2020-2023 UCCE Irrigation Survey: Collaborators Needed

UCCE Sonoma County is looking for growers who are interested in collaborating on a survey of vineyard irrigation water use.

Currently, the Groundwater Sustainability Agencies (GSAs) are estimating the total volume of water applied to vines with the use of models. It is very likely that modeled irrigation volumes overestimate actual vineyard water use because of site variability and deficit irrigation practices.

The UCCE survey is designed to measure actual water volume applied in individual blocks with the use of a pressure switch plumbed into a single irrigation drip line. A data logger records the irrigation run time and is downloaded at the end of 4 years. The association of each property to its data is destroyed thus insuring the anonymity of the irrigation application information. A similar survey of vineyard irrigation water use was conducted in 84 blocks in Paso Robles and is described in California Agriculture.

Background

Red grapes in vineyard. Photo from UC ANR.
The project is funded by a one-year grant from the American Vineyard Foundation. The co- investigators are Mark Battany, Water Management and Biometeorology Advisor, San Luis Obispo/Santa Barbara Counties and Rhonda Smith, Viticulture Advisor, Sonoma County.

This is a hands-off project designed to learn how growers utilize irrigation water over the course of several years and improve the estimates of groundwater extraction used by the GSA’s. Data generated by the UCCE study in Paso Robles informed the vineyard irrigation component of the Paso Robles Groundwater Basin model.

The region covered by the survey is inside the area of the three mapped groundwater basins in Sonoma County which are currently designated as medium priority by the California Department of Water Resources (Santa Rosa Plain, Petaluma Valley and Sonoma Valley) as well as the Alexander Valley groundwater basin which is not currently designated as a medium priority. If you are uncertain if your property falls within the survey area, you can enter the address into the DWR Groundwater Basin Boundary Assessment Tool.

Details

There is some urgency in learning if a sufficient number of growers with vineyards located in the three groundwater basins which have GSA’s and the Alexander Valley basin will commit to participating. Ideally, 30 sites can be identified in each of the four basins. Equipment for the sensor-logger units must be purchased in September! The units will be built then installed over the winter; however knowing the quantity of all required components as soon as possible is important.

Collaborators will have a single sensor-logger unit installed by UCCE. After they are installed in the winter of 2019/2020, they are removed after the 2023 season. All data are stored in the data logger and are downloaded after the units are retrieved. The data are not associated with the location or owner/manager. The units used in Sonoma County will be slightly modified from those used in the Paso Robles study as shown in the photo in the California Agriculture article.

More than one block on a property can be included in the survey depending on the total vineyard acreage on the property. Also, a survey block can be placed on separate properties under the same owner/company when located either within a single basin or different basins.

Participating growers will be requested to have their irrigation systems evaluated at mid-point during the four-year study period to determine their actual application rates, and to share these results with the investigators to help improve the accuracy of the automated measurements.

If you are interested in participating

If you would like to volunteer to participate in the survey, I will need a vineyard block map of the ranch. We will randomly select one block on the map to install a sensor-logger unit.

Given that we need to collect data for 4 years, any blocks which are likely to be removed in 2020 through 2023 should be crossed out on your map.

We are only surveying blocks which receive applied water through a drip system. Blocks with any form of sprinkler irrigation should be crossed out on your map.

To participate, please email me a block map of the vineyard and call if you have questions.

Rhonda Smith, Viticulture Farm Advisor, UCCE Sonoma County 
rhsmith@ucanr.edu 
707-565-2621