Details:

Creators:
Sansalone, John ; Cartledge, Frank
Sansalone, John ; Cartledge, Frank Less -
Corporate Creators:
Louisiana State University. Department of Civil and Environmental Engineering
Subject/TRT Terms:
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Bridge Decks Bridges--Floors Hydrology Particulates Pavements, Porous Porous Concrete Rainfall Runoff Sustainable Development Toxicity Urban Runoff¿Management
Publication/ Report Number:
FHWA/LA.09/448
Resource Type:
Tech Report
Geographical Coverage:
Louisiana
Edition:
Final report.
Corporate Publisher:
Louisiana. Dept. of Transportation and Development
Abstract:
Stormwater from transportation land uses is a complex heterogeneous mixture of particulate matter, nutrients (phosphorus and nitrogen), heavy metals, inorganic, and organic compounds with variations in flow and mass loadings by orders of magnitude during a single hydrologic event. To effectively manage stormwater, the transport, toxicity, and viability of treatment must be examined. Management is particularly challenging in Louisiana where many transportation-related discharges are directly to receiving waters. This study investigated: (1) transport and treatability of particles and phosphorus in urban rainfall-runoff on an event-basis, (2) influence of hydrology on rainfall-runoff metal element speciation, (3) toxicity of particulates in urban rainfall-runoff, (4) event-based treatability with hydrodynamic separation, and (5) gravimetric evaluation of hydrodynamic separation. With respect to transport and treatability of particles and phosphorus in urban rainfall runoff, a screened hydrodynamic separator (HS) was used on a test site draining the bridge deck on the I-10 over City Park Lake in Baton Rouge, Louisiana. Mass separation efficiencies (from 38 percent to 70 percent for particles and 8 percent to 49 percent for total phosphorus) of the screened HS and coarse particle size distributions (d50m of 270 to 2202 μm) exhibited very large variability. Regarding the influence of hydrology on rainfall runoff metal element speciation, it was found that Cd and Zn dominated the dissolved species, while Pb was predominately associated with dissolved organic matter and Cu was predominately associated with carbonate species or DOM. The toxicity of particulates in runoff is a concern because many chemicals are bound to particles and transported through the aquatic environment. Early post-larvae life stages are more sensitive to toxicity from runoff containing particulates. Testing of screened HS units revealed that suspended sediment concentration treatment efficiency were generally less than 50 percent even when units were cleaned after every treatment event to ensure no scour. Treatment is a function of surface loading rate, screen size, and scour. After extensive testing of screened HS units, results indicated that treatment and maintenance requirements were not sustainable and, therefore, four additional green infrastructure treatment designs were examined. These results indicated that either Buoyant Adsorptive Media (BAM) filters in the lake or cementitious permeable pavement (CPP) with a BAM network met treatment requirements, were sustainable, and provided context-sensitive implementation.
Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
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urn:sha256:a7462a846a1076a019d771b0c3e579a8273036d8ae097fd12abbc99736709cef
Download URL:
https://rosap.ntl.bts.gov/view/dot/25676/dot_25676_DS1.pdf
File Type:

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