Saturday, February 7, 2015

The storm has passed



Last night we had a strong Pacific storm that blew over plants in our yard.  As I am the Green Machine the plants were potted and some large pots toppled but thankfully the pots did not break.  One pot with a large tree is too large and too heavy for me to right, so I will get some help in straightening things out.  Nature is very powerful.

In a twenty four hour period three inches of rain fell here on the Tiburon peninsular.  Let’s assume that the land area of our small peninsular is ten square miles.  This equals an area of 278.78 million square feet.  Three inches is a quarter of a foot, hence multiplying area by height we get the volume of water that fell in the twenty four hour period and this equals 69.695 million cubic feet of water fell upon us.

This equals 521.319 million gallons or over half a billion gallons of water.  For argument sake let’s assume the clouds were at an elevation of 5,000 feet and the potential energy lost in the 24 hour period by this mass of water is approximately 8.268 million kilowatt hours.  The 4,000 homes on the peninsular used approximately 100,000 kilowatt hours of electricity in the 24 hour period.  This means that the potential energy in the storm that was lost by the water dropping from the clouds to the ground could have powered all homes in the peninsular for 82 days.

The Marin Municipal Water District claims all of its customers use approximately 15 million gallons in a day.  This means the single rainstorm’s quantity of water that fell on our peninsular in that one day could have served all of the Marin Municipal Water District’s customers for almost 35 days.  Of course 99% of the water went to the San Francisco Bay.  The land was already soaked and we don’t have dams to collect the rain that falls upon the small Tiburon Peninsular that is surrounded by the bay.

These data show how powerful the rainstorm was.   The Hoover Dam generates about two million kilowatt hours each hour.  The rain that fell upon us here in the Peninsular  in that one day could have powered the Hoover Dam turbines for 4 hours.  Think of the rainstorm above only the small Tiburon Peninsular as being one sixth as powerful as the Hoover Dam.

Of course the storm covered an area far larger than the peninsular where I live.   The area of the storm was perhaps ten thousand square miles and the power in the lost potential energy of all of water in the storm approximately equaled the combined power of 160 Hoover Dams.  This was one powerful storm.

The Marin Municipal Water District reported that on February 1, 2015 that the dams in the district are already 97% full and that storage is at 120% of normal for this time of year and twice as full as last year when we had a terrible drought.  The district has raised rates for six of the seven previous years and has asked customers to cut back on usage as we had experienced a drought.  Now that the drought is broken here in Southern Marin will the district roll back rates and tell us to use more water?   I doubt that will happen but then again I did not believe the long story of our drought would end so rapidly with a few massive storms of the century.  Of course we are still in the early part of the century.  Last year we had 3.8 inches of rain from July 1 to Feb 1, this year we have had 31.4 inches in the same period and adding this latest storm that will end on Monday our rainfall for this year has been plentiful.


Just like the weather it is hard to predict the price of oil.  My spectator blog got a few irate responses that the Green Machine must not be a spectator.    Guess what some things are just beyond my power to move like the large potted tree that toppled over.  I know my limitations and obey the second law of thermodynamics as well as Newton’s laws.  In a large storm I know to stay inside and just watch through my window, I will let others pretend they can tame the flow of 160 Hoover Dams.

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