Groundwater David R. Maidment CE 394K.2 Spring 2005 Reading: Handbook of Hydrology, Chapter 6, Sec 6.1 to 6.7

Groundwater Investigation Can’t “see” groundwater so a lot more is done by inference and interpretation than for surface water Site investigation –Conceptual model of geological environment and the flow system through it –Field measurements (bore holes, pump tests, geophysics) –Hydrogeologic simulation model (e.g. Modflow)

Groundwater Investigation Figure 6.1.1

Geological Time Scale

Comal and San Marcos Springs are the major outflow points for the “Southern Segment” of the Edwards Aquifer

Barton Springs Segment of Edwards Aquifer

Geological Evolution

Hydrogeology of Aquifer

Karst terrain – caves, sinkholes and underground streams

Flow in Barton Springs

Piezometric Head Map Tucson, Az. Figure 6.3.2

Monitoring Points Buda Dowell Negley Lovelady Barton Springs (surface water) Well Stream gage

Piezometric Head Level Depth from the ground surface Elevation head Pressure head Piezometric head

Buda

Piezometric head in monitoring wells Dowell Monitoring Well Buda Dowell Buda Monitoring Well

Equipotential Lines and Flow q = K dh/dx Figure 6.3.5

Flow Net Figure 6.4.1