The Clerk shall establish a proper system of accounts and shall keep proper books, records and accounts in which complete and correct entries shall be made of all transactions relative to the sewerage system and wastewater treatment works, and at regular annual intervals shall cause to be made an audit by an independent auditing concern of the books to show the receipts and disbursements of the sewerage system. In addition to the customary operating statements, the annual audit report shall also reflect the revenues and operating expenses of the wastewater facilities, including a replacement cost, to indicate that the wastewater service charges do in fact meet these regulations. In addition to the proper system of accounts established for the transactions relating to the sewerage system and wastewater treatment works a Sewer Replacement Fund shall be established specifically for direct costs related to replacement of capital equipment. The City shall deposit into the Sewer Replacement Fund on an annual basis a minimum of $62,500, or an amount to be calculated by the staff and approved by the Council.