Will digging 12/15 inches for a dry creek bed alleviate flooding in backyard?

Planning on putting a dry creek bed in yard. Have a flooding issue when it rains, flows right over the existing landscape. If I dig 12/15 inches deep finish the dry creek bed will water stay there or continue to flood the rest of the yard? Help, thanks m

it depends on the slope of the land and where the ditch goes, if it is all flat and the ditch doesn't drain anywhere then it wont help at all.