The department shall have the overall responsibility and authority for the formulation and implementation of a long-range master plan for the improvement of the Capitol Mall. Such plan shall be integrated and compatible with the development plans of all appropriate public and private interests, including the Sacramento Central City Development Projects. The principal objective of this master plan shall be to provide a physical and aesthetic expression in the approaches to the State Capitol Complex and to embody the best the state can produce in coordinated environmental planning and architectural integrity.