§ 8. Any agency of the state or any city, town, village, or public
corporation, which is empowered by law to take private property by
eminent domain for any of the public purposes specified in section one
of this article, may be empowered by the legislature to take property
necessary for any such purpose but in excess of that required for public
use after such purpose shall have been accomplished; and to improve and
utilize such excess, wholly or partly for any other public purpose, or
to lease or sell such excess with restrictions to preserve and protect
such improvement or improvements.