The Growing Water Crisis and the Promise of Green Infrastructure
The world is facing a growing water crisis. From Bogotá, Colombia to Mexico City, and Cape Town, South Africa, cities are grappling with severe water shortages that threaten the health and well-being of millions. Climate change, deforestation, and ecosystem degradation are primary culprits, leading to unpredictable weather patterns, dwindling water supplies, and unreliable water sources.
In Bogotá, the situation has become dire. After months of dry weather caused by El Niño, the Chingaza reservoir system, which provides 70% of the city’s water, reached its lowest level in history. The over 8 million residents are now rationing water, with each neighborhood facing a 24-hour water shut-off three times per month. People are encouraged to shower for less than three minutes, and households face fines of up to $300 if they go over their monthly water allotment. These rationing measures are expected to remain in place through October 2024, or until there is enough rainfall to course correct.
Bogotá is not alone in its struggle. Mexico City currently faces the possibility of taps running dry in a matter of weeks, and Cape Town, South Africa narrowly avoided a “Day Zero” in 2018, when the entire city nearly ran out of water after a rare drought. As climate change continues to raise global temperatures and cause unpredictable weather patterns, more cities will likely face these kinds of water crises.
Harnessing the Power of Nature-Based Solutions
Amidst these dire circumstances, there is hope. Nature-based solutions, also known as “green infrastructure,” offer a promising approach to improving water security and building resilience to climate impacts. By protecting, restoring, and sustainably managing forests within their watersheds, cities can improve water quality and quantity in a cost-effective way.
Forests play a crucial role in the water cycle, supporting and improving water supplies in several key ways:
- Infiltration and Groundwater Recharge: Trees and vegetation help slow the flow of water, allowing it to seep into the ground and recharge aquifers and groundwater supplies.
- Erosion and Sedimentation Control: Forests stabilize soil, reducing erosion and the amount of sediment that ends up in water sources, which can negatively impact water quality and treatment costs.
- Water Regulation and Purification: Forests help regulate water flows, reducing the risk of flooding during heavy rainfall events and maintaining more consistent water supplies during dry periods. They also filter out pollutants and improve water quality.
In the United States alone, 180 million people rely on forested lands for their drinking water, with some cities relying on national forests and grasslands for almost 90% of their water supplies. Halting deforestation, particularly around water sources, is therefore critical to ensuring a reliable and sustainable water supply.
Successful Nature-Based Approaches in Bogotá, Vitória, Nairobi, and Delhi
Cities around the world are already demonstrating the power of nature-based solutions to address water insecurity. Let’s explore how four cities are leveraging green infrastructure to improve their water security:
Bogotá, Colombia
Recent research from WRI Colombia, Conservation International Colombia, and Bogotá’s water utility has shown that nature-based solutions can play a crucial role in diversifying the city’s water sources, saving money for the local water utility, and ultimately improving water security. The study identified significant opportunities for ecosystem restoration and silvopastoral systems (combining tree growth and livestock production) in the nearby páramos, or high-altitude grasslands. Implementing such solutions across just 2% of the Bogotá River’s upper basin, the second-largest water source for the city, would help reduce sediment in the water and save the local utility money on treatment. Improvements to water quality would also make the Bogotá River basin a more reliable water source, allowing the city to diversify its supply and become less reliant on the Chingaza reservoir system.
Vitória, Brazil
The mountainous state of Espírito Santo, Brazil is no stranger to droughts. In 2015 alone, the state experienced half of its average historical rainfall, and more erratic rainfall patterns driven by climate change have also led to intense flooding. However, research has shown that reforestation across 2,500 hectares of degraded land in the Jucu and Santa Maria da Vitória river basins would improve water security and save the local water utility money through reduced sedimentation. In the Jucu River alone, restoration could prevent 40 dump trucks worth of sediment from reaching the river every year. Additionally, the trees can intercept and slow rainfall, reducing flood risks.
Nairobi, Kenya
Nairobi is deeply intertwined with its river systems, but the city faces a range of interconnected challenges, including severe drought, rapid urbanization, and significant water pollution. In early 2023, the Nairobi Rivers Commission launched a plan to rejuvenate and restore the Nairobi River. The commission and its partners are currently working to identify priority areas for restoration and find ways to integrate nature-based solutions, such as reforesting areas along the river, into urban planning. These efforts will help reduce pollution, improve access to clean drinking water for the city’s over 4 million residents (only half of whom currently have access to piped water), and create new job opportunities in wetland management, particularly for the city’s youth. The project will also support Kenya’s goal to grow 15 billion trees by 2032 and help reduce flood risk in the city.
Delhi, India
India is among the most water-stressed countries in the world, holding 18% of the world’s population but only 4% of its water. Many of the nation’s main water reservoirs are hitting record-low levels, and over 70% of India’s wastewater is untreated, leading to significant water pollution. To address these interconnected issues, TheCityFix Labs, an initiative by Cities4Forests and WRI India, is supporting two local projects that leverage nature-based solutions. BacTreatEnvironmental Solutions is using constructed wetlands to manage wastewater, while Padma Clean Environs has created a sustainable drainage system that cleans wastewater naturally using vegetation and filters it into engineered soil, allowing the water to recharge groundwater effectively and at a lower cost than other recharge systems.
The Economic and Environmental Benefits of Green Infrastructure
The economic case for nature-based solutions is also compelling. WRI has studied the water benefits and cost savings of combining natural and traditional infrastructure in several cities, including Bogotá, Brazil, and Vitória. The analyses consistently showed that investing in natural infrastructure can yield significant water benefits for cities while also producing cost savings for water utilities.
In Bogotá, for example, the water utility could save approximately $45 million over 30 years by investing $5.3 million upfront in nature-based solutions such as ecosystem restoration. These savings often come from reducing sedimentation and nutrients in water, which can lower costs from dredging, wear and tear on traditional infrastructure, and water treatment. Reducing the need for chemical products and decreasing the amount of energy used to pump and distribute water can also lead to significant cost savings.
Beyond the economic benefits, nature-based solutions offer a range of environmental and social co-benefits. Restoring forests and wetlands can improve biodiversity, enhance carbon sequestration, and provide recreational and educational opportunities for local communities. By integrating green infrastructure into urban planning and climate action, cities can create more resilient, livable, and sustainable communities.
A Call to Action: Scaling Up Nature-Based Solutions
As the threats of water scarcity continue to spread, cities around the world must take action to safeguard their water supplies. Bogotá, Mexico City, and Cape Town may be among the most prominent examples of water insecurity in recent memory, but many other cities face similar challenges. The time to act is now.
By embracing nature-based solutions and leveraging the power of natural ecosystems, cities can improve water quality and quantity, build resilience to climate impacts, and create a more sustainable future. The examples from Bogotá, Vitória, Nairobi, and Delhi demonstrate the vast potential of green infrastructure to address water challenges while delivering a range of co-benefits.
To scale up these solutions, cities must integrate nature-based approaches into their urban planning, water management, and climate action strategies. This will require collaboration between local governments, water utilities, community organizations, and environmental experts. It will also necessitate increased investment in research, pilot projects, and the implementation of successful models across different contexts.
The Joint Action for Water blog is committed to sharing knowledge, best practices, and inspiring stories from communities around the world that are leading the way in water security and sustainability. Visit our website to learn more about how you can get involved and be part of the solution.
Together, we can create a future where everyone enjoys reliable access to clean water, resilient cities, and thriving natural ecosystems. The path forward is clear – it’s time to harness the power of nature to secure our water future.
