Twelve-Month Period means a period of twelve consecutive months determined on a rolling basis where a new twelve month period begins on the first day of each calendar month.
Month means calendar month.
months shall be construed in accordance with Clause 1.3;
Working level month (WLM) means an exposure to 1 working level for 170 hours (2,000 working hours per year divided by 12 months per year is approximately equal to 170 hours per month).
Average monthly discharge limitation means the highest allowable average of "daily discharges" over a calendar month, calculated as the sum of all "daily discharges" measured during a calendar month divided by the number of "daily discharges" measured during that month. Compliance with fecal coliform bacteria or E coli bacteria limitations shall be determined using the geometric mean.