Monday, October 29, 2007

Thoughts on the California Fires

Random thoughts as Southern California burns:

* fires are nature's way of clearing for re-growth--clearing out the dense undergrowth and letting new growth thrive
* the fires are cyclical

Knowing this, wouldn't one think that Californians would be cognizant and thus maintain fire breaks, build houses (and other structures) that were fire retardant?

And, then who should pay for the rebuilding?

This is a question that is pertinant not only for California, but for the Eastern seaboard where we build on the dunes and beaches knowing full well the force of the ocean's waves and of normal beach erosion*, not to mention the erosion caused by storms; we build along our mighty (and not so mighty) rivers' flood plains...

* Australia does not allow for building on dunes or beaches because they have realized the normal shifting of the sands From the Australian State of the Environment Report 2001

Erosion of beaches and dunes
The movement of sand is a natural feature of beaches. Beaches can be described as eroding (losing sand and foredunes) or accreting (gaining sand). The frequency and severity of cyclonic or storm events and seasonal weather patterns can result in fluctuations of beach width and slope.
The causes of erosion can be classified as follows (Tomlinson 2001):
short-term natural variability - beach fluctuations, storms,
medium-term natural variability - periodic changes in coastal climate and beach conditions,
medium-term erosion - disruption to local sediment budget due to people's activities, or
long-term natural variability - sea level rise, geological realignment, reduction in sediment supply.
Where development has occurred, property and infrastructure integrity can be threatened by landward movement of the erosion. The south-east Queensland - northern New South Wales coastline has been greatly developed since the mid 1970s but has not experienced a significant erosion event similar to the 1967 event that caused five houses to collapse into the sea on the Gold Coast.
Structures designed to reduce the extent of beach erosion can sometimes result in the opposite effects; that is, increased erosion, either on the beach or on an adjacent stretch of coastline. Similarly, the increasing popularity of offshore undersea barriers to create surfing waves or to dissipate wave energy from sensitive beaches will have ecological impacts that have yet to be determined.
It should be an objective of any coastal management plan for an area such as the Gold Coast to proactively mitigate any erosion caused by groynes and retaining walls (Tomlinson 2001). It should also be an objective to enhance the capability of the natural system to respond to natural sand movement by encouraging dune rehabilitation, for example. However, long-term studies to assess the effectiveness of coastal management strategies are hard to find

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