The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
As used in hydrology, this term refers to rock and soil material that occurs at the earth's surface or within the subsurface which does not permit water to enter or move through them in any perceptible amounts. These materials normally have small-sized pores or have pores that have become clogged (sealed) which severely restrict water entry and movement. At the ground surface, rock outcrops, road surfaces, or soil surfaces that have been severely compacted would be considered impervious. These areas shed rainfall easily, causing overland flow or surface runoff which pick up and transport soil particles and cause excessive soil erosion. Soils or geologic strata beneath the earth's surface are considered impervious, or impermeable, if the size of the pores is small and/or if the pores are not connected.