Portland Nonprofit Depave Transforms 8.4 Acres of Pavement into Green Space, NASA Confirms Cooling

Since its formal launch in 2008, the Portland-based nonprofit Depave has transformed 8.4 acres of pavement into gardens, rain gardens, and gathering spaces across 80 sites at schools, churches, and community spaces. The organization began when residents removed pavement from their own properties, sparking a movement that now trains community groups across North America to run similar projects.

A typical project removes about 3,600 square feet of asphalt or concrete. NASA researchers analyzed six Depave sites using remote-sensing data and recorded decreases of up to 7.7 degrees Fahrenheit in reflected heat. The researchers hypothesized that cooling effects would continue to grow as vegetation matures, providing rare third-party verification for a grassroots environmental intervention.

Stormwater benefits are also quantified. Portland receives 37 inches of annual rainfall, and Depave estimates that a typical project footprint, combined with runoff from adjacent impervious surfaces, reclaims roughly 208,872 gallons per year. Across the full portfolio of 80 projects spanning 8.4 acres of direct pavement removal plus 12.6 acres of adjacent drainage area, the organization estimates 24.4 million gallons are redirected into soil annually, easing pressure on storm drains and cutting pollution runoff.

Carbon sequestration adds another measured benefit. Urban soils store 1.5 to 3 times as much carbon as non-urban soils, and Depave estimates each typical project sequesters 0.05 to 0.10 metric tons of soil carbon annually. Across the portfolio, that amounts to 5 to 10 metric tons captured annually, not including additional sequestration from newly planted trees.

Depave pursues a network model rather than depaving every city itself, training community groups across North America to run projects in their own neighborhoods. The organization also advocates for policy change, pushing cities to reduce parking requirements and legalize sustainable urban design; Los Angeles, Seattle, and Tacoma have begun exploring similar depaving policies.

Long-term care is built into the model through ongoing Community Care programs where volunteers tend green schoolyards and gathering spaces well after the initial transformation. A Green Thumb Maintenance Crew treats each project as a lasting commitment rather than a one-day event, allowing sites planted years ago to keep maturing and cooling.

Environmental justice shapes where Depave works. The organization intentionally partners with communities facing disproportionate heat exposure and historically less access to green space, directing volunteer labor and resources toward neighborhoods that need cooling and stormwater relief the most.