If the governing body finds that the bonds authorized by the original resolution or ordinance shall be insufficient to accomplish the purpose desired, additional bonds may be authorized, issued, and disposed of under the procedure provided in this chapter, but the additional issues shall be junior to all prior issues, unless provision has been made in the contract and covenants of the first or second class municipality with the holders of the original bonds for the issuance of additional bonds on a parity therewith.
SDCL 9-41-3