What if you have a diversion where NO standard measurement device works, at all? There could be several reasons where a device just will not get the amount of your diversion properly:
- Your diversion is by seepage underground, subsurface flow that comes to the surface in your field. There is no ditch to put a measurement device in.
- Your channel runs to a reservoir or a field acting like a shallow pond, but the
flow either runs in or back out into the stream depending on how high the stream flow is. In this case, flow might go either way, for a positive or negative value of diversion, or none at all for standing water, depending on when you look.
- Your diversion is a bunch of small channels, with holes dug in the streambank where water comes out in shallow ditches. Sometimes the major part of the diversion switches between small channels, so no device or devices will adequately measure the diverted flow.
Here’s where Alternative Compliance will be more accurate than a guess, and may be the only way of measuring your diversion! What reasonable options might work to measure what you divert? Here are some methods used:
- If your diversion goes to a reservoir, survey it to develop an elevation-storage table. Engineers call these area-capacity curves, the terms are interchangeable. This only works if the reservoir is not being filled and used at the same time! In other words, you fill it, then you empty it, and maybe you fill it again. If you do fill at the same time you release from the reservoir, then you will need two standard flow measurement devices and two data collectors: a device and data logger at both the entrance and the exit.
If a field is flooded and then the diversion is shut off, then treat it as a reservoir. How big is it, in acres? What is the average depth, in feet? Multiply the area by depth, and you have acre-feet. You probably need to add a value for infiltration, what soaks in before the field is flooded. This will likely be at least 5%, up to 20% or even higher for volcanic soils.
- Use acceptable values from CIMIS for evapotranspiration for your crop. Work with NRCS or DWR to get infiltration values – what soaks into the ground and ends up as groundwater.
- Measure the flow in the stream, upstream and downstream of the area where diversion occurs. This is actually done as a matter of course in places like Sierra Valley, where each diversion may be taken at 3 to 8 locations for one ranch or farm.
Measure a stream as a system – with a gage at the upper and lower ends, like the Hat Creek top gage and bottom gage, at least the diverters can be sure the total water right is not exceeded. This doesn’t satisfy the law for individuals, but it will show agencies that the stream as a whole has the right amount of flow left in, so it might keep out the Water Board, Fish and Game, U.S. Fish and Wildlife, National Marine Fisheries Service, etc.
The great thing about Alternative Compliance is, a diverter just submits the plan
to the Water Board and then starts using it! There is no approval or denial process. The catch is, the plan will be posted online where neighbors, other diverters, and various government agencies can read it and make comments to the Water Board. If the plan does not seem reasonable, at that point the Water Board can insist on a different plan. If the new plan is done and certified by the appropriate professional, then the diverter is in the clear. If not, then after a span of time the Water Board may assess up to $1,000 per day fines.
The key to making Alternative Compliance work and not get push-back from the Water Board, is communication. Talk to the Water Board staff, make a working relationship with one or two, send them an email of updates, don’t just rely on submitting the form. Having a relationship with someone on staff can cut through the confusion and help you get your point across. If not that, then make sure the person who is doing the plan for you, is one who talks to Water Board folks regularly!