I appreciate the graphical endeavor

As CalG replied, slowing down the water would be bad. In fact I'm pretty sure my December washout was either because one culvert became overwhelmed, or because the ditch had enough debris in the form of ice/snow/other that the water couldn't move fast enough. There was a 15 foot section of driveway where the water just overflowed the ditch and went across the driveway. Though in that place it didn't wash out too much gravel because it was such a wide overflow. Maybe I just need another culvert, bedrock permitting. I don't know if they had to blast and/or jackhammer or whatever to place the original pipes.
Still I'll definitely take a look at those next time I'm at Home Depot.