Photographed in very shallow water in a roadside ditch following big rain event (Ditch is usually or more often dry.)
Habitat was very small perennial stream feeding into larger, wooded vernal pool.
Constructed in center of decaying stump.
Big! Appeared to extend straight down the main trunk.
Was at surface level in small hole next to creek. No raised mounds present, hole under decaying piece of wood. I thought this might be C. fodiens or similar in the field but I didn't have my camera with me or long to take photos of the specimen unfortunately.