Environmental Engineering Reference
In-Depth Information
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Issuance of building permit
. The developer can begin construction and will have to
submit to local building code inspection as the project progresses. If an erosion
control ordinance is present, the site may be inspected by the local enforcing agent
for compliance.
This sequence of steps appears to be a logical approach to land development. You have
generalists from the public who might catch problems the professionals miss during their
review of the site plan. If problems arise with the proposed plan, they can be fixed by the
developer provided there is not too much of a financial or scheduling burden. Substantial
consideration also seems to exist for environmental concerns, like stormwater manage-
ment and erosion.
There is, however, a problem of geographic scale with this approach. If the proposed
development is a subdivision, the overall environmental performance of the individual
parcels has already been largely compromised by how the original tract of land was
divided.
Most subdivision land developed in the United States is based on the density principle.
The specific lot sizes and the overall size of the entire site are predetermined. As a result, a
spatial form is imposed on the landscape before development proceeds. A 20 ha site “plat”
map may specify 20 single-family residential structures on lots from 0.1 to 0.2 ha. The
developer gets an architect, and a site plan is developed conforming to these constraints.
Any land area left over can be dedicated to greenspace, trails, parks, or detention storage,
depending upon the local zoning regulations.
The problem with this approach is that it specifies what the land should hold based
solely on local community goals (e.g., “low-density development”), rather than first iden-
tifying the actual physical capabilities of the landscape to support specific uses. Instead,
we leap before we look, as homes are sited in flood-prone areas, native topsoil is removed
indiscriminately (and often sold back to the homeowner after being adulterated to “fill”),
and homes are constructed and oriented in a way that fails to maximize their energy-sav-
ing potential. These practices reflect an inefficient land use planning process and generate
a haphazard development pattern.
In the United States, suburban sprawl has been the dominant pattern of metropolitan
growth in the last 50 years (Downs 1998). Sprawl refers to a pattern of urban and metro-
politan growth that reflects low-density, auto-dependent, and exclusionary new develop-
ment on the fringe of settled areas often surrounding a deteriorating city (Squires 2002).
Within many of the urbanized watersheds of the United States, a large percentage of their
land area consists of suburbs comprised largely of subdivision-style developments. For
instance, the heavily urbanized Rouge River watershed in southeast Michigan has an area
of 1134 km
2
, with the city of Detroit occupying only 370 km
2
.
15.2.2 Narrowing the Science-Policy Gap
To narrow the science-policy gap, a thorough physical planning process should precede
the specification of development density on parcels scheduled for subdivision. The capa-
bilities of the landscape should dictate the uses, density, and arrangement of the built
environment, with a comprehensive physical planning process conducted to assess and
map the geologic environment, map (and sample) the soils, inventory and analyze vegeta-
tion, slope, drainage, and sun angles, and perform a groundwater vulnerability study.
Geographic information system (GIS) overlay techniques can be used to manage and ana-
lyze the data, with field checks used to verify the GIS results. The objective is to identify
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