Whenever a part of a larger parcel of property is to be acquired by a public entity for public use and the remainder, or a portion of the remainder, will be left in such size, shape, or condition as to be of little value to its owner or to give rise to a claim for severance or other damages, the public entity may acquire the remainder, or portion of the remainder, by any means (including eminent domain) expressly consented to by the owner.
Ca. Civ. Proc. Code § 1240.150