Prvevious flood flows cut a path through this gully floor, but the damage done to the field is still minor, because the valley is very wide. This would not be true if the gully floor is relatively narrow. The majority of gullies must be protected from floods.
Some early design for flood drainage is quite elaborate, as shown in this site at Fenxi, Shanxi, where concrete ditches are employed, but this is far too complex, and would not be cost effective. It will be simpler just build a key dam upstream to arrest the entire flood flow.
For more on Fenxi's dam system, see Fenxi.