Microbiological Assessments of Groundwater/Surface Water Interactions

Common regulations call for bacterial testing that does not fully identify the true microbiological communities existing down hole. Surface water influence is often not determined or even assessed until several years after wells have been in operation. Wells evaluated for bacteria are often only classified by the results of coliform testing.  This broad definition of bacteria often is insufficient to understand not only the microbiological flora within the well but also any potential influence from surface water sources, be they recharge, flooding, or contamination. Similar inconsistencies in testing requirements exist for inorganic water chemistry as well as sediment influence, compounding the level of interaction and the potential for harm. This presentation will focus on case studies of potable and environmental well systems influenced by surface water, as well as present a discussion of investigative laboratory methods.