An update on the Klondyke Proposal
Rangitata Diversion Race Management Limited (‘RDRML’) continues to advance the resource consent applications necessary for a water storage facility to supplement the Rangitata Diversion Race (‘RDR’).
Investigations by the RDRML over the past four years have assessed a variety of options relating to water storage capacities, ranging from 5 million cubic metres to 100 million cubic metres. The investigations included preliminary engineering and technical assessments of each option.
Of note is that while emphasising the need to carefully consider and advance the water storage proposal, none of the work that has been completed identified a fatal flaw in the proposal.
Preliminary consultation with stakeholders and interested parties has taken place over the past 12 months. Two community information events were publicly advertised and held in May 2015. This consultation and investigations undertaken by a team of respected environmental experts guided RDRML in its decision that the option of a 53 million cubic metres water storage facility is the most favourable.
In summary, the water storage facility will:
- Improve the irrigation reliability for RDRML’s existing shareholders taking water from the RDR, and supply sufficient water to enable further irrigation in Mid-‐Canterbury and / or enable the RDRML to refocus the existing take such that users in South Canterbury can also abstract water from the RDR;
- Provide a physical tool to assist in achieving Regional water targets and outcomes by artificial recharge of groundwater by using Managed Aquifer Recharge / Targeted Steam Augmentation;
- Be located on the river terraces at the upstream end of the RDR, with the Rangitata River to the west, Ealing Montalto Road to the east, and farmland south of Shepherds Bush Road to the south. A location plan is provided within this information pack on page 4;
- Have a total construction area of approximately 500 hectares of land, including the storage facility (286 hectares), temporary works, spoil disposal and pond outlet areas, that currently supports agricultural endeavour;
- Be supported by a supplementary water take of up to 10 cubic metres per second from the same location as the existing RDR consented take from the Rangitata River. This take flow, which will be in addition to the existing operational takes, will only be taken during periods of flood flows;
- Require the existing RDR canal to be widened and raised in height between the intake and the water storage facility to convey the supplementary water take and in accordance with the approach set out by the Rangitata Water Conservation Order, as illustrated in the Canal Modification Plan within this information pack on page 5;
- Construct earth embankments that range from 2.5 metres in height to a maximum of 30.5 metres. The water storage facility will have a maximum water depth of 24 metres;
- Require approximately 11 million cubic metres of excavated material, of which, 10 million cubic metres will be used during construction. 1 million cubic metres of surplus material will be spread across disposal areas to the north and south of the pond;
- Be lined with synthetic material so that any impounded water does not leak through the porous soils that underlie the footprint of the water storage facility;
- Be constructed over a period of approximately five years. Construction methodology plans prepared by MWH are included within this information pack on page 6; and
- Contain an outlet at the southern end of the storage pond that conveys flow to the Mayfield Hinds Irrigation canal, which has been designed to include a recreational kayak course that is available for public use. A preliminary example of the kayak course is also set out on the plans included within the downloadable information pack on page 8.
Where to from here?
Now that the preferred option has been selected, the RDRML wish to lodge a resource consent application in mid-‐2016.
To inform the resource consent application the RDRML has commissioned a significant number of independent technical assessments. Table A, which follows, sets out the assessments and their respective experts (authors). Each of the assessments will be available for public view on request from the RDRML and posted on this website.