United States v. 57.09 Acres of Land in Skamania Cty. (Peterson I), 706 F.2d 280, 281 (9th Cir. 1983), citing United States v. Grizzard, 219 U.S. 180 (1911), and United States v. Welch, 217 U.S. 333, 339 (1910) (“the value of the easement cannot be ascertained without reference to the dominant estate to which it was attached”).