New South Wales Consolidated Regulations

WATER SHARING PLAN FOR THE WYBONG CREEK WATER SOURCE 2003 - REG 76

76 Amendment of flow levels, pool protection provisions and TDELs

(1) The Minister may, under section 45 (1) (b) of the Act and by notice published in the NSW Government Gazette:

(a) vary the very low flow levels, and the bottom of B class flows established in clause 17, following field verification,

(b) vary the initial pool control levels and key sites established in clause 22 (3) (f),

(c) vary the TDEL for any flow class as specified in clause 46, following a study of water usage and a study of the connectivity of surface water and groundwater, and/or

(d) vary the environmental health water specified in clause 22 as a result of any variation to a TDEL arising from subclause (1) (c).

(2) Any variation made under subclause (1) (a) should not result in the very low flow class being greater than 1 ML/day or less than 0.5 ML/day on a falling river.

(3) Any variation made under subclause (1) (c) should be limited to:

(a) for B class, no more than 60% of the surface flow assessed in subclause (8) at the 50th percentile flow of all days at the flow reference point, but not less than 4 ML/day,

(b) for C class, no more than 60% of the surface flow assessed in subclause (8) at the 30th percentile flow (of all days) at the flow reference point, but not less than 11.5 ML/day,

(c) for D class a maximum of 6.5 ML/day above the TDEL for C class, but not less than 20 ML/day, and

(d) for E class a maximum of 50 ML/day, but not less than 37 ML/day.

(4) The Minister should undertake the field verification in subclause (1) (a) as soon as practical, but before the review of this Plan under section 43 (2) of the Act.

(5) The Minister should review the pool control levels and key sites in subclause (1) (b) in conjunction with the field verification in subclause (4).

(6) The Minister should cause the studies established in subclause (1) (c) to be undertaken after at least 3 years of measurement of use, but before the review of this Plan under section 43 (2) of the Act.

(7) The field verification established in subclauses (1) (a) and the pool control level review in subclause (1) (b) should assess:

(a) whether the flow level meets the objectives at clause 11 (a) and (b) of this Plan, and

(b) whether the pool control levels and key sites meet the objectives specified in clauses 11 (a) and (i), and specifically consider the following:

(i) the suitability of the location of the key sites used in assessing pool health upstream of the site,

(ii) the drawdown of the water levels within the pools upstream of the key sites during periods of extraction, and

(iii) the significance of pools that are impacted by drawdown.

(8) The studies established in subclause (1) (c) shall:

(a) assess whether existing and proposed TDELs meet the objectives specified in clause 11 (e) and (f), and

(b) specifically determine the assessed surface flow at the flow reference point by developing the relationship between the flow reference point flow and daily extracted volumes, including consideration of the following matters:

(i) summation of surface flow and extraction on any day,

(ii) development of a theoretical flow duration curve for the period of the study based on the summation of surface flow and extraction,

(iii) calibration of the theoretical flow duration curve using historical rainfall data and by using a control site in another water source,

(iv) reassessment of the river and groundwater connectivity and specifically, review of the groundwater sustainable yield,

(v) the relationship of river flow at various sites within this water source for different flow classes, determined by information from any or all river flow gauging stations, and

(vi) the water level behaviour of groundwater monitoring bores.

(9) In undertaking the field verification and studies of water usage and connectivity of surface water and groundwater in this clause, the Minister should:

(a) consult with the NSW Environment Protection Authority, NSW Fisheries, NSW Agriculture and the NSW National Parks and Wildlife Service, and

(b) prepare a report documenting:

(i) the methodology adopted,

(ii) the hypotheses tested,

(iii) the field results and conclusions in terms of the degree to which the objectives in subclauses (7) and (8) are met,

(iv) the flow levels, pool control levels and key sites and TDELs recommended to meet the objectives, and

(v) the socio-economic impacts of recommended changes to the flow levels, pool control levels and key sites, and changes to TDELs.