As Wilmington grows, thousands of acres of rain-absorbing trees are replaced by thousands of acres of hardscapes like roofs, roads, parking lots and driveways. New developments plant few trees to replace thousands removed, and new young trees have almost no effect in controlling stormwater runoff.

What’s the big deal about stormwater? Stormwater is a leading cause of water pollution. It runs off solid surfaces and collects pollutants such as oil, pesticides, and other chemicals, and deposits them into our waterways. Untreated stormwater entering streams can result in the contamination of drinking water supplies and swimming and fishing prohibitions.

As solid surfaces replace natural vegetation, flooding increases because water is unable to slowly filter into the landscape. An acre of forest will release only 750 gallons of runoff from a one-inch rainfall, with almost all the rain absorbed by the plants or channeled into the soil. The same rainstorm in a one-acre parking lot will result in 27,000 gallons of runoff.

In addition to pollution, runoff from hardscapes deposits sediment that decreases the depth of waterways, further increasing flooding and damage to nearby roads and homes.

So, what’s the best strategy for controlling stormwater runoff in Wilmington? Protecting and nourishing our remaining tree canopy is the recommendation of the Green Infrastructure Center, a research organization engaged by the North Carolina Forest Service to study how urban trees help control stormwater and improve water quality. Wilmington was one of only two North Carolina cities chosen for the study.

“Retain the current tree canopy,” our green infrastructure, is the best way to fight the destructive, polluting effects of stormwater runoff. It is preferred to building more “gray infrastructure” like stormwater pipe lines, big muddy retention ponds, and drainage “canals.”

Two meetings have been held for public input with 60 local residents attending last November’s meeting. The experts recommended three basic actions for the City of Wilmington: Plant new trees on both private and public property; limit negative impacts from development; and take care of the trees we have by keeping our urban forest healthier.

This means hiring new staff to review impacts of new development and save more mature trees with sensible planning; and adopting proactive tree protection ordinances, rather than reacting to problems after tree loss.

The Alliance for Cape Fear Trees asks residents to review the November meeting on the City’s website at Tree Canopy Study, and urge City leadership’s support of our urban tree canopy with robust, sustained funding.

Bill Jayne is vice president of the Alliance for Cape Fear Trees.