The Waimakariri catchment; a study of some aspects of the present systems of land use, with recommendations for the future

Abstract

1. The Waimakariri River has been a constant threat to the Christchurch area. From the earliest days of settlement, river works have been carried out to control flooding, and the present value of these works now exceeds five million pounds. However, only in more recent times has it been suggested that the condition of the upper catchment could be an important factor in flood control. 2. This study describes the upper catchment, examines its use, and potential, and makes recommendations for future use and research. 3. The area is described as a high-altitude, mountain catchment with predominantly steep, unstable slopes, and shallow, infertile, and erodible soils. The vegetation has been drastically modified in pre-European and European times and consequently half the catchment is in a severely to extremely eroded condition. 4. In recent years the condition of some plant communities has improved but others, particularly above about 3,000 feet, continue to deteriorate. The deterioration is greatest on those areas grazed by both domestic and noxious animals. 5. These are areas of high precipitation with a considerable potential for water conservation and detention. However this potential will not be realised under continued grazing. This report therefore recommends that all stock should be excluded from high altitude land. 6. However, as most of the present occupiers have legal rights to the pastureage of this land it is recommended that they be adequately compensated for its loss. Compensation should be based on the productive value of the retired land, and reinvested in the remainder of the property. 7. Despite a reduction in the grazable area, agricultural production could be increased three-fold, an increase which would be consistent with the water and soil conservation requirements of the catchment as a whole. 8. Increased agricultural productivity will not be possible without major changes in the present system of farming. The feasibility and economics of the necessary changes are discussed, and twelve recommendations are made for their adoption. 9. As many decisions on future use have been based on rather inadequate data, six recommendations are made for further research and investigation. Results from the recommended studies would be of benefit to future planning. 10. The recommendations for future land use would be best implemented through the North Canterbury Catchment Board’s Run Plans. The estimated cost of £370,000 would be spread over a number of years as the proposals were progressively incorporated in future run plans.