Files from the Symposium, November 2013 are in my Dropbox. These give details on calculating ETc and figuring out how much to irrigate to reach the target. Pay particular attention to Kay Bogart's Vineyard Enology2 powerpoint, which describes the astonishing recent advances in water management at U.C. Davis.
Surface Covariance provides a direct measure of crop factor based on actual conditions. Although not a new method, its determination has recently become quite affordable, so that it now has the potential to replace weather stations with a more relevant and less expensive methodology.
It's importance to agriculture, as our most precious natural resource becomes less available in the coming years.
All of the articles available on Tom Shapland and Andrew McElrone’s surface renewal work can be found on his website http://mcelrone.ucdavis.edu/publications (let me know if you can’t get to them). These are highly technical.
The weather station is available at https://www.tuletechnologies.com/ and is portable and very economical. It covers a 5 to 10 acre planting depending on the variability of the topography. It directly measures crop evapotranspiration without reference to the now-obsolete crop coefficient.
Data points are taken in real time over a given period. The grower can then decide what percentage of transpired water is to be replaced.
In comparison to previous methodologies, this is much more accurate and robust, making possible for the first time control of metabolic switching at veraison together with substantial water savings.
Nick Dokoozlian, Vineyard Cultural Practices: The Biggest Bang for Your Buck http://lecture.ucanr.org/Mediasite/Play/1ea43f699e4c4cdf95d1fa6249b3ff371d
Martin Mendez at Gallo. Management of Irrigation during Hang Time http://stream.ucanr.org/cabernet/Mendez/index.htm very good data here demonstrating that full water should always be maintained in the period leading up to harvest. Gallo's stated policy to growers is full water after 20 brix.
Phil Freese Global Perspective on Cabernet Management Strategies http://stream.ucanr.org/cabernet/Freese/index.htm
Alan DeLoire Berry Sugar Ripeness http://lecture.ucanr.org/Mediasite/Play/02b572322638435ea52003e52dbb96d01d
Mark Matthews tells us why we go to all the trouble to try to figure out ET. This paper clearly outlines the impact on the berry and thus, on the wine. https://www.dropbox.com/sh/a030vy45rbaorwk/gETEOGJ4wV .