Zhang, director of the General Office of the State Council, is mainly responsible for the South-to-North Water Transfer Project. He told the national conference that more surface tributaries will be developed along the two major rivers of the world's largest water transfer project.

There is no definite article after Zhang's comma because there is no specific meaning here. He is just the office director in charge of one of the projects.

Ambitious originally meant "ambitious, ambitious; Ambitious "can be translated as" grand, great and huge "according to the context here.