Whenever the commissioner takes any land he may find necessary for the layout, alteration, extension, widening, change of grade or improvement of any state highway, pursuant to the provisions of subsection (b) of § 13a-73 and sections 13a-74 and 13a-78, the state shall pay the owner just compensation therefor. In determining the amount of all benefits received by the owner resulting from taking such land and the amount of damages for taking such land as suffered loss due to flood or any other natural disaster occurring from August 18 to October 31, 1955, due consideration shall be given to the real and potential value of the land based upon its use and location, that is, the value which the property would have were it deemed to be restored to the productive uses it had prior to August 18, 1955, and in arriving at such value there shall be used a sum not less than the full valuation of the real property by the assessors of the town in which the property is located for the last-completed grand list of such town less the amount of any payment received by the owner from any public or private agency for damage to such real property. Any grantee who took title to any such real property between August 18, 1955, and December 23, 1955, shall receive benefits in accordance with this section for the flood-damaged property and the record owner as of August 17, 1955, shall be entitled to such benefits for the improvements on such real property as of August 18, 1955; provided no compensation has been received therefor by any other person from the state. This section shall be effective only as to any land determined to be taken by the Highway Commissioner before July 1, 1963.