Every county shall have the right of entry upon every irrigation, drainage, or flood control canal or ditch right-of-way within its boundaries for all purposes necessary to safeguard the public from the hazards of open canals or ditches, including the right to clean such canals or ditches to prevent their flooding adjacent lands, and the right to cause to be constructed and maintained on such rights-of-way or adjacent thereto safeguards as authorized by RCW 36.88.015: PROVIDED, That such safeguards must not unreasonably interfere with maintenance of the canal or ditch or with the operation thereof.