Generation of long-term record of contaminant transport

A long-term record (1900-1993) of streamflow, sediment, and metal transport was simulated for an urbanized watershed, the Aberjona River watershed, located near Boston, Mass. The approach is an innovative procedure that includes the use of a watershed-specific contaminant transport model. The input to the program is hourly precipitation; the output is hourly streamflow, sediment, and metal fluxes. Hourly precipitation was available for part of the record. For time periods for which only daily precipitation data were available, the data were disaggregated into hourly values. The effects of urbanization on streamflow were simulated by adjusting the timing of river flood routing and the area contributing to different flow components. Variations in industrial water withdrawals were also considered. Sediment core data were utilized to estimate changes in source metal concentrations in time. The long-term record that were generated confirms that urbanization can account for a flashier river response including larger peaks in streamflow and sediment transport. Metal transport was affected by changes in metal source characteristics as well as hydrologic factors.