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Browsing by Author "Wang, Yang"

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    Application of a nonpoint source pollution model to a small watershed in Virginia
    Wang, Yang (Virginia Tech, 1991)
    AGNPS, a nonpoint source pollution model, was selected to stimulate sediment yield and chemical loadings from Owl Run watershed. The model was validated to demonstrate its applicability to Virginia Piedmont conditions. The validation was carried out by comparing simulation results with measured data including runoff, sediment yield, and nitrogen and phosphorus loadings to downstream water bodies. Statistical measures, including simple linear regression, determination of root mean square errors, and test on differences between simulated and measured data, were used in this study to evaluate errors. Results from these statistical procedures indicated that the errors between simulated and measured results are within acceptable limits. An annualization procedure was used to provide the basis for evaluating the long-term impact of various BMP’s. Critical areas in the watershed, which are responsible for majority of the pollutant loadings, were identified by the model using the annulization procedure. A FORTRAN program was developed to convery critical areas for individual events to “annualized critical areas” so that evaluations were made on long-term basis. BMPs currently installed in Owl Run watershed and several alternative BMP implementation scenarios were simulated. Their impacts on reducing pollutant loadings and their cost effectiveness were evaluated by using the AGNPS model and the annualization procedure. The current BMP scenario will eventually reduce sediment yield, total nitrogen, and total phosphorus loadings by 26%, 32%, and 32% respectively. Some of the proposed scenarios can reduce these pollutant loadings by up to 59%, 66%, and 67% respectively.
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    A Systematic Review of the Scientific Literature on Pollutant Removal from Stormwater Runoff from Vacant Urban Lands
    Wang, Yang; Yin, Hao; Liu, Zhiruo; Wang, Xinyu (MDPI, 2022-10-10)
    Even though the common acknowledgment that vacant urban lands (VUL) can play a positive role in improving stormwater management, little synthesized literature is focused on understanding how VUL can take advantage of different stormwater control measures (SCMs) to advance urban water quality. The project aims to provide urban planners with information on the remediation of vacant lands using urban runoff pollutant removal techniques. To find the most effective removal method, relevant scholarly papers and case studies are reviewed to see what types of vacant land have many urban runoff pollutants and how to effectively remove contaminants from stormwater runoff in the city by SCMs. The results show that previously developed/used land (but now vacant) has been identified as contaminated sites, including prior residential, commercial, industrial, and parking lot land use from urban areas. SCMs are effective management approaches to reduce nonpoint source pollution problems runoff. It is an umbrella concept that can be used to capture nature-based, cost-effective, and eco-friendly treatment technologies and redevelopment strategies that are socially inclusive, economically viable, and with good public acceptance. Among these removal techniques, a bioretention system tends to be effective for removing dissolved and particulate components of heavy metals and phosphorus. Using different plant species and increasing filter media depth has identified the effectiveness of eliminating nitrate nitrogen (NO3-N). A medium with a high hydraulic conductivity covers an existing medium with low hydraulic conductivity, and the result will be a higher and more effective decrease for phosphorus (P) pollutants. In addition, wet ponds were found to be highly effective at removing polycyclic aromatic hydrocarbons, with removal rates as high as 99%. For the removal of perfluoroalkyl acid (PFAA) pollutants, despite the implementation of SCMs in urban areas to remove PFAAs and particulate-related contaminants in stormwater runoff, the current literature has little information on SCMs’ removal of PFAAs. Studies have also found that VUL’s size, shape, and connectivity are significantly inversely correlated with the reduction in stormwater runoff. This paper will help planners and landscape designers make efficient decisions around removing pollutants from VUL stormwater runoff, leading to better use of these spaces.