People and water in the Assabet River basin, eastern Massachusetts

An accounting of the inflows, outflows, and uses of water in the rapidly developing Assabet River Basin, along Interstate 495 in eastern Massachusetts, was done to quantify how people's activities alter the hydrologic system. The study identified subbasins and seasons in which outflows resulting from people's activities were relatively large percentages of total flows, and quantified the fraction of streamflow in the Assabet River that is treated wastewater. Computer models of ground-water flow were also used to test how the components of the hydrologic system, particularly streamflow, would change with future development and increased water use. Computer simulations showed that, when water use was increased to currently permitted levels, streamflows in tributaries would decrease, particularly during the low-flow period. In the Assabet River, increased wastewater discharges resulted in a slight increase in total streamflow and an increase in the fraction of streamflow in the river that is wastewater, relative to existing conditions.