Water Resources Research Act Program

Details for Project ID 2020IN096B

Impacts of urbanization on urban runoff and water quality in the contiguous U.S.

Institute: Indiana
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $1,000 Total Non-Federal Funds: $2,000

Principal Investigators: Jingqiu Chen

Abstract: Urbanization has significant impacts on hydrologic processes, water quantity, and quality. Impervious surfaces developed during urbanization contribute more surface runoff. In regions where impervious surface dominates, high total nitrogen (TN) and total phosphorus (TP) loads of runoff may also have a comprehensive impact that influence sustainability including leakage from bioretention systems, organic pollution from sewers, and health risk of human body. This study enhanced the Long-Term Hydrologic Impact Assessment (L-THIA) Tabular Tool, which is previously developed by the investigators, by the event mean concentration method to assess urbanization impacts on runoff and water quality from urban areas of the contiguous U.S. based on the National Land Cover Database 2016. The preliminary results showed that (1) urbanization occurred non-uniformly across the contiguous U.S.; (2) urban expansion and intensification resulted in more medium and very high urban runoff counties; (3) urban expansion and intensification contributed about 3.7 billion m3 (24%) to average annual runoff from 2001 to 2016; (4) the distribution of TN & TP loads follows an uneven spatial pattern, with heavy loads often occur in large metropolitan areas; and (5) more than half of the counties experienced an increase of nutrient load, which covers 60% of the contiguous U.S. area. This work would provide valuable information that are vital to indicate latent risks and corresponding precautions regarding urban runoff, TN, and TP loads for decision makers such as urban planners, watershed managers, and city sanitary managers when considering urban development or re-development strategies. For each U.S. state, including the state of Indiana, quantitative assessments of urban runoff and water quality can support the decision making on conservation implementations. The methodology used in this work can help evaluate the effects of conservation practices and support the urban communities by developing hands-on and online learning opportunities regarding urban runoff and pollutants management.