All right, I don't believe they're gophers (golfers!) but they are surface burrowers.
I see these curvy 2" high, maybe 4" across, humps running around portions of my lawn, sometimes for 15' feet or more. (primarily where there really isn't much turf -- more tufts and the weed of the season. Step on 'em, they squish back down., a little excavation and the tunnels are over an 1", 2" tops in diameter.
The other day some _other_ critter seemed to be attempting to snack on the burrower. along the curvy hump were a series of digs with tufts upturned and lots of exposed dirt.
I love how nature can send a helper (possum? 'coon?) to balance the population -- but aside from hiring a scrum of possums, Does anyone have an idea of what these burrowers are? And maybe an effective, and as enviro-friendly-as-possible, solution?
If it helps: I've seen, what I presume are surface (literally) trails from the same species in the winter during warm breaks (downstate NY). Much Tighter curves in the path during winter. Usually around/through/near a "rougher" area (lot of leaf litter/bushy area), but also into the lawn. Trough construction rather than tunnel. Similar width/diameter (1-2").
I've got plenty of chipmunks (lot of exposed rocky slope here). Just doesn't seem like a chipmunk travel mode though.