Colo. Rev. Stat. § 37-24-101
After adopting a plan for a drainage system and providing for the payment of the same, or a designated part thereof by assessment or bonds, the board of directors shall give notice, by publication not less than twenty days prior to the date of opening proposals in a newspaper published in the county where the office of the drainage district is kept and in such other newspaper as may be deemed advisable, calling for bids for the construction of said work or any portion thereof; if less than the whole, then the portion of said system to be constructed shall be described in the notice. The notice shall set forth where the plans and specifications may be seen and that sealed proposals will be received at the office of the drainage district and a contract let to the lowest responsible bidder, giving the time and place for opening the proposals, which, at said time and place, shall be opened in public. The board of directors may enter into a contract with the lowest responsible bidder for the construction of the whole or any portion of the work mentioned in the notice, or may reject any and all bids and readvertise for proposals, or may proceed to construct the work under the supervision of the board of directors, and in that event all material shall be purchased from the lowest responsible bidders after proposals have been invited and notice thereof published.
C.R.S. § 37-24-101
For publication of legal notices, see part 1 of article 70 of title 24.