When the owners of ten percent of the land in a drainage or levee district having and operating a pumping station shall petition the board of supervisors to extend the time of payment of the taxes assessed against the lands within said district for a period not exceeding twenty years, under such rules and regulations as said board may direct, the interest on such assessments to be paid annually the same as other taxes levied against the property, not less than one-twentieth of the principal of said extended tax to be paid each year until the entire tax is paid, and the lien of such tax to continue until fully paid, the board of supervisors may settle, adjust, renew, or extend the legal indebtedness of such district as shown by the assessments levied against the lands therein whether evidenced by certificates, warrants, bonds, or judgments by refunding all such indebtedness and issuing coupon bonds therefor when such indebtedness amounts to one thousand dollars or upwards, but for no other purpose.