Section 9. When injury has been caused to the real estate of any person by the establishment, construction, maintenance, operation, alteration, repair or discontinuance of a public improvement which does not involve the taking of private property, and he is entitled to compensation by law for such injury, if such establishment, construction, maintenance, operation, alteration, repair or discontinuance was effected by or in accordance with a formal vote or order of the board of officers of a body politic or corporate duly authorized by law, the damages shall be awarded, determined and collected and notice of the order shall be given in the same manner as if there had been a taking of property on behalf of such body politic or corporate under section one. In case such establishment, construction, maintenance, operation, alteration, repair or discontinuance is an improvement for which betterments may be assessed, such vote or order shall state whether betterments are to be assessed therefor. The damages shall be assessed as of the date when the vote or order is adopted, but the right to damages shall not vest and the damages shall not be paid until the work which caused the injury has been completed, or until the public improvement which has been discontinued has ceased to be open to public use, or, in the case of injury to any water, water source or water or flowage right, until the water is actually withdrawn or diverted, and if the order does not go into effect, or is rescinded or altered, only so much of the damages shall be paid as has been actually sustained.