Is it possible that low-flow sampling may not be a good approach if you are designing a pump and treat system?

Remedial systems are best designed on the basis of the site conceptual model. The data you get from monitoring wells that are pumped at a higher flow, while they may represent the “worst case scenario,” they do not represent the ambient groundwater flow conditions and the naturally mobile contaminant load. By developing a site conceptual model from a number of sampling points using low flow purging and sampling, you get a much better idea of the contaminant distribution on the site. If you are trying to determine what the loading will be into your remedial system for a pump and treat system it is important to first take some samples from the extraction wells and identify the concentrations that you’re getting there and the loading you’re getting in terms of turbidity. In terms of designing the actual pump and treat system, installing the extractions wells and taking samples from the high flow wells to design the remedial system makes sense. But, in term of determining where the contaminant mass is located, those high flow samples will not give you good input into a site conceptual model.