Broadly-stated statutory objects and water management principles do not create mandatory requirements as to the method of scientific analysis (such as requiring a sound numerical groundwater model) before a Minister can validly make a water sharing plan. A ministerial decision based on a flawed scientific model is not manifestly unreasonable where the model retains some probative value, the decision-maker is aware of its limitations, and the plan contains mitigating measures. Misleading departmental advice to a Minister does not invalidate a decision unless the subject matter of the advice is a mandatory relevant consideration under the statute. An obligation to have 'due regard' to socio-economic impacts does not require any particular methodology such as a formal study or farm-by-farm analysis.
The full text is available to signed-in members, including the 10 later cases that cite this judgment.
1 of the 10 citing cases carry a classified treatment. How each court treated it is available to signed-in members.