Farm drainage ditches help keep thousands of acres of Minnesota cropland dry enough to produce crops each year. Some say the ditches do their job too well and are such efficient water movers they contribute to downstream flooding. During this year's floods one county engineer said ditches became "raging rivers", with their own distinct flood plains. Economic gain versus environmental damage....that's the arguement behind a dispute between two southwest Minnesota counties over the reconstruction of a farm drainage ditch. Mark Steil of Mainstreet Radio reports: The farmland water Yellow Medicine and Lyon