(Added by Ordinance No. 160515 effective Mar. 28, 1988.)  The Sewer System Operating Fund is hereby made a part of the Code of the City of Portland, Oregon, for the receipt and expenditure of monies associated with operation and maintenance of the sewer system, including sanitary and drainage services.  Monies in the Sewer System Operating Fund may be transferred to the Sewer System Debt Redemption Fund, the Sewer System Construction Fund, or the Sewer System Rate Stabilization Fund.  Money in the Sewer System Operating fund may be commingled with other City money for investment purposes.