|Title||Steady groundwater transport of highway deicing agent constituents from an infiltration basin|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Authors||Ostendorf DW, Rotaru C, Hinlein ES|
|Journal||Journal of Irrigation and Drainage Engineering|
|Issue||SPECIAL ISSUE: Urban Storm-Water Management|
|Keywords||Deicing, Highways and roads, Infiltration, Massachusetts, Runoff, Stormwater management|
The highway deicing agent groundwater plume from an infiltration basin in the Plymouth-Carver Aquifer near State Route 25 in southeastern Massachusetts is modeled and measured in order to assess the impact of the basin on groundwater transport processes. The advective transport model superimposes the existing steady models of axisymmetric basin hydraulics of Zlotnik and Ledder in 1992 and the two-dimensional ambient flow of Gelhar and Wilson in 1974. The basin component incorporates a surface source of finite-radius into a Hankel transform model for unconfined aquifers, whereas the ambient component varies linearly in the horizontal and vertical directions. Contaminant streamlines describe the resulting groundwater plume, and highway deicing agent constituents provide useful tracers. A simple vertical dispersion model quantifies the spread of contaminants across the bottom of the plume. Deicing agent constituent data calibrate a 17m17m basin radius, a 45m45m plume width, a bottom streamline 6–10m6–10m below the water table, and a vertical dispersivity of 34cm34cm . The latter value is comparable to the amplitude of vertical excursions caused by storm scale fluctuations of hydraulic head, as measured by Ostendorf et al. in 2007. Infiltration basins alter ambient advection by displacing streamlines downward and augment vertical mixing by imposing aperiodic vertical fluctuations on the ambient flow field.