The Torre del Oro ("Tower of Gold") is a small medieval fort on the banks of the Guadalquivir River in Sevilla, Spain. Originally constructed in 1220 by the Moorish rulers of Seville to defend the city from Christian attackers who would sail 70 miles up the Guadalquivir River to attack the city, the fort was repurposed by the Spainish after they reconquered Seville in 1248. First it was used as a prison, but after Christopher Columbus discovered the New World the Torre del Oro became the designated Royal repository for all the gold and silver brought back from the Americas by the Spanish conquistadores. All the Spanish treasure ships sailing from the New World to Spain would call at Seville, and all the gold and silver was offloaded and stored in the Torre del Oro before being taken to the royal treasury in Madrid.
Today the only gold and silver coming into the Torre del Oro comes from tourists. The tower is one of the main touristic sights of Seville.
At first glance the Torre del Oro and the city of Seville itself would seem to be immune from the effects of global warming and rising sea levels. After all, the city lies 70 miles up river from the coast. But alas, natural systems tend to be interconnected, and the Guadalquivir River debouches into the Straits of Gibraltar near the city of Cadiz While its obvious that coastal areas will be affected by rising sea levels, its less well understood that rising sea levels inevitably mean large changes far upstream along the river basins that empty into the world's oceans.
If sea levels were currently falling, its easy to understand that rivers would have to erode their channels lower to remain connected with the falling ocean surface. But sea levels are currently rising, and rivers around the world are going to have to respond. If sea level goes up 10 feet, then the river channel and floodplain will also have to go up 10 feet to allow the river to continue to flow into the surface of the ocean. The amount of aggradation produced by rising sea levels will progressively decrease upstream, but at sites like Seville, 70 miles from the ocean, the river is still going to agrade some amount. The river will do this by flooding and depositing sediment to build up its banks and its channel. Eventually the Guadalquivir river will agreed to the point that it floods the lower part of the Torre del Oro, and that will inevitably lead to the collapse of the ancient tower.
The Torre del Oro gots its name from its golden color, and the color results from the fact that the Moors constructed it out of mortar, lime, and clay with a good portion of straw mixed in. What looks like a strong stone tower is actually made of blocks of dried mud and straw. Once the Guadalquivir River rises enough to flood the base of the Torre de Oro the 800-year-old blocks of dried mud at the base of the tower will become river mud once again and the Torre de Oro will come tumbling down.rising sea levels will progressively decrease upstream, but at sites like Seville, 70 miles from the ocean, the river is still going to agrade some amount. The river will do this by flooding and depositing sediment to build up its banks and its channel. Eventually the Guadalquivir river will agreed to the point that it floods the lower part of the Torre del Oro, and that will inevitably lead to the collapse of the ancient tower.
The Torre del Oro gots its name from its golden color, and the color results from the fact that the Moors constructed it out of mortar, lime, and clay with a good portion of straw mixed in. What looks like a strong stone tower is actually made of blocks of dried mud and straw. Once the Guadalquivir River rises enough to flood the base of the Torre de Oro the blocks of dried mud at the base of the tower will become river mud once again and the 800-year-old Torre de Oro will come tumbling down.
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