Why does a distributed irrigation system (DIS) need air reliefs?

A distributed irrigation system (DIS) requires air reliefs primarily to allow water to drain back to the dosing tank when the system is not pressurized. When irrigation systems are designed, they often incorporate features that allow for gravity drainage or backflow of water into certain components, particularly when pressure releases or fluctuates. Air reliefs serve as a mechanism to introduce air into the system, which counters the vacuum created when water is drawn out. This prevents potential siphoning, ensuring that water can freely flow back into the dosing tank when not under pressure.

The presence of air relief valves helps maintain the system's functionality by facilitating proper drainage. This aspect is crucial not only for reducing the risks of potential clogging and pressure buildup but also for enhancing the overall efficiency of the irrigation cycle. Proper drainage contributes to effective system operation, allowing water management in accordance with varying rainfall or irrigation needs.

In contrast, options relating to heavy rains, sediment buildup, or soil aeration do not accurately address the primary function of air reliefs in a DIS, which is specifically designed to manage water drainage effectively within the system.