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Water Issues
Water Issues
See TACNA - Perun water issues below
Lima, Peru—the second-largest desert city in the world—reimagines the "sponge city" concept. Instead of managing heavy rainfall, Lima’s green infrastructure focuses on capturing Andean runoff and coastal fog to combat extreme water scarcity. Pre-Inca "amunas" and modern fog nets act as the city's natural sponges. [1, 2, 3, 4, 5]
Water Capturing Mechanisms
Lima's adaptation focuses on two main natural infrastructure initiatives: [1]
Pre-Inca Amunas: Restoring 1,400-year-old mountain canal systems. Water is diverted from streams and spread over rocky, porous hillsides. This natural sponge effect slows down the water flow, storing it underground to emerge as springs during the dry season. [1, 2]
Fog Catchers (Atrapanieblas): Deploying fine-mesh nets along the arid hillsides to capture moisture from Lima’s dense, coastal fog (known as "la panza de burro"). These droplets are condensed, filtered, and directed into tanks for community irrigation and drinking water. [1, 2]
“Forests, grasslands, and wetlands can act like sponges, absorbing water during the wet season and slowly releasing it through the year.”
“The technique uses a canal system that diverts water from streams to small ponds or spreads it over rocky hillslopes that act as natural sponges.”
As the world's second-largest desert capital, receiving virtually no rainfall. Instead of capturing rain, the city focuses on "softening" its surfaces—such as de-paving, creating parks, and building wetlands—to reuse recycled wastewater, combat the "urban heat island" effect, and capture seasonal mist (garúa). [1, 2, 3, 4, 5]
How Lima Softens Its Urban Environment
Instead of relying on rain, Lima implements nature-based and de-paving strategies to manage extreme aridity and water scarcity: [1, 2, 3, 4]
Green Infrastructure Master Plan: The city diverts water fees to restore Andean wetlands, grasslands, and forests, protecting the mountain watersheds that supply the urban area. [1]
Wetland Parks: The city incorporates multifunctional city parks and artificial wetlands. These spaces are specifically designed to treat local wastewater and support urban vegetation without taxing the main drinking water supply. [1, 2]
Fog Catching (Lomas): Because Lima receives almost no precipitation but high humidity, peripheral communities and environmentalists use giant mesh nets on hillsides to condense the coastal fog into liquid water for irrigation and drinking. [1, 2]
“Despite its tropical position, the city receives virtually no rain, a stark contrast to other tropical metropolises. Lima instead experiences persistent high humidity, frequent low clouds and fog, and extremely dry weather overall.”
“Many streets remain unsealed with a bare soil surface. The restricted access to water, in addition to natural aridity, limits the scope for urban vegetation in public areas. The neighborhood features a small artificial wetland located in one of the parks.”
On Thursday July 3, 2025, the Inter-American Court of Human Rights (IACHR) issued Advisory Opinion No.32, a 234 page document the first of its kind from the tribunal. In it, the court says “states have legal obligations to protect people alive today and future generations from the impacts of climate breakdown”, ruling that access to a stable climate is a human right that states must protect. Some of the actions that must be taken include working on cutting greenhouse gas emissions, cooperating internationally, guarding against the threat of climate disinformation, adapting to evolving needs and utilizing the best available science to inform decisions.
Advisory opinion on the Climate Emergency and Human Rights
submitted to the Inter-American Court of Human Rights by the Republic of Colombia and the Republic of Chile
--ENGLISH and SPANISH VERSONS
SPONGE CITY
SPONGE CITY
Rain-heavy cities around the world are aggressively stripping out concrete and tarmac to create "Sponge Cities". Instead of relying on traditional pipes and storm drains, these urban areas are "de-paving" to allow heavy downpours to sink naturally into the earth, preventing devastating surface floods.
"Sponge City" is an urban planning and design concept aiming to make cities more resilient to the impacts of heavy rainfall, urban flooding, and climate change. The idea is to mimic the natural water cycle by using green infrastructure and other permeable surfaces to absorb, store, and release rainwater in a controlled and beneficial manner.
"Sponge City" is an urban planning and design concept aiming to make cities more resilient to the impacts of heavy rainfall, urban flooding, and climate change. The idea is to mimic the natural water cycle by using green infrastructure and other permeable surfaces to absorb, store, and release rainwater in a controlled and beneficial manner.
The Sponge City concept originated in China in response to the growing frequency and intensity of urban flooding. Since the successful 2014 Suzhou pilot, the Chinese government has launched a nationwide program promoting the development of Sponge Cities. The concept has also been adopted by several cities in the US and Singapore.
Interestingly, in contrast to global trends, the Auckland mayor has controversially proposed cuts to climate and environmental programs.
Outdated stormwater infrastructure, proximity to the coast and low-lying areas make New Zealand cities vulnerable. Clearly evidenced by the widespread flooding, damage and disruption caused by recent summer storms.
Naturally occurring large green spaces, while beneficial, may not offer the absorbency or holding capacity required in more densely populated spaces. We need to employ site-specific supporting infrastructure, with media designed for its ‘sponginess’ or capacity to retain, detain and clean rainwater.
Different green infrastructure devices offer varying levels of ‘sponginess’:
· Super sponge: Green Roofs, Rain Gardens, Bio swales, Wetlands
· High sponge: Stormwater Tree Pits,Permeable paving, asphalt and concrete alternatives.
· Moderate sponge: Tree Pits, Gardens,Parks, Golf Course
The efficacy of these devices was recently demonstrated in Auckland’s Wynyard Quarter and Hobsonville Point. Both areas where bioretention devices have been installed were resilient to unprecedented rain fall, while flooding was severe in neighbouring areas.
Extreme weather events are a sign of things to come. Auckland and other cities must explore ways to increase urban sponginess, promoting and prioritising the use of green infrastructure to improve overall sustainability and resilience. Taking our lead from the global community we could look to update our best-practice and council standards, mandate the use of green infrastructure in new developments, retrofit existing infrastructure to incorporate green elements, or incentivize private property owners to invest in green infrastructure.
Implementing Sponge Cities requires coordination and collaboration between agencies and stakeholders, investment in infrastructure, as well as changes to building codes and zoning regulations to promote the use of permeable surfaces and other green infrastructure.
As many North Islanders’ will attest, it is increasingly important for our cities to work together to increase resilience to flooding and other impacts of heavy rainfall and climate change. By promoting the development of Sponge Cities, and refreshing best-practice guidelines, we can create more sustainable, resilient, and liveable urban environments.
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