Cal. PCC § 20961

No levees, dikes, or other works for the benefit of the district may be constructed or repaired except on the order of the board of trustees of the district and when the repair or construction will exceed five hundred dollars ($500) the work may be performed only under a contract let, after reasonable notice given by the board of trustees by publishing the notice at least once a week for two weeks in a newspaper published and circulated in the county and designated by the board of trustees. All bids shall be sealed and shall be opened at the time specified in the notice, and the contract shall be awarded to the lowest responsible bidder. The board may, however, reject any and all bids. The contract and bond for its performance must be entered into and approved by the board of trustees, except, however, in cases of emergency, by the unanimous consent of the whole board of trustees they may proceed at once to replace or repair levees, dikes, or other works without notice. In case of emergency, if notice for bids to let contracts will not be given, the board shall comply with Chapter 2.5 (commencing with Section 22050). Prior to the publication of the notice of the letting of any contract for the erection or repair of dikes, levees, or other works, the board of trustees shall have prepared by a competent engineer, plans and specifications and working details of the work, that shall be adopted by the board of trustees and filed in the office of the board and shall be subject to inspection by any person for at least two weeks prior to the date of the letting of the contract. The board of trustees shall appoint an engineer to supervise the construction, repair, or other works to be done under the plans and specifications and no claim shall be allowed for any work done under any contract let under those plans and specifications without a certificate being first filed in the office of the board of trustees and in the office of the clerk of the board of supervisors of the county signed by the engineer, certifying that the work has been completed and constructed according to the plans and specifications and the terms of the contract. The engineer shall be paid the compensation agreed upon by the board of trustees and the compensation shall be paid in the same manner as other claims against the district.