Charles River Dam Bridge
Encyclopedia
The Charles River Dam Bridge, officially the Craigie Bridge
, also called Craigie's Bridge or the Canal Bridge, is a six-lane bascule bridge
Bascule bridge
A bascule bridge is a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic....

 across the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...

, connecting Leverett Circle
Leverett Circle
Leverett Circle is an intersection in Boston, Massachusetts. Completely rebuilt during the Big Dig, it is no longer a rotary. It marks the confluence of Storrow Drive, Charles River Dam Road, Nashua Street, Charles Street, and Martha Road....

 in downtown Boston, to Monsignor O'Brien Highway in East Cambridge, Massachusetts
East Cambridge, Massachusetts
East Cambridge is a neighborhood of Cambridge, Massachusetts. Referred to as Area 1, East Cambridge is bounded by the Charles River on the East, the Somerville border on the North, Broadway and Main Street on the South, and the railroad tracks on the West...

. The bridge, maintained by the Massachusetts Department of Conservation and Recreation (DCR, formerly the MDC), carries Route 28 next to the Green Line
Green Line (MBTA)
The Green Line is a streetcar system run by the Massachusetts Bay Transportation Authority in the Boston, Massachusetts area of the United States. It is the oldest line of Boston's subway, which is known locally as the 'T'. The Green Line runs underground downtown and on the surface in outlying...

's Lechmere Viaduct
Lechmere Viaduct
The Lechmere Viaduct is the last remaining elevated portion of the MBTA's Green Line in Boston, Massachusetts. Opened June 1, 1912, the Viaduct connects the Lechmere stop to the Science Park Station at Leverett Circle. Currently, the Green Line descends into a tunnel just east of Science Park...

. The bridge is fully within Boston, with the city line to the north, at the center of the original river. The Museum of Science
Museum of Science, Boston
The Museum of Science is a Boston, Massachusetts landmark, located in Science Park, a plot of land spanning the Charles River. Along with over 500 interactive exhibits, the Museum features a number of live presentations throughout the building every day, along with shows at the Charles Hayden...

 is located on the dam and nearby piers.

The original lock
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 for the Charles River was just west of the Charles River Dam Bridge, but the lock services was relocated east to the Charles River Dam
Charles River Dam
The Charles River Dam is a flood control structure on the Charles River in Boston, Massachusetts, located just downstream of the Leonard P. Zakim Bunker Hill Memorial Bridge, near Lovejoy Wharf, on the former location of the Warren Bridge.-History:...

 and incorporated as three parallel locks on the site of the old Warren Bridge.

The former lock at the Charles River Dam Bridge now allows water and small ships to flow freely. Taller ships require the opening of the drawbridge, operated by the Massachusetts Department of Transportation.

History

The first bridge on the site was known as the Canal Bridge, named after the Middlesex Canal
Middlesex Canal
The Middlesex Canal was a 27-mile barge canal connecting the Merrimack River with the port of Boston. When operational it was 30 feet wide, and 3 feet deep, with 20 locks, each 80 feet long and between 10 and 11 feet wide...

 which ran from the Charlestown Mill Pond to Middlesex Village in East Chelmsford Massachusetts; later p/o Lowell. (It was not named after the short Lechmere Canal
Lechmere Canal
Lechmere Canal is a short canal in East Cambridge, Massachusetts. It opens onto the Charles River and used to be an active port for Boston Harbor and the Atlantic Ocean....

 which is now near the Cambridge side of the bridge, but did not exist at the time.) As an investment, businessman Andrew Craigie purchased the largely undeveloped farmland on the Cambridge side around Lechmere Point from various owners (including Mary Lechmere and heirs) in preparation for building the bridge. The investors incorporated in 1807 with a charter to build a bridge from Leverett Street in the West End, Boston to the eastern end of Lechmere Point. One-third of shares were owned by the Middlesex Canal Corporation.

The bridge opened in 1809, and came to be known as Craigie's Bridge. The construction of the bridge prompted the laying out of roads to the center of Cambridge (now Cambridge Street, running to Harvard Square) and Somerville/Medford (Bridge Street, now Monsignor O'Brien Highway/Massachusetts Route 28). Craigie and associates, who formed the Lechemere Point Corporation, benefited from the building boom that followed, spurred on by their efforts to expand the public street grid. Residential cross streets were constructed and some were named after investors (Otis, Thorndike, and Gore) The bridge was sold to the Hancock Free Bridge Corporation in 1846, and became toll-free on January 30, 1858.

The current bridge was constructed in 1910, along with the dam that turned the lower Charles River from a tidal estuary
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 into a fresh-water basin. It was completed on June 30, and greeted with a two-hour fireworks display that Fourth of July. Thousands of people watching from the new Boston Embankment (the early Charles River Esplanade) which took the place of the former tidal flats.

Construction of the Museum of Science
Museum of Science, Boston
The Museum of Science is a Boston, Massachusetts landmark, located in Science Park, a plot of land spanning the Charles River. Along with over 500 interactive exhibits, the Museum features a number of live presentations throughout the building every day, along with shows at the Charles Hayden...

began on the dam in 1948, and finished in 1951.

2010-2011 Construction Project

The Massachusetts Department of Transportation is engaged in a 2-year project to rehabilitate the Craigie Bridge and to completely replace the drawbridge. This project will necessitate the closure of the Boston-bound lanes from November 6, 2010 through mid December, 2010, and again from early February, 2011 through mid April, 2011, necessitating traffic detours.
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