Environmental Engineering Reference
In-Depth Information
NDS goals, refl ecting the struggle between ecological and neotraditional
designers over the last three decades.
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For instance, street widths were
reduced to twenty-fi ve feet from the standard thirty-two-foot width to
create a more walkable and historic feel to the streetscape. This change
created more intensive development and reduced the amount of space in
the right-of-way for drainage strategies. The design team had to scrutinize
the placement of each driveway, parking space, fi re hydrant, and curb cut
to balance the competing demands in the minimized right-of way area. In
addition, the inclusion of the NDS approach to accommodate rather than
convey stormwater runoff would have spillover impacts on all facets of the
neighborhood's design. At times, there was an undercurrent of resentment
by the design team that the project was being compromised by the NDS
approach, but eventually the team members found amenable design solu-
tions to satisfy the numerous and sometimes confl icting project goals.
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Housing density at High Point is about sixteen units per acre (about
double the surrounding neighborhoods) and includes 1,600 apartments
units and houses to serve 4,000 residents in a mix of low-income and
market-rate rental units as well as market-rate for-sale units.
75
The overall
impervious surface coverage of the project is 65 percent, which is high for
a residential neighborhood and signifi cantly higher than the other NDS
projects.
76
The fi rst phase of the project was completed from 2003 to
2006, and the second phase was completed in 2010; even before construc-
tion began, the project received numerous local, regional, and national
awards for its innovative design, the most prestigious of which was the
Urban Land Institute's 2007 Global Award for Excellence. Today, the
project is internationally known as one of the most successful attempts
to date to combine social and environmental sustainability goals in an
urban context.
77
With respect to drainage, the design refl ects a hybrid of the NDS ap-
proach and a conventional curb-and-gutter network. Narrow streets slant
to one side rather than from the center to each shoulder, and curb and
gutter is used to direct stormwater to twenty-two-thousand linear feet of
bioswales, where it is absorbed and fi ltered. Some of the swales were de-
signed to be shallower than the standard NDS swale to provide more play
area for children.
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SPU developed a
Technical Requirements Manual
that
spelled out the philosophy and design implications for the site developers.
The fi nal design includes compromises for all involved actors, but over-
all, the team felt that it achieved all of its goals. Despite the documented
performance of the previous NDS projects, the state Department of Ecol-
ogy questioned the effi cacy of the NDS approach for larger storms and
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