Stormwater runoff quality and quantity from asphalt, paver, and crushed stone driveways in Connecticut.
ABSTRACT This study compared the quality and quantity of stormwater runoff from replicated asphalt, permeable paver, and crushed-stone driveways. Rainfall was measured on-site and runoff was recorded using tipping buckets. Flow-weighted composite runoff samples were analyzed weekly for total suspended solids, total Kjeldahl nitrogen, nitrate-nitrogen, ammonia-nitrogen, total phosphorus (TP), zinc, lead, and copper. Infiltration rate was determined on each driveway annually. Repeated measures analysis of variance indicated that stormwater runoff was significantly different among each driveway type; the order of decreasing runoff was asphalt> paver> stone. Average infiltration rates were 0, 11.2 and 9.0 cm/h for asphalt, paver, and crushed stone driveways, respectively. Both paver and crushed stone driveways reduced stormwater runoff as compared to asphalt driveways. Runoff from paver driveways contained significantly lower concentrations of all pollutants measured than runoff from asphalt driveways. However, runoff from crushed stone driveways was similar in concentrations to runoff from asphalt driveways, except for TP concentrations, which were lower in runoff from crushed stone driveways than runoff from asphalt driveways. The mass export of measured pollutants followed the relative differences in stormwater runoff, rather than differences in concentrations.
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ABSTRACT: Stream daylighting projects are highly complex and require prolonged coopera-tion between multiple agencies and col-laboration between diverse actors. Given most of these projects are quite expen-sive and require extensive effort in a very small area, a "frog dilemma" emerges in which the ecological benefits might seem to not justify the resources required. How-ever such projects can bring significant ecological, economic and social benefits to urban areas, and aid in challenging the nature/culture divide. Two stream daylight-ing projects in the lower mainland of British Columbia, Canada are examined, the part-nerships needed to bring the projects to completion are explored, and the long term outcomes and prospects of the projects are investigated. Both projects required public/ private partnerships, high levels of commu-nity agency, and the more successful of the two projects includes an ongoing monitor-ing and education program.Environments Journal. 01/2012; 38(1).
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ABSTRACT: Storm runoff from six types of underlying surface area during five rainfall events in two urban study areas of Wenzhou City, China was investigated to measure phosphorus (P) concentrations and discharge rates. The average event mean concentrations (EMCs) of total phosphorus (TP), total dissolved phosphorus (TDP), and particulate phosphorus (PP) ranged from 0.02 to 2.5 mg · L(-1), 0.01 to 0.48 mg · L(-1), and 0.02 to 2.43 mg · L(-1), respectively. PP was generally the dominant component of TP in storm runoff, while the major form of P varied over time, especially in roof runoff, where TDP made up the largest portion in the latter stages of runoff events. Both TP and PP concentrations were positively correlated with pH, total suspended solids (TSS), and biochemical oxygen demand (BOD)/chemical oxygen demand (COD) concentrations (p < 0.01), while TDP was positively correlated with BOD/COD only (p < 0.01). In addition, the EMCs of TP and PP were negatively correlated with maximum rainfall intensity (p < 0.05), while the EMCs of TDP positively correlated with the antecedent dry weather period (p < 0.05). The annual TP emission fluxes from the two study areas were 367.33 and 237.85 kg, respectively. Underlying surface type determined the TP and PP loadings in storm runoff, but regional environmental conditions affected the export of TDP more significantly. Our results indicate that the removal of particles from storm runoff could be an effective measure to attenuate P loadings to receiving water bodies.Environmental Science and Pollution Research 05/2013; · 2.62 Impact Factor
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ABSTRACT: This paper investigates the possibility that some aggregate gradations could be considered functionally ‘pervious’, based on comparison of an aggregate's permeability with either natural soil permeabilities or local rainfall intensities. Permeability was estimated by calculation for 27 American standard gradations, based on their porosity, coefficient of uniformity and effective particle size. In addition aggregate's cost relative to other urban surfaces was estimated. The results show that gradations of ASTM D448 No. 9, 89 and larger have high permeabilities relative to both the most permeable soil and the most intense rainfall in the central and eastern United States and so could be considered pervious surfaces in that large region. Denser gradations have lower permeabilities and less claim to be considered pervious. Properly selected aggregate's combination of high permeability and low cost make it an attractive option for reducing impervious cover, under the detailed traffic types for which it is suited.Urban Water Journal 01/2012; · 1.19 Impact Factor