If a water plan states that the volumetric limit for a water allocation is to be based on an assessment of water taken under the existing authorisation and the efficiency of the use of the water, the volumetric limit for the allocation is the volume decided by the chief executive having regard to the following—
(a) the conditions under which water may be taken under the existing authorisation;
(b) the water taking capacity of any works for taking water under the allocation;
(c) the volume of water required for the allocation’s intended purpose;
(d) the annual volumes of water for the period stated in the relevant water plan estimated by the chief executive to have been taken under the existing authorisation with the works that were in place immediately before the commencement of this section;
(e) the efficiency of the use of the water mentioned in paragraph (d) ;
(f) any other criteria, for making the decision, stated in the relevant water plan.