Environmental Engineering Reference
In-Depth Information
framework proposed here. Research presented so far in this topic has made it clear that
science—especially geology—has not been used to its full potential in urban watershed
management, and without a full tank of science, attaining sustainable urban watersheds
is not possible.
Our conclusion is that the best way to overcome this deficit and capitalize on the ben-
efits generated along the way is to start at the individual parcel scale. It is at the parcel
scale where geologic investigations occur, data are generated to characterize the geological
environment, the major agent of landscape change—water—is given a full inventory, risk
factors for chemicals are computed and applied, synergy between contaminant properties
and the geological environment is evaluated, and point source controls are implemented.
At the parcel scale is also where science-based landscape planning can most effectively
prevent further environmental damage to land being considered for new development or
redevelopment. In this strategy, contaminated sites are also an asset: the data they produce
from environmental investigations benefits science-based landscape planning at uncon-
taminated sites and can help reduce their releases of stormwater, lower erosion rates, and
protect soil, groundwater, and air through source control.
Linkages between the beginning framework presented here and the broader watershed-
wide management themes are shown in Figure 16.6. Each linkage represents a way to trans-
fer the outputs from the parcel level efforts upward to the watershed scale. Underlying this
approach is the hypothesis that what is learned at the parcel level functions as a catalyst
for ameliorating the environmental concerns at the watershed scale, and also provides
the basis to begin aligning the out-of-whack institutional arrangements present. This pro-
cess is modeled by depicting the five major themes characterizing the status of watershed
management at two geographic scales. The center of the diagram identifies the linkages
between the themes at the parcel and watershed scales. Discussion of Figure 16.6 begins
with the boxes in the top row and proceeds downward.
16.4.1 Boundaries
The linkage preserves community control of land use decisions, but requires science-based
site and watershed-scale planning (Chapter 15). The new institutional arrangement used
to enable the linkage is the inclusion of watershed councils in the site plan review pro-
cess. The most common criticism of community “home rule” is that this practice focuses
communities' land use decisions within their own borders while ignoring the potential
watershed-wide implications. Since a bad site plan has environmental implications for the
entire watershed, a good site plan can help prevent further contamination and protect
undamaged land. The use of a watershed-level institutional form to review site plans ele-
vates the consideration of their outcomes to the scale of the entire watershed. Communities
still retain some level of control over their land use decisions, but site plans would now
promote the sustainable development of the entire watershed. The use of a formal water-
shed body with administrative powers might also facilitate inter-watershed collaboration
on cross-boundary environmental issues, such as acid rain.
16.4.2 Structural and Nonstructural Controls
Geologic and vulnerability maps depict many of the physical processes that form land-
scapes, and these maps show the flows and location of surface water and groundwater
(Chapters 5 and 6). Information gathered from environmental site investigations includes
soil and water samples and the locations of low points in buildings where contaminant
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