In case any of the permanent grades are not practical, any owner or owners of property along the block where it is alleged such grade is impractical may petition the council in writing for a change of such grade, which petition shall set forth what the grade is as per the survey, what the conditions are which render the same impractical, and what is a practical survey or grade, and the council shall have a right to thereupon by resolution change such grade or survey, and such new grade shall be the permanent grade thereafter, and the clerk shall keep a proper record of such change. (1957 code § 8.08.040.)