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Potential Demands for Waitaki Catchment Water (non Hydro, Irrigation or Stock)

Executive Summary

1 Introduction

2 Methodology

3 Discussions and Interviews Summary

4 Water Conservation

5 Results and Recommendations

References

Applicability

Appendix A: Potential water demands from significant catchments - consents data

Appendix B: Potential water demands including out-of-catchment - recorded flow and population data

Appendix C: Demand growth summary information

Appendix D: Seasonal variation of water demand by consumer type

Appendix E: Classification of use codes from Environment Canterbury consents database

Appendix F: Catchment numbering for significant catchment analysis and LINZ land parcel summary

Appendix G: Unproductive land use descriptions from LINZ DCDB

Executive Summary

This report estimates the current peak flow and yearly demands for water from the Waitaki Catchment for community, private, commercial, industrial and recreation/tourism water supplies. It does not include estimates of water required for hydro-electricity generation, irrigation or stock water uses.

Mackenzie, Waimate and Waitaki District Councils preside over the Waitaki Catchment while Timaru District Council (east of the catchment) and Dunedin City Council (south of the catchment) are close enough to the Waitaki Catchment that some water supply may be possible in the future. Councils are generally concerned that a number of their communities are water short now, or are likely to be water short in the future.

The initial data collection phase indicated that some councils' data recording systems, although relatively basic, were effective in providing good quality water demand information. However some council systems are not metered and therefore demands had to be inferred.

The framework we have developed uses estimates of current water demand and then projects demands forward to account for reasonably expected growth over the future 10, 20 and 50-year period. Current water demands have been estimated by two parallel methods. Method 1 uses Environment Canterbury consent information as its basis and Method 2 uses recorded flow data and census population as its basis. Method 2 was required to estimate current demands outside the Waitaki Catchment where consent information was lacking.

Even with the two methods for estimating current demands there is still a proportion of potential demand that is not accounted for. An example is situations where landholdings are not connected to a community or rural supply and do not need a resource consent. By counting land parcels and assigning them a nominal demand we were able to account for this demand. This figure was then added to the results for Methods 1 and 2.

Three growth scenarios were developed (low, medium and high growth) from Statistics New Zealand national population growth figures and estimated economic growth data. When applied to the estimated current demands this gave us a range of peak flow and annual demand values. Due to the general nature of population and industry growth projection data used, the results should be regarded as approximate only.

Water demand for household uses arise primarily from community and rural water supply schemes. There are only a few industrial and large commercial operations presently drawing water from the Waitaki Catchment and most of this is used for meat processing. Snow making is the largest independent tourism-related water take in the Waitaki Catchment; most other tourism and recreation ventures are located in communities and hence the water is accounted for as a community demand.

Water demand for irrigation is not part of this report. However it is likely that on-farm secondary water demands could increase as a result of irrigation, as present dry land farming converts to dairy or horticulture.

The tables below show the results from the demand modelling for the various growth scenarios. Additional tables can be found in Section 5 and in the Appendices.

Table 5.4: Summary of peak flows from the Waitaki Catchment (high growth scenarios)

View summary of peak flows from the Waitaki Catchment (high growth scenarios) (large table)

Table 5.5: Summary by use type within Waitaki Catchment (high growth scenarios - consents data only)