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John C Clausen - One of the best experts on this subject based on the ideXlab platform.

  • effect of a modular extensive green roof on Stormwater Runoff and water quality
    Ecological Engineering, 2011
    Co-Authors: Bruce G Gregoire, John C Clausen
    Abstract:

    Abstract Runoff quantity and quality from a 248 m 2 extensive green roof and a control were compared in Connecticut using a paired watershed study. Weekly and individual rain storm samples of Runoff and precipitation were analyzed for TKN, NO 3  + NO 2 –N, NH 3 –N, TP, PO 4 –P, and total and dissolved Cu, Pb, Zn, Cd, Cr, and Hg. The green roof watershed retained 51.4% of precipitation during the study period based on area extrapolation. Overall, the green roof retained 34% more precipitation than predicted by the paired watershed calibration equation. TP and PO 4 –P mean concentrations in green roof Runoff were higher than in precipitation but lower than in Runoff from the control. The green roof was a sink for NH 3 –N, Zn, and Pb, but not for TP, PO 4 –P, and total Cu. It also reduced the mass export of TN, TKN, NO 3  + NO 2 –N, Hg, and dissolved Cu primarily through a reduction in Stormwater Runoff. Greater than 90% of the total Cu, Hg, and Zn concentrations in the green roof Runoff were in the dissolved form. The growing media and slow release fertilizer were probable sources of P and Cu in green roof Runoff. Overall, the green roof was effective in reducing Stormwater Runoff and overall pollutant loading for most water quality contaminants.

  • Stormwater Runoff quality and quantity from traditional and low impact development watersheds
    Journal of The American Water Resources Association, 2009
    Co-Authors: Erik S Bedan, John C Clausen
    Abstract:

    The quality and quantity of residential Stormwater Runoff from a control, traditional, and low impact development (LID) watershed were compared in a paired watershed study. A traditional neighborhood was built using typical subdivision standards while a LID design was constructed with best management practices including grass swales, cluster housing, shared driveways, rain gardens, and a narrower pervious concretepaver road. Weekly, flow-weighted, composite samples of Stormwater were analyzed for nitrate + nitrite-nitrogen (NO 3 + NO 2 -N), ammonia-nitrogen (NH 3 -N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total suspended solids (TSS). Monthly composite samples were analyzed for total copper (Cu), lead (Pb), and zinc (Zn). Mean weekly storm flow increased (600x) from the traditional watershed in the postconstruction period. Increased exports of TKN, NO 3 + NO 2 -N, NH 3 -N, TP, Cu, Zn, and TSS in Runoff were associated with the increased storm flow. Postconstruction storm flow in the LID watershed was reduced by 42% while peak discharge did not change from preconstruction conditions. Exports were reduced from the LID watershed for NH 3 -N, TKN, Pb, and Zn, while TSS and TP exports increased.

  • Stormwater Runoff quality and quantity from traditional and low impact development watersheds
    Journal of The American Water Resources Association, 2009
    Co-Authors: Erik S Bedan, John C Clausen
    Abstract:

    The quality and quantity of residential Stormwater Runoff from a control, traditional, and low impact development (LID) watershed were compared in a paired watershed study. A traditional neighborhood was built using typical subdivision standards while a LID design was constructed with best management practices including grass swales, cluster housing, shared driveways, rain gardens, and a narrower pervious concretepaver road. Weekly, flow-weighted, composite samples of Stormwater were analyzed for nitrate + nitrite-nitrogen (NO 3 + NO 2 -N), ammonia-nitrogen (NH 3 -N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total suspended solids (TSS). Monthly composite samples were analyzed for total copper (Cu), lead (Pb), and zinc (Zn). Mean weekly storm flow increased (600x) from the traditional watershed in the postconstruction period. Increased exports of TKN, NO 3 + NO 2 -N, NH 3 -N, TP, Cu, Zn, and TSS in Runoff were associated with the increased storm flow. Postconstruction storm flow in the LID watershed was reduced by 42% while peak discharge did not change from preconstruction conditions. Exports were reduced from the LID watershed for NH 3 -N, TKN, Pb, and Zn, while TSS and TP exports increased.

  • Stormwater Runoff and export changes with development in a traditional and low impact subdivision
    Journal of Environmental Management, 2008
    Co-Authors: Michael E Dietz, John C Clausen
    Abstract:

    Development continues at a rapid pace throughout the country. Runoff from the impervious surfaces in these watersheds continues to be a major cause of degradation to freshwater bodies and estuaries. Low impact development techniques have been recommended to reduce these impacts. In this study, Stormwater Runoff and pollutant concentrations were measured as development progressed in both a traditional development, and a development that used low impact development techniques. Increases in total impervious area in each watershed were also measured. Regression relationships were developed between total impervious area and Stormwater Runoff/pollutant export. Significant, logarithmic increases in Stormwater Runoff and nitrogen and phosphorus export were found as development occurred in the traditional subdivision. The increases in Stormwater Runoff and pollutant export were more than two orders of magnitude. TN and TP export after development was 10 and 1 kg ha � 1 yr � 1 , respectively, which was consistent with export from other urban/developed areas. In contrast, Stormwater Runoff and pollutant export from the low impact subdivision remained unchanged from pre-development levels. TN and TP export from the low impact subdivision were consistent with export values from forested watersheds. The results of this study indicate that the use of low impact development techniques on a watershed scale can greatly reduce the impacts of development on local waterways. r 2007 Elsevier Ltd. All rights reserved.

  • Stormwater Runoff and export changes with development in a traditional and low impact subdivision
    Journal of Environmental Management, 2008
    Co-Authors: Michael E Dietz, John C Clausen
    Abstract:

    Development continues at a rapid pace throughout the country. Runoff from the impervious surfaces in these watersheds continues to be a major cause of degradation to freshwater bodies and estuaries. Low impact development techniques have been recommended to reduce these impacts. In this study, Stormwater Runoff and pollutant concentrations were measured as development progressed in both a traditional development, and a development that used low impact development techniques. Increases in total impervious area in each watershed were also measured. Regression relationships were developed between total impervious area and Stormwater Runoff/pollutant export. Significant, logarithmic increases in Stormwater Runoff and nitrogen and phosphorus export were found as development occurred in the traditional subdivision. The increases in Stormwater Runoff and pollutant export were more than two orders of magnitude. TN and TP export after development was 10 and 1 kg ha � 1 yr � 1 , respectively, which was consistent with export from other urban/developed areas. In contrast, Stormwater Runoff and pollutant export from the low impact subdivision remained unchanged from pre-development levels. TN and TP export from the low impact subdivision were consistent with export values from forested watersheds. The results of this study indicate that the use of low impact development techniques on a watershed scale can greatly reduce the impacts of development on local waterways. r 2007 Elsevier Ltd. All rights reserved.

Hyunmin Hwang - One of the best experts on this subject based on the ideXlab platform.

  • review of pollutants in urban road dust and Stormwater Runoff part 1 heavy metals released from vehicles
    The International Journal of Urban Sciences, 2016
    Co-Authors: Hyunmin Hwang, Matthew J Fiala, Dongjoo Park, Terry L Wade
    Abstract:

    ABSTRACTUrban road dust can be highly enriched with trace metals such as copper, lead, zinc, and platinum group elements (PGEs) that are released primarily from vehicles. Concentrations of these metals are up to about 100 times higher than background levels. Lead concentrations in sediment core have declined dramatically due to phase out of leaded gasoline. Recent ban on the use of lead wheel balancing weight in Europe and in some US states will accelerate the decline of lead in the environment. Concentrations of copper, zinc, and PGEs in sediments in many urban areas have increased continuously due to increase of urban sprawl and increased numbers and travel distance of vehicle. Wear of brake pads and tyres are the primary sources of copper and zinc in urban road dust. PGEs have been released from catalytic converters since the mid-1970s. Contaminated urban road dust is picked up by Stormwater Runoff and delivered into local receiving waterbodies (e.g. streams, rivers, lakes, and estuaries). Concentratio...

  • polychlorinated biphenyls in Stormwater Runoff entering the tidal anacostia river washington dc through small urban catchments and combined sewer outfalls
    Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2008
    Co-Authors: Hyunmin Hwang, Gregory D Foster
    Abstract:

    To investigate the loadings, solid-water partitioning, transport dynamics, and sources of polychlorinated biphenyls (PCBs) in urban Stormwater Runoff entering into the lower tidal Anacostia River, which flows south of Washington, DC, USA, storm and base flow samples were collected in six branches. Stormwater Runoff contained elevated levels of PCBs (9.82 to 211 ng/L) higher than base flow by up to 80-fold. The present study suggests that input of PCBs from Lower Beaverdam Creek is likely to be greater than those from the two major branches (Northeast and Northwest Branches) that were believed as primary source areas. PCBs in storm flow were significantly enriched in the particle phase, which accounted for more than 90% of the total PCBs. Particles were the primary vector transporting PCBs into the Anacostia River, suggesting that removal of particles in Stormwater Runoff using best management practices (BMPs) such as post treatment system likely decrease PCBs significantly. PCB congener patterns found in Stormwater samples clearly explain Stormwater Runoff is a major transport pathway adding substantial amount of PCBs to the tidal Anacostia River.

  • characterization of polycyclic aromatic hydrocarbons in urban Stormwater Runoff flowing into the tidal anacostia river washington dc usa
    Environmental Pollution, 2006
    Co-Authors: Hyunmin Hwang, Gregory D Foster
    Abstract:

    To investigate the sources, fate, and transport dynamics of PAHs (polycyclic aromatic hydrocarbons) in Stormwater Runoff that is a leading source of pollution in urban watersheds, storm and base flow samples were collected in six branches along the lower Anacostia River. PAHs in storm flow (1510-12,500 ng/L) were significantly enriched in the particle phase, which accounted for 68-97% of the total PAHs. It suggests that reducing particles in Stormwater using post-treatment system would decrease PAHs considerably. The solid-water distribution coefficients (KD) of PAHs in the storm flow samples were up to 340 times higher than predicted values. A greater portion of high molecular weight PAHs and their distribution patterns indicate higher contribution of automobile originated pyrogenic PAHs. Total suspended solids in storm flow had a positive relationship with flow rates and exceeded benchmark level for the protection of aquatic biota in some samples.

Gregory D Foster - One of the best experts on this subject based on the ideXlab platform.

  • polychlorinated biphenyls in Stormwater Runoff entering the tidal anacostia river washington dc through small urban catchments and combined sewer outfalls
    Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2008
    Co-Authors: Hyunmin Hwang, Gregory D Foster
    Abstract:

    To investigate the loadings, solid-water partitioning, transport dynamics, and sources of polychlorinated biphenyls (PCBs) in urban Stormwater Runoff entering into the lower tidal Anacostia River, which flows south of Washington, DC, USA, storm and base flow samples were collected in six branches. Stormwater Runoff contained elevated levels of PCBs (9.82 to 211 ng/L) higher than base flow by up to 80-fold. The present study suggests that input of PCBs from Lower Beaverdam Creek is likely to be greater than those from the two major branches (Northeast and Northwest Branches) that were believed as primary source areas. PCBs in storm flow were significantly enriched in the particle phase, which accounted for more than 90% of the total PCBs. Particles were the primary vector transporting PCBs into the Anacostia River, suggesting that removal of particles in Stormwater Runoff using best management practices (BMPs) such as post treatment system likely decrease PCBs significantly. PCB congener patterns found in Stormwater samples clearly explain Stormwater Runoff is a major transport pathway adding substantial amount of PCBs to the tidal Anacostia River.

  • characterization of polycyclic aromatic hydrocarbons in urban Stormwater Runoff flowing into the tidal anacostia river washington dc usa
    Environmental Pollution, 2006
    Co-Authors: Hyunmin Hwang, Gregory D Foster
    Abstract:

    To investigate the sources, fate, and transport dynamics of PAHs (polycyclic aromatic hydrocarbons) in Stormwater Runoff that is a leading source of pollution in urban watersheds, storm and base flow samples were collected in six branches along the lower Anacostia River. PAHs in storm flow (1510-12,500 ng/L) were significantly enriched in the particle phase, which accounted for 68-97% of the total PAHs. It suggests that reducing particles in Stormwater using post-treatment system would decrease PAHs considerably. The solid-water distribution coefficients (KD) of PAHs in the storm flow samples were up to 340 times higher than predicted values. A greater portion of high molecular weight PAHs and their distribution patterns indicate higher contribution of automobile originated pyrogenic PAHs. Total suspended solids in storm flow had a positive relationship with flow rates and exceeded benchmark level for the protection of aquatic biota in some samples.

Gurpal S Toor - One of the best experts on this subject based on the ideXlab platform.

  • organic nitrogen in residential Stormwater Runoff implications for Stormwater management in urban watersheds
    Science of The Total Environment, 2020
    Co-Authors: Mary G Lusk, Gurpal S Toor, Patrick W Inglett
    Abstract:

    Abstract Stormwater Runoff containing organic nitrogen (N) is a source of potentially bioavailable N in water bodies. Characterization and concentrations of dissolved organic N (DON) and particulate organic N (PON) in urban Stormwater Runoff are rarely reported and considered in Stormwater management. Our objectives were to (1) characterize the organic (DON, PON) and inorganic (NO3− and NH4+) N pools in residential Stormwater Runoff and (2) determine the rainfall driven landscape sources of Runoff PON using an isotopic mixing model with 13C and 15N during a wet season (June–September). We instrumented a 13 ha (0.13 km2) residential catchment located in Florida, United States with an ISCO autosampler and collected Stormwater Runoff samples (n = 52) over 11 individual Stormwater Runoff events. Mean concentration of total N in Runoff during the wet season was 1.61 mg L−1, of which 37% was DON and 25% was PON. A strong seasonal first flush of PON, giving rise to a large PON:TN ratio, was observed as the wet season progressed from June (PON:TN = 0.39;) to September (PON:TN = 0.12), whereas DON did not display any seasonal variability (mean: 0.66 mg L−1). The isotope mixing model estimated that 76% of PON in the Runoff originated from oak detritus (leaves: 50%, acorns: 26%) and the remaining 24% from lawn grass clippings. The dominance of organic N fractions in the urban Stormwater Runoff suggests that landscape controls on PON and DON are needed to reduce N loading in the urban Stormwater Runoff. The seasonal first flush of PON indicates that monitoring strategies should focus on how nutrient concentrations in Runoff may respond to seasonal drivers such as leaf litterfall and that there may be optimal times for N management, such as after a prolonged dry season in which materials accumulate and pose the risk for later mobilization.

  • composition of nitrogen in urban residential Stormwater Runoff concentrations loads and source characterization of nitrate and organic nitrogen
    PLOS ONE, 2020
    Co-Authors: Jariani Jani, Mary G Lusk, Yunya Yang, Gurpal S Toor
    Abstract:

    Stormwater Runoff is a leading cause of nitrogen (N) transport to water bodies and hence one means of water quality deterioration. Stormwater Runoff was monitored in an urban residential catchment (drainage area: 3.89 hectares) in Florida, United States to investigate the concentrations, forms, and sources of N. Runoff samples were collected over 22 storm events (May to September 2016) at the end of a Stormwater pipe that delivers Runoff from the catchment to the Stormwater pond. Various N forms such as ammonium (NH4-N), nitrate (NOx-N), dissolved organic nitrogen (DON), and particulate organic nitrogen (PON) were determined and isotopic characterization tools were used to infer sources of NO3-N and PON in collected Runoff samples. The DON was the dominant N form in Runoff (47%) followed by PON (22%), NOx-N (17%), and NH4-N (14%). Three N forms (NOx-N, NH4-N, and PON) were positively correlated with total rainfall and antecedent dry period, suggesting longer dry periods and higher rainfall amounts are significant drivers for transport of these N forms. Whereas DON was positively correlated to only rainfall intensity indicating that higher intensity rain may flush out DON from soils and cause leaching of DON from particulates present in the residential catchment. We discovered, using stable isotopes of NO3-, a shifting pattern of NO3- sources from atmospheric deposition to inorganic N fertilizers in events with higher and longer duration of rainfall. The stable isotopes of PON confirmed that plant material (oak detritus, grass clippings) were the primary sources of PON in Stormwater Runoff. Our results demonstrate that practices targeting both inorganic and organic N are needed to control N transport from residential catchments to receiving waters.

  • sources and mechanisms of nitrate and orthophosphate transport in urban Stormwater Runoff from residential catchments
    Water Research, 2017
    Co-Authors: Yunya Yang, Gurpal S Toor
    Abstract:

    Nutrients export from residential catchments contributes to water quality impairment in urban water bodies. We investigated the concentrations, transport mechanisms, and sources of nitrate-nitrogen (NO3-N) and orthophosphate-phosphorus (PO4-P) in urban Stormwater Runoff generated in residential catchments in Tampa Bay, Florida, United States. Street Runoff samples, collected over 21 storm events, were supplemented with rainfall and roof Runoff samples from six representative residential catchments. Samples were analyzed for N and P forms, N and oxygen (O) isotopes of nitrate (δ18O-NO3- and δ15N-NO3-), and δ18O and hydrogen (δD) isotopes of water (H2O). We found that the main NO3-N source in street Runoff was atmospheric deposition (range: 35-64%), followed by chemical N fertilizers (range: 1-39%), and soil and organic N (range: 7-33%), whereas PO4-P in the street Runoff likely originated from erosion of soil particles and mineralization from organic materials (leaves, grass clippings). The variability in the sources and concentrations of NO3-N and PO4-P across catchments is attributed to different development designs and patterns, use of various fill materials during land development, and landscaping practices. This data can be useful to develop strategies to offset the impacts of urban development (e.g., designs and patterns resulting in variable impervious areas) and management (e.g., fertilizer use, landscaping practices) on NO3-N and PO4-P transport in urban residential catchments.

  • biodegradability and molecular composition of dissolved organic nitrogen in urban Stormwater Runoff and outflow water from a Stormwater retention pond
    Environmental Science & Technology, 2016
    Co-Authors: Mary G Lusk, Gurpal S Toor
    Abstract:

    Dissolved organic nitrogen (DON) can be a significant part of the reactive N in aquatic ecosystems and can accelerate eutrophication and harmful algal blooms. A bioassay method was coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to determine the biodegradability and molecular composition of DON in the urban Stormwater Runoff and outflow water from an urban Stormwater retention pond. The biodegradability of DON increased from 10% in the Stormwater Runoff to 40% in the pond outflow water and DON was less aromatic and had lower overall molecular weight in the pond outflow water than in the Stormwater Runoff. More than 1227 N-bearing organic formulas were identified with FT-ICR-MS in the Stormwater Runoff and pond outflow water, which were only 13% different in Runoff and outflow water. These molecular formulas represented a wide range of biomolecules such as lipids, proteins, amino sugars, lignins, and tannins in DON from Runoff and pond outflow water. This work implies t...

  • δ15n and δ18o reveal the sources of nitrate nitrogen in urban residential Stormwater Runoff
    Environmental Science & Technology, 2016
    Co-Authors: Yunya Yang, Gurpal S Toor
    Abstract:

    Nitrogen (N) sources are widely distributed in the complex urban environment. High-resolution data elucidating N sources in the residential catchments are not available. We used stable isotopes of N and oxygen (O) of nitrate (δ18O-NO3– and δ15N-NO3–) along with δ18O and hydrogen (δD) of water (H2O) to understand the sources and transformations of N in residential Stormwater Runoff. Stormwater Runoff samples were collected over 25 Stormwater events at 5 min intervals using an autosampler installed at the residential catchment outlet pipe that drained 31 low-density homes with a total drainage area of 0.11 km2. Bayesian mixing model results indicated that atmospheric deposition (range 43–71%) and chemical N fertilizers (range <1–49%) were the dominant NO3-N sources in the Stormwater Runoff and that there was a continuum of source changes during the Stormwater events. Further, the NO3-N transport in the Stormwater Runoff from the residential catchment was driven by mixing of multiple sources and biotic (i.e....

Wen Liu - One of the best experts on this subject based on the ideXlab platform.

  • the impacts of substrate and vegetation on Stormwater Runoff quality from extensive green roofs
    Journal of Hydrology, 2019
    Co-Authors: Wen Liu, Weiping Chen, Wei Wei, Ravinesh C Deo, Qi Feng
    Abstract:

    Abstract Green roofs are emerging as practical strategies to retain Stormwater Runoff and improve water environment quality of urban cities. However, the impacts of green roofs on Stormwater Runoff quality remains a topic of concern to urban planners and mangers. In this study, we designed the scale based Runoff plots of extensive green roofs with different substrate and vegetation types, and investigate whether the studied green roofs act as a sink or source of nutrients and suspended solids in their Runoff compared to a conventional roof. The influences of substrate and vegetation on the water quality of green roof outflows were also assessed. The results showed that the average TSS (total suspended solids), TN (total nitrogen), and TP (total phosphorus) concentrations of the green roof Runoff were all significantly higher than that of the conventional roof Runoff. Except substrate S3 (the composition ratio of rural soil:peat soil:perlite:vermiculite was 2.5:5:2:0.5) and S1 (the composition ratio of rural soil: peat soil was 1:1) in TP, the substrate S2 (the composition ratio of rural soil:peat soil:pine needle:perlite was 1:1:1:1) displayed significantly higher TN and TP concentrations than either of the Runoff from the substrate S1 and S3. The TN and TP concentrations of 5 cm substrate depth were significantly lower than that in the 15 cm substrate depth treatments. Significant differences were observed in TN concentrations between vegetation Sedum Spectabile and Radix Ophiopogonis. However, no significant differences were observed between any of the vegetation types with regard to TP concentrations. Therefore, we suggest that green roofs need to be constructed of suitable substrate materials and plants based on their function on Runoff water quality in order to mitigate the pollution risk of green roof Runoff on urban water environment.

  • influences of setting sizes and combination of green infrastructures on community s Stormwater Runoff reduction
    Ecological Modelling, 2015
    Co-Authors: Wen Liu, Weiping Chen, Chi Peng
    Abstract:

    Implementation of green infrastructures is an effective option for mitigating the impacts of increasing urbanization on Stormwater runo ff. In this study, we evaluated the Runoff reduction effectiveness under various setting sizes of green infrastructures using a process-based Stormwater Runoff model. The model was validated with field data from a typical community in Beijing and proved to be accurate in estimating Stormwater Runoff under larger rain events. The pervious area percentage and soil hydraulic properties were key parameters influencing Stormwater Runoff. The four types of green infrastructures, including green area expanding, concave green space, storage pond and porous brick pavement were effective in reducing Stormwater Runoff, but single facility except the storage pond could not fully control Runoff of 5-year recurrence storm. With integrated green infrastructures, Runoff of 5-year recurrence storm could be 100% reduced by expanding the pervious area percentage to over 50%, or increase storage pond volume to over 1800 m(3), whereas a maximum Runoff reduction of 95% could be achieved when the green land was reformed to concave with a depth of 4 cm, or 50% of the impervious area was replaced with porous brick pavement with a storage capacity of 8 mm. The combination of green infrastructures with proper setting sizes is necessary for optimal control of Stormwater Runoff management. (C) 2014 Elsevier B.V. All rights reserved.