Drainage channels and floodplains which exist and are essential for the maintenance of the health and general welfare of the people must be inviolate. Any encroachment upon, filling or destruction of these drainage channels or floodplains is a violation of this chapter. In order to provide for the development of property for its best use, such as new subdivisions, the City Engineer shall determine what facilities are adequate to maintain the prime purpose of the drainage channel or floodplain.
('65 Code, § 1323.22)