water resources study
The Southland Water Resources Project was initiated in 2003 in response to ongoing changes in land use and an overall increase in water allocation from early 2002. Recognition of potential for water resource development in the Southland Region following trends established elsewhere in New Zealand was a further stimulus for the study.
Copies of the final reports on the Southland Water Resources Study are available to download from this website as PDF documents.
The study was funded by MAF through the Sustainable Farming Fund and managed by Venture Southland, which contracted the work to a consortium of Lincoln Environmental, MWH and NIWA (for Stages 1-3) and SKM (Stage 4). In-kind support was provided by Environment Southland, the Southland District Council, Invercargill City Council and Gore District Council.
Objectives
The objectives of the study were to provide fundamental information to:
Identify the potential long-term requirement for water in the Southland Region;
Determine the capacity of the Region to support those requirements;
Identify water resources likely to come under greatest stress in the future;
Establish the reliability, over the long-term, of water supplied from natural systems for abstractive use.
Project Structure
The project was divided into four stages:
An overall assessment of water requirements for abstractive needs;
Quantification of water availability from surface and groundwater sources;
Identification of likely shortfalls and surpluses in water availability;
Options to address any identified shortfalls in water availability.
Stages 1-3 were carried out together and a consolidated report prepared by the consultants in September 2003.
Key findings
Southland has sufficient water to meet reasonable foreseeable water requirements. However, water is not always at the right place at the right time.
The water resources zones of the Mataura catchment are likely to experience the greatest shortfalls in water availability.
Irrigation is likely to be the major source of water demand into the future.
Forestry development is likely to reduce the amount of water available for abstractive uses.
A robust allocation framework is required to manage long-term development of Southland’s water resources.
Stage 4
Following wide public consultation on the report on Stages 1-3, and further consideration by the Steering Committee managing the project, a project brief for Stage 4 was developed and put out to tender. The contract was let to Sinclair Knight Merz (SKM), who were asked to study and report on three aspects:
- The economic impact of drought conditions in Southland
- The economics of irrigation in Southland
- Options for water harvesting and storage.
This part of the project was completed in June 2006. The report by contractors SKM found that the overall economic viability of irrigation in Southland is significantly lower than in other regions of New Zealand but irrigation transition is a viable option for drought mitigation in limited areas of northern Southland, especially on dairy farms. Existing ground and surface water resources are unlikely to be sufficient to meet projected future demand in these areas and options for water harvesting and storage are significantly constrained by technical and regulatory considerations.