Viceroyalty of Peru arrived in Lima with Antonio José de Sucre to plan the offensive. In February 1824 the royalists briefly regained control of Lima. Olañeta's Rebellion started by surprise and the entire royalist army of Upper Peru (today's Bolivia) revolted, led by Pedro Antonio Olañeta (royalist) against La Serna, the viceroy of Peru (a liberal). This broke the royal army and started a civil war in Upper Peru. Having regrouped in Trujillo, Bolívar in June led his rebel forces south to confront the Spanish under Field Marshal José de Canterac. The two armies met on the plains of Junín on August 6,
Water resources management in Peru upper basins, whereas the southern part of the country is particularly prone to droughts. Aside from natural causes, such as El Niño Southern Oscillation, the effects of droughts and floods have been exacerbated by manmade interventions including soil erosion stemming from poor cropping and grazing practices, deforestation, and poor land use-practices. El Niño hits Peru approximately once every seven years and consists of heavy winds and rainfall associated with devastating floods and landslides. In 1997–1998 the costs of damages reached US$2 billion. Droughts severely affect the southern coast, producing agricultural losses as well as limitations on human water consumption. Preventive