“Local agency” means any local agency, other than a local government, formed pursuant to general law or special act for the local performance of governmental or proprietary functions within limited boundaries or which maintains facilities within the delta. “Local agency” includes, but is not limited to, a port, water agency, flood control district, county service area, maintenance district or area, improvement district or improvement area, mosquito abatement district, resource conservation district, irrigation district, reclamation district, sanitary or sewer district, or any other zone or area, formed for the purpose of designating an area within which either an assessment or a property tax rate will be levied to pay for a service or improvement benefiting that area or a special function will be carried out within that area.