California AgQuest Consulting Well Water Use Calculator

The amount of water used during a growing season for a grape vineyard can be estimated based on research work by the University of California. This research work is used as the basis of the "well-watered" calculations.
Background Discussion About This Calculator
Enter your Starting Date		5/1 5/2 5/3 5/4 5/5 5/6 5/7 5/8 5/9 5/10 5/11 5/12 5/13 5/14 5/15 5/16 5/17 5/18 5/19 5/20 5/21 5/22 5/23 5/24 5/25 5/26 5/27 5/28 5/29 5/30 5/31 6/1 6/2 6/3 6/4 6/5 6/6 6/7 6/8 6/9 6/10 6/11 6/12 6/13 6/14 6/15 6/16 6/17 6/18 6/19 6/20 6/21 6/22 6/23 6/24 6/25 6/26 6/27 6/28 6/29 6/30 7/1 7/2 7/3 7/4 7/5 7/6 7/7 7/8 7/9 7/10 7/11 7/12 7/13 7/14 7/15 7/16 7/17 7/18 7/19 7/20 7/21 7/22 7/23 7/24 7/25 7/26 7/27 7/28 7/29 7/30 7/31 8/1 8/2 8/3 8/4 8/5 8/6 8/7 8/8 8/9 8/10 8/11 8/12 8/13 8/14 8/15 8/16 8/17 8/18 8/19 8/20 8/21 8/22 8/23 8/24 8/25 8/26 8/27 8/28 8/29 8/30 8/31 9/1 9/2 9/3 9/4 9/5 9/6 9/7 9/8 9/9 9/10 9/11 9/12 9/13 9/14 9/15 9/16 9/17 9/18 9/19 9/20 9/21 9/22 9/23 9/24 9/25 9/26 9/27 9/28 9/29 9/30 10/1 10/2 10/3 10/4 10/5 10/6 10/7 10/8 10/9 10/10 10/11 10/12 10/13 10/14 10/15
Select your Weather Station		Cuyama - CIMIS 088 Los Banos - CIMIS 056 Los Tables Crk - PRVGA LTC Madera - CIMIS 145 Manteca - CIMIS 070 Modesto - CIMIS 071 Oakville - CIMIS 077 Parlier - CIMIS 039 Paso Robles - PRVGA PR1 Salinas - CIMIS 089 San Luis Obispo - CIMIS 052 Santa Ynez - CIMIS 064 Shafter - CIMIS 005 Visalia - CIMIS 033 Windsor - CIMIS 103 Zamora - CIMIS 027
Trellis System		California Sprawl - Head/Caned Pruned California Sprawl - Bilateral Cordon Lyre (or Wye) Quad Cordon - One Cross Arm Quad Cordon - Two Cross Arms VSC - Scott Henry VSP
Cross Arm Width (in)		0" 12" 18" 24" 30" 36"
Row Spacing (ft)		3' 4' 5' 6' 7' 8' 9' 10' 11' 12' 13'
Vine Spacing (ft)		3' 4' 5' 6' 7' 8' 9' 10'
			*Well Watered Use For Week
	Inches/wk	Crop Coeff, Kc	% Shaded Area	Gallons /vine/wk
			*These amounts must be adjusted for RDI and irrigation distribution uniformity.

Notes for Applying Well-Water Use Results
1.	The calculation is based on "normal" climate conditions for the specified weather station and "clean" cultivation (i.e. no actively growing cover crop).
2.	The calculated well water use for the week should be multiplied by the percentage of well-water use intended for a specific vineyard. The weekly water use will be decreased by the degree of RDI. If the degree of RDI is intended to be 70%, then the weekly water use should be multiplied by 0.70.
3.	The calculated well-water use for the week is for an irrigation system that distributes water with a 100% uniformity. Therefore, the weekly water use should be increased by the estimated Distribution Uniformity (DU) of a specific system. This is done by dividing the calculated weekly use by the DU. If an irrigation system has a DU of 80%, then the weekly water use should be divided by 0.8.
4.	A beginning date for calculations is limited to May 1 or later since the equations developed through research tend to over predict water use very early in the growing season
	Disclaimer:
	The calculation of grapevine well-water use is intended as a guideline for growers. California AgQuest Consulting assumes no liability for the application of this information to a specific vineyard situation. Factors that can influence local conditions include the soil chemistry and/or the presence of soil pests. In addition to understanding local conditions for a specific vineyard, the implementation of an irrigation strategy should be supported by monitoring the status of both the soil moisture and vine stress.

Well Water Use calculator provided by by California AgQuest Consulting

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California AgQuest Consulting, Inc., 4545 N. Brawley Avenue, Fresno, CA 93722
Ph. (559) 275-8095 * FAX (559) 275-5301, e-mail: webmaster@calagquest.com