Urbanization and the Disruption of Matter and Energy Flows within Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 431

Novi

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0 50 km

FIGURE 12.9
Novi, Michigan, within the Rouge watershed.

(Rogers 1997). During Novi's rapid urbanization, when this soil type was combined with
the creation of impervious surface, the conditions for generating high amounts of runoff
were created.
The first response in Novi, as in many communities, was to require new developments
to build on-site detention basins to hold the water and attenuate the peak flows (Figure
12.10). The goals were to maintain predevelopment streamflows and improve water qual-
ity through the settling of some sediments during the brief detention period.
As development in Novi accelerated during the 1970s, the number of on-site detention
basins grew. By 1980, there were almost 50 detention storage facilities. Despite this rise
in detention basin use, stormwater problems continued. Major arterial roads were often
immersed by stormwater runoff, and the large number of detention basins was becoming
a maintenance problem. Local associations with no expertise in on-site detention manage-
ment took over the upkeep of the basins after subdivisions were completed. On-site deten-
tion also created an additional expense to developers, a health hazard, and a confiscation
of developable land (Kaufman 1994).
After a bond issue in 1980 designed to raise money for additional drainage failed, the
City hired an engineering firm. The firm developed a plan to use 28 regional detention
basins for holding the excess runoff. At the proposed rate of construction, there would
have been over 600 on-site detention ponds when the City was fully developed. In an
urbanized area of 80 km 2 , this translated into an average of 7.5 ponds/km 2 . Faced with this
prospect, residents in 1982 approved the regional detention plan and the flooding stopped.
The timing, placement, and character of human interventions are critical to minimiz-
ing environmental impacts. The use of on-site detention as the first response fragmented

FIGURE 12.10
Detention basin. (Photo by Daniel T. Rogers.)