Charles River Dam altered the river from tidal estuary to basin (adjacent to Museum of Science)

The construction of the Charles River Dam (initially completed in 1910, with later replacements and modifications) converted the lower Charles River from a tidal estuary into a largely non-tidal basin, fundamentally changing local tides and shoreline conditions. The dam and its locks regulate water levels in the Charles River Basin and protect the riverfront from tidal fluctuations. The dam structure and basin are directly adjacent to the Museum of Science, which overlooks the river and the dam.