Up at the very crest of the Mayacamas Mountains, where our 235 acres of forest, chaparral and vineyard drape across the Napa-Sonoma county line, water availability has always been something to pay attention to. The groundwater aquifers up here are in fractured volcanic rock and do not contain much water even though we receive considerable winter rain compared to the surrounding valleys. From the very beginning of Pride Mountain Vineyards in 1990, we have used pond water to irrigate our vines and well water for our household and winery needs. No well water has ever been used in the vineyards.
Our main “Sonoma Pond”, that you see as you drive up our driveway toward the winery, was constructed in the 1970s and always fills up in the first few winter storms, collecting water that would otherwise flow out to the Russian River and the Pacific Ocean. In the late 1990s, as my Dad was expanding the size of the original vineyards, he received permitting for and built a second smaller “Napa Pond” (on the Napa side of the property) that collects winter rain that would otherwise flow down to the Napa River and into the San Francisco Bay. Just recently in 2019, after diligently going through the permitting process for 15 years, I received permitting for and built a new pond on the Eastern side of the property that we call the “County Line Pond”. It too collects water during the winter collection period from December 15 to March 15 that would otherwise have flowed out to the Pacific Ocean. By collecting winter water and dripping that water back into the watershed in the summertime through our drip-irrigation system, our vineyards provide a net good to the watershed.
There is an ongoing concern among environmentalists and residents about water availability in our local creeks and the associated fish populations. While pulling water out of the ground from wells in the watershed has steadily increased over the last two decades as new homes have been built, our vineyards do not use well water for summertime irrigation nor for frost protection. Any decrease of flow in the downstream creeks is not due to our 85 acres of vines but is due to a combination of drought and enhanced well-water use throughout the watershed. There is indeed a justifiable concern about increasing groundwater use causing a decrease in well-flow rates, spring-flow rates and creek-flow rates, especially during drought years. And on average over the last 20 years, we have had slightly more drought years than plentiful rain years.
A colleague and friend of mine at UC Berkeley, Dr. Norm Miller, is a leading climate scientist and has made climate forecasts for the Napa and Sonoma regions over the 80 years to come. Using computer models trained on the past 40 year’s worth of weather data, his Napa and Sonoma regional forecasts predict that climate variability will increase significantly. For example, there will be more frequent droughts and more severe winter rain events in the decades to come with the average rainfall each winter increasing with each passing decade. Temperatures are predicted to steadily increase as well with roughly a 5 degree Fahrenheit increase in the average summer temperatures over the next 40 years. The number of heatwaves in the summertime will also be increasing both in number and severity. For example, over the past 40 years in Sonoma County, there was on average one three-day heatwave per year that had a maximum temperature of 98 F or higher and with a maximum temperature of roughly 100 F. However, 40 years in the future, we will average 30 such 98 F or higher heat spells per year with the maximum temperature during the hottest such heatwave increasing to roughly 110F. So we are in for wetter winters and much hotter summers going forward with many more heatwaves. It is difficult to predict what the summertime creek flows will be given greater winter rain but greater summer evaporation rates.
For our vineyard operation, the 2019 vintage may be a glimpse of the future. We had a very wet winter in 2019 that continued with rain and cool temperatures through to the end of May which was about 6 weeks longer than normal. When the temperatures finally began to increase in mid June, the growth of the vines was as severe as any vintage in memory. A new shoot grows out of a bud on a cane left over from last year. And from buds along that new shoot, additional “lateral” shoots can grow. Some years, the lateral shoots hardly grow at all or grow out to say 6 inches. This year, with the warm weather and so much water in the soils, we have been removing lateral shoots that are 3 to 6 feet (or more) in length; and just two weeks after removing one set of later, others were growing out another couple feet. We have never seen anything like it and it has required all of us, not just the regular vineyard workers, to spend many weeks cutting back all of this vigorous growth so that sunlight can get onto the grape clusters and onto next year’s buds. If this year is typical of the wet winter and hot summer future that my friend Norm is forecasting, we are going to be busier than ever each June and July from now on.
But one thing we likely won’t have to worry about going forward is water availability for our now three ponds that will help during each of the predicted heatwaves. Overall, despite the unwanted change to our climate, I am trying my best to poise ourselves for continuing to make killer red wines over the decades to come; its even likely that all of our best vintages are still in future. That said, I am happy that we are located high on the western crest of the Mayacamas where the cooling afternoon breezes coming from the Pacific Ocean will forever keep the afternoon temperatures cooler than the surrounding valleys.