Simulating the Impact of Land Use Change on Contaminant Transferal during Flood Events in Houston, Texas

Many studies have evaluated the impacts of urbanization on runoff and non-point source pollutants, few studies have combined hydrologic and water quality simulation models with spatial analyses to assess these impacts at the neighborhood scale, thereby exposing any environmental inequalities. This study applies the Long-Term Hydrologic Impact Assessment (L-THIA) model in Houston, TX, to estimate the current and future urban runoff and nonpoint pollutants for 88 Houston super-neighborhoods. We use hotspot analysis to explore the effects of land use changes on runoff and pollutant loads under different socioeconomic conditions. Comparing current land uses with the predicted 2045 Houston land uses shows that runoff and non-point source pollutants in all Houston super-neighborhoods would worsen by 55%, on average. Particularly, nitrogen, phosphorous, and nickel would have the greatest increase (76.88%, 60.29%, and 59.23%, respectively). Bacterial pollutants, including fecal coliform and fecal strep, are projected to increase by more than 60%. Results also show that disadvantaged communities tend to experience increased flood risk and are likely to face more public health problems from contaminant exposure, compared with advantaged communities. To reduce these risks, prevention and mitigation efforts should be diverted toward improving green infrastructure. Advocacy planning is needed to empower marginalized neighborhoods to combat inequitable effects related to land use change.