Environmental Engineering Reference
In-Depth Information
nature and location of recharge and discharge.
Descriptions of hydrologic processes within
the regions are drawn from Meinzer (
1923
),
Thomas (
1952
), and Heath (
1984
), as well as
from references cited for each region. Although
the regions are uniquely defined, similar con-
ceptual models of recharge processes are often
adopted in multiple regions, and areas over
which a method is applied can overlap reg ional
boundaries. Recharge characteristics in urban
settings, topics that pertain to all 10 regions,
are discussed in
Section 9.4.11
.
Discussion of groundwater regions is limited
to those within the United States only because
of the author's familiarity with groundwater
conditions in this country. Recharge processes
in similar regions in other parts of the world
are no doubt similar in many respects to those
described below. So readers involved with
recharge studies outside of the United States
can still benefit from the material contained in
the following sections.
No attempt is made to balance the discus-
sion among the different regions. Some discus-
sions are extended in length; others are brief.
This could be because of the number of studies
conducted in a region or the relative import-
ance of groundwater resources in a region or
simply the existence of well-documented stud-
ies. Examples were selected to illustrate a point
or a method and represent only a small fraction
of studies conducted. Details on all the individ-
ual methods cited in the following sections are
provided in
Chapters 2
through
8
and are sum-
marized in
Tables 9.1
and
9.2
.
Seldom do publications of recharge stud-
ies chronicle the development of a conceptual
model of a hydrologic system. Usually, only the
final conceptual model and estimated recharge
rates are reported, and the process by which the
final conceptual model was arrived at remains
largely unknown to the reader. An exception
is the study of water movement through the
unsaturated zone at Yucca Mountain, Nevada.
0
300 Miles
0
400 Kilometers
Figure 9.1
Groundwater regions of the contiguous
United States (Thomas,
1952
).
