Sunday, January 18, 2009

Sustainability Part Two

Sustainability can be differentiated from the town vision statements and comprehensive plans. A sustainable community might be one that is over-developed. The concept there is called "carrying capacity." The easiest example is to compare when the island has exceeded its carrying capacity, such as during:
  • Texas Week, Spring Break
  • Memorial Day
  • Fourth of July
The threshold could be about 50,000 people on the island although numbers are difficult to pin down, other than we know when it happens because the bridge, main drag, and parking become so congested it takes hours to travel a few miles. There are 17,000 taxable residence units on SPI and perhaps about another 6,000 hotel rental units; in addition there are "day trippers" that leave each night, at times estimated at over 10,000 on peak days. There are very serious questions if the island could handle more people even with another causeway constructed to the north, as well as additional dwelling/rental units on the North End. What are all those people going to do?

This is an interesting case because during the off season, SPI can be considered a rural area having a density of less than 5,000 people per square mile, but can have a density of 25,000 per square mile on those peak weekends and holidays. One has to design the city for the peak activity, however. Once a threshold has been exceeded, the "island experience" becomes a negative due to crowding, congestion, and conflicts that create accidents and incidents. This "out of control" situation indicates that the study area is clearly not sustainable.

Yet at the same time, there is an acceptance that more and more houses and condos will be built on the island, which would increase loads even more. Some experts like to call this "managed growth" so as to minimize the negative impacts we already are seeing. Others call it bad names. I'll take on the proposed second causeway and North End development next.

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