SEC. 13. Section sixty-one of the same Act is hereby amended to read as follows:
"SEC. 61. The leases executed under this chapter by the Secretary of Agriculture and Natural Resources shall, among other conditions, contain the following:
"(a) The rental shall not be less than three per centum of the appraised and reappraised value of the lands and one per centum of the appraised or reappraised value of the improvements.
"(b) The land rented, or the improvements thereon, as the case may be, shall be reappraised every ten years if the term of the lease is in excess of that period.
"(c) The term of the lease shall be as prescribed by section thirty-seven of this Act.
"(d) The lessee shall construct permanent improvements appropriate for the purpose for which the lease is granted, shall commence the construction thereof within six months from the date of the award of the contract of lease, and shall complete the said construction within eighteen months from the date of the execution of the contract.
"(e) At the expiration of the lease or of any extension of the same, all improvements made by the lessee, his heirs, executors, administrators, successors, or assigns shall become the property of the Government.
"(f) The regulation of all rates and fees charged to the public; and the annual submission to the Government for approval of all tariffs of such rates and fees.
"(g) The continuance of the easements of the coast police and other easements reserved by existing law or by any laws hereafter enacted by the Legislature.
"(h) Subjection to all easements and other rights acquired by the owners of lands bordering upon the foreshore or marshy land.
"The violation of one or any of the conditions specified in the contract shall give rise to the rescission of said contract. The Secretary of Agriculture and Natural Resources may, however, subject to such conditions as he may prescribe, waive the rescission arising from a violation of the conditions of subsection (d), or extend the time within which the construction of the improvements shall be commenced and completed."