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.

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AllWaterRights - Rights To Water Engineering, Inc.

Solving Diverters' Headaches To Provide Peace Of Mind And Help Stay Out Of Trouble. Helping California residents understand, define, and protect their water rights since 2005.

3 thoughts on “Data Loggers – Convenient…But Data Will Be Lost”

  1. We’re a ‘daily’ logger of reservoir stage/storage, on the coast north of Santa Cruz. Data piles up in the logger, downloaded every 90 days, always backed up on another computer besides the laptop. That makes a wad of data, particularly when the inflow of the diversion is also measured daily and the reservoir inflow/outflow is tabulated accordingly.

    For 2017, we’d invented and compiled a spreadsheet to account for all those gallons BUT the Water Board wasn’t prepared to deal with it. They told us they’ll have a standard form to report for the 2018 year. Has All Water Rights heard anything further about such standard forms?

    1. Hi Hank,

      I checked with Jeff Yeazell, our public contact at the Water Board. Folks will be able to file data with their annual reports in 2019, so you’ll do it while you are already in the Report Management System to file your Reports of Licensee (due April 1) or Supplemental Statements (due July 1). The new forms will likely be available in January of 2019.

      Jeff is a great guy, knowledgeable, very responsive, and easy to talk with. His email is and you can call him at (916) 341-5322.

      Please let me know if you have any questions,


      1. Hi Shawn, that’s great information, and many thanks to you. I’ll ask him about our 2017 data.

        Our lake level sensor is one you recommended a couple of years ago, the PMC VL4511-WLS-31. I’ve had some glorious battles with its software, but also some great help from its sales person and the software company as well, and it seems to be working faithfully. Many thanks for that tip as well.

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