The water under the ground

THREE AQUIFER SYSTEMS, TWO OF THEM PENN'S

The Department of Natural Resources' Division of Water maps eight unconsolidated aquifer systems across St. Joseph County, and three of its published descriptions are the ones that describe Penn's ground: the St. Joseph Aquifer System, "composed of fine to medium grained sand with zones of coarse sand and gravel," varying "from 20 feet near the southern boundary of the St. Joseph River Basin to approximately 400 feet thick over the buried bedrock valley," an area "of excellent groundwater availability (100 to 1500 gpm)" that "is highly susceptible to groundwater contamination"; the Tributary Valleys system, "similar to the main stem St. Joseph Aquifer System, but often contains coarser outwash deposits," with good to excellent availability (100 to 1,000 gallons per minute); and the Nappanee Aquifer System of the southern till plain, "interbedded medium to coarse sand and gravel zones contained within a thick till sequence," the layers 3 to 10 feet thick, "present under the glacial till plain in eastern St. Joseph County," at moderate to good availability (50 to 600 gallons per minute). Read against the township's two-part surface, the Penn riverfront and the Baugo valley sit in the St. Joseph and Tributary Valleys ground and the southern till plain in the Nappanee ground; that assignment is this build's reading of the Division's system descriptions against the survey's physiography, and it is printed as a reading — the Division's county map sheet itself was not re-verified for this section, and no Penn Township-specific yield figure is published in the text reached. The figures above are the systems' published ranges, printed as such.