Time-of-Travel in the Lower Mississippi River: Model Development, Calibration, and Application

The Mississippi River is the source of drinking water for more than 1 million Louisiana residents. The river also is used for transportation of hazardous chemicals and petroleum products, and is the receiving stream for wastewater effluents from numerous industries and municipalities. To minimize the public's risk from contaminant spills and accidental discharges, drinking water providers need timely warning of approaching contaminants. Based on a modified plug-flow (MPF) formulation, a time-of-travel model has been developed to provide projections of the time of arrival, peak arrival time, time of passage, and duration of contaminant spills on the Mississippi River. Estimates of the peak concentrations of contaminants passing downstream locations are calculated from spill mass, discharge, and calculated duration. The model used for this research was calibrated using dye time-of-travel studies. The primary objective of this model is to facilitate the timely warning of drinking water providers. Additionally, this model may be of value in other water quality management applications, including contingency planning, impact assessment, monitoring, enforcement, and surveillance.