Cal. Wat. Code § 12617.1
The department, in making investigations and plans for water projects and for the solution of the water problems of the state pursuant to Sections 12616 and 12617, shall include plans and recommendations for the protection of the quality of the waters affected, including downstream waters, with respect to all sources of impairment and factors affecting quality. In doing so, the department shall cooperate with counties, cities, state agencies, and public districts to the end that planning for water quality control shall be coordinated to the maximum extent possible. Such plans and recommendations shall be transmitted to the State Water Resources Control Board and to the appropriate California regional water quality control boards for their consideration in the adoption of state policy for water quality control, water quality control plans, and waste discharge requirements.
Ca. Water Code § 12617.1