Sunday, July 1, 2012

A New Rain Year Dawns

Here in California - or at least the bay area - we track our rain annually from July 1 through June 30. That's because our rainy season falls in the winter and spans the new year. If you are trying to figure out how much water the farmers, watershed, reservoirs, and/or water table is going to get, you need to track it around when it falls, rather than splitting it across an artificial date like January first.

So, July 1 marks the start of the 2012-2013 rain year, and the end of our 20th year of collecting rain data at our home.

This year I tested a bunch of rain gauges, and have revised the way I record and display data. I'll write another post about the rain gauges shortly, but first, here are links to the data I have available:
Those pages hosted on my personal web site, where it is easier to make this work than here on Blogger, where column widths make displaying this stuff something of a challenge.

I will provide links to those pages in the right side navigation bar as well, so you can find them in the future without having to find this post.

I leave you to draw your own conclusions from the data. I stress, though, that rain fall amounts vary widely over even small distances, and we have nothing like a statistically valid sample to analyze anything over the long term. We use this data mostly to try and assess how our well will perform over the coming year. If we have less rainfall we can bet we'll our well will low on water before the next rain year gets going and the aquifer can be recharged.

Another thing this data helps us understand is our local fire danger. Rainfall that is well spread out in time keeps the vegetation moist and thus less likely to be a problem. 2011/2012 was the first time I recorded actual rainfall amounts by the day and kept them, so we still have a lot to learn here.

I hope this data is interesting and useful to someone other than me.