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

http://www.bseacd.org/geology.html

Geological Evolution

http://www.edwardsaquifer.net/geology.html

Hydrogeology of Aquifer

http://www.bseacd.org/hydrogeology.html

Karst terrain – caves, sinkholes and underground streams

http://www.bseacd.org/karst.html

Flow in Barton Springs

2001

2000

2002 2003 2004

http://www.bseacd.org/cc_water_levels.html

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

http://www.bseacd.org/cc_water_levels.html

2002 2003 2004

Buda

Piezometric head in monitoring wells

Dowell Monitoring Well

2002 2002 2003 2004

20032004

BudaDowell

Buda Monitoring Well

Equipotential Lines and Flow

q = K dh/dx

Figure 6.3.5

Flow Net

Figure 6.4.1