01628090

Component

https://doi.org/10.3141/2638-12

The Massachusetts Department of Transportation (DOT) and the Rhode Island DOT are assessing and addressing roadway contributions to total maximum daily loads (TMDLs). Example analyses for total nitrogen, total phosphorus, suspended sediment, and total zinc in highway runoff were done by the U.S. Geological Survey in cooperation with FHWA to simulate long-term annual loads for TMDL analyses with the stochastic empirical loading and dilution model known as SELDM. Concentration statistics from 19 highway runoff monitoring sites in Massachusetts were used with precipitation statistics from 11 long-term monitoring sites to simulate long-term pavement yields (loads per unit area). Highway sites were stratified by traffic volume or surrounding land use to calculate concentration statistics for rural roads, low-volume highways, high-volume highways, and ultraurban highways. The median of the event mean concentration statistics in each traffic volume category was used to simulate annual yields from pavement for a 29- or 30-year period. Long-term average yields for total nitrogen, phosphorus, and zinc from rural roads are lower than yields from the other categories, but yields of sediment are higher than for the low-volume highways. The average yields of the selected water quality constituents from high-volume highways are 1.35 to 2.52 times the associated yields from low-volume highways. The average yields of the selected constituents from ultraurban highways are 1.52 to 3.46 times the associated yields from high-volume highways. Example simulations indicate that both concentration reduction and flow reduction by structural best management practices are crucial for reducing runoff yields.

01629806

17-00328

English

pp 104–112

2017

Transportation Research Record: Journal of the Transportation Research Board

9780309441803

Digital/other

Figures (4) ; References (18) ; Tables (5)

Best practices; Concentration (Chemistry); Dilution; Estimating; Highways; Nitrogen; Phosphorus; Runoff; Sediments; Simulation; Traffic volume; Water quality management; Zinc

Massachusetts; Rhode Island

Design; Environment; Highways; Hydraulics and Hydrology

PRP, TRIS, TRB, ATRI

Dec 8 2016 10:01AM

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