Consider throwing some straw bails into the larger ditches until dirt and re-seeding can take place. I am talking about a single bail here and there to stop some of the dirt from washing all the way down the ditch. Staking them down may be necessary if the washout carries a lot of water.
I wonder if re-seeding now would be recommended for your area of the country? If your original seed is gone, re-seeding the good places makes sense to me.
