Why this law exists and what it allows

(a) The provisions which are set forth hereinafter are authorized pursuant to HRS § 46-11.5, relating to the maintenance of channels, streambeds, streambanks, and drainageways. (b) The provisions set forth hereinafter are intended to provide the necessary power and authority to the department of facility maintenance, an executive agency of the city, to provide for and enforce the maintenance of channels, streambeds, streambanks, and drainageways, including their exits to the ocean, in suitable condition to carry off stormwaters, prevent flooding and to ensure that the natural flow of water runs unimpaired; and for the removal from the channels, streambeds, streambanks, and drainageways, any debris, vegetation, silt, or other items or material of any nature, which is likely to create an unsanitary condition, blockage, or otherwise become a public nuisance to the health, safety, and welfare of the residents of the city; provided that to the extent any of the foregoing work is a private responsibility, the responsibility may be enforced by the city in lieu of the work being done at city expense, and any private entity or person refusing to comply with any final order issued by the city shall be in violation of this article and HRS § 46-11.5.