Exclusion is generally not practical and it has had limited success. However, in some circumstances, exclusion can prevent damage. An underground fence of 1/4- or 1/2-inch wire mesh can be used to protect individual flower beds, trees, or shrubs. The fence needs to be buried at least 18 inches. Additionally buried utility cables or irrigation pipes may need protection by enclosing them in various materials that resist gopher gnawing. Also, when installing underground cable or pipe, the trench should be filled with large gravel, at least 1 inch or greater. The gravel should surround the pipe at least 6 inches, to keep gophers from digging near the pipe. Gophers cannot bite into the surface of a cable or pipe if it exceeds 2 7/8 inches in diameter.