All maintenance to be performed upon and within the streets, alleys, avenues, public places and public ways, shall be performed, done and completed by forces employed by the city, or by contract with independent contractors, in such manner and upon such terms as the city council may, from time to time, by ordinance, elect. All maintenance performed within the district shall be performed and completed according to the then current standards or norms for that type of maintenance work accepted and practiced within the area of the city, taking into consideration the climate, weather and time of year upon which the maintenance is performed, as well as the type of street construction, whether it be asphalt, gravel or concrete, as well as all other pertinent factors, so that the maintenance performed will be of a durable and continuing benefit to the streets, avenues, alleyways, public ways and public places within the district. (Ord. 493 § 1, 1987)