1. Potentiometric surface of the principal alluvial aquifers in the Rio Espiritu Santo to Rio Demajagua area, Puerto Rico, March 23-24,1994 Yale Public content 1996. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). U.S. Geological Survey. English. Public. Puerto Rico, Fajardo Region, Demajagua River Watershed, and Espiritu Santo River Watershed.