Side-by-side evaluation of four level spreader–vegetated filter strips and a swale in eastern North Carolina

Level spreader–vegetated filter strips (LS–VFSs) and swales are versatile, low cost stormwater control measures (SCMs). The purpose of this study was to determine the runoff volume and pollutant reductions of four LS–VFSs and a swale in eastern North Carolina (NC). Two vegetated filter strips (VFSs) of 8 m long by 6 m wide (26 ft long by 20 ft wide), two VFSs of 20 m by 6 m (66 ft by 20 ft), and a trapezoidal swale with 3:1 side slopes (0.15 m [0.5 ft] bottom width and 10.4 m [34 ft] long) were constructed. One VFS of each size was amended with a mixture of sand and ViroPhos, a proprietary phosphorus (P) sorptive aggregate. Hydrologic data were collected for rainfall events during the 11-month sampling period. Influent and effluent samples were collected from select rainfall events and analyzed for concentrations of nitrogen (N) and P species, total suspended solids (TSS), cadmium (Cd), copper (Cu), and zinc (Zn). Significant runoff volume reductions averaging 36%, 59%, 42%, 57%, and 23% were found for the small and large unamended VFSs, the small and large amended VFSs, and the swale, respectively (n = 30). In general, concentrations of total nitrogen (TN) and TSS were reduced, while total phosphorus (TP) increased in nearly all treatments. The reductions in TN concentrations were significant in the amended VFSs and the swale, and TN was found to be irreducible at influent concentrations <1 mg L−1 (<1 ppm). TN load reductions in all treatments exceeded the 30% reduction credit assigned by NC, while only the amended VFSs and the swale exceeded the 35% load reduction credit assigned for TP.TN and TP load reductions were not significantly different between the VFSs and the swale. All treatments exceeded 75% TSS load reduction, far exceeding the 40% TSS removal credit that these systems receive in NC. In general, swale and VFS performance was similar in terms of TN and TP load reduction, while the VFSs significantly outperformed the swale in average volume and TSS load reduction.

[1]  J M Zanders,et al.  Road sediment: characterization and implications for the performance of vegetated strips for treating road run-off. , 2005, The Science of the total environment.

[2]  Ana Deletic,et al.  Sediment transport in urban runoff over grassed areas , 2005 .

[3]  William F. Hunt,et al.  Establishing Storm-Water BMP Evaluation Metrics Based upon Ambient Water Quality Associated with Benthic Macroinvertebrate Populations , 2010 .

[4]  William F. Hunt,et al.  Field Evaluation of Four Level Spreader-Vegetative Filter Strips to Improve Urban Storm-Water Quality , 2011 .

[5]  J. Lester,et al.  Leaching of chromated copper arsenate wood preservatives: a review. , 2001, Environmental pollution.

[6]  Craig J. Allan,et al.  CHARACTERIZATION AND POLLUTANT LOADING ESTIMATION FOR HIGHWAY RUNOFF , 1998 .

[7]  Awwa,et al.  Standard Methods for the examination of water and wastewater , 1999 .

[8]  Ana Deletic,et al.  Performance of grass filters used for stormwater treatment—a field and modelling study , 2006 .

[9]  K. Collins.  A field evaluation of four types of permeable pavement with respect to water quality improvement and flood control , 2007 .

[10]  Shen-En Chen,et al.  Compaction’s Impacts on Urban Storm-Water Infiltration , 2008 .

[11]  Allen T. Hjelmfelt,et al.  Runoff Curve Number Method: Examination of the Initial Abstraction Ratio , 2003 .

[12]  William F. Hunt,et al.  Influent Pollutant Concentrations as Predictors of Effluent Pollutant Concentrations for Mid-Atlantic Bioretention , 2011 .

[13]  J. Sansalone,et al.  Event-based size distributions of particulate matter transported during urban rainfall-runoff events. , 2008, Water research.

[14]  William F. Hunt,et al.  Asphalt Parking Lot Runoff Nutrient Characterization for Eight Sites in North Carolina, USA , 2009 .

[15]  J. Vaze,et al.  Nutrient Loads Associated with Different Sediment Sizes in Urban Stormwater and Surface Pollutants , 2004 .

[16]  I C Edmundson,et al.  Particle size analysis , 2013 .

[17]  Keith R. Solomon,et al.  Acidity as a factor in leaching of copper, chromium and arsenic from CCA-treated dimension lumber , 1990 .

[18]  R. Bannerman,et al.  Sources of phosphorus in stormwater and street dirt from two urban residential basins in Madison, Wisconsin, 1994-95 , 2000 .

[19]  Eric Strecker,et al.  DETERMINING URBAN STORM WATER BMP EFFECTIVENESS , 2001 .

[20]  Michael E. Barrett,et al.  USE OF VEGETATIVE CONTROLS FOR TREATMENT OF HIGHWAY RUNOFF , 1998 .

[21]  D. E. Line,et al.  Performance of a Bioretention Area and a Level Spreader-Grass Filter Strip at Two Highway Sites in North Carolina , 2009 .

[22]  S. Lau,et al.  Metals and PAHs adsorbed to street particles. , 2005, Water research.

[23]  E. Youngs.  Hydraulic Conductivity of Saturated Soils , 2000 .

[24]  E. Bean.  A Field Study to Evaluate Permeable Pavement Surface Infiltration Rates, Runoff Quantity, Runoff Quality, and Exfiltrate Quality , 2005 .

[25]  Betty T. Rushton,et al.  Low-Impact Parking Lot Design Reduces Runoff and Pollutant Loads , 2001 .

[26]  Michael E Barrett,et al.  Performance Comparison of Structural Stormwater Best Management Practices , 2005, Water environment research : a research publication of the Water Environment Federation.

[27]  William F. Hunt,et al.  Runoff Volume Reduction by a Level Spreader-Vegetated Filter Strip System in Suburban Charlotte, N.C. , 2010 .

[28]  Sue Charlesworth,et al.  The distribution of heavy metals in deposited urban dusts and sediments, Coventry, England , 1999 .

[29]  Michael E. Barrett,et al.  Storm Water Pollutant Removal in Roadside Vegetated Buffer Strips , 2004 .

[30]  Michael E. Barrett,et al.  PERFORMANCE OF VEGETATIVE CONTROLS FOR TREATING HIGHWAY RUNOFF , 1998 .

[31]  D. K. Walkowiak,et al.  Isco open channel flow measurement handbook , 2006 .

[32]  Ana Deletic,et al.  Sediment behaviour in grass filter strips , 1999 .

[33]  M. Bäckström,et al.  Sediment transport in grassed swales during simulated runoff events. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[34]  M. Bäckström,et al.  Grassed swales for stormwater pollution control during rain and snowmelt. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[35]  A. E. Greenberg,et al.  Standard Methods for the Examination of Water and Wastewater seventh edition , 2013 .

[36]  A. R. Jarrett,et al.  Evaluating bioretention hydrology and nutrient removal at three field sites in North Carolina , 2006 .