The State Department of Health Care Services may contract with counties whose programs have been approved by the department and selected pursuant to Article 4 (commencing with Section 5857). A county may request to participate under this part each year according to the terms set forth in Section 5705 for the purpose of establishing a three-year program proposal for developing and implementing a children’s comprehensive mental health services system. The contract shall be negotiated on a yearly basis, based on the scope of work plan for each implementation phase.