The Charles River Basin looks to all appearances like the most visible and carefully preserved natural feature of Boston. Nothing could be further from the truth. In the nineteenth century the shallow basin, its nine-mile length edged with broad salt marshes from Watertown to Boston Harbor, was dammed for mills and filled for commercial and residential ventures. The bays of the lower Charles at low tide became vast expanses of stinking, sewage-laden mud flats.

Not until the end of the century did the citizens of greater Boston take the first steps to clean up the river and transform its shores. Today nothing remains of the tidal estuary that was once the lower Charles – the margins of the Basin are an entirely man-made landscape. Though man-made and in that sense artificial—the Basin is also a wildlife habitat for hundreds of animal and plant species that play a role in the ecology of the region and enrich the experience of urban park users. Water quality in the once heavily polluted Basin has improved dramatically in recent years, creating better habitat for wildlife and attracting people back to the river.

The character of the Basin changes upstream at the BU Bridge, where the river narrows. From the Charles River Dam to the BU Bridge the Basin is two and one-half miles long and up to two thousand feet wide. The panoramas define the image of Boston and Cambridge. Sweeping views of the skyline from the seawalls are captivating. The Longfellow Bridge is a powerful presence, as are the slope of Beacon Hill and the gold dome of the State House.

Particular park sections within the Reservation, such as the Teddy Ebersol Red Sox Field , Magazine Beach, and Herter Park, provide intensely used open space for the bordering urban neighborhoods. The Storrow Memorial Embankment – universally known as the Esplanade – was dedicated in 1936, and provides opportunities for walking, biking, running and roller-blading along leafy paths. The Hatch Shell on the Esplanade attracts hundreds of thousands of people to special events each year, including the Boston Pops concert every Independence Day.

From the BU Bridge to the Watertown Dam is a zone of transition from urban and formal to rural and natural. Parkways lining the Charles River Basin separate it from contiguous open spaces. The largest open space is between the Harvard University athletic fields on the south and Mt. Auburn and Cambridge cemeteries on the north. Together, these areas form a critical oasis for migrating birds.

Reclaiming the Charles River Basin

Until the 1890s, the Charles was treated as an industrial resource rather than a natural heritage. The degradation of the river began with the construction of a mill dam, built in 1821 along the line of today’s Beacon Street. Causeways for the Worcester and Providence railroads further impeded the sluggish, increasingly fouled streams that flowed into the bay. In 1857 the Commonwealth reclaimed title to the polluted tidelands and filled the bay with gravel, brought by trains running round the clock from Needham to Boston for more than 25 years.

Downstream of the Back Bay, the Boston & Lowell Railroad also built trestles over the tidal flats and open water to reach the Boston peninsula. Other industries continued to expand in East Cambridge and Charlestown, largely unregulated by the state. But as the city’s population swelled, the escalating pollution of the region’s rivers and bays alarmed the state’s new board of public health. Along the Charles were two prisons, three coal-burning power plants, several gas works, and many other industrial sites. Two large slaughterhouses, one on the Millers River and the other upstream of the Brighton marshes, dumped offal into the river.

In 1893 the newly-established Boston Metropolitan Park Commission published its first report, written by Sylvester Baxter and Charles Eliot. They proposed a parks system that would preserve the natural features of the region and establish a framework for planned urban development. In spite of the foul condition of the Charles River Basin, Eliot was certain that the river would become the most celebrated “water park” in the entire country.

Six years later James Storrow led a campaign for a dam half a mile upstream from the harbor, with the purpose of creating a fresh water river basin and river front park in Boston. The tides were excluded above the dam, and the now-stable water level covered the mud flats forever. The newly landscaped banks of the river became known as the Charles River Esplanade.

The Esplanade was widened and lengthened in 1928; the first lagoon was built, as well as the Music Oval, where a temporary band shell was placed. The summer of 1929 was the first year Arthur Fiedler and the Boston Pops performed on the Esplanade. In 1941, the construction of the Hatch Memorial Shell gave the Pops, and a wide range of other artists and performers, a first class stage for popular summer events.

Another major change to the Esplanade began in 1949, with the construction of Storrow Drive. To make up for park land lost to the new road, additional islands were built along the the Esplanade. In the 1960's, the Esplanade was linked to Herter Park in Brighton, and other upstream parks, with the construction of the Dr. Paul Dudley White Bike path. This 18-mile loop travels along the entire basin on both the North and South sides of the river.

New park lands were acquired by the Commonwealth as part of the construction of a new dam, completed in 1978, and in the late 1980s another twenty acres in Cambridge, Charlestown, and Boston. They are now Paul Revere Park, North Point Park, and Nashua Street Park, forming part of the New Charles River Basin.