The powers conferred by this chapter are in addition to, and not in place of, any other powers conferred upon the Chino Basin districts. Production assessments levied pursuant to this chapter shall be deemed necessary to further the activities of the Chino Basin districts in the protection of the ground water supplies of the Chino Basin for the public health, safety, and welfare. Production assessments are authorized to be levied upon the production of ground water from the Chino Basin for the benefit of all members of the public who rely directly or indirectly upon such ground water supplies.