Winter is approaching, so is the rain: Controlling erosion in the vineyard during the off-season | Local News

While it is important to prevent leaching from your vineyard for obvious practical reasons, rain carrying sediment down the valley and into waterways also has a negative impact on the terroir.

County regulations require most wineries to work with a civil engineer and establish an erosion control plan before obtaining necessary building permits, and various restoration projects and certification programs have sprung up over the years. time to keep Napa soil intact and the waters clean.

“Not everyone is familiar with Napa County’s conservation regulations, and on top of that, the efforts of winegrowers to winterize their property and protect the watershed from soil erosion,” says Molly Moran Williams, Director of Industry and Community Relations at Napa Valley Grapegrowers. . “The recent and historic weather conditions of the river coupled with areas marked by fire could have been a perfect storm for disaster,” she said.

“Instead, it was a success story of what has been achieved through an ongoing focus on conservation in a community.”

Erosion control measures weren’t always on the minds of vineyard owners, and even when they were, properties have historically relied on less than effective methods that have since been gradually adopted. abandoned.

“The erosion control plan really came into effect in the 90s when it became more of a concern, especially with the terraces located in areas with very steep slopes,” said Justin Leigon, winemaker for Piña Vineyard. Management. “The terraces weren’t staying intact and that was causing issues, so it was really nice to see this move towards a greater focus on soil health. “

Leigon says terraces aren’t as easy to manage as water tends to pool, and then you have to find a way to filter it around the vineyard into some storage pond of some sort.

Nowadays, he says the civil engineers his company works with often develop the plan by examining the grade, overall soil type, and terrain, then help his crews determine the best spots to mulch or build a bypass ditch. .

“I think that’s a lot of our understanding, and our current knowledge is different now than it was then,” he said. “We are constantly adapting and evolving and learning more about best practices. “

At Premiere Viticulture Services, the feeling is similar.

“In many cases the first thing we can do for a property is to slow down the water so that it doesn’t create a runoff that will start to dig and erode our soils,” said Garrett Buckland, Premiere partner. . “With the rain case we just had, even though you’re on a relatively flat vineyard, you can get real erosion and concentrated flows,” he explained.

“The water can really speed up over those areas and pick up a lot of sediment and material and deposit it in other places… If that is to happen, we want it to stay on our property before it gets into a lane. navigable so that we can keep sediment out of the waterway.

Premiere also uses straw barbs – which Buckland says look like skinny burritos – which are basically plastic mesh tubes stuffed with straw.

“They basically serve as a tool to draw the contour, and they will intercept the water, filter it and slow it down,” he said.

Premiere also uses strategically placed bales of straw to slow down the water and create “mini speed bumps” for water throughout the property. According to county regulations, Buckland says they must winterize all of their properties by Oct. 15 to Sept. 15 for those in a municipal watershed, which he says is quite advanced but beneficial.

“Normally we don’t see big precipitation until it gets to the end of October, so it’s designed so that all of these erosion control elements are in place before one of these big storms,” he said. -he declares.

And while these response measures are helpful in preventing soil erosion, Buckland says that if given raw land, the goal would be to design something that doesn’t require putting in straw.

“So looking at a property, there are sort of two ways: the unconditional engineer method, which is to build a dam and run it and control it and have a sluice gate here and there…. But we’re looking for natural ways to slow this down, ”Buckland said. “Having a permanent cover crop, where we can cover at least 80 percent of the vegetation cover, is really the best way to slow down the water. “

After heavy rains last month, Buckland gives credit to practices such as cover crops, the use of straw and bypass ditches to avoid water-related problems, and other than areas marked by the fire, says he has not heard of any major problems in his or his vineyards from his peers.

“What we have done over the past 30 years is working and we should be passing our story on to the rest of the growing regions of the world,” he said.