Assessment of surface inlets performance on sediment transport to subsurface drainage system

Infield ponding can have detrimental effects on crops and soils and result in reduced yields and increased sedimentation. Surface inlets are commonly used to prevent or reduce incidents of ponding. In this study, the flow and sediment transport characteristics of four surface inlets-the standard Hickenbottom inlet, two inlets (standard and Quick- Drain®) designed by Ag-Solutions, and an inlet developed by AgriDrain-were evaluated in both laboratory and field settings with simulation rainfall. The Hickenbottom and QuickDrain® Ag-solutions inlet had higher sediment concentration and sediment load compared to the other inlets. The average sediment concentration and sediment load for Hickenbottom and QuickDrain® Ag-solutions inlets were measured to be 3532.70 mg/L, 64919.05 mg/min, and 3104.31 mg/L, 24880.69 mg/min, respectively. The measured sediment concentration and sediment load for standard Ag-solutions inlet were smaller than Hickenbottom and QuickDrain® Ag-solutions inlets but higher than the AgriDrain inlet. The AgriDrain inlet was the most effective among the four inlets in reducing sediment (66% concentration and 23.2% load compared to Hickenbottom) (p<0.01), but it removed water at a much lower rate compared to other inlets. Additional research is recommended to determine how contaminants like nitrate, phosphorus, and pesticides are transported through these inlets.