The groundwater allocation zone summary report for Chertsey
Recharge Component
Method of Estimation
Background Notes
In recent years groundwater levels have exhibited summer lows of increasing magnitude with only some generally recovering to normal levels in winter. This indicates that the groundwater system is unable to sustain the current level of groundwater usage in very dry years or a succession of dry years. Of note also is downward trend in groundwater levels in deep aquifers of both summer and winter levels in areas which have undergone significant development in the past 3 or 4 years, particularly Urral-Chertsey and Te Pirita.
In addition to rainfall recharge, the shallow aquifer immediately adjoining the Rakaia River is sourced predominantly by recharge from the river. This river-sourced recharge plays a significant role in maintaining groundwater levels in the riparian zone adjacent to the river and also provides a base level of recharge to the Rakaia-Selwyn and Chertsey allocation zones.
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 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
- Brown, L. J, 2000, 'Groundwaters of the Canterbury Region' Environment Canterbury Report R00/10.
- Sanders, R.A, 1999., 'Groundwater in the Ashburton-Rakaia plans area: a recent perspective'. Environment Canterbury Report U99/31.
- Sanders and Weeber 2001, 'Urral Investigation and Monitoring Well', Environment Canterbury Unpublished Technical Report U01/43
- SCOTT, D.M., THORPE, H.R., 1986: Groundwater Resources Between the Rakaia and Ashburton Rivers. Publication No. 6 of the Hydrology Centre, Christchurch.
Allocation History
Effective Allocation
30 August 2010
Effective Allocation (million m3): 119.61
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 106%
3 May 2010
Effective Allocation (million m3): 119.44
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 106%
11 January 2010
Effective Allocation (million m3): 119.25
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 106%
7 December 2009
Effective Allocation (million m3): 120.05
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 107%
3 November 2009
Effective Allocation (million m3): 120.22
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 107%
2 June 2009
Effective Allocation (million m3): 120.04
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 107%
9 February 2009
Effective Allocation (million m3): 119.65
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 106%
13 October 2008
Effective Allocation (million m3): 119.32
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 106%
11 August2008
Effective Allocation (million m3): 117.40
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 104%
7 July2008
Effective Allocation (million m3): 118.14
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 105%
9 June2008
Effective Allocation (million m3): 118.22
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 105%
12 May2008
Effective Allocation (million m3): 117.98
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 105%
3 December 2007
Effective Allocation (million m3): 117.78
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 105%
5 November2007
Effective Allocation (million m3): 117.53
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 105%
3 September 2007
Effective Allocation (million m3): 117.52
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 104%
23 July2007
Effective Allocation (million m3): 117.33
Reason for Change: Consents corrections
Source: Consents database live-read
Proportion Allocated: 104%
7 May2007
Effective Allocation (million m3): 117.10
Reason for Change: Consents corrections
Source: Consents database live-read
Proportion Allocated: 104%
19 February2007
Effective Allocation (million m3): 118.19
Reason for Change: Consents corrections
Source: Consents database live-read
Proportion Allocated: 104%
5 December 2006
Effective Allocation (million m3): 117.45
Reason for Change: Consents corrections
Source: Consents database live-read
Proportion Allocated: 104%
13 November 2006
Effective Allocation (million m3): 117.41
Reason for Change: Consents corrections
Source: Consents database live-read
Proportion Allocated: 104%
18 September 2006
Effective Allocation (million m3): 113.7
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 101%
17 January 2006
Effective Allocation (million m3): 113.3
Reason for Change: Consents update
Source: Consents database live-read
Proportion Allocated: 101%
29 June2005
Effective Allocation (million m3): 107.33
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: 95.00%
24 January 2005
Effective Allocation (million m3): 114.5
Reason for Change: Effective allocation recalculated using the 150 day methoddue to concerns with Schedule WQN 9 of Chapter 5 NRRP, as approved by the Water Allocation Panel
Source: Consents database live-read on 4 Feb 05
Proportion Allocated: 101.87%
20 December2004
Effective Allocation (million m3): 68.73
Reason for Change: Consents update Source: Consents database
Proportion Allocated: 61.15%
24 November2004
Effective Allocation (million m3): 71.85
Reason for Change: No change
Source: n/a
Proportion Allocated: 63.92%
Proportion Allocated & colour changed due to Allocation Limit change
9 August2004
Effective Allocation (million m3): 71.85
Reason for Change: Effective allocation estimate updated based on Schedule WQN9, Chapter 5 NRRP
Source: Memo to Groundwater Allocation Implementation Group
Proportion Allocated: 80.55%
1 June2004
Effective Allocation (million m3): 90.61
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 101.58%
31 March2004
Effective Allocation (million m3): 87.22
Reason for Change: Consents update
Source: Consents database
Proportion Allocated: 97.78%
23 January 2004
Effective Allocation (million m3): 86.4
Reason for Change: This is the first estimate made
Source: Report U04/02 (Table 6.2)
Proportion Allocated: 96.86%
Allocation Limit
24 November 2004
Allocation Limit (million m3): 112.4
Reason for Change: Implementation of 2nd order approach as approved by Directorate
Source: Report U04/97
23 January 2004
Allocation Limit (million m3): 89.2
Reason for Change: This is the first estimate made using the 1st Order Approach
Source: Report U04/02 (Table 6.2)