The Pacific Northwest (PNW), sometimes referred to as Cascadia, is a geographic region in western North America bounded by the Pacific Ocean to the west and (loosely) by the Cascade Mountain Range on the east.
Mean time between failures (MTBF) describes the expected time between two failures for a repairable system, while mean time to failure (MTTF) denotes the expected time to failure for a non-repairable system. the MTBF is the sum of the operational periods divided by the number of observed failures.
Peak rates of flow are related to hourly volumes through the use of the peak-hour factor. This factor is defined as the ratio of total hourly volume to the peak rate of flow within the hour: PHF = Hourly volume/Peak rate of flow (within the hour) If 15-min periods are used, the PHF may be computed as.