All bonds and evidences of indebtedness issued by the commissioners under the terms of this chapter shall be secured by a lien on all lands and railroads subject to taxation under this chapter, in an amount not to exceed the amount of benefits assessed against such lands and railroads. The board of commissioners shall see to it that an assessment is levied annually and collected under the provisions of this chapter, so long as it may be necessary for the payment of any bonds issued or obligations contracted under its authority, together with the interest thereon; and the making or levying of said assessment or levy may be enforced by mandamus at the instance of any person interested.