The finance officer shall establish a separate fund for each fee listed in Section 9-41(a). Money from the storm sewer trunk line fund and the sanitary sewer trunk line fund may be pooled for purposes of jointly funding storm and sanitary sewer projects. Any interest accrued on money in each fund shall be added to that fund. Expenditures from each respective fund shall be made only in accordance with the purposes for which that fund was established. (Ord. No. 1847 (NCS), § 1.)