Funds in the SRF shall not be used to provide grants. SRF balances must be available in perpetuity and must be used solely to provide loans and other authorized forms of financial assistance:

(a) To municipalities, inter-municipal, interstate, or State agencies for the construction of publicly owned wastewater treatment works as these are defined in section 212 of the Act and that appear on the State's priority list developed pursuant to section 216 of the Act; and

(b) For implementation of a nonpoint source pollution control management program under section 319 of the Act; and

(c) For development and implementation of an estuary conservation and management plan under section 320 of the Act.