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7. Causes of sediment loss in drainage discharge

Potential causes for sediment loss in drainage discharge include:

(1) During the early period after installation, some sediment will enter the pipe and move with water following flow events (Stuyt et al., 2005). This is because the soil around the pipe was disturbed during installation.

(2) A surface inlet moves sediment from surface runoff into the subsurface system.

(3) A poor connection or a broken pipe can let sediment into the system.

(4) Overly wide slots can allow sediment into the pipe (Ghane, 2023a).

(5) In shrinking and swelling clay soil, high-intensity rainfall can cause rapid movement of water through macropores, thereby eroding the macropore walls and moving sediment into the system (Nazari et al., 2020).