How frequently should flow-proportioned automatic samplers collect samples in a 24-hour period?

Flow-proportioned automatic samplers are essential tools in environmental monitoring, particularly in assessing wastewater and stormwater discharge quality. The frequency of sample collection is crucial for obtaining representative data that accurately reflects variations in flow and pollutant concentration throughout the day.

Collecting samples at least once every hour allows for adequate representation of daily flow variations that can occur due to changes in water usage, precipitation, and other factors. This high sampling frequency is important because pollutants may fluctuate significantly within short time frames, especially during peak flow periods or following rain events that introduce runoff into systems. By sampling every hour, the automatic sampler can better capture these fluctuations and provide a more comprehensive picture of the water quality over time.

Conversely, less frequent sampling intervals, such as every 2 hours, 12 hours, or every 5 hours, may miss critical variations and lead to an underrepresentation of short-term spikes in pollutant levels. As a result, the data collected could give a misleading view of the environmental impact, which is why the choice of sampling frequency is critical in achieving reliable and informative results.