Rooted in Resilience: How Trees Tame Urban Stormwater

Rooted in Resilience: How Trees Tame Urban Stormwater 

by Zachary Root, Certified Arborist

Trees are an asset in the urban environment and when used correctly can be one of the most valuable assets to your city or town. Trees cool our neighborhoods, clean the air, support wildlife, improve health, and enhance the value and vibe of our communities.  

When implemented correctly, trees provide one of the most cost effective and natural solutions for managing stormwater in urban areas. Rising costs and tighter city budgets, increasing rainfall intensity, aging infrastructure, and expanding development have made stormwater a growing challenge. Trees can be supplemented to address these issues by managing water where it falls, reducing strain on traditional infrastructure and taxpayer dollars. 

Why Stormwater is a Challenge in Urban Areas 

Natural landscapes allow rainwater to soak into the ground, replenish groundwater, and slowly move through soil and vegetation. All of these are ways to collect, clean, and store stormwater. However, urban areas are dominated by impervious surfaces such as roads, sidewalks, roofs, and parking lots. These surfaces do not allow water to percolate and infiltrate like natural landscapes do. Cities have spent taxpayer dollars on engineering these surfaces to direct water to drains and retention or detention ponds. This runoff is later run through sewage treatment plants—another taxpayer funded expense. This can work during smaller, low intensity storms, but the increase in impervious surfaces combined with more frequent extreme weather events often leaves taxpayers to deal with driving through flooded areas or canceling events altogether. 

Trees and green infrastructure, when utilized correctly, can provide an alternative and less expensive approach. They reduce the burden on tax-funded infrastructure and maintenance while delivering multiple benefits traditional stormwater infrastructure cannot. 

Natural Alternatives 

Rainfall Interception

Tree canopies intercept rainfall on their leaves, branches, and bark, allowing some of the water to evaporate back into the atmosphere. One mature deciduous tree can intercept over 500 gallons of rainfall in a year, and a mature evergreen tree can intercept more than 4,000 gallons of rainfall in a year.  This reduces peak runoff levels during heavy storms. 

Increased Infiltration Through Healthy Soils 

Tree roots improve soil structure by creating pathways that allow water to infiltrate more easily, reducing surface runoff.

Uptake and Storage of Water 

Trees absorb stormwater through their roots and use it for growth and transpiration, reducing the total volume of water entering storm sewer systems. 

Slowing and Filtering Runoff 

Trees and associated vegetation slow stormwater as it moves across the landscape, reducing erosion, and filtering pollutants before they reach waterways, and, when integrated with rain gardens, bioswales, and permeable pavements, they significantly enhance the effectiveness of nature-based stormwater solutions. 

Trees as Stormwater Infrastructure   

Trees are increasingly recognized as green stormwater infrastructure, providing a cost effective, multi-benefit complement to traditional systems.  

Compared to pipes and storage systems, trees: 

• Reduce runoff at the source
• Lower long-term infrastructure costs
• Extend the lifespan of stormwater systems
• Adapt and improve over time as they grow

Municipalities that invest in tree planting and preservation often see measurable reductions in stormwater volumes, infrastructure demands, and associated costs, while also achieving environmental compliance and sustainability goals. 

Beyond Water: The Added Value of Trees 

While stormwater management may be the focus, it is important to remember that trees provide a wider range of benefits compared to traditional stormwater engineering,  such as: 

• Clean air and reduced urban heat 
• Improved public health and mental well-being
• Enhanced property values and economic vitality
• More attractive neighborhoods

This combination of environmental, social, and economic returns makes tree based stormwater solutions one of the most efficient investments cities can make. 

Growing Resilient Communities from the Ground Up 

As storm events become more intense and urban areas continue to grow, communities can integrate trees, a proven, scalable, sustainable, and low cost solution for stormwater planning, development, and infrastructure projects. We are not just planting for today’s challenges, we’re building healthier, more resilient communities for the future.