Developing pipeline installation options for the Hunter Downs irrigation scheme

Abstract

The purpose of this investigation is to determine options for the installation of irrigation piping in the proposed Hunter Downs Irrigation Scheme that will: create delivery cost savings, maintain and improve health and safety, and enable compliance to obtain warranties. The Hunter Downs Irrigation Scheme is located between Timaru and Waimate. The scheme aims to irrigate 15,000 - 20,000 Ha of farmland. Water for this scheme will be transported via 112 km of underground pressurised glass reinforced plastic (GRP) pipe. Pipe installation is the second largest capital expenditure cost for the scheme . This amounts to 17% of the overall cost of the scheme. Installation options were brainstormed and a range of options were developed for excavation, pipe handling, backfilling and compaction. These options were then analysed using information gathered from interviews with engineers, pipe suppliers, and contractors. Outranking multi-criteria decision-making method was used to shortlist the options that best fit with the project's objectives . The shortlist underwent further analysis against GRP limitations and backfill selection issues. This investigation presents the most viable installation options that will meet the scheme objectives and assist in scheme development.