In the heart of urbanized Delhi, where asphalt and concrete typically accelerate runoff during the monsoon, a single tract of restored land functions differently: it acts like a sponge, soaking up rainfall and slowing its rush toward the streets.
A recent study revealed that the Aravalli Biodiversity Park retains nearly three million liters of rainwater annually, curbing surface runoff and mitigating the risk of localized flooding.
Spanning 692 acres along the city’s southern ridge, the park was once a derelict mining site characterized by craters and spoil heaps.
Today, it is home to approximately 202,000 trees that not only intercept water but also purify the air, sequester carbon, and sustain a rich array of biodiversity.
Researchers from Delhi University, who conducted the study in 2023, utilized the i-Tree Eco model alongside local meteorological data to quantify these ecosystem services.
They found that the trees prevent nearly three million liters of runoff each year, allowing water to percolate into the soil and recharge underground reserves.
Situated over a critical aquifer, the park’s role in groundwater recharge is particularly vital in Delhi’s dry subtropical climate, which receives an average annual rainfall of 774 millimeters.
Beyond water management, the trees remove approximately 127 tons of air pollutants annually, providing an estimated economic benefit of nearly 1.89 crore rupees.
The park’s biomass holds a carbon stock of roughly 8,360 tons, with an additional 1,236 tons sequestered annually, contributing a further 11.34 crore rupees in value.
Previously dominated by invasive species like Prosopis juliflora and Lantana, the area is now led by native trees such as Dhak, Indian Elm, White-barked Acacia, and Kadamba.
The park hosts nearly 700 plant species across 20 ecological communities and 80 types of native trees, creating a resilient and diverse habitat.
The uneven terrain left behind by morrum mining has fostered varied micro-habitats—ranging from forests to grasslands and wetlands—which collectively enhance the park’s capacity to handle torrential downpours.
The study highlights that restoring degraded land with indigenous species yields more than just aesthetic rewards; it provides practical returns through flood mitigation, improved air quality, and replenished water resources.
In the face of rapid urbanization, such green islands are becoming increasingly precious for cities where expanding development typically exacerbates water-related challenges.
