Best practices for vineyard water use and conservation

(NVR) - “How is the drought affecting you?” This one of the first questions that anyone in wine country is bound to hear from a visitor this year.

Before the big storm of early February, which dropped 7 to 14 inches over Napa Valley vineyards, and the subsequent storms in March, the response to that question came after a thoughtful pause. Even though there remain a couple of months when rainfall is possible, the lack of early winter storms and the fact that we are in a low rainfall year, on the heels of a relatively dry 2013 growing season, has our full attention.

The topic of water management is a perennial one for all farmers. We are fortunate here in Napa to have ample rainfall in average years, stable groundwater resources, a crop that does not demand much water relative to other crops, and an industry that is well-educated about best practices.

There is a positive outcome of this year’s low rainfall, which is that it has brought the industry together around best practices for water conservation going forward. The Napa Valley Grapegrowers have hosted two events already this year focusing on appropriate water use strategies, and will offer two more in the coming months.

So just how are growers managing?

For one thing, vineyards here use much less water per acre than other crops and even less than winegrape crops in other regions of California, which have bigger vines and hotter summers. Grapevine roots can be remarkably efficient, growing deep into the ground and pulling moisture from far below the surface.

Growers get water from several sources: surface water (these supplies can vary significantly from year to year and are affected by drought years), groundwater (the underground reservoir or aquifer, which in most parts of Napa is relatively stable) and recycled water. Managing these resources responsibly is a high priority for all growers and is based on using less water — and using it strategically at critical points in the vine’s growing season. Many Napa grapegrowers regularly employ what we call “deficit irrigation,” as it is directly tied to wine quality.