The assessment of benefits against, and award of damages to, every lot or land owner who has been notified as provided in section 31-909 and who fails to file objections or having filed objections fails to prosecute appeal from ruling thereon, shall be final. The collection of any assessment levied shall not be enjoined, nor shall it be set aside or be held void because of any irregularity or error committed in any of the proceedings had under sections 31-901 to 31-933. The award of damages to any such lot or land owner shall likewise be final and no claim shall be made against the county or the area benefited because of any claimed subsequent or consequential damages arising because of said improvement.