(a) The moneys derived from the tax levied under the provisions of this subchapter on the increased value, or betterment, which will accrue to the lands, town lots, blocks, railroads and tramroads, telegraph and telephone lines, electric power lines, and other real property, by reason of the construction of the flood control and drainage works provided for in the adopted and authorized project, shall be designated as the tributary tax fund.
(b) These moneys shall be expended for the purposes of:
(1) Paying the principal and interest indebtedness evidenced by bonds or notes issued by the district as provided in this subchapter; and
(2) Enabling the district to comply with the obligations imposed upon, and assumed by, the board of directors in contracts and agreements it makes with the United States of America, the Secretary of the Army, the Chief of Engineers of the United States Army, or any other federal agency with respect to the construction of the flood control and drainage works as provided for in the adopted and authorized project and the perpetual operation and maintenance thereof under regulations prescribed by the Secretary of the Army; and
(3) Payment of administrative and operating expenses incurred by the district in the performance of its obligations hereunder.
(c) The board of directors of the district shall apportion all administrative and operating expenses of the district between the tributary tax fund and the other operating funds of the district in such manner and amounts as the board of directors shall deem reasonable and proper, and shall pay that part of the administrative and operating expenses apportioned to the tributary project from tributary tax funds.