If the proceeds of the assessments levied for the payment of the original bonds shall at any time prove insufficient to pay principal of and interest on such refunding bonds, or if it shall at any time appear to the board of viewers that there is likelihood of the insufficiency of such assessments, the board shall provide for the levy and collection of additional assessments sufficient for such purpose and the holder or holders of refunding bonds issued hereunder shall have a right of action to compel such levy in the manner provided in this chapter.
Va. Code § 21-417