Data Loggers – Convenient…But Data Will Be Lost

The Water Board requires diversions and storage over 10 acre-feet per year to be recorded, per SB 88, other state laws, the California Water Code, and agency regulations.  Data must be recorded monthly, weekly, daily, or hourly, depending on the size of the diversion or reservoir:

But we don’t live in a perfect world.  Things will go wrong.  Whether you record data by hand in a notebook, or a data collector records data electronically, data will get lost.  Why not just use a notebook or phone camera?  That works when the data collection interval is monthly, and might work for weekly.

However, if diversions are over 100 AF or storage is over 200 AF per year, data must be collected daily, and diversion or storage of 1,000 AF per year or more requires hourly data collection.  That daily or hourly interval makes electronic data collectors of some kind a requirement to have the data and avoid those fines of possibly $500/day.


We’re all busy, so we have to make time to spend half a day or more downloading loggers 2 or 3 times each year.  The leaves the possibility of data loss between the times data is downloaded.  Why not download data once a month, or weekly?  That’s not doable for ranchers and farmers who are already spending long days just to try and make a profit.

At some point, data will be lost.  You could just use the last measured value for all the intervals that were lost, but in reality storage volumes change based on rainfall, evaporation, stock and wildlife use, and releases.  Diversions change based on available flows in the stream and changes in irrigation, stockwater, or other uses at the place of use.  Sometimes diversions are maxed out for a day or two for filling a ditch or flooding up, and other times they are shut off for haying or maintenance.

How will you tell the Water Board that data is lost, even though you did your level best to do everything rig

ht?  Perhaps data was downloaded in February, June, and October…but the fields for February 15 through June 10 are blank.


As always, if you are behind the 8-Ball, communicate early and often.  Jeff Yeazell is the public contact outside of the Delta, and Jeff is scrupulous about replying and hanging on to emails.  If you’re really worried, include someone else in an email.  Notice I said “email” and not “phone”.  Phone calls are a lot more work on the receiving end, and information can get lost more easily.

Of course, also take extraordinary steps to recover the data.  Maybe an expert can try a few things to get the data off the unit.  You might have to send it to the manufacturer and see if they can download it.

Be diligent, check setups twice and three times, save downloaded data in 2 places immediately after downloading, download as often as you can, and otherwise be diligent and careful.  In the end, though, data will be lost, but don’t panic.  Communicate early, often, completely, and repetitively.  Keep estimates or spot-check notes throughout the year, and use those to fill in gaps if you have to.