Approximate solution to simulate dissolved contaminant transport in groundwater from prism source

Most analytical solutions for contaminant transport in groundwater require numerical integration, which can be difficult to apply in spreadsheets. The Domenico solution provides an approximate solution without the integral term for a planar source oriented normal to the direction of groundwater flow. In this paper, the Domenico solution is extended to a prism source by considering off-domain contaminant transport. The source was lengthened by using the ratio between longitudinal and horizontal transverse hydrodynamic dispersion coefficients and source thickness by using the ratio between vertical velocity of source loading and longitudinal velocity of contaminant transport. The modified Domenico solution was tested against previous exact solutions. Results show that the modified Domenico solution simulates higher contaminant concentrations near the source and in the bottom of the domain than the Domenico solution but yields similar plumes to the exact solutions. The modified Domenico solution provides quick estimation of the plume length and concentrations and is convenient for testing the response of plume length and concentrations to measurable input parameters when a three-dimensional representation of the source is important.