12 June 2014

Who has the right to leaked water?

SM sent this question a few months ago:
My thesis is about conjunctive water use and the hydrologic externalities that arise from a change in water use (e.g., increased irrigation efficiency or canal lining).

I am focusing in the canal seepage/lining scenario.

My question is, in the Prior Appropriation Doctrine,* where is the balance between the "diverted use" and the "consumptive use" statute?

I am aware of the right to recapture, but I am also aware of the "do no harm" ethic in changing a water right. I am also aware that there is not a requirement to submit a "change" in a water right when switching to efficient irrigation methods.

Every time I present my issue of who receives benefits and who receives costs in canal seepage/lining, the same controversy comes up in questions:
"Who cares if they line that canal if its their water?" or
"They can't line their canal because the water has been historically allocated to the groundwater irrigators."

It all comes down to consumptive v.s. diverted use rights.

Of course in the case of an externality, the basis of how to internalize it completely depends on who owns (has a right to) the good. This stumps me because of the darn laws.

So... is there a clear answer on who gets the water? Does it depend on the laws? Do some laws need to change?
In response, I sent this post on accounting for water flows and this example of how canal lining can harm "leak beneficiaries." In addition, I said that the specification of rights drives the discussion of harm, adding that "do no harm" tends to apply to riparian rights while prior appropriation ASSUMES no harm from the use of quantified rights. Accounting problems will arise if some rights are based on de facto return flows. (In my book, I write in favor of "assumed 100 percent consumption" as a way of (1) protecting environmental flows and (2) encouraging more in-situ "efficiency" without harming neighbors.) I also added that these accounting problems fall into an "emergent externality" category as water scarcity and stress increases.

Do you have any ideas, arguments or examples to add to this discussion?
* SM adds:
The Prior Appropriation Doctrine is a frustrating thing but still only the tip of the iceberg in water law. These emerging externalities come at the hands of both climate change and population growth and are certain to continue. The diverted use basis of Prior Appropriations might end up causing more harm than good when a few people raise there benefits to the detrimental costs to large numbers of people. Won't it be nice when the costs and benefits of these can be quantified? It would certainly help in analyzing situations.

* From your references, the best thought I noticed was how complicated it would be to implement a consumptive use-based system. Coming up with even semi-feasible ideas would be a gargantuan project involving several disciplines, and teamwork effort to figure out the best way to do that. Certainly a lot of soil physicists would be involved. Maybe some day...


  1. Hi David,

    Probably I should first read your book to see how you came to that conclusion, favoring 100% consumption and insitu efficiency measures, but of course we should be aware that these insitu measures can also increase consumptive use (acreage, more water demanding crops) and put in danger precisely e-flows. Also problem now faced in many areas like SE Spain that farmers realize that all the investments in insitu efficiency measures (drip irrigatino) are energy-demanding and higher energy prices is killing them. So energy efficiency may be at least as important as water efficiency.

  2. @Johannes -- I *assume* 100% consumption so that in-situ improvements in "efficiency" (water use that reduces tail flows) do NOT impair other users or eflows.

  3. You linked this very interesting in today´s speedblogging post: The World Bank and Chinese government use remote sensing to allocate water rights. Sustainability, productivity and incomes are UP! http://www.aguanomics.com/2014/06/speed-blogging_16.html. We have discussed on this project on your blog before: http://www.aguanomics.com/2010/05/whats-your-evapotranspiration.html

    Can´t this be the solution then, for the problem described in this post? Using remote sensing and hydrologic functioning of the catchemtn to determine rights for consumptive and diverted use of water for each farmer? Monitor this each year for each farmer, and if necessary adjust charging scheme (just like energy bill is paid in some countries like Holland: you pay each month something based on your estimated use and then by the end you see whether that was enough or not)

    Of course, in most areas you have existing water rights - and therefore remote sensing technologies and the inclusion of hydrological flows into the charging scheme may be seen as a threat by farmers and politicians, because of over-allocation. And that´s the main issue described here as far as I understand.

  4. @Johannes. Yes, I agree. (And I'm glad to see you've tracked the older post!) Remote sensing can do quite a bit when it's available. The "100% consumption" default can work when it is not.


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