(a)
General definition
As used in this subchapter, the term “improved property” means a detached, one-family dwelling, construction of which—
(1)
was begun before December 31, 1964, or
(2)
for the purposes of section
460x–9
(b) or (d) of this title, was begun on or after December 31, 1964, and before October 21, 1970, and has been openly and continuously used, at least during the summer months of each year when similar dwellings in the area are used, as a residential dwelling since such construction was completed, and with respect to the portion of such period after any acquisition of such property by the United States, by the owner, or a member of the immediate family of the owner, of such dwelling on the date of such acquisition,
together with so much of the land on which the dwelling is situated, such land being in the same ownership as the dwelling, as the Secretary shall designate to be reasonably necessary for the enjoyment of the dwelling for the sole purpose of noncommercial residential use, together with any structures accessory to the dwelling which are situated on the lands so designated. The amount of land so designated shall in every case be at least three acres in area, or all of such lesser acreage as may be held in the same ownership as the dwelling, and in making such designation the Secretary shall take into account the manner of noncommercial residential use in which the dwelling and land have customarily been enjoyed.
(b)
Authorization to exclude beach lands
The Secretary may exclude from the land designated under subsection (a) of this section any beach or waters on Lake Michigan, together with so much of the land adjoining any such beach or waters as the Secretary may deem necessary for public access thereto. If the Secretary makes such exclusion, an appropriate buffer zone shall be provided between any residence and the public access or beach.