May BRGS Meeting: Preliminary Characterization of Site Hydrogeology

There are many methods and strategies used to characterize the hydrogeology of areas of interest in which no previous investigation has been completed, or no records of previous work exist. Textbook approaches to hydrogeology characterization are often too intensive to be practical or not economical to use. However, there are approaches to prepare preliminary characterizations of locations of interest prior to committing to a full-scale investigation. The approaches presented can enable better planning and practical evaluation of a location, reduce time and cost, and provide the preliminary information needed. A sound preliminary characterization of site hydrogeology can be prepared from the use of basic existing information and site reconnaissance using basic hydrogeology concepts.

To initiate characterization of an unknown site, obtaining the available regional and local hydrogeologic setting information relevant to evaluating the location is the most obvious starting point. Research literature often provides much of the data needed for preliminary characterization. The expected regional stratigraphy, the depth of groundwater, the physiography and geomorphology, and the regional groundwater flow direction can be useful to define site specific characteristics. Site reconnaissance is invaluable to evaluate site location factors that influence groundwater flow direction and velocity and identify sources for recharge and discharge in the shallow groundwater.  Considering both research literature and site reconnaissance information will enable the estimation of well yields, groundwater quality, and identify key hydrogeologic risks at the location. Preparing a preliminary characterization results in better sampling programs, drilling methods, well designs, and well placement leading to reduced costs and time needed to complete site investigation.