The Global Water Crisis and the Role of Nature-Based Infrastructure
Water scarcity is a growing crisis facing cities around the world. In recent years, major urban centers like Bogotá, Mexico City, and Cape Town have made headlines for facing severe water shortages, with residents forced to ration their usage and face the very real threat of taps running dry. These water crises are driven by a combination of factors, including climate change, deforestation, and unsustainable water management practices.
As temperatures rise and precipitation patterns become more erratic due to global warming, many regions are experiencing prolonged droughts and greater variability in water availability. In Bogotá, Colombia, for example, decreases in rainfall since 1971 have severely depleted the Chingaza reservoir system, which provides 70% of the city’s water supply. Similar trends are playing out in other parts of the world, from the Horn of Africa to India, where groundwater levels and surface water sources are declining at alarming rates.
Deforestation is another major culprit, as the loss of vital forest ecosystems disrupts the natural water cycle and reduces the ability of watersheds to capture, filter, and regulate water flows. In the United States alone, 180 million people rely on forested lands for their drinking water, demonstrating the critical role that healthy natural landscapes play in maintaining water security.
But as cities face these mounting challenges, nature-based solutions are emerging as a promising approach to bolstering water infrastructure and enhancing resilience. By protecting, restoring, and sustainably managing ecosystems within their watersheds, urban areas can improve water quantity and quality in a cost-effective manner while also making their water sources more resilient to climate change.
Unlocking the Power of Nature-Based Solutions
Nature-based solutions, or “green infrastructure,” leverage natural processes and features to fulfill infrastructure needs and build climate resilience. In the context of water security, these solutions can take many forms, from reforestation and wetland restoration to the implementation of sustainable drainage systems and constructed wetlands.
One of the key benefits of nature-based solutions is their ability to enhance the natural water cycle. By restoring forest cover within a watershed, for example, cities can increase groundwater recharge, regulate water flows, and reduce erosion and sedimentation – all of which contribute to a more reliable and higher-quality water supply. Wetlands and other natural landscapes can also filter out pollutants and nutrients, reducing the need for energy-intensive and chemically-intensive water treatment.
Moreover, nature-based solutions can complement traditional “gray” infrastructure, such as reservoirs and treatment plants, to create a more integrated and resilient water management system. In Bogotá, for instance, research has shown that restoring just 2% of the Bogotá River’s upper basin could yield significant water quality and cost-saving benefits for the city’s water utility, allowing it to diversify its water sources and become less reliant on the vulnerable Chingaza reservoir.
The economic case for nature-based solutions is also compelling. By reducing sedimentation, decreasing wear and tear on infrastructure, and lowering energy and chemical usage, these approaches can generate substantial cost savings for water utilities over the long term. In Bogotá, the water utility could save approximately $45 million over 30 years by investing just $5.3 million upfront in ecosystem restoration and other nature-based interventions.
Showcasing Successful Nature-Based Approaches Around the World
As cities grapple with water scarcity, several urban centers have already begun to harness the power of nature-based solutions, offering valuable lessons and inspiration for others facing similar challenges.
Espírito Santo, Brazil: Reforesting for Water Security and Flood Resilience
The Brazilian state of Espírito Santo, home to the metropolitan area of Vitória, has long struggled with severe droughts and erratic rainfall patterns. In response, the state has adopted a law to prioritize reforestation in the key watersheds that supply water to the region, recognizing the critical role that healthy forests play in regulating water flows and reducing sedimentation.
Our analysis showed that reforesting just 2,500 hectares of degraded land in the Jucu and Santa Maria da Vitória river basins could prevent 40 dump trucks worth of sediment from reaching the rivers each year, significantly improving water quality and reducing treatment costs for the local water utility. Additionally, the increased tree cover would help slow and intercept rainfall, mitigating the risk of flash floods that have recently devastated the region.
Nairobi, Kenya: Revitalizing Urban Waterways through Nature-Based Restoration
The Nairobi River, which flows through the heart of Kenya’s capital, has become a symbol of the city’s environmental challenges, with severe pollution and declining water quality threatening the health and livelihoods of its 4 million residents. In response, the Nairobi Rivers Commission has launched a comprehensive plan to rejuvenate and restore the city’s river systems, integrating nature-based solutions as a key component.
By reforesting priority areas along the riverbanks and creating new wetlands, the commission aims to improve water quality, enhance flood resilience, and increase access to clean drinking water. These efforts will not only benefit the urban population but also support Kenya’s broader goal of growing 15 billion trees by 2032, while creating new job opportunities in wetland management and restoration.
India: Scaling Up Nature-Based Wastewater Treatment and Groundwater Recharge
As one of the most water-stressed countries in the world, India faces a complex array of water-related challenges, from declining groundwater levels to rampant water pollution. In addressing these issues, the TheCityFix Labs initiative, a partnership between Cities4Forests and WRI India, is supporting the scaling of innovative nature-based solutions.
One such project, BacTreatEnvironmental Solutions, is using constructed wetlands to manage urban wastewater, leveraging the natural filtration and treatment capabilities of wetland plants and soils. Meanwhile, Padma Clean Environs has developed a sustainable drainage system that cleanses wastewater through vegetation and engineered soil, enabling effective groundwater recharge without the need for large land areas.
These nature-based approaches not only provide cost-effective and environmentally-friendly alternatives to traditional wastewater treatment but also help replenish vital groundwater supplies, addressing multiple facets of India’s water crisis.
Integrating Nature-Based Solutions into Urban Planning and Climate Action
As the world grapples with the mounting challenges of water scarcity, cities must look to innovative, nature-based solutions as a critical component of their water management strategies and climate adaptation efforts. By protecting, restoring, and sustainably managing the natural ecosystems within their watersheds, urban areas can enhance water security, improve resilience to climate change, and realize significant cost savings.
The success stories from Espírito Santo, Nairobi, and India demonstrate the vast potential of nature-based solutions to address complex water issues. However, for these approaches to be widely adopted, cities must take proactive steps to integrate them into their urban planning, infrastructure investments, and climate action plans.
This begins with conducting thorough assessments of local watersheds and natural assets, identifying priority areas for conservation, restoration, and sustainable management. Cities should then work closely with water utilities, community stakeholders, and environmental experts to develop comprehensive, nature-based strategies that complement traditional gray infrastructure and address the unique water challenges they face.
Securing the necessary funding and political support for these initiatives is also crucial. By highlighting the economic and environmental benefits of nature-based solutions, cities can make a compelling case for increased investment and foster cross-sector collaboration to drive these transformative projects forward.
Ultimately, the cities of the future must learn to coexist in harmony with the natural world, harnessing the power of ecosystems to build a more water-secure and climate-resilient future. As the water crisis continues to intensify, the time for bold, nature-based action is now. By embracing these solutions, cities can transition from being the exception to becoming the new norm – where water scarcity is no longer an imminent threat, but a challenge that has been successfully overcome.
To learn more about the Joint Action for Water initiative and explore other resources on water and sanitation, visit our website today.
