Aquifer (vectorized)
<a href="//commons.wikimedia.org/wiki/User:Biopics" title="User:Biopics">Hans Hillewaert</a>
<a href="//commons.wikimedia.org/wiki/File:Schematic_aquifer_xsection_usgs_cir1186.png" title="File:Schematic aquifer xsection usgs cir1186.png">Schematic aquifer xsection usgs cir1186.png</a>