(1) The assessment made or levied for watershed improvement shall be a lien on the respective tracts of land upon which it is assessed, and this lien shall be enforced in the same manner as provided for the enforcement of the lien for drainage assessment under chapter 5 of this title, which is incorporated in this section by reference. In no event shall watershed improvement assessment be deemed to be the personal obligations of the landowners.
(2) The court may authorize the issuance of bonds by the district to cover the cost of the project, for the payment of which bonds the assessments upon the lands benefited by the project may be pledged. The terms and conditions of the bonds, as well as their schedule of payment, shall be fixed by the court, but in no event shall the date of the maturity of the final payment under such bond schedule exceed thirty (30) years after the date of issue.