*By Germán Sturzenegger (IDB), Jeffrey Cowan (TNC) and Carlos Hurtado (FEMSA Foundation)
Cities have historically developed around one key resource: water. This dependence explains why water security is at the core of every city’s future. This is particularly important in Latin American and the Caribbean (LAC), where 80% of the population lives in urban areas.
When it comes to water resources management, cities have heavily relied on gray infrastructure solutions. But this “business as usual approach” could be unaffordable and insufficient to deal with the current water security challenges many urban areas face. An approach focusing only on gray infrastructure risks excluding investment in water sources for downstream areas. Cities that protect their sources have a better chance of dealing with increasing challenges such as population growth and climate change.
Watershed conservation is a means of protecting lakes, rivers, and streams by managing the entire watershed that drains into them. Forests, wetlands, and other natural ecosystems have the capacity to filter, store and regulate the flow of water. That is green infrastructure: natural ecosystems that make the watershed work. Coupled with gray infrastructure, these ecosystems can play a decisive role in guaranteeing the resilience and water security of our cities.
Some cities are already pioneering innovative green infrastructure solutions to overcome their water security challenges. Monterrey, Medellin, Sao Paulo, and San José, among others, are mainstreaming green infrastructure solutions such as reforestation or wetland restoration into their investment portfolios. They visualize green infrastructure as a cost-effective approach for managing water-related issues. Below, we highlight four reasons why these LAC cities are investing in these nature-based solutions.
- Green infrastructure contributes to water availability
The city of Sao Paulo recently faced its harshest water crisis in 80 years. Fostered by the Alto Tiête Water Fund, Sao Paulo’s private and public sectors came together to promote investment in green infrastructure to ensure water availability for the more than 22 million people living in the metropolitan area. Through a payment for ecosystem services model, the city aims at protecting and restoring key natural ecosystems that will improve the control of speed at which water flows and the natural short- and long-term water storage in the environment. This change on peak and base flows is expected to increase water quantity during Sao Paulo’s dry season and help this mega-city be better prepared to deal with similar crisis.
- Green infrastructure contributes to water quality
Medellin and the Aburrá Valley are home to 3.5 million people. Medellin is Colombia’s second-largest city and one of the most important industrial areas in the country. Urban expansion, industrial activity and cattle ranching are currently destroying forests, increasing sediments and reducing water quality at the watershed level. This could place the future of the city’s water supply system at risk. Natural vegetation has a filtering and barrier effect against water pollution from pesticides, fertilizers and other pollutants derived from poorly managed agriculture and cattle ranching. Vegetation can absorb several pollutants and store them in its tissues or transform them into less dangerous substances. The city’s proactive water utility, Empresas Públicas de Medellin, is investing in the Rio Grande and La Fe watersheds more than US$8.5 million over a 5-year period to protect, through green infrastructure, the quality of the city’s water supply. The investments in these two watersheds are implemented and supervised by Cuenca Verde, the Medellin Water Fund, and focus on improving agricultural practices, recovering riparian areas and regenerating forest and wetlands to maintain nature´s capacity to filtrate water and thus increase water quality in these basins.
- Green infrastructure contributes to flood prevention
Watersheds upstream might seem like places far away from cities’ problems. However, the link between them is not only real, but, if ignored, can prove to be disastrous. In the city of Monterrey, Mexico, a plan is underway to raise over USD $150 million for green infrastructure to mitigate flooding such as the one it experienced in 2010. That year, hurricane Alex devastated the city, leaving damages calculated at over USD $1.35 billion. By strategically investing in restoration, reforestation, and soil management activities in 33,000 hectares of the San Juan River watershed, the Monterrey Metropolitan Water Fund estimates that the impact of a similar hurricane will be reduced. The water fund has already raised over US$ 15 million towards this end. This green infrastructure in the upper part of the watershed will work together with an existing flood check dam to prevent and mitigate future water-related disasters.
4. Green infrastructure contributes to biodiversity conservation
Costa Rica is home to 4% of the world’s biodiversity. In the Greater San José Metropolitan Area, population growth and land-use change have severely degraded the natural landscape in the Rio Grande and Rio Virilla watersheds, which provide part of the capital’s water supply. Water-focused protection of the city’s watershed includes efforts to protect biodiversity by supporting environmentally friendly land use practices that contribute to improved biodiversity conservation. Through Agua Tica, a Water Fund launched in 2015, stakeholders invest in agroforestry systems, assisted ecosystem regeneration, and best agricultural practices to protect the watershed. These approaches to address land use change help conserve native biodiversity and attract species that may not interact with more traditional forestry or agricultural systems. Helping maintain the country’s water and biological resources is critical in a country with such a natural heritage.
These four examples showcase how green infrastructure can complement traditional water infrastructure systems, and why cities must consider investing in nature-based solutions to help overcome their water security challenges. To learn more, tune in EYE on LAC at World Water Week on August 31st 2016, where we will discuss how to keep advancing a green infrastructure agenda in LAC (#wwweek).
The Latin American Water Funds Partnership: All the investments mentioned above were co-financed by the Latin American Water Funds Partnership, a mechanism that provides technical and financial assistance for the creation and strengthening of Water Funds throughout LAC. The partnership gives support to existing funds, structures new funds, leverages additional resources, creates strategic alliances, implements technical guidelines and creates tools to enhance Water Fund initiatives with the objective of contributing to improve water security through the protection of watersheds.
 In this World Resources Institute post you can find more info on the Sao Paulo case: Natural Infrastructure Could Help Solve Brazilian Cities’ Water Crises