It is the intent that employees take their accrued vacation leave during the calendar year. Employees who are unable to take accrued vacation leave for which they are eligible within the year due to work incurred disability or work requirements as determined by the department director that cannot be carried over as provided in PCC 3.72.040 shall, upon approval of the Human Resources Director, be allowed to carry over additional vacation leave provided it is used prior to July 1st of the following year and may not be cashed out in a lump sum payment due to termination.