As Delaware’s coastal communities face intensifying storms, rising tides and overburdened drainage systems, many residents are asking what can be done – and at what cost. The answer may already be growing quietly along our streets and backyards. Trees are among the most effective, most cost‑efficient and most underutilized stormwater tools available. It is time we begin treating them as critical public infrastructure. 

A 2023 meta‑analysis of 92 peer‑reviewed studies found that trees provide the strongest runoff protection of any land use, outperforming grass, bare soil and other vegetation across climate zones. Trees reduce stormwater through canopy interception, evapotranspiration and root infiltration – capturing rainfall before it hits the ground, returning water to the atmosphere and increasing soil permeability so water moves downward instead of flooding streets and drains. 

Another 2023 review identified traits that maximize these benefits – high leaf area index, dense crowns and multi‑leader canopies – giving planners guidance for selecting effective species. A paired‑catchment study further quantified these effects: a single street tree retained an average of 1,684 gallons of stormwater per growing season, measured by tracking increased runoff after trees were removed across 42 storms.

Trees are also a fiscal bargain. Engineered stormwater systems carry high capital and maintenance costs. A 2024 modeling study using the SWMM‑Canopy framework found that street trees deliver more runoff reduction per dollar spent than bioretention facilities; in one case, achieving a 1% reduction in annual runoff required $3.4 million less investment in trees. The U.S. EPA notes that trees reduce stormwater entering combined sewer systems and can defer or eliminate the need for expensive pipe expansion. For fast‑growing coastal towns, these avoided costs matter: Every gallon kept out of the drainage system reduces strain on aging infrastructure and stretches limited municipal budgets.

The benefits extend beyond flood mitigation. Trees cool neighborhoods, filter pollutants, provide wildlife habitat, improve air quality and raise property values. Yet Sussex County has lost about 43,000 acres of woodland over the past 25 years. Coastal communities facing saltwater intrusion and heavier rainfall cannot afford to keep losing trees faster than we plant them. 

I urge local planners and legislators to treat tree preservation and strategic planting as frontline stormwater management. Residents can help by planting native trees and speaking up when mature trees are threatened. The evidence is clear: Trees work. And they work better than almost anything else we can build.