Depths shown by bathymetric tints. "Prepared in cooperation with the United States Environmental Protection Agency, Massachusetts Department of Environmental Management, and the New England Interstate Water Pollution Control Commission."--In upper margin. "Orthophoto map base by MassGIS, state plane coordinates, 2 km grid, NAD83."--In lower left margin. Shipping list no.: 2001-0163-P. Includes text, 1 location index map with 2 insets, 18 cartographic diagram insets, 3 tables, and 1 graph. Figure 1. Water quality sampling locations and bathymetry of the lower Charles River, Massachusetts. Scale approximately 1:13,000 -- Figure 2. Geographical distribution of salt wedge in the lower Charles River on selected dates. Scales differ -- Figure 3. Comparison between measured and calculated salt mass in the basin between water-quality surveys from estimated daily mean discharge for the Charles River Dam and the number of lock cycles (one cycle is one opening and closing of the locks) per day at the new Charles River Dam. Includes bibliographical references.