Rodriguez & Sons Pty Ltd v Queensland Bulk Water Supply Authority trading as Seqwater (No 16)

During the course of the cross-examination of Dr Altinakar, senior counsel for Seqwater suggested, in effect, that he had adopted two erroneous figures for the discharge into the system he was modelling. In particular, it was contended that at a point along the Bremer River and another place known as Rifle Range Road, Dr Altinakar had underestimated the flow from sources other than Wivenhoe Dam and that this was at least potentially material to the flood levels that he modelled.

Following that cross-examination an expert retained by the third defendant to consider, amongst other matters, Dr Altinakar's modelling, Mr Collins, revised an earlier report that he had prepared which appeared to generally express satisfaction with the inflows adopted by Dr Altinakar. Mr Collins qualified his opinion in respect of the two matters raised in Dr Altinakar's cross-examination.

At this point, some months later, objection is now made to parts of Mr Collins's report that addresses that issue. Having first identified the two suggested errors, Mr Collins then states:

The basis for the objection to this passage has varied but has included the proposition that Dr Altinakar did not have the opportunity to respond to these conclusions, as well as the proposition that proper reasoning underlying these conclusions is not laid out in Mr Collins’ report.

I do not accept the former in that these matters were raised in cross-examination with Dr Altinakar and he did have the opportunity to respond.

I would add otherwise that I have already, and continue to, express some disquiet about the proposition that something that could be potentially so important to the case as to the materiality of discrepancies in the inflows modelled by Dr Altinakar will simply turn upon one party or another pointing to the uncertainty or otherwise surrounding its materiality, rather than simply having Dr Altinakar’s simulations take into account what the defendants say are the correct inflow figures and then leaving it to the Court to determine what are the figures that should be adopted.

In any event, the first sentence of the above passage will be admitted. The basis for the conclusion that it is material to the modelling is clearly specified, that simply being a mathematical comparison of the respective contributions to flooding from Wivenhoe discharges and other sources. However, the last sentence will be rejected. Without further analysis, it cannot be discerned the precise reasons why Mr Collins concludes that the discrepancy in the inflow figures “would have” a significant effect on predicted flood levels.

The next part of Mr Collins's report reads as follows:

The difficulty with the first three sentences in this passage is that they are all "based on the BRCFS", that being a detailed and comprehensive study of the Brisbane River, only parts of which are in evidence. At this stage, without more, and in particular, without knowing what part of the BRCFS supports the first sentence, then the basis for the admissibility of these three sentences is not made out. Whether the third defendant would seek to re-tender these sentences, having identified the relevant part of BRCFS, is a matter for it.

The difficulty with the last sentence in the passage is the ultimate conclusion that "higher flood levels for these simulations than reported would occur at the Plaintiff's property". Without knowing more, and in particular without some more detailed engagement with Dr Altinakar's modelling, it is not known what the basis for that conclusion is.

Accordingly, I will allow the first sentence of the last paragraph on the report at EXP.QLD.002.0033 at 0037. I reject the last sentence of that paragraph. I will reject the paragraph on page EXP.QLD.002.0038, although, as noted, it will be a matter for the third defendant whether it seeks to retender the first three sentences of that passage.