hydrographic

This curious map that divides the Spanish state into blue and red could represent political or administrative borders, but the partition is much more curious and striking: it shows the final destination of each drop of rain that falls in Spain. Each line you see is one of the many rivers that run through this part of the Iberian Peninsula and its color reveals where it will end: in the Mediterranean Sea or in the Atlantic Ocean. The result is one of the most beautiful and revealing hydrological portraits of the Iberian Peninsula. Based on data from the Ministry for the Ecological Transition and Demographic Challenge, the cartographer and GIS consultant Joe Davies has put together This map of watersheds that reveals the invisible spine that runs through the state, the continental watershed. The result is surprising to say the least. In addition to the colors, the route is more or less marked depending on the flow of the river, thus revealing which rivers are the largest. That invisible line slides approximately through the Iberian System and the Pyrenean foothills, dividing the territory into two water worlds. There are several things that draw attention to the image: the first thing is the proportion. The Atlantic takes up about two thirds of the territory. But also that although Spain “looks” towards the Mediterranean, its rivers flow mostly to the west. There is a geological reason that explains it: the Central Plateau It tilts slightly towards the Atlantic, a legacy of the Hercynian tectonics that shaped the Iberian base 300 million years ago. The curious layout of the continental watershed in Spain He Ebro river is the great traitor: Born in Cantabria, just 20 kilometers from the Cantabrian Sea. By geographical logic one would expect it to be Atlantic, but no: its entire large basin is painted the color of the Mediterranean, where it empties after traveling almost a thousand kilometers. The Pyrenees functioned as a barrier and the Iberian and Catalan Systems as a funnel, so the river was forced to flow westwards. A striking example of how the orography is capable of hijacking a river and taking it to another sea different from the one where it would belong. Another river that constitutes a curious case is the Segura: it originates in the Sierra de Segura in Jaen, more than 300 kilometers from the sea. Afterwards, it travels an enormous distance to empty into Alicante with a low flow, something that can be seen in comparison with neighboring Gualquivir. The explanation lies in the extreme aridity of its basin and the intense agricultural pressure. Where does each drop of rain that falls in Spain go. Joe Davies with data from the Ministry for the Ecological Transition and Demographic Challenge As one might expect, Galicia is very red on Davies’ map: it is a truly dense tangle that contrasts with the rest, especially if we move away from the Cantabrian coast. Galicia receive between 1,500 and 2,000 mm of annual precipitation, on a substrate of practically impermeable granites and slates, so the water does not filter, it drains. The result is that density of rivers and streams, all Atlantic, short and mighty. It is the region that best illustrates the direct relationship between geology, climate and river network. If the map were of all of Europe, Galicia would still stand out. The map also gives us unthinkable colorslike Pamplona being colored in Blue despite being a northern city extremely close to the Cantabrian Sea: its waters go to the Mediterranean through the Ebro and its tributaries. Madrid is red: the Manzanares-Jarama-Tajo takes it to the Atlantic. It has the continental divide very close, less than 80 kilometers away. On either side of that barrier, the water that falls in the same downpour ends up in seas separated by thousands of kilometers. 3D version with inverted colors. Joe Davies with data from the Ministry for the Ecological Transition and Demographic Challenge In Xataka | The definitive tool for a historic year of astronomy in Spain: the light pollution map In Xataka | Much more than tourism, cars and oil: the entire industry that Spain exports to the world, gathered in one graph Cover | Joe Davies