IMPROVING CONVEYANCE AND DISTRIBUTION EFFICIENCY THROUGH CONVERSION OF AN OPEN CHANNEL LATERAL CANAL TO A LOW PRESSURE PIPELINE AT AL- HASSA IRRIGATION PROJECT, SAUDI ARABIA

摘要

This paper describes a field case study on the use of a semi-buried poly-vinyl chloride (PVC) pipeline system in Al-Hassa oasis, Saudi Arabia and its contribution in improving water conservation. Deteriorated concrete canals at Al-Hassa irrigation project, enhanced irrigation water losses, and the annual cost of maintenance became un economical for the long term. The PVC pipes easy maintenance, durability, modification, and flexibility, give them the potential to be an economical alternative to replace a concrete lateral canal, P1H4, at Al-Hassa irrigation project. Due to the availability of PVC pipes at low cost in the Kingdom and their common use in irrigation, they were selected to construct a pipeline, 362 m in length. An energy head, 2.7m of water, was used in determining the pipeline capacity and its internal diameter, using the continuity equation. Dismantling of the concrete canal and installing of the pipeline took place simultaneously without water stresses to the grown crops. The conveyance and the distribution efficiencies increased by 25.3 % and 25% respectively due to installation of the pipeline. The water use with illegal extra siphons, was reduced by 29.2 % under the pipeline system.