It shall be unlawful for any person to obstruct, or cause to be obstructed, any drains, ditches or watercourses within the corporate limits. Every person owning, controlling or in possession of land, through which or through part of which a stream, ditch, gully or any natural drain runs, shall keep the bed of same free from obstructions. They shall not allow any growth of weeds or shrubbery on or along the banks thereof which will prevent sunlight from entering therein. When overflows or floods form pools or backwaters therein, they shall be promptly drained.