Viewer question: Why do we measure the aquifer in tenths-of-feet instead of inches?

Sometimes we get viewer questions we can answer and sometimes we get questions that make us say... now, that’s a good question!

Such was the case here, as Martha asked the KSAT Weather team why the aquifer is measured in tenths-of-feet versus inches. It’s a fairly easy conversion between the two, but inches are a more common unit. I posed the question to the EAA (Edwards Aquifer Authority) and this is what they had say:

“The EAA’s Aquifer Science department measures the water levels at J-17 and J-27 index wells with equipment that uses tenth of a feet increments, and for data collection purposes, tenth of a feet values present the data in more easily recordable readings.”

There you go. A pretty simple answer. I actually find it interesting that metric units aren’t used, as that is the universal science language. But, that probably has to do with history. This is the way the aquifer has been measured for a long time. And if you are curious about what the aquifer level actually means, that’s a far more complicated answer.

We found out about that process when we visited the J-17 for our KSAT Explains: The Edwards Aquifer. Here’s what we learned:

Pressure transducers are dropped into the aquifer down a well. The pressure is measured and that data is sent through electronic cables to the surface into a data logger. From there, conversions take place. The conversion eventually gets to a number that represents the feet above the instrument. This allows them to know where exactly the instrument has settled (atop the aquifer). From there, they calculate the depth to water, which provides the measurement from the top of the land surface to the top of the water. More conversions take place, which calculates water elevation. That is the measurement of the elevation of that water level in reference to mean feet above sea level. And boom! There’s your aquifer level, in tenths-of-feet no less. See... I told you it was complicated!

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