Water Act 2007

The Basin Plan must also:

specify the conditions under which, due to one or more of the circumstances referred to in subsection (2):

Tier 2 water sharing arrangements cease to apply; and

other arrangements (Tier 3 water sharing arrangements), provided for in the Agreement, commence; and

specify the conditions under which Tier 3 water sharing arrangements cease to apply and Tier 2 water sharing arrangements recommence.

For the purposes of paragraph (1)(a), the circumstances are:

there are extreme and unprecedented low levels of water availability in the River Murray System; or

there is extreme and unprecedented poor water quality in the water available in the River Murray System to meet critical human water needs; or

there is an extremely high risk that water will not be available in the River Murray System to meet critical human water needs during the next 12 months.