Introduction to Physicaland Chemical Hydrogeology (GEO 346C)

Instructor: Bayani CardenasTAs: Travis Swanson and John Nowinski

www.geo.utexas.edu/course/geo346c/

Hydrology and Hydrogeology

Hydrology is the study of the occurrence, distribution, movement, and chemistry of all waters of the earth.Hydrogeology is a subdiscipline of hydrology that focuses on the interrelationships of geologic materials and processes with water.

Hydrogeology typically emphasizes subsurface environments and is similar to groundwater hydrology.

Why study water?

The rise and fall of civilizations are almost always centered around water.

Life, as we know it, would not exist without water.

The geologic cycle is intimately tied to the hydrologic cycle.

Water resources can only be understood within the context of the dynamics of the water cycle.

-United Nations World Water Assessment Programme

The world water cycle seems unlikely to be able to adapt to the demands that will be made of it in the coming decades.

-United Nations Environment ProgrammeGlobal Environmental Outlook 2000

Global Water Distribution

Basic terms: zones

Vadose zone, zone of aeration or unsaturated zone- portion of the subsurface where pores are filled with air and water. –soil moisture or vadose water

Capillary zone or fringe- transition zone

Zone of saturation, saturated zone- pores are completely filled with water.- ground-water

Water table-top of the saturated zone

Surface water- ponds, lakes, rivers, streams, wetlands

Magmatic water- contained within magmas in the deep crust

Connate water- water trapped in minerals/ rocks during deposition, separate from water cycle for some time

Meteoric water- water on the land surface or subsurface that comes from the atmosphere

Basic terms: pathways

Depression storage- ice, snow and water (puddles) that is locally stored on the surface.

Overland flow- water drainage across the land but not in channels

Infiltration- seepage of water into the ground

Gravity drainage- downward movement of water in the vadose zone due to gravity.

Interflow-lateral movement of water in the vadose zone

Basic terms: pathways

Evaporation/ precipitation

Ground-water flow- any movement of water in the saturated zone

Baseflow- groundwater flow to stream

Submarine groundwater discharge- outflow of groundwater to the sea

Gravity drainage- downward movement of water in the vadose zone due to gravity.

Streamflow=runoff

Transpiration- moisture release by plants to the atmosphere

Evapotranspiration- evaporation + transpiration

Overland flow- water drainage across the land but not in channels

Interflow-lateral movement of water in the vadose zone

Baseflow- groundwater flow to stream

Streamflow

Water balanceor

hydrologic equation

Inflow-outflow=changes in storage

What drives the water cycle?

The Sun

and

Gravity