So on Tuesday, January 20, “The State Water Resources Control Board (State Water Board) adopted regulations Tuesday evening requiring all surface water right holders and claimants to report their diversions. Those who divert more than 10 acre-feet of water per year must also measure their diversions.” Click the logo above to see the 2-page document on the Board’s website.
Well, how bad can it be? Before January 20, most diverters had to report monthly diversions, so 12 volumes per year, plus the annual total. That’s 13 numbers. The required frequency a year from now will be increased quite a bit, to weekly, or daily, or hourly:
“For instance, large diverters with a claimed right to take 1,000 acre feet of water or more per year are required to have a measuring device or measuring method capable of recording at least hourly in place by Jan. 1, 2017; those with claimed rights to divert 100 acre feet or more must comply by July 1, 2017 and record at least daily; and those with claimed rights to divert more than 10 acre feet must comply by Jan. 1, 2018 and record at least weekly.”
How can flows even be reported hourly? See the end of this post. What if someone decides to skip reporting, and let the Board catch up with them later? The FINES can be large enough to hurt – we’ll discuss this in a later post.
At the minimum reporting requirement of weekly, the volume is 10 acre feet (AF) to 100 AF. What is 10 AF in terms of a seasonal agricultural diversion? All the flows shown below are year-round; if the diversion only runs seasonally, the actual water right might be 2 to 10 times the calculated amount, depending on how long the season is and when the stream dries up.
10 AF = 0.014 cubic feet per second (cfs) year-round, or 6.2 gallons per minute (gpm). That’s a domestic right, enough for a family house, garden, and perhaps 15 trees or a yard.
100 AF = 0.140 cfs, or 62 gpm year-round. Depending on soil, this is enough for 3 to 15 acres of pasture or hay, maybe 15 cows or steers, or maybe 30 acres of a mature walnut orchard with micro-sprinklers. This is enough for a little extra money, still not enough to support a family.
1,000 AF = 1.40 cfs or 620 gpm year-round. This is enough for 30 to 150 acres of pasture or hay, or maybe 300 acres of orchard. Water in this quantity could support a family and would be considered a ranch or farm. The 4′ weir above has about 1.4 cfs going over it. As mentioned above, if this diversion only runs 6 months of the year, and really only gets the full flow for 3 months, then the actual continuous water right might be 5 cfs. It might be easier to reverse the thinking: a 5 cfs right might run at 5 cfs for 3 months, 3 cfs for a month, 2 cfs for 2 months, and be off the rest of the year. That’s closer to a 2 cfs right year-round, or about 1,400 AF per year.
How is flow measured HOURLY? The only practical ways to do this used to be an old mechanical recorder, like a Stevens F Recorder (pen on paper on rotating drum) you can still see on some creeks.
More likely today, it will require a battery-powered pressure transducer set inside a 2″ pipe bolted on the side of the weir, or headwall, or other permanent structure. These cost from $400 to $1,200 or more, depending on the brand and more importantly, quality. The higher the quality, the less they have to be checked, and have dirt removed from the bottom sensor. The maintenance can be significant – in warm water with algae, the sensor might have to be cleaned once a week. If it’s not maintained…well, then at some point it stops recording that data that the Board requires.
Here’s one that would do the job, from http://www.globalw.com/ products/levelsensor.html. It sits there and records water levels night and day, for months at a time before it has to be downloaded to a computer. The data file that is downloaded is what is actually sent to the Board – a spreadsheet of flows for 6 months would be half an inch think and unusable!
That’s enough for now, a good night to you all.