Idaho Code § 42-2948

In the construction of any diking system under the provisions of this chapter, where it is desired to construct the same along the right of way of any public road which has theretofore been legally established, said district shall have a right to construct its dikes along such road: provided, that the dikes so constructed along such road shall not destroy or impair the same for use as a public highway; and in case of the construction or improvement of any dike along any public highway, such dike shall be constructed of sufficient width and in such manner as will be of use as a public highway.