In Term two of the engineering and CAD course, we will be looking at UrbanSprawl as an issue confronting modern architects, planners and societies.
Basically, when everybody in a society must live in a freestanding building on its own piece of land, and the land and building are only used for housing, then lots of land gets used up to house relatively few people. This results in a low poplulation density compared to when people live in buildings that house more than one family, and sometimes businesses as well. When density is low, then land and other resources are used less efficiently.
Low population density means greater use of resources like building materials, and infratructure such as streets and utilities. It is also more difficult to design and use public transportation systems when people are spread out over large areas.
When There are lots of houses, buildings, streets and other things covering the ground, it puts a greater stress on the environment. Groundwater is replenished when the rain falls on the ground. When rain falls on buildings and pavement, the water forms runoff, which then goes to streams, rivers, ponds, lakes and the oceans. Many cities in the US are experiencing water shortages. This is particularly difficult in the west and Southwest, but is also a problem in cities like Atlanta.
When land is developed in clusters with large areas of undeveloped land, then the effect is to preserve open space while concentrating human use to specific areas. This makes both the living areas more convenient to the people living there, and allows use of the open space for wildlife and recreation.
Here in Duxbury, we can see the effects of sprawl in the increased time that it takes to get to places like Boston, or even neighboring communities like West Plymouth. duxbury was originally settled by people who travelled by foot, then horses and carriages, then trolleys and trains were introduced, then dismantled. In the past 60 years, people have moved to travelling almost exclusively by passenger car. The resumption of the commuter train in the late 1990's has made it easier to get to the city, but people must still drive to the train.
There are several villages in Duxbury where the population density is higher, Hall's Corner, Millbrook, Snug Harbor, Cox Corner and the area around Bennett's. In these areas you can see examples of mixed use development.
Here is a link to PicturesofUrbanSprawl
Here are some links to help you understand the issues around UrbanSprawl:
A brief overview of how the issue is seen in Pennsylvania - http://lal.cas.psu.edu/Research/sprawl.html
How sprawl is affecting the Gulf Coast - http://www.ucsusa.org/gulf/gcsolutionsspeed.html
Overall view of sprawl - http://www.cwac.net/landuse/index.html
The view from NASA - http://science.nasa.gov/headlines/y2002/11oct_sprawl.htm
Wikipedia Entry - http://en.wikipedia.org/wiki/Urban_sprawl
UN study of Santiago Chile - http://na.unep.net/digital_atlas2/webatlas.php?id=32
Resource on sprawl - http://www.sprawlcity.org/