The Brazo del Este was one of the two branches into which the lower section of the River Guadalquivir was divided. In the marshland plain, The River Guadalquivir splits into several branches when it reaches the marsh plains. The three largest branches were the Brazo del Este, Enmedio, which is the current watercourse, and Torre, also known as the Northwest Branch.
The Nature Reserve of the Endorreic Complex of Lebrija-Las Cabezas, together with that of Espera, are the last redoubt of a great lagoon system that ran through the entire countryside between Seville and Cadiz. Human activity has gradually reduced the wetland to the lagoons of La Cigarrera, Galiana, Peña, Pilón, Taraje (the only permanent one) and Charroao, known as Bujadillo or Herradura.
The Cordobilla Natural Park, with an area of 1,460 hectares, is located on the River Genil. It is reached by the road that connects Badolatosa with Puente Genil. It is surrounded by agricultural land, in an area where the predominant crops are olive groves, cereals and some other irrigated crops.
From a geological point of view, the Malpasillo reservoir is part of the Sub-Baetic unit of the Betic mountain ranges.
This natural enclave is one of the most important in Europe. It is an extremely important wintering, migratory and breeding area for many bird species. Furthermore, it is one of the last havens for endangered wildlife species such as the Imperial eagle or the Iberian lynx.