Environmental Engineering Reference
In-Depth Information
A few examples include
• Names of highways and roads. The names of highways and roads sometimes pro-
vide insight into a region's geology. For instance, a highway named “Ridge Road”
creates a potential association between topography and geology. Others perform-
ing this task include Muddy Road, Sandy Flats, Rocky Road, Sandy Hill Road,
Wash Road, Winding Road, Coastal Highway, Beach Highway, Marsh Creek Road,
Peat Bog Road, etc.
• Location of cemeteries. Cemeteries provide information on a region's geology,
because cemeteries during the nineteenth and early twentieth centuries were usu-
ally located in areas of well-drained soil such as sand or gravel. This siting pre-
vented the occasional casket from popping out of the ground after burial; an event
possible in more poorly drained soil such as a clay.
• Location of parks and recreational areas. Parks and recreational areas are often
found in areas with a scenic or educational theme related to the geology of a region.
• Historical markers and historical sites. These locations often exist over or near
significant natural disasters, battlefields, and trails.
• Locations of historical settlements and buildings. Before urbanization occurred,
many historical settlements used foundation materials of native stone collected
from nearby locations, and these items are useful when assessing a region's geology.
These sources of information must be carefully inspected for integrity and usefulness.
Perhaps, the information was not initially collected for geological purposes and may not
have been collected by a qualified geologist. What if you are consulting historical geologi-
cal maps? Unfortunately, most historical mapping of urban regions was produced in two
dimensions and did not map the subsurface geology to a depth of more than a few meters.
Relying upon a two-dimensional map is problematic because effective and useful urban
geologic maps produced for environmental purposes must represent three dimensions.
This spatial requirement means these maps are much more complex and require signifi-
cantly more information (Barnes 1993). Some forensic methods described throughout this
chapter can help evaluate the accuracy and ultimate usability of questionable historical
geologic information.
Just when things are starting to sound bleak, we get some relief in the form of geologic
and hydrogeologic information obtained from environmental investigations. These activi-
ties can supply much of the baseline information to evaluate whether questionable geologic
information is usable and also supply the necessary geologic information to enable detailed
three-dimensional mapping. In many urban areas, environmental investigations have been
conducted at thousands of locations. A large percentage of these environmental investiga-
tions yield very detailed geologic and hydrogeologic information collected by qualified
and certified professionals. This information is readily accessible through federal, state, and
local environmental regulatory agencies. For example, over 3000 reports of the subsurface
geologic investigations performed in the Rouge River watershed are available for review in
one state agency, the Michigan Department of Environmental Quality (now the Michigan
Department of Natural Resources and Environment) (MDEQ 2008). It is therefore quite pos-
sible the best sources of geologic and hydrogeologic information are within easy reach.
Figure 5.1 shows the location of nearly 500 sites where detailed and large-scale envi-
ronmental investigations have been conducted within the Rouge River watershed (Rogers
1996). In terms of the geologic and hydrogeologic data collected, each site had a minimum
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