DESIGN OF LID SYSTEMS - Low Impact Development and Sustainable Stormwater Management - page 128

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DESIGN OF LID SYSTEMS
7.1 NONSTRUCTURAL MEASURES
In Chapter 4, the site design process for low-impact development (LID) begins
with measures that will reduce or avoid the impacts of conventional site design,
as illustrated in Figure 4-7, step 6. The basic concept of nonstructural LID mea-
sures is to prevent the problem created by land development, including runoff
from new impervious surfaces, loss of vegetation, and compaction of the soil
mantle, before they happen. These nonstructural measures are applied at the site
planning stage and include three basic concepts: (1) reduction of the impervious
surface required to achieve a desired building program, (2) limitation of the site
disturbance necessary to meet the design program, and (3) planning the site to
achieve the program within less space. These measures have taken a number of
different forms, based on the imagination of the design team and the willingness
of both the owner and the local government to allow flexibility in the site plan-
ning process. Examples of successful applications of each approach are provided
here not as a standard but as successful examples of the principle.
Impervious Surface Reduction
When we build a building or set of buildings for a given function, we have
traditionally surrounded it with an impervious surface on which to store or move
our transportation vehicles, augmented by similar surfaces to connect the vehicles