined by the Chief Executive or an Authorised Officer at a rate equal to the unrestricted capacity of the outlet pipes and/or siphon pipe/s (with the downstream end of the pipe/s at bed level) or equal to the rate at which water is entering the storage, whichever is the lesser, or at such rate as may be determined by the Chief Executive or Authorised Officer. When directed by the Chief Executive, the licensee shall install and maintain to the satisfaction of the Chief Executive approved flow measuring devices for the purposes of measuring flows entering and leaving the storage.”

There can be no doubt that the decision of the chief executive was made only after considerable investigation, albeit based on the limited survey and flow data information available. It was Mr Wallwork's evidence that the applicants had applied at the same time, for four licences, the other two applications having been for diversion channels to enable water harvesting. Those applications “have not been fully investigated as there is an over commitment in waterharvesting in Thuraggi Watercourse and further investigations are needed to determine the required starting flows. The starting flows will be determined so that there is sufficient water to supply existing licensees downstream of the application.”

The modelling conducted by the Department indicated that the works as licensed for the dam or overshot weir had no deleterious effect on upstream properties. The dam licence also had a special term (SPEC 01) which restricted the crest level to E.L.12.00M (SMK).  This according to Mr Wallwork ensured that when the dam was full, ponded water would not encroach on any adjoining owner's land.  In Mr Wallwork's opinion the provision relating to the outlet pipe was

sufficient to protect the interests of downstream riparian owners. In terms of the works as licensed, Mr Wallwork was unable to see “that the level of contaminants would be other than that normally associated with the growing of cotton in the St George Irrigation Area”.

It became clear during the hearing that the principal issues of concern were those relating to the diversion channel application. With regard to the appellants' contention that alternative design and construction options were available, Mr Wallwork's response was as follows:

“The Department's concerns were to analyse the works as applied for and to

make changes to satisfy the concerns of the Department and the adjacent landholders. The Department was not hired to design the most economical or efficient works. The applicant at all times retained the design role for the proposed works.”

Clearly, while the chief executive may have satisfied himself as to the concerns of adjoining owners, he was unsuccessful in satisfying the concerns of the appellants or their expert consultant.

It would be regrettable if indeed there was an alternative, comparably economical and efficient scheme of works which would remove the concerns of the appellants.  Nevertheless, as it was not the task of Mr Purcell to do other than suggest the possibility or even probability of an alternative scheme being available, that would become of relevance to the applicants only if their application for the existing proposal had failed, or, if on the merits of this matter, the decision of the chief executive was varied or revoked.

For that to occur, the burden of proof rests with the appellants to prove the grounds of

appeal.

I will now deal with those grounds as follows:  Ground 1

The Chief Executive, Primary Industries Corporation ("the Chief Executive") erred in

considering the applications by failing to give the objections of the Appellants (validly lodged) adequate or proper weight prior to granting the Licences.

Certainly the chief executive considered and investigated the earlier objections of the appellants and in my opinion, gave adequate and proper weight to those objections prior to deciding to issue the licences.

Ground 2

The Chief Executive erred in considering the applications by taking into account inappropriate or insufficient data relating to the effect of the proposed works on the rights of the Appellants and other land owners and the effect of the proposed works on the area in general.

It is not proved, in my opinion, that the chief executive took into account inappropriate data.  There is conflict of opinion whether the data was sufficient for the chief executive to make the decision, which he did. It is agreed between the experts that the more survey and flow data available, the lesser the chance of analyses and predictions being outside acceptable margins of accuracy.  It is also agreed that the criteria critical to the computer

modelling as conducted, was limited. Nevertheless, just as Mr Purcell's expertise and experience was obvious, so was that of Mr Wallwork. Mr Purcell's approach appeared to me to be somewhat committed to exposing the possibility rather than the probability of risk to his clients' interests.

To the contrary, Mr Wallwork's evidence indicated that his commitment was to what he saw as an equitable result to all concerned, based on the proposal as put before the Department. Where factual data was unavailable, a plausible reasoning process was demonstrated in adoption of probabilities.  For example, investigation had indicated, that in the 25 year history since development of the local irrigation area, the highest flood height observed by the local property owners (but not formally recorded) had been equivalent to a flow rate of 100m³/s. Such a flow seemed to Mr Wallwork to be realistic when he took into consideration the formally recorded flow rates in the Moonie River over a period of 27 years. The Thuraggi Watercourse eventually finds its way into the Moonie River. Although the highest flow rate in the Moonie had been recorded at 400m³/s the catchment area for that stream was something like 66 times greater than for the Thuraggi Watercourse. Mr Wallwork had also given consideration to the design details which related to the Buckinbah Weir, a public structure on the Thuraggi Watercourse upstream of the subject proposal. Mr Wallwork believed that while that structure may have been designed for a flow rate of 250m³/s that would also have envisaged a recurrence interval of approximately 1 in 10,000 years. File notes had indicated to him that a previous district engineer had estimated a flow equivalent to 115m³/s which he presumed may have related to some recorded maximum flow.

Mr Purcell sought to have the more pessimistic (higher) flood flow rate of 125m³/s adopted. There seems to be no factual basis or historical information to support that flow rate, but it was argued that because data was far from ideal, conservatism should be adopted.

In the end result I prefer Mr Wallwork's reasoning for adopting 100m³/s.

There is no doubt that even at a flow rate of 100m³/s increased inundation will occur on the appellants' cultivation to a depth of about 50mm, when it will back up into the cultivation with potential for crop damage. Potential for some inundation and crop damage existed in the absence of the applicants' proposal even with the levee bank protection constructed by the appellants. That existing inundation potential, even to a lesser degree, did not seem to overly concern the appellants. Mr Wallwork held the opinion that relative to floodplain design practice in the locality, and criteria set, for example, by the Lower Balonne Advisory Committee, the increased inundation potential on the appellants' land, should be accepted as very small, particularly as the flood flow as analysed was the highest that had occurred over a 25 year period. In Mr Wallwork's tendered report, he pointed out that "the current flood flows are generally kept from the cotton paddock by an unlicensed levee.  The downstream section of the levee adjacent to the boundary has a through-pipe which allows tailwater to access the watercourse. A small increase in levee height and a flap valve on the drainage pipe would be all that would be required to negate any impacts of the works downstream (his emphasis). Neither Mr Saunders nor Mr Purcell disputed the opinion that inundation could be prevented, although the means of disposal of ponded water within the property was a concern. The fact is that the appellants have seen fit to mitigate against but not to completely prevent inundation of their cultivation by the construction of a substantial levee.   Mr Wallwork has indicated that there should be no difficulty experienced in

licensing the existing works. Although Mr Saunders saw it as unreasonable that the appellants should bear the cost of further flood mitigation, the potential exists to do that at the same time as making more efficient the existing protection, if indeed the frequency of risk warrants further expenditure.

Ground 3

The Chief Executive erred in failing to take into account or to give adequate weight to the following matters when considering the applications:-

(a)    that in times of high flow in the watercourse, the proposed works would confine and constrict the flow of water from its natural course (in the floodplain of the watercourse) and concentrate it upon the land of the Appellants and other upstream land owners and thereby cause damage to such land or property;

See discussion under Ground 2.

(b)    that the proposed works would have the effect of increasing erosion of the bed of the watercourse to the detriment of the Appellants and other land owners and the area in general;

I accept, on the evidence, that as Mr Purcell said, it is not so much a question of if some erosion will occur, but when. The degree of erosion both upstream and particularly downstream of the physical transition from the natural bed level to the proposed excavated level, will be dependant on both management of the flow path and natural conditions and grass cover at the time when various flow events occur. It seems to me that the extent of risk will be largely contained, if not completely, within the applicants' property. That risk has been recognised in the licence conditions which would, if significant erosion occurs, place onerous responsibility for remedial action on the present or subsequent owners of Lot 13.

On the evidence of Mr Purcell, the cost of stabilisation of erosion if, for example, rock pitching was found to be necessary over any significant part of the diversion transition could be "$1 million or more".

It would be hoped that the applicants would be fully aware of the extent of potential financial commitment imposed as Mr Purcell sees it, in the Special Term SPEC 01, which was added to the licence issued by the chief executive and reads as follows:

“The licensee shall ensure that, following construction of the works authorised by this licence, the bed (including any  excavated bed) and banks of Thuraggi Watercourse are maintained in a stable condition and the licensee shall undertake any remedial work, including rock protection, which may be required from time to time by the Chief Executive.”

While potential erosion is seen as a valid concern, I am not persuaded that the chief executive has failed to take the potentialities into account or give adequate weight to consideration of the appellants' interests when deciding to issue the licence, particularly when the works as originally proposed, have been modified relative to the point of transition from natural conditions.

(c)     that the proposed works would dam a watercourse and thereby deprive the Appellants and other land owners of their rights as lower riparian owners to take and use water from that watercourse;

I am satisfied based on Mr Wallwork's evidence relevant to the outlet and the flow conditions in the licence, that the appellants' rights as riparian owners have been given proper consideration.

(d)    that the proposed works would dam surface waters which would otherwise have flowed onto the Appellants' and other land owners' land to their benefit;

See (c)

(e)     that the proposed works would dam surface waters and cause consequential “back up” of surface waters causing flooding on the Appellants' land and the land of other proximate land owners;

As already stated the crest elevation of the proposed works in the dam licence is such that water, at rest, when the weir was full, would not pond onto upstream properties.

(f)   that the proposed works would result in a diminished supply of water to downstream land owners and those lower riparian owners would be deprived of the benefit of licences, permits and other authorities to take and use water which had previously been issued to them by the Chief Executive;

See (c).

(g)    that as a result of the matters referred to in paragraph (d) above, the benefit of such licences, permits and other authorities to take and use water previously issued by the Chief Executive to downstream land owners would be diminished;

See (c)

(h)    that the proposed works may have the effect of redirecting water from the watercourse over the left bank (looking downstream at the entrance to the proposed works) into another watercourse;

This, as I understood Mr Purcell's evidence, could occur if and when flow of water reached 125m³/s caused by the effect of the “squeezing together of the banks of the watercourse”.

Mr Purcell also predicted significant damage to any structures including dams and levee banks in the watercourse in the event of “a big flood”.  The predicted diversion of water to the east may be a matter best considered when the applications for waterharvesting licences are under investigation. However in the meantime I have for the reasons already given, adopted for this consideration, a flow of 100m³/s.

(i)   that the proposed works would have the effect of increasing the level of contaminants which would be deposited upon the Appellants' and other land owners' land in the vicinity of the proposed works; and

I accept Mr Wallwork's considerations relevant to this matter as it relates to these

particular licences.  It may be that this will become a consideration relevant to proposed tailwater drainage.

(j)that there existed means of design and construction other than those involved in the proposed works which would have achieved the objects of the Applicants for those licences in an economic manner and which would have minimised the effects of additional flooding and additional depositing of contaminants.

The question of alternate design and construction has already been addressed.

Conclusion

The appellants' investigation of this matter through Mr Purcell has, in my opinion, concentrated in the absence of factual data, on proving the respondent's decision was based on too optimistic a view of probabilities. It seems to me that Mr Purcell's conclusions have however been shown to be overly pessimistic based on the same information. For private projects of the scale of the subject, it would not be appropriate, in my opinion to require design criteria to be based on events which have not and cannot be proved, or reasonably adopted on the balance of probabilities.

If that is unacceptable to the appellants then the opportunity for mitigation works, at their expense, is available, in association with the licensing of their presently unlicensed works which must also impact on the behaviour patterns of the watercourse.

Order

The appeal is dismissed and the decision of the chief executive in issuing Licences G54371 and G54372 is confirmed.

It is ordered that a copy of this decision be forwarded to the applicants, by the respondent. The applicants should note the evidence of both Mr Purcell and Mr Wallwork as it relates to alternative design and the potential financial implications imposed by Special Term SPEC01 in Licence G54372.

RE WENCK MEMBER OF THE LAND COURT