Where the person causing any damage, alteration, enlargement or obstruction to any irrigation work without proper authority cannot, after such inquiry as the Collector may deem sufficient, be ascertained or identified, the Collector may on a requisition from the Irrigation Officer and after giving not lea than one month's notice to the owners of all the lands benefited by the damage alteration, enlargement or obstruction, as the case may be, and after hearing their representations, if any, recover from them, in such proportion as he thinks fit, the cost of repairing such damage, or of removing such alteration, enlargement o obstruction.