Geoff Vanden Heuvel
Director of Regulatory and Economic Affairs
A very important paper was released this week outlining a dairy facility's water consumption. This is a particularly important paper because most Groundwater Sustainability Agencies that are implementing groundwater allocations to landowners are using satellite evapotranspiration (ET) information to calculate groundwater consumption. The footprint of a dairy facility – the corrals, milking barns, feed area, etc. – do give off an ET signature, but water on a dairy facility is recycled several times and there is water in the feed that is brought on to the dairy facility as well as milk that is shipped off of the facility.
The paper produced by the 4Creeks Engineering firm details the water flow onto and off of a dairy facility and concludes that actual groundwater consumption by the acres associated with the footprint of the dairy is about 6 inches per year. You can access the study here and download the calculator (Microsoft Excel spreadsheet) here, which will allow you to adjust cow numbers and acres to find the number that fits your operation.
A USDA-NRCS funded study is being launched to validate these numbers. Several dairy facilities will be part of this study which will precisely meter and measure all water coming onto the facility and leaving the facility. In the meantime, the 4Creeks paper will serve as a valuable resource for GSAs in determining how to allocate the water footprint to a dairy facility.