Water-sensitive design of open space systems: Ecological infrastructure strategy for metropolitan Lima, Peru

The Peruvian capital of Lima is located in the coastal desert on the Pacific Ocean. The water-scarce Pacific basin possesses only 1.8% of the total water resources of the country, but it hosts 62.40% of its population. (PNUD 2009, 40 part II). According to the 2007 National Census, metropolitan Lima, including the Callao Province, had 8.5 million inhabitants, and its population was projected to reach 9,585,636 in 2013 and 9,886,647 in 2015 (INEI 2012, 32). Due to these characteristics, Lima is considered the second most extensive city in the world built in a desert after Cairo. In Lima, however, there is much less water than in Cairo: It only has an average of 9 mm of rainfall per year (compared to 35 mm in Cairo), and its three rivers, Rimac, Lurin, and Chillon-which are mainly seasonal torrents of water-have an average monthly flow of 39 m3/s (compared to the Nile River, which has an average flow of 2830 m3/s). Large infrastructural projects were put in place to collect and transfer rainwater from the Andean mountains to feed the rivers supplying Lima. Additionally, the Transandean tunnel was constructed to transfer rainwater from the Amazon basin to the Pacific basin to cover the water deficit of the city. Because Lima’s water supply is dependent on water transfers, rain, and glaciers in the Andes that are quickly melting due to climate change, Lima is considered one of the most vulnerable cities in the world to the effects of climate change. Additionally, the water vulnerability is increased by a lack of awareness about water saving and efficient technologies by stakeholders and the population (Zucchetti et al. 2010). Although there is almost no rain, Lima’s climate is very humid due to the effects caused by the interface of the cold Humboldt current and the hot equatorial current over the Pacific Ocean in the west and the high Andes mountains in the east. Therefore, from June through December, a thick fog covers the city and turns some of the desert hills into temporarily green, blooming meadows called lomas (Figure 18.1).