The Ashburton River Management Plan expired in 1990. The Canterbury Regional Council, under the statutory requirements of the Resource Management Act (1991), is responsible for the drafting of a new Ashburton Catchment Management Plan. The Act requires that the costs and benefits of resource management plans are identified as part of the planning process. A component of the suite of studies commissioned by the Regional Council was an estimation of the impact on farm and community economies.of changing the availability of,the AShburton River for irrigation.
In total 53 farmers use the Ashburton River, its tributaries and groundwater sources which are affected by restrictions placed on:' abstraction from the river, as their primary source of irrigation water. These include irrigators in the Greenstreet Scheme and private irrigators. In addition, a further 349 farmers are contracted to the three irrigation schemes which irrigate from the Rangitata Diversion Race. The Rangitata Diversion Race (RDR) takes, on average, 10 percent of its water from the Ashburton River.
The study comprised two parts. The fIrst involved the conduct of a postal survey of approximately 200 farmers to establish existing landuses and irrigation practices. From the responses to this survey, the landuse for the entire area affected by restrictions on the Ashburton River was calculated.
Secondly, a detailed personal interview survey of thirty farmers was undertaken to estimate the extent of changes in farm production and profitability which would accompany changes in water availability. The percentage changes estimated on the basis of responses to the personal interview survey were applied to total crop areas and stock numbers to derive changes in total productivity.
The probabilities of differing levels of water restriction were calculated on the basis of the available hydrological data. These probabilities were used as a means of explaining the impacts of individual water allocation rules to farmer participants. They were also used in the analysis to weight the estimates obtained under the defined water restriction scenarios, in order to calculate production and profitability parameters which incorporated between season variability, for each allocation rule.
CONTENTS
TABLES
FIGURES
PREFACE
ACKNOWLEDGEMENTS
SUMMARY
CHAPTER 1 INTRODUCTION
1.1 The Ashburton Water Management Plan
1.2 The Objective and Scope of the Study
1.3 The Organisation of the Report
CHAPTER 2 DEFINITION OF IRRIGATION RESTRICTION SCENARIOS
2.1 Allocation Rules to be Evaluated
2.2 Restrictions Predicted Under the Allocation Rules
2.3 Derivation of Restriction Scenarios
2.4 Derivation of the Probabilities
2.5 Relationship Between Allocation Rules and Scenarios
CHAPTER 3 THE SURYEY METHODOLOGY
3.1 The Samples
3.2 The Postal Survey
3.3 The Personal Interview Survey
CHAPTER 4 LAND USE, IRRIGATION PRACTICES AND LABOUR USE ON PROPERTIES IRRIGATING FROM THE ASHBURTON RIVER - RESULTS OF THE POSTAL SURVEY
4.1 Response to the Postal Survey
4.2 Farm and Irrigation Areas
4.3 Land Use by Respondents to the Postal Survey
4.4 Extrapolation from Survey to Scheme Land Use
4.5 Respondents' Responses to Water Restrictions
4.6 Employment and School Attendance
CHAPTER 5 FARM OUTPUT AND PROFITABILITY UNDER VARYING WATER ALLOCATIONS
5.1 Changes in Land Use and Fann Output
5.2 Changes in the Value of Agricultural Production
- 5.2.1 Values Based on Current Prices
5.2.2 Sensitivity Analysis
5.2.3 Regional Effects
5.3 Changes at the Individual Fann Level
- 5.3.1 Changes in the Value of Fann Output
5.3.2 Changes in Net Farm Profit
5.3.3 Fann Viability
5.3.4 Fanner Reaction
5.4 Agribusiness Sector Reaction
CHAPTER 6 SUMMARY AND CONCLUSIONS
REFERENCES
APPENDIX I PREDICTED RESTRICTIONS ON AVAILABILITY OF IRRIGATION WATER FROM THE ASHBURTON RIVER
APPENDIX II FLOW DATA FROM THE SOUTH ASHBURTON RIVER 1967/68 TO 1990/91
APPENDIX III THE POSTAL QUESTIONNAIRE
