In addition to all other powers and duties prescribed by law, the state parks and recreation commission is authorized and directed to acquire such real property, easements, or rights in the Green River Gorge in King county, together with such real property, easements, and rights as is necessary for such park and conservation purposes in any manner authorized by law for the acquisition of lands for parks and parkway purposes. Except for such real property as is necessary and convenient for development of picnicking or camping areas and their related facilities, it is the intent of this section that such property shall be acquired to preserve, as much as possible, the gorge within the canyon rim in its natural pristine state.