By January 1, 1991, mental health identification and intervention services must be available to meet the needs of all children and their families residing in the county, consistent with section 245.4873. Mental health identification and intervention services must be designed to identify children who are at risk of needing or who need mental health services. The county board must provide intervention and offer treatment services to each child who is identified as needing mental health services. The county board must offer intervention services to each child who is identified as being at risk of needing mental health services.