Zone Name:	Rakaia - Selwyn	Current Status:	(Red)
Allocation Limit:	215 million m3/yr	Valid date:	8 March 2006
Order of Approach:	Second (50% of land-surface recharge)

Recharge Component

Method of Estimation

Background Notes

The Rakaia-Selwyn Zone is highly allocated. It has changed from '1^st -order' to a '2^nd -order' allocation limit. The '1^st -order' limit of 208 million cubic metres, adopted in January 2004, was based on 30 percent of the mean annual rainfall over the zone together with a preliminary estimate of the intermittent recharge contribution from the Selwyn River. The allocation limit was set as 50 percent of the sum of these two terms.

The 2nd order approach incorporates estimates of annual average recharge from rainfall plus irrigation (land-surface recharge), together with the recharge component contributed by intermittent streams.

For the Rakaia-Selwyn groundwater zone, the average annual land-surface recharge is estimated to be 430 million cubic metres - approximately 36 percent greater than the rainfall recharge estimate on which the 1st order limit was based. In part, the increase reflects the contribution that irrigation makes to groundwater recharge. In addition the detailed analysis of climate and soil data has shown a higher proportion of rainfall recharge than adopted for the 1st order limits. The methodology and estimates of rainfall and irrigation recharge are described in Groundwater Allocation Limits: land-based recharge estimates (Environment Canterbury Report No U04/97).

As recommended in that report, further work has been undertaken to determine the recharge contribution from intermittent streams, specifically the Selwyn River and its tributaries, which would normally be included in a 2nd order allocation limit. It has been concluded that there is no net-gain from the Selwyn River to the Rakaia-Selwyn groundwater allocation zone. Losses to groundwater from the Selwyn River and its tributaries are considered to be largely retained within the gravels associated with the Selwyn River Fan (within which the Selwyn River flows).

This groundwater emerges from these gravels to supply the lower Selwyn River, Wood Creek, the Irwell River and arguably the Hanmer Road Drain. Accordingly, no inputs from the Selwyn River are included in this 2nd order allocation limit.

The adopted 2nd order allocation limit, derived as 50 percent of the land surface recharge is 215 million cubic metres per year.

This now replaces the 1st order allocation limit of 208 million cubic metres per year. The current groundwater allocation in the Rakaia-Selwyn groundwater zone exceeds this revised allocation limit of 215 million cubic metres per year and therefore the zone status of "red" remains unchanged.

The shallow aquifer immediately adjoining the Rakaia River is considered to be sourced by recharge from the river and from rainfall. This was recognised by Environment Canterbury appointed Commissioners who granted groundwater applications by Meadowflower Dairies Ltd and SR & RC Inch late in 2004.

A more recent resource consent decision for a groundwater take (Hayes 2007) was granted only after it was modified to ensure nearly all the water came from additional recharge from the Rakaia River. Recharge from the river contributes to the total recharge in the Rakaia-Selwyn groundwater allocation zone.

While at this stage it is not intended to create a formal "sub-zone" within the Chertsey and Rakaia-Selwyn Zones (and recalculate allocation limits), this may be pursued at some future stage through a variation to the NRRP. In the meantime any consents granted within the riparian sub-area will be counted as part of the "parent" zone.
The eastern boundary of the seaward portion of the riparian sub-area, located in the area east and south-east of Southbridge is currently subject to study that may lead to a review of the existing boundary.

Other Available Information Sources

These reports may be used to provide a full description of groundwater resources in this area. They may include information that will be of use in a consent application, but are not necessarily a comprehensive list.

• Aitchison-Earl, P., Davey, G., Ettema, M., McKerchar, A., Scott, D., Smith, E., and Weeber, J. 'State of the Canterbury Region Water Resource October 2004 (pdf 3.83MB)', U04/101
• Anderson, B., 1994, Groundwater between the Selwyn and Rakaia Rivers, Canterbury, New Zealand, MSc Thesis, University of Otago
• Brooks, T., Aitchison-Earl, P.,1999, Observations of the Irwell River Area in a Drought, 1999, CRC Technical Report U99/34
• Brooks, T (1998) Groundwater Resources near Te Pirita, Central Plains. Canterbury Regional Council Report U98/42
• Brown, L. J, 2000, 'Groundwaters of the Canterbury Region' Environment Canterbury Report R00/10.
• Evans, C and Aitchison-Earl, P. L., 'Te Pirita Groundwater Usage and Development as at March 2002' Environment Canterbury unpublished technical report U02/14.
• Taylor, K J W (ed), 1996, The Natural Resources of Lake Ellesmere (Te Waihora) and its Catchments, Canterbury Regional Council Report 96(7)
• Randers, R., Scott, DM., Brooks, T., 1997, Stream Depletion in the Doyleston: An assessment of the Effects of Groundwater abstraction over the 1996-97 irrigation season U97/33
• Facer, S., 2000, Surface-Groundwater Interactions in the Harts Creek and Birdlings Brook Catchments U00/27
• Smith, M., 2001, The Surface & Groundwater Resources of the Catchment of the Waikekewai Creek: a Tributary of Lake Ellesmere, Te Waihora U01/51
• Grant, H., 2003, The surface and groundwater resources of the Little Rakaia Zone: Lee River, Tent Burn & Jollies Brook U03/35

Allocation History

Effective Allocation

 06 October 2011

Effective Allocation (million m³): 311.585
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 145%

 30 August 2010

Effective Allocation (million m³): 272.15
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 127%

 3 May 2010

Effective Allocation (million m³): 272.12
Reason for Change: Consents update
Source: Rakaia Selwyn Groundwater Review
Proportion Allocated: 127%

 11 January 2010

Effective Allocation (million m³): 247.03
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 127%

 7 December 2009

Effective Allocation (million m³): 246.68
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 115%

3 November 2009

Effective Allocation (million m³): 246.81
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 115%

3 August 2009

Effective Allocation (million m³): 246.38
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 115%

6 July 2009

Effective Allocation (million m³): 246.89
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 115%

2 June 2009

Effective Allocation (million m³): 244.53
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

2 March 2009

Effective Allocation (million m³): 244.48
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

9 February 2009

Effective Allocation (million m³): 244.49
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

1 December 2008

Effective Allocation (million m³): 243.27
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 113%

3 November 2008

Effective Allocation (million m³): 243.22
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 113%

13 October 2008

Effective Allocation (million m³): 244.70
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

14 August 2008

Effective Allocation (million m³): 244.46
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

14 August 2008

Effective Allocation (million m³): 244.40
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

7 July 2008

Effective Allocation (million m³): 244.20
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

9 June 2008

Effective Allocation (million m³): 244.09
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 114%

12 May 2008

Effective Allocation (million m³): 243.97
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 113%

31 March 2008

Effective Allocation (million m³): 243.93
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 113%

3 March 2008

Effective Allocation (million m³): 243.61
Reason for Change: Rakaia Selwyn Hearing - Decided by Commissioners
Source: Consents database live-read
Proportion Allocated: 113%

4 February 2008

Effective Allocation (million m³): 224.79
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 105%

3 December 2007

Effective Allocation (million m³): 224.76
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 105%

5 November 2007

Effective Allocation (million m³): 223.70
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104%

1 October 2007

Effective Allocation (million m³): 223.65
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104%

3 September 2007

Effective Allocation (million m³): 223.70
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104%

23 July 2007

Effective Allocation (million m³): 223.68
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104.18%

7 May 2007

Effective Allocation (million m³): 224.00
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104.18%

19 February 2007

Effective Allocation (million m³): 223.78
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 104.08%

5 December 2006

Effective Allocation (million m³): 222.67
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 103.6%

16 October 2006

Effective Allocation (million m³): 222.46
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 103.47%

9 October 2006

Effective Allocation (million m³): 222.68
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 103.57%

25 September 2006

Effective Allocation (million m³): 222.53
Reason for Change: Consents update.
Source: Consents database live-read
Proportion Allocated: 103.50%

8 March 2006

Effective Allocation (million m³): 220.37
Reason for Change: Consents update. Stream depletion taken into account, north bank of the Rakaia River
Source: Consents database live-read on 8 March 2006
Proportion Allocated: 102.00%

29 June 2005

Effective Allocation (million m³): 232.23
Reason for Change: Effective allocation recalculated using a revised table of irrigation standards to address concerns with Schedule WQN9 of Chapter 5 NRRP, as approved by the Water Allocation Panel
Source: Consents database live-read on 29 June 2005
Proportion Allocated: 111.00%

21 February 2005

Effective Allocation (million m³): 219.1
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 101.91%

20 December 2004

Effective Allocation (million m³): 232.96
Reason for Change: Consents update (corrections only, no new consents granted)
Source: Consents database
Proportion Allocated: 108.35%

15 October 2004

Effective Allocation (million m³): 234.27
Reason for Change: Consents update (corrections only, no new consents granted)
Source: Consents database
Proportion Allocated: 108.96%

27 August 2004

Effective Allocation (million m³): 233.17
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 111.83%

6 August 2004

Effective Allocation (million m³): 232.67
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 111.59%

26 July 2004

Effective Allocation (million m³): 232.85
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 111.68%

11 June 2004

Effective Allocation (million m³): 233.12
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 111.81%

23 January 2004

Effective Allocation (million m³): 230.4
Reason for Change: This is the first estimate made
Source: Report U04/02 (Table 6.2)
Proportion Allocated: 110.50%

Allocation Limit

8 March 2006

Allocation Limit (million m³): 215
Reason for Change: Adoption of a 2nd order allocation limit. Based on 50% land -surface recharge
Source: Environment Canterbury's Water Allocation Panel

23 January 2004

Allocation Limit (million m³): 208.5
Reason for Change: This is the first estimate made and includes an additional 50 million m³/yr recharge from the Selwyn River
Source: Report U04/02 (Table 6.2)