The Council shall have power to determine by resolution that the whole or any part of the expense of any public improvement shall be defrayed by special assessments upon the property especially benefitted. Such resolution shall state the estimated cost of the improvement, what proportion of the cost thereof, if any, shall be paid by special assessment, and what part, if any, shall be a general obligation of the City, and the number of installments in which assessments may be paid, and shall designate the districts or land and premises upon which special assessments shall be levied.