Comments on: Ag Water Use Estimated Too High

By: Dr. Bruce

Dr. Bruce — Sun, 20 Jul 2014 01:01:00 +0000

To Wayne;
Because in a wet year no one cares.

By: Bob Hill

Bob Hill — Sun, 22 Jan 2012 07:39:48 +0000

Interesting. By environmental, I presume we are talking about increasing the fresh water outflow of the SF bay, and of course saving Mono Lake, both worthy causes. I suggest that to show good faith up north, they should drain and restore Hetch-Hetchy reservoir. Paid for out of the water bills of the citizens of San Francisco. Oh yeah, baby.

By: Wayne Lusvardi

Wayne Lusvardi — Fri, 08 Apr 2011 23:54:12 +0000

Dr. Lund:

We don’t want to know your number (80% goes go ag). We already know that.

What we want is for you to disclose the assumptions on which this number is based which you continue on this website to avoid.

Don’t be an expert witness sir. A good prosecutor would clean your clock.

By: Susan

Susan — Fri, 08 Apr 2011 22:11:20 +0000

Dr. Lund: If it is such nonsense why would you waste your time responding to it?

By: J Lund

J Lund — Fri, 08 Apr 2011 20:16:17 +0000

I stand by my estimate of the rough percent of agricultural use of agricultural and urban (human) use.

Just as poor use of words creates nonsense, so does the poor use of numbers.

By: Wayne Lusvardi

Wayne Lusvardi — Fri, 08 Apr 2011 19:51:24 +0000

Dr. Lund
With all due respect to you and your institution, why do you think academics and environmentalists are prone to one number and those in industry and agriculture and government another? Why should the media act as umpire and merely print one statistic? There is something sociological, not scientific, operating here is my guess.

Algebra is for finding unknown numbers. Here we are dealing with known estimates.

My contingency table exposes the sets of assumptions needed to support one number or another. Real estate appraisers, brokers, and car dealers are held to a standard of full disclosure of assumptions and any hidden conditions. Why can’t academics? If you want to continue to use the 80% figure, fine! But please disclose that number is predicated on perpetual dry years and water that goes to the environment not being counted.

Thank you.

By: J Lund

J Lund — Fri, 08 Apr 2011 15:43:37 +0000

This is a nice explication of algebra.

Before estimating a number, it is important to specify the question you want answered. The question should define the end-point of the calculation’s logic. Mathematics is ideally used as symbolic logic to get from the question to a logical answer. What question are you interested in answering?

You have shown nicely that the answer varies with the question. Alas, many questions are asked rhetorically to get an answer that sounds good, but is not very insightful.

By: Wayne Lusvardi

Wayne Lusvardi — Fri, 08 Apr 2011 15:39:38 +0000

Dr. Jay R. Lund, U.C. Davis, left a comment on this website inferring there was a consensus that agriculture used 80% of the water in California.

If you polled academics and environmentalists they probably would have a consensus of 80%.

If you polled those in agriculture the percentage would probably be more like the 41% reported by the Dept. of Water Resources as the proportion of water used by agriculture in the State Water Project.

If you polled the press, however, they would probably use the 80% figure, which is based on the misassumptions that every year is a dry year and that water that goes to the environment should not be counted. So journalists don’t live in the real world, but the social fictions created by others.

I find it interesting that no one uses the 8% figure of the amount that agriculture uses in a wet year based on all the precipitation and imports.

By: Chris Gulick

Chris Gulick — Fri, 08 Apr 2011 15:37:51 +0000

Thanks for assembling this in a simple to read format.
Assuming your numbers are accurate what we learn from this is you can make the figures say anything you want.It further illustrates that we have no lack of water falling on our heads, just a lack of storage.
Kinda puts the peripheral canal debate into perspective. Even if it was complete and ready to use today it would be sitting idle for lack of a storage.Perhaps this would be a good time to reexamine our priorities.

By: DA

DA — Fri, 08 Apr 2011 01:21:35 +0000

I think what you’re saying is, “figures don’t lie, but lies do figure.”