Chile's approach to water

The Andes are the dominant feature of Chile’s geography, an enormous natural barrier that separates the country from Argentina. The snow melt from Latin America’s highest mountain range is also of vital importance to the Chilean wine industry, much of which uses irrigation water from the rivers that flow east to west from the Andes towards the Pacific Ocean.

Producers who have no access to this Andean bounty depend on rain to irrigate their vineyards. And rain is an increasingly scarce commodity.

Precipitation has generally decreased in areas of high pressure, where the climate is influenced by anticyclones; this is certainly the case for the central zone in Chile, according to Bioclimatology Professor Fernando Santibáñez Quezada from the Universidad de Chile. Combine this shortage with the additional demands of an ever-larger area under vine and other crops, and a growing population, and the problem is even more acute.

Regional differences

Circumstances vary throughout the country. In the northern Limarí Province, Viña De Martino has had to discontinue its renowned Chardonnay Quebrada Seca (ironically “Dry Creek”). “Insufficient water resulted in a low-vigour canopy that could not protect the fruit from burning, so the grower decided to focus on avocado trees instead,” explains commercial manager Marco de Martino.

“I remember in the 1990s, Isla de Maipo had average rainfall of 500mm but in recent years we haven’t even had 200mm, and this year it will be less than 100mm,” says De Martino. “The groundwater here has certainly diminished but it is still abundant because at Isla de Maipo, the Maipo River changes direction from north-south to east-west and this river bend makes the water flow faster.” De Martino says his family considered a project to stabilise groundwater levels at 3m in order to reduce vigour but discarded it for financial reasons. However, it happened naturally after the 2010 earthquake.

Conversely, in Lago Ranco, 1,300km further south, Casa Silva’s viticultural manager René Vásquez explains that rainfall has remained constant at 1,200mm a year since the project began in 2006.

Meanwhile in Casablanca, east of the capital Santiago in the central Valparaíso Province, the water shortage is such that Jean-Charles Villard of Villard Fine Wines has had major issues with rabbits that come to drink from the irrigation system and eat the bark of the vines. He has lost 6ha already, so has built a fence along the whole 40ha property and has an employee dedicated to the problem.

Casablanca has no river and so water access depends on drilling wells. “I have not been able to replant those 6ha because the aquifer is drying out, so we are prohibited from extracting the amount of water that the law entitles us to,” says Villard. Furthermore, with spring frosts intensifying due to climate change and most Casablanca producers responding by using water aspersion (sprinkling) to protect the vines, even more water will be required in the future.

Responses

Most quality producers have opted for drip irrigation systems. These generate moderate hydric stress early in the season to stop excessive vegetative growth and focus the plant’s energy on fruit ripening. They are also adding technology to the decision-making process, for example tools such as soil moisture sensors and meteorological stations. However, the traditional system of irrigation canals is still used for 50% of agricultural land, despite the fact that it wastes 50% of the water compared to a 5% loss with drip irrigation systems.

Since 2007, Viña Montes has gradually implemented a Fseries of water-saving initiatives at its Marchigüe vineyard in Colchagua, about 180km south of the capital. These include precision irrigation and the addition of five water tanks with a total capacity of 1.5m cubic metres (costing $1.8 million), thereby reducing consumption from 4,000m3 to 2,000m3 per hectare. Also, and after several cover crop studies, Viña Montes started mulching the vineyard floor with pine bark to reduce evaporation, leading to water savings of 19%.

Further south in the Itata Valley, there are no water extraction rights, so the only water the vines receive is from rain. “The whole year’s production can be compromised in a dry summer,” says Leonardo Erazo, owner and winemaker of A Los Viñateros Bravos. The only economically reasonable option is to work the soils between winter and late November to ensure good aeration and to help the water infiltrate them. Fortunately, the considerable age of the vines and their deep root systems help with water retention.

Most Mediterranean varieties are less affected by lack of water because they have been selected by growers for drought resistance. In the Maule region three hours south of Santiago, the Carignan producers who comprise the group VIGNO are coping well with climate change because they only produce from plants at least 30 years old, which means the plants have well-established root systems and can easily adapt to dry conditions.
With 500mm average rainfall in the past ten years, and only 350mm in the last agricultural year in Maule, Bouchon Family Wines decided to plant 5ha of ungrafted goblet-trained País and Carignan. “Drought is here to stay so we are moving towards the most suitable varieties,” says winemaker Christian Sepúlveda.

Using drought-resistant plant material (grape varieties and rootstocks) is an environmentally friendly and cost-effective option for decreasing vineyards’ vulnerability to water shortages. Renowned Chilean viticulturist Samuel Barros explains that the most popular drought-resistant rootstocks in Chile are 110 Richter and 140 Ruggeri, with the former offering better performance.

Changing varieties does not work for everyone though. De Martino, for example, is categorical that his winery will not change varieties. “Cabernet Sauvignon and the Bordeaux varieties are not only the history in Maipo, they are what the market wants.”

The Chilean government needs to rise to the challenge of adapting to this complex new climate reality. Viña Montes’s chief winemaker, Aurelio Montes Jr, believes none of the past governments has invested enough in water infrastructure. “No serious research has been done into Chile’s real groundwater capacity,” he says.

Climate change and decreased rainfall pose a significant threat to all forms of agriculture in Chile, both irrigated and dry-farmed. Irrigation is an option but raises questions about sustainability. Sustainable responses include private and public water accumulation investment, technology for decision-making and adapting Chilean viticulture to cooler climate areas and drought-resistant plant material. These days, the Andes may not be enough.