Friday, May 1, 2009

Predictive closures

Back to items I really know.
After work 20 years perfecting Stamford's policy of closing the beaches when conditions say that there is a good chance that there will be bacteria type problems in the recreational water, I became a bit defensive when I challenged the State's person in regards his take on this.
There is legislation in the US House to increase funding for testing (it will go to state agencies only) and require the development of rapid (2 hour) testing.
The portion I find laughable is that more or faster testing does not mean a great deal to me.
The example is when we were trying to understand problems that occurred at Cummings' beach and did time/tide/location studies.
We took a lot of samples.
They varied tremendously over all of the parameters. the sample sites were only about 10 feet apart.
This taught me a great lesson, bacteria are very different than chemicals and this was in 1988.
They clump together, they grow, they separate, they get eaten, they die.
The best I could do for my little 100 mL samples was get a hint of the activity beneath the waves.
So we began keeping very good records.
We tracked tides, rainfall, wind, temperature, bather load and other issues and slowly over thousands of samples we began to see things.
We established our bathing prohibitions based mostly on what was known from testing shellfish water, that rain will wash bacteria into the water, where it will live for a recordable time.
We knew this was not sewage, just normal bacteria that lives in everyday soil from every animal population that exists.
We figured that it lived in wet sand, but not dry. It seemed to exist in the water for at most 24 hours, then it was gone.
When you go to the beaches in Stamford after a heavy rain, there will be no bathing permitted. Enjoy the sand, the sun, but not the water until the next day.
We spent a lot of time trying to make sure you do not get sick from something that should be enjoyable.
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