Environmental Engineering Reference
In-Depth Information
humans. Conducting geological investigations, employing contaminant risk factors, and
following a science-based landscape planning approach provide this knowledge.
Geological investigations (Chapter 4) can determine whether a landscape is damaged,
and whether the source of the damage was from natural or anthropocentric origins. The
inspections and data collected during Phase I and Phase II Environmental Site Assessments
(ESAs) will detect the presence of human impacts, residual chemicals and their types, and
the extent of their damage. Geologic maps (Chapter 5) can be used to establish the loca-
tions and cause of original landforms, and reconstruct the flows of water into, out of, and
within the landscape. Since water is a key determinant of landscape change, this informa-
tion will help indicate the extent of human modification. Information collated from these
sources provides one of the pieces necessary to assess the degree of land degradation.
The next piece is provided by the contaminant risk factors developed for chemicals in
soil, groundwater, and air. If chemicals are present at a site, the CRFs for each chemical
detected can be evaluated to assess their toxicity and persistence. When this information
is combined with the landforms and water flow information, the fate and transport of the
contaminant can be determined (Chapters 8 and 9).
Completing the assessment of a landscape's condition is a science-based planning pro-
cess (Chapter 15). An infrastructure evaluation can be used to characterize the types and
levels of human modifications and assess their likelihood of destabilizing the landscape.
During this process, investigators should be conscious of the potential for synergy between
anthropocentric impacts and contaminant fate and transport. For example, if there are
stormwater detention ponds present, these structures may serve as sinks for highly con-
taminated stormwater with the potential to contaminant groundwater and surface water.
Within urbanized watersheds, undamaged and relatively undamaged land may exist at
some unexpected locations. In a study of brownfields in southwestern Detroit, Murray et
al. (2008) found that 22 of the 87 properties (25%) were not contaminated, and another 35%
were only minimally impacted. These properties are therefore available for redevelopment
or may be employed for environmental purposes such as groundwater recharge, stormwa-
ter detention, and increasing the amount of tree canopy coverage.
Inputs of contaminants from adjacent and distant watersheds through acid rain and
wind deposition prevent urban watersheds from being pristine. Nevertheless, large tracts
of land may still possess a large share of their original capability to support sustainable
development. Preservation of land as an activity thus includes the broader role of main-
taining the natural landscape functions across the atmosphere, biosphere, lithosphere, and
hydrosphere.
The asset-based approach presented here is derived from the main principles embod-
ied in asset-based community planning (Kretzmann and McKnight 1993) and the water-
shed restoration strategy called Rapid Biotic and Ecosystem Response (Doppelt et al. 1993).
Asset-based planning was developed as a way to rehabilitate damaged communities by
using the assets present, rather than relying upon outside assistance and becoming “client
neighborhoods.” A community's main asset is its people—who have specific knowledge
and skills to bring about positive change (Kretzmann and McKnight 1993).
In rapid biotic and emergency response (RBER), the initial efforts of watershed restora-
tion do not focus on the most damaged areas. Instead, relatively undamaged areas are tar-
geted first because they possess the ability to serve as locations for reestablishing habitat
corridors, providing habitats and refugia, and rebuilding species diversity (Doppelt et al.
1993).
There is always some risk involved with taking principles from one discipline and
applying them to another. The application of the evolutionary principle of “survival of the
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