Development of low- pressure irrigation systems (application history, advantageous and challenges)

Implement of pressurized irrigation systems within the farms are not possible in some provinces of Iran, due to high cost of energy supply, evaporation and wind-drift losses, salinity conditions and ownership patterns. Therefore, the appropriate option is the application of low- pressure irrigation systems. The low- pressure system is a series of tubes that are supported by the canal, water tank or pumping station and distributes water to the farm ditches with a low pressure. The history, advantages and challenges of the application of low-pressure irrigation systems and some extension approaches are mentioned in this study. The major advantages can be referred to the reducing water conveyance time, increasing the irrigation efficiency, decreasing energy losses, preventing pollution of groundwater resources, controlling human diseases and reducing the cost of maintenance and applications. The challenges of application of low- pressure irrigation systems include the more complication relative to open irrigation systems, the inability of designer engineers to design and implement systems, the need for higher hydraulic height, and impossibility for monitoring water flow in the distribution system. It highlighted the importance of factors of design and implementation of low - pressure systems such soil and water characteristics; cultivation pattern and water requirements; irrigation management; design of border, furrows and basins dimensions; design of conveyance lines and pools; design of gated pipes; irrigation scheduling; maintenance procedure; cost of project implementation; economic evaluation; project management ; dimensional design; and design criteria for surface irrigation methods