Excavations in streets and alleys for the purpose of constructing, repairing, altering or tapping sewers shall be made in a manner that will impede travel as little as possible. The director may determine and limit the time such excavations remain open and when unnecessarily delayed, may direct that the number of workmen be increased. Warning lights shall be maintained at all unfinished work, from dark to daylight. All work is to be done in accordance with OSHA rules and regulations. After the work has been completed, the streets or alleys shall be repaired to the satisfaction of the director. Within one year of the excavation, the director may require the excavation to be refilled if settling has occurred.