Rodriguez & Sons Pty Ltd v Queensland Bulk Water Supply Authority trading as Seqwater (No 15)

The matter involved Rodriguez & Sons Pty Ltd, a civil construction company, and the Queensland Bulk Water Supply Authority trading as Seqwater, a statutory authority responsible for managing water resources in Queensland. The dispute centred around the adequacy of expert evidence provided by Seqwater's flood engineer, regarding the capacity of a dam following a flood event. The case was heard in the Supreme Court of Queensland. The primary issue was whether the engineer's opinion, which relied on events that occurred after the flood, was reasonable and supported by appropriate reasoning.

The court considered the principles applicable to the assessment of expert evidence in this context. It examined whether the expert's belief about the dam's capacity was based on a reasonable assessment and whether the opinion was supported by reasoning. The court emphasised the importance of the expert providing a clear and reasoned opinion, particularly when it relied on post-event data. The absence of reasoning in the engineer's opinion was a significant factor in determining its admissibility and weight. The court also noted that there were no questions of principle that required further judicial consideration.

The court found that the engineer's opinion was not reasonable as it lacked the necessary reasoning to support the belief about the dam's capacity. The reliance on post-event data without adequate explanation or justification undermined the reliability of the opinion. Consequently, the court determined that the evidence was not admissible. The court did not need to consider the question of principle, as the primary issue was the reasonableness and adequacy of the reasoning provided by the expert.

The court ordered that the engineer's opinion be excluded from the evidence and that the matter proceed without it. The court did not make any further orders regarding the dispute between the parties.