New South Wales Consolidated Regulations

WATER SHARING PLAN FOR THE DORRIGO PLATEAU SURFACE WATER SOURCE AND DORRIGO BASALT GROUNDWATER SOURCE 2003 - REG 17

17 Flow classes for the surface water source

This Plan establishes, the following flow classes as the basis for sharing of daily flows from this surface water source:

(a) For Zone 1:

(i) very low flow class at or less than 75 megalitres/day (hereafter "ML/day"),

Note: The 75 ML/day corresponds to the estimated 95 th percentile of flows in November, the critical month, and is referred to as the cease to pump on a falling river and the commence to pump on a rising river.

(ii) A class flows greater than 75 ML/day and at or less than 128 ML/day,

(iii) B class flows greater than 128 ML/day and at or less than 221 ML/day, and

(iv) C class flows greater than 221 ML/day.

(b) For Zone 2:

(i) very low flow class at or less than 23 ML/day,

Note: The 23 ML/day corresponds to the estimated 98 th percentile of flows in November, the critical month, and is referred to as the cease to pump on a falling river and the commence to pump on a rising river.

(ii) A class flows greater than 23 ML/day and at or less than 60 ML/day,

(iii) B class flows greater than 60 ML/day and at or less than 128 ML/day, and

(iv) C class flows greater than 128 ML/day.

(c) For Zone 3:

(i) very low flow class at or less than 17 ML/day,

Note: The 17 ML/day corresponds to the estimated 90 th percentile of flows in November, the critical month, and is referred to as the cease to pump on a falling river and the commence to pump on a rising river.

(ii) A class flows greater than 17 ML/day and at or less than 22 ML/day,

(iii) B class flows greater than 22 ML/day and at or less than 54 ML/day, and

(iv) C class flows greater than 54 ML/day.

(d) For Zone 4:

(i) very low flow class at or less than 13 ML/day,

Note: The 13 ML/day corresponds to the estimated 95 th percentile of flows in December, the critical month, and is referred to as the cease to pump on a falling river and the commence to pump on a rising river.

(ii) A class flows greater than 13 ML/day and at or less than 40 ML/day,

(iii) B class flows greater than 40 ML/day and at or less than 119 ML/day, and

(iv) C class flows greater than 119 ML/day.

Note: Very low flow access conditions are established under clause 73 for cleaning for dairy plants and clause 75 (a) for local water utilities.

Note: The flow classes have been determined based on flow information that inherently includes seasonal effects as well as evaporation and seepage losses.