The unit financial charge shall be reviewed annually and shall be revised as necessary to keep revenues reasonably in balance with anticipated expenditures.  Excess funds may be carried forward from year to year in order to build sufficient funds for large drainage construction projects which are scheduled or programmed for the near future.  In addition, funds may be carried over to provide sufficient monies for unanticipated repairs, replacements, or maintenance of the drainage system.  (Ord. 90/T-9312)