With its 9 million inhabitants, the city of Lima, Peru, is exposed to water shortages during its seven-month long dry season. Rather than building a desalination plant, the city’s water utility company, Sedapal, is to invest in conservation projects to keep the rivers flowing more reliably throughout the year, such as wetlands restoration. It will also revive a system of ancient stone canals that were built by the Wari culture between AD 500 and 1000. The canals were designed to regulate the watershed, capturing abundant water during the rainy season so that it would infiltrate rocks and feed rivers downstream as needed. Their degradation over the centuries has resulted in water running straight from the mountains into the ocean without being captured. It is estimated that the whole initiative will reduce water deficit by 60% for a $23 million price tag.