Chapter 16. Groundwater
1. describe the phenomenon of ground water.
2. draw a cross-sectional view of an area to show the zone of aeration, water table, capillary fringe, and zone of saturation.
3. add to your drawing the water table's relationship to streams and lakes.
4. discuss the properties of soil which determine whether water will percolate through it: porosity, sorting, packing, and sphericity.
5. draw a cross-sectional view to indicate how water maybe trapped in an aquifer between confining beds (=aquiclude), or lay atop of an impermeable bed to form a perched water table.
6. explain the forces which lead to an artesian well.
7. determine whether Tunkhannock Creek is an influent or effluent stream.
8. explain the common occurrence of springs in this area.
9. explain how pumping water from wells can lead to a cone of depression, and problems such as groundwater depletion, subsidence, and saltwater encroachment (in coastal areas).
10. using the Ogallala aquifer as an example, explain the problems that occur when withdrawal exceeds the recharge of groundwater.
11. contrast the volume and residence time of water in the earth's major compartments.
12. discuss the formation of caves in areas where groundwater is the causative agent.
13. write the chemical reaction which describes the formation of carbonic acid; now show how it combines with calcite to dissolve it away, forming a cave.
14. describe typical cave formations such as stalactites, stalagmites, and soda straws.
15. identify several areas of karst topography in the US.
16. explain why geysers, hot springs, and fumaroles occur only in limited areas.
17. explain why it is so easy to pollute groundwater, and so difficult to clean it up.
Critical Thinking Questions and Activities:1. Why does it take so long for the deep ocean waters to circulate through the hydrologic cycle? What happens to substances that contaminate deep ocean water of deep aquifers in the ground? Why is such ground water pollution difficult or impossible to clean up?
2. A porous material is not necessarily permeable. Explain.
3. In our area, the siting of a low-level radioactive waste dump and landfills are important issues. Why must thorough hydrological studies of proposed areas be carried out?
4. In a semi-rural area such as this, there are few central water supplies and most folks count on wells and septic tanks. How do septic systems work? How do they typically malfunction? What is a perc test?
5. Where does your water from for your home? At Keystone? What is its quality? How is it treated, if at all, before it is used? Is a long term shortage likely in your area? If so, what plans are being made to avert it?
Resources:Barker, James. 1986. Pennsylvania Groundwater Quality. USGS Water Supply Paper 2325, National Water Summary, 1986.
Becher, A. 1962. Groundwater in Pennsylvania. Pennsylvania Geological Survey Educational Series No.3.
Dolan, R. and H. Goodell. 1986. Sinking cities. American Scientist 74 (January-February): 38-47.
Makuch, J. 1986. Groundwater and Agriculture in Pennsylvania. Pennsylvania State University, college of Agriculture. Cooperative Extension Circular 341.
Zwingle, E. 1993. Ogallala aquifer: Wellspring of the High Plains. National Geographic 84 (March): 80-109.
Field Trip Opportunities:1. Visit the handiwork of groundwater up close and personal . . . go caving in the limestone areas near Albany, Allentown, or State College.
2. Visit Keystone's well field. Have Dr. Cook explain the hydrology of Ackerly Creek.