A recent study at the Texas A&M University (TAMU) Superfund Research Program (SRP) Center suggests that installing green infrastructure features, such as water-absorbing rain gardens, on vacant lands can provide ecological and economic benefits, particularly in communities with frequent flooding.
Many urban areas have vacant lots, and areas with a history of flooding are especially prone to challenges when considering redevelopment of the properties. The Texas coast is one of the most heavily impacted areas from coastal storms in the world. TAMU SRP researcher Galen Newman, Ph.D., set out to evaluate the economic and hydrologic performance of green infrastructure development projects in three neighborhoods in Houston, Texas, with high risks of flooding. The plans are based on a design approach they call "Resilience through Regeneration" that focuses on reducing effects of flooding in communities through vacant lot reuse.
The TAMU SRP Center, established in 2017, focuses on exposures to chemical mixtures during environmental emergencies and developing tools to understand and prevent the health consequences of those exposures. Newman is an associate professor in the Department of Landscape Architecture and Urban Planning, and co-principal investigator of the Community Engagement Core at TAMU SRP.
Green infrastructure involves building rain gardens, rain water detention areas, green roofs, and other features that can act as sponges to absorb and retain large volumes of water during flooding events. Planners refer to this approach as using "Sponge City principles." For this study, TAMU researchers analyzed land use plans using Sponge City principles they developed for each of the three neighborhoods to predict water flow and retention, as well as economic costs and benefits, if the plans were implemented.
Their analysis showed that the designs would capture 7 – 40 million gallons of stormwater per year across the three communities, representing an increased capacity of 22.2 million gallons annually. Other benefits include more tree coverage, walkable space, and green space, including improvements to nearly all of the vacant lands.
The researchers also analyzed construction and maintenance costs and economic benefits of implementing the plans in the three communities. For the three sites analyzed, construction costs ranged from $8 million to $30 million. Sunnyside had the highest total annual green benefits of $5 million, and the site would take 20 years to produce a return on investment. On average, the sites would take about 40 years to produce a return on investment.
The researchers concluded that applying Sponge City principles to urban planning for vacant lands could provide ecological and economic benefits to local communities. Their report includes details that other urban planners could apply in their work.