Widely revered as the Garden of Eden, Iraqs Ahwar marshlands, covering some 2 to 4 thousand square kilometres, are under threat. These treasured wetlands, which have been designated a UNESCO World Heritage Site, are facing severe ecological stress due to a combination of the worst drought in a century, upstream dam building, over-abstraction, prolonged extreme heat and widespread contamination from untreated wastewater.
Yet, one thing playing a vital role in restoring this landscape is nature itself. In Iraqs southern Thi-Qar Governorate, the United Nations Environment programme (UNEP) and the International Organization for Migration (IOM) have been working with the local sewerage authorities and the Ministry of Water Resources on a five-hectare constructed wetland pilot. Set in the Abu Zirig wetland ecosystem an integral part of the Ahwar marshlands the project treats wastewater through an approach that not only reduces waterborne pathogens but also enhances water quality and helps restore nature in this heat-stressed region.
The need for ecological improvement is acute. Thi-Qar is Iraqs governate most affected by climate-induced displacement, accounting for nearly half of displaced people nationwide. As of September 2025, more than 85,500 people had been displaced in the governorate due to land degradation, water scarcity, and rising river salinity impacts that have also severely disrupted farming and livestock-dependent livelihoods.
The ecological decline has also undermined centuries-old ways of life. For generations, communities here have relied on the wetlands for fishing, water buffalo herding, reed harvesting and seasonal agriculture. These practices are rooted in Indigenous knowledge developed through close observation of water cycles, vegetation and seasonal rhythms. As water systems deteriorate, the survival of traditional knowledge gets threatened, social cohesion is strained and displacement becomes more likely.
The constructed wetland pilot project helps mitigate these challenges and benefits more than 30,000 people, offering a practical, sustainable solution for cleaning polluted water and restoring dry wetlands. While current government restrictions prohibit local use of the water due to the ongoing drought, farmers are keen to use the treated water for agriculture once the restrictions are lifted.
Previously, untreated wastewater from the nearby Islah town flowed through an open-air channel and spread across the dried-up Abu Zirig wetlands. Since June 2025, under this initiative, the wastewater flow has been redirected into a pipeline that discharges it into earthen constructed basins located within the wetlands, where dense reed beds support its treatment. These plants and their extensive microbial communities remove and break down contaminants through physical, biological and biochemical processes. This natural innovation, which has also been used elsewhere in the world, is particularly well-suited to hot and arid climates, proving beneficial in this region.
The Islah constructed wetland project captures Iraqs drive for sustainable, forwardlooking solutions deploying modern, naturebased technologies to treat wastewater and improve water quality, said Aoun Diab Abdullah, Iraqs Minister of Water Resources. It strengthens responsible waterresource management while boosting the countrys ability to adapt to climate change and mounting water pressures."
The constructed basins take a tiered approach to cleaning the wastewater. First, theres a sedimentation basin, where gravity settles heavy solid at the bottom, allowing cleaner water to flow into the next wetland basin. In this key stage, reed beds break down organic matter, transform nutrients and reduce pathogens and heavy metals. The treated water then flows out of the wetland and back to into natural waterways.
Initial water quality tests are showing remarkable results. Significant removal of organic matter has been achieved, and concentrations of nitrogen and phosphorous as well as microbial pathogens have been reduced. Dissolved oxygen has also been restored, which has helped bring back wildlife around the wetlands, including birds, turtles, dragonflies, frogs, fish and even wild boar.
Despite its relatively small scale, this multi-functional system is providing a clear demonstration of a cost-effective, nature-based solution that contributes to climate, nature and pollution goals in an integrated manner. It highlights how global targets such as those under the Ramsar Convention on Wetlands, the Kunming-Montreal Global Biodiversity Framework (GBF) and the United Nations Convention to Combat Desertification (UNCCD) can be delivered at the local level, with strong potential for replication and scaling.
This constructed wetland project shows how nature can support people, said Susan Gardner, Director of Ecosystems at UNEP. Nature-based solutions are clean and often more efficient and cost-effective than built infrastructure. They deliver critical solutions for sustainable development, peace and the environment.
Learn more about how wetlands around the world are being tracked through UNEPs Global Wetland Watch, which is being developed to globally map and monitor wetlands at high resolution across all countries, with insights available through an interactive StoryMap and a preview of the Global Wetlands Watch Viewer.
World Wetlands Day is celebrated annually 2 February to raise global awareness about the vital role of wetlands and mark the anniversary of the Ramsar Convention on Wetlands adoption in 1971. The 2026 theme is Wetlands and traditional knowledge: Celebrating cultural heritage.
