The bar guard intakes or type 2 inlets are used to maximize inflow into a tile. In a terrace situation with type 2 risers, tile size and grade are used to prevent outflow on the downhill inlets. In a terrace situation, you should replace damaged inlets with the same kind that was originally installed.
Sometimes inlets are used in closed depressions to increase drain water out of the depression faster. In those situations, if water is not getting away fast enough with a type 1 riser, you could try a type 2.
So which one is better? It depends on engineering requirements.
|Type 1 inlet|
|Type 2 inlet|