Neb. Rev. Stat. §§ 13-1414
In the construction of docks, levees, wharves, and their appurtenances, or in contracting for the construction of any work or structures authorized by sections 13-1401 to 13-1417, the dock board shall proceed only after full and complete plans, approved by the board, and specifications for said work, have been prepared and submitted and filed with the board by its engineer for public inspection, and after public notice asking for bids for the construction of such work, based upon such plans and specifications, has been published in some legal newspaper of general circulation published within the county or municipality, as the case may be, or if none is so published, then in the nearest legal newspaper published in this state. Such publications shall be made at least thirty days before the time fixed for the opening of said bids and contracting for such work. A contract may then be made with the lowest responsible bidder therefor, unless the board deems the bids excessive or unsuitable, in which event it may proceed to readvertise for bids, or the board may do the work directly, purchasing such materials and contracting for such labor as may be necessary without further notice or proposal for bids; except that it shall make no purchase of materials in amounts exceeding five hundred dollars except by public letting upon ten days' notice, published as aforesaid, specifying the materials proposed to be purchased; Provided, that said public letting shall not be required in case no satisfactory bids are received, or in case of an emergency where the delay of advertising and public letting might cause serious loss or injury to the work. The board shall, in all cases, have the right to reject any and all bids, and may either readvertise therefor, contract with others at a figure not exceeding that of the lowest bidder without further advertising, or do the work directly as hereinbefore provided.
Neb. Rev. Stat. §§ 13-1414