“Through the use of concession contracts or commercial use authorizations, the National Park Service will provide comercial visitor services that are necessary and appropriate for public use and enjoyment. Concession operations will be consistent to the highest practicable degree with the preservation and conservation of resources and values of the park unit. Concession operations will demonstrate sound environmental management and stewardship. Public accommodations, facilities, and services must be consistent to highest practicable degree with the preservation and conservation of park resources and values”. Fonte: o editor