Natur-al-Andalus: Washout

Thursday, February 18, 2010

Washout

This was the view from my window this evening. It was during a break in the weather! The view is of the northern peak of the Rock. The area of white limestone showing through the cloud is a 19th Century watercatchment. It has been abandoned for decades and the olive maquis is slowly recovering the area. It is the site of a large breeding colony of Yellow-legged Gulls. Just about the only thing you can guarantee about the climate down here is a summer drought that lasts at least three months. This winter's rains didn't come until December so the drought lasted 6 months! In the old, pre-desalination, days people would have been suffering badly because of the drought. The solution was to open up areas that would collect winter rainwater which was then stored inside huge reservoirs,each the size of a football pitch, excavated inside the Rock. In the 20th Century huge areas of sand slope on the eastern side of the Rock were turned into catchments by placing corrugated iron sheets onto wooden frames. Even with these engineering feats the summer drought was a problem and in the second half of the 20th Century oil tankers were often requisitioned to bring freshwater from Britain. The winter rains may have been delayed but they eventually came with a vengeance, producing one of the wettest winters of recent times. Seeing not much could be done today, here is a sequence of photos showing the age plumage sequence in Yellow-legged Gulls that I took yesterday evening: