Piedmont and Blue Ridge Crystalline rocks with glacial cover

Paleozoic history of southern Piedmont From Hatcher

Metamorphic and igneous rock Sandstone and diabase in rift basins Limestone

Piedmont Chimney rock Blue Ridge Province

flow through fractures

Transition Fractured metamorphic and igneous rock Saprolite

Gneiss, schist bedrock Granite or other intrusive bedrock Distinct transition Gradational transition

Storage and transmission properties High porosity S y ? porosity Low storage cm/s

Saprolite sampled at different depths. Measure density and chemical composition. S.G. decreases from 2.1 in rock to 1.6 in shallow saprolite. S.G. decreases as minerals are altered and mass is removed. 0.5 gm/cc removed during weathering. Chemical concentrations indicate S.G. change largely due to weathering of feldspar to kaolinite as a two-stage reaction.

Porosity Specific yield K cm/sec Granitic Gneiss E-08 Mica Schist E-09 Hornblende-feldspar gneiss E-09 Quartzite E-09 Amphibolite E-09 Laboratory determinations of properties of crystalline rocks. from Randall and others 1966

Saprolite thickness Typically 50 ft, but variable ft w.t ft bgs Frx zones in valleys Flat-lying frx

Saprolite thickness Greatest over valley or highland? Could be either

Ground watersheds

Open Hole Multi-level completion

Important: Exception to the Conceptual Model

Specific capacity Well Performance and Lineaments

Lineaments

Effects of lineaments on well yields in the Piedmont Other effects of location on well yield Factor of 2 to 7 difference in yield Factors from 3 to 25 between valley and hill

Well yields in different rock types and regions in the Piedmont gpm typical Roughly 20 gpm

Effects of well depth and diameter on yield in the Piedmont. Based on Daniels

Glaciated crystalline rocks in northern Appalachians

Other Hydrogeologic Settings in the Piedmont

Stockton Fm. Lockatong Fm. Passaic Fm. Orange Mt. Basalt Feltville Fm. Preakness Basalt Towaco Fm. Hook Mt. Basalt Boonton Fm. Conglomerates Palisade sill

Newark Basin, NJ Mesozoic Basins Sandstone aquifers Shale confining units Redbeds in the Hartford Basin, Conn Conglomerate Basalt Arkose

Carbonate rock aquifers

Water Chemistry Reminder Major Cations: Na +, K +, Ca 2+, Mg 2+ Major Anions: HCO 3 -, Cl -,SO 4 2- TDS: Total Dissolved Solids MCL= 500 mg/l Values: Fresh < 1000 mg/l; brackish ,000; saline; 10, ,000 mg/l Seawater: 35,000 mg/l Hardness: Ca and Mg scaled to Ca on a meq basis –Soft water < 60 mg/l total hardness –Use water softener= mg/l –Very hard >150 mg/l

Milliequivalent Charges/volumes Concmg millimol evalencecharge meqmillimole charge liter Mole weight mgliter

Water quality in Crystalline Rock aquifers

Crystalline rock Triassic Basin Carbonate rock meq/L

Crystalline Rock Triassic Basins Carbonate Aquifers

SC, GA, Al =100 Mgpd