It shall be unlawful for any persons, firm, or corporation, municipality or district to place or cause to be placed in the channel or bed of any river, stream, wash, or arroyo, or upon any property over which the Los Angeles County Flood Control District has an easement for flood control purposes duly recorded in the office of the County Recorder in Los Angeles County, any wires, fence, building, or other structures, or any refuse, rubbish, tin cans, or other matter that may impede, retard, or change the direction of the flow of water in such river, stream, wash, or arroyo, or that will catch or collect debris carried by such water, or that is placed where the natural flow of the storm and floodwaters will carry the same downstream to the damage or detriment of either private or public property adjacent to such river, stream, arroyo or channel.
(`83 Code, § 12.28.010)