Since 1994, groundwater level data has been monitored in shallow wells at OAI's "Gulf Coast Groundwater Research Center".  The wells are completed in a shallow alluvial aquifer adjacent to Eslava Creek in Mobile, Alabama (USA).  The water level in the wells is influenced by precipitation events and the stage of Eslava Creek.  Over the years, both periodic and detailed water level mesurements were collected with the data analyzed.  The periodic data was recorded at various time frequencies for specific events such as hurricanes or as a logger was available.  The first chart, see below, is a composite chart showing the groundwater elevation recorded in MW-2 between Novemebr 2000 and June 2005.  From Hurricane Katrina in August 2005 to September 2007, southwest Alabama was been drier than normal.  On April 1, 2007, a data logger was installed to continuously record water level in OAI's MW-2.  The water level is recorded at various intervals*.  In addition, precipitation received on site is recorded and plotted.  The data from this effort, see below, shows a recurring, typical and predictable pattern of rise and fall of groundwater elevation found in the shallow aquifer in response to precipitation events on-site and, in some cases, from precipitation in Eslava Creek's watershed but away from the project site. The effect of the rise and fall of the potentiometric surface on direction of groundwater flow must be considered when evaluating groundwater flow patterns at this site (and others subject to temporal variations in groundwater levels) before remedial measures are planned and implemented.  A 1995 study completed by Daniel J. O'Donnell at this site found groundwater flow direction shifts 180 degrees from the "normal" or "expected" flow direction after significant precipitation events. The resumption of a "normal" flow pattern took about two weeks. * 2-hour intervals April 1- May 13, 2007; 4-hour intervals May 13 - July 29, 2007; 1-hour intervals July 29 - ending date posted above