(a) To secure the due and prompt payment of both principal and interest of any bonds issued under the provisions of this subchapter, the entire revenues, or a fractional part thereof as the board deems expedient and necessary, arising from annual taxes to be levied on the increased value or betterment to accrue to the lands, town lots, blocks, railroads and tramroads, telegraph and telephone lines, electric power lines, and other real property, are pledged.
(b) The board of directors of the district is required to set aside annually from the first revenue collected a sum sufficient in amount to secure and pay the interest on the bonds and the principal thereof, as the interest and principal may become due. Its duty to do so may be enforced by mandamus proceedings.
(c) The principal and interest of the bonds shall be secured by a lien on all the lands, town lots, blocks, railroads and tramroads, telegraph and telephone lines, and electric power lines, and all other real property in the district.
(d) The board of directors may pledge all or any part of the assessment of benefits and its revenues as security for the payment of the principal and interest of the bonds.