City Well Levels
Drought Index Well
The District has selected a group of water wells for monitoring the water levels of our portion of the Edwards-Trinity Aquifer. These wells are measured monthly, using steel tape, "e-line," or by downloading an electronic sensor that is installed in the well. The steel tape measures feet and tenths of feet, and is used to measure water levels in wells that have a small opening in the baseplate, typically windmills. The e-line is used in wells with larger access. It has an electric sensor on the end of a tape that is marked in feet and tenths. When the sensor touches the water it completes a circuit and sounds an alarm. At the sound, the distance to the water can be read on the tape.
The electronic sensors are programmed to record the level of the water at set intervals. These sensors are downloaded monthly and the information received can be used to make graphs of changing water levels. An example is "City Well Levels" (link at top of page) which shows two graphs of the water levels in one of the wells used to supply the City of Sonora.
We also have a group of rain loggers; these are downloaded monthly. Most of them are paired with monitor wells. An example of this pairing is at "Drought Index Well" (link at top of page). The well sensor graph shows the well water levels and the rain gauge graph shows the rainfall at that well. The dates on both graphs line up so you can see if the rainfall affected the well's water level.