There is hereby created in the state treasury the central support indirect fund, which shall be administered by the director of environmental protection. Money credited to the fund shall be used for administrative costs of the environmental protection agency. The director may assess any operating funds from which the agency receives appropriations, except the central support indirect fund, for a share of the administrative costs of the agency. The amounts assessed shall be transferred to the central support indirect fund by means of intrastate transfer vouchers. The director shall determine the rate of assessments.