Natural and Cultural History of the Douro Valley
When the river was formed, it created an inhospitable landscape with precipitous slopes along the valley. Sheltered from harsh winds and heavy, humid air from the Atlantic Ocean, resourceful families saw potential not only for vineyards, but also olive groves and almond trees. These early settlers worked at transforming the landscape through extensive terracing of the steep banks of the river. The slopes were composed primarily of shist, a coarse-grained rock consisting of different layers of minerals (similar to shale) which had to be broken apart. This was often done by hand, an arduous process one can only imagine! Once the rock was broken down, terraces had to be built to protect the vines and rocky soil from erosion.
Throughout history, the terraces have been built using varying techniques. The original terraces or socalcos, which date prior to 1860, are architecturally very narrow and irregular and only able to handle a few rows of vines per terrace. Visualize a wide staircase or stadium seating at an outdoor arts complex. Although laborious to create and difficult to maintain (shist is not the sturdiest of building materials), socalcos are still the best method to minimize soil erosion.
Possibly looking to increase the number of vines that could be planted, farmers started to build larger terraces with a shallower slope. This allowed mules or horses to be used to help cultivate the soil. The biggest impact of closer, more condensed vines is saving the region’s most precious commodity—water.
The most common method of terracing you will see today is from building patamares or earth-banked terraces. You can cultivate the single or double rows with machines, but without the stone walls, the slopes are extremely susceptible to erosion.
Where is the balance between production and preservation?On slopes steeper than 35% (or 19.29 degrees), erosion is the biggest threat throughout the valley. Farmers are being proactive to combat erosion by planting cover crops which have multiple benefits. They bind the soil, act as a wind barrier for the vines and help with increased biodiversity. One might think that cover crops compete with the vines for water, but many vineyards mow the grasses before the vines bud in the Spring, leaving the rainwater for the grapes.
Many of the vineyards in the region are “dry-farmed,” which means they rely on annual rainfall to supply the necessary moisture for their crops. But the river is right there! Why don’t they utilize water from the Douro river?
There are many debates stemming around taking water from the river. While it seems like it would be an obvious choice, creating an irrigation system would be no small task! Installment on the steep slopes could potentially exacerbate the issue of erosion. Digging to lay piping would not only disturb current farms, it would also destabilize the schist soil base.
It’s also necessary to take the health of the river into account, which has suffered its own issues with drought. The source of the Douro in Spain dried up for the first time in the fall of 2017.
Agriculturally, most vineyards have dams to help collect winter rainwater and to steadily supply crops with water. The dams also help prevent runoff from washing down the hillside, further eroding the slopes and adding additional sediment once it splashes into the river. Some advocates want to see fewer dams to encourage “free water.” They believe dams are detrimental to the overall health of the river, including loss of wildlife habitat.
Partnered with The Portugal Association of Nature, along with WWF, The Rede Douro Vivo is an organization which “exists to study and protect the Douro river and its tributaries”. This is accomplished through collaboration with scientists, environmentalists, legal specialists and public representatives, to make sure that they are seeing the river from all of its unique angles.
“A flowing river is itself a nature reserve and an ecosystem that provides habitat for countless species; it is a vital source of leisure and sport for local economies. Preserving rivers is a matter of survival for the people and species that make them their home. The contribution of ANP | WWF in this project is to show that there are more sustainable alternatives for life and nature in the Douro, as opposed to the construction of new dams.”
—Ângela Morgado, Executive Director of ANP | WWF.
You will be able to experience these conservation issues first-hand from a unique perspective—the river itself! As you float on the surface, your mind can wander and wonder, and every sense will be engaged. You will feel the heat emanating from the valley cliffs and the breeze lifting the brim of your hat; you will see the vibrant green vines gripping what earth they can find on the riverside cliffs; and you will feel the cool water that has flowed through this valley for centuries as you trail your hand in the river alongside your kayak.
Fertile land and a healthy river translate into a robust economy. Without viable vineyards, the majority of people in the Douro Valley would lose their livelihood. Working with the land, preserving the soil and managing water resources ensures future generations all over the world will be able to raise a glass of port wine and be intricately tied to the preservation of the cultural landscape of this beautiful region. You are tasting history and protecting the future at the same time.