No land shall be open to entry and no water rights shall be sold by the parties under contract with the Water Resources Commission until the construction of the works is sufficiently advanced to insure a water supply, and the entry of an order by the commission opening the land or any portion thereof to entry and sale. All applications to purchase lands, or for release of lien for construction of the reclamation works, shall be upon the forms provided by the commission. The ‘date of reclamation,’ for the purposes of ORS § 555.010 to 555.160, shall be the date shown by the proof furnished the Secretary of the Interior by the commission at which water was furnished available for the reclamation of each tract in the list of lands.