page_title: Middlesex Canal
section_title: Construction
hierarchical_section_title: Middlesex Canal / History / Construction
caption_attribution_description: English: Loammi Baldwin who died in 1807.
context_page_description: 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. It also had eight aqueducts.
  Built from 1793 to 1803, the canal was one of the first civil engineering projects of its type in the United States, and was studied by engineers working on other major canal projects such as the Erie Canal. A number of innovations made the canal possible, including hydraulic cement, which was used to mortar its locks, and an ingenious floating towpath to span the Concord River. The canal operated until 1851, its transportation function largely surpassed by railroads. Remnants of the canal still survive, and the route is listed on the National Register of Historic Places.
context_section_description: The route of the canal was first surveyed in August 1793. Local lore is that it is on this expedition that Baldwin was introduced to a particular apple variety that now bears his name.  The route survey, however, was sufficiently uncertain that a second survey was made in October. Due to discrepancies in their results, Baldwin was authorized by the proprietors to travel to Philadelphia in an effort to secure the services of William Weston, a British engineer working on several canal and turnpike projects in Pennsylvania under contract to the Schuylkill and Susquehanna Navigation Company. Baldwin's application to the Navigation company was successful: Weston was authorized to travel to Massachusetts. In July and August 1794, Weston, accompanied by Baldwin and several of the latter's sons surveyed and identified two possible routes for the proposed canal. The proprietors then secured contracts to acquire the land for the canal, some of which was donated by its owners; in sixteen cases the proprietors used eminent domain proceedings to take land.
  The basic plan was for the canal's principal water source to be the Concord River at its highest point in North Billerica, with additional water to be drawn as needed from Horn Pond in Woburn. The site where the canal met the Concord River had been the site of a grist mill since the 17th century, which the proprietors purchased along with all of its water rights. From this point the canal descended six miles to the Merrimack River in East Chelmsford (now western Lowell) and 22 miles to the Charles River in Charlestown.
  In late September 1794 ground was broken in North Billerica. Work on the canal was performed by a number of contractors. In some instances local workers were contracted to dig sections, while in other areas contract labor was brought in from Massachusetts and New Hampshire for the construction work. A variety of engineering challenges were overcome, leading to innovations in construction materials and equipment. A form of hydraulic cement (made in part from volcanic materials imported at great expense from Sint Eustatius in the West Indies) was used to make the stone locks watertight. Because of its cost and the cost of working in stone, a number of the locks were made of wood instead. An innovation was made in earth-moving equipment with the development of a precursor of the dump truck, where one side of the carrier was hinged to allow the rapid dumping of material at the desired location.
  Water was diverted into the canal in December 1800, and by 1803 the canal was filled to Charlestown. The first boat operated on part of the canal on April 22, 1802.
caption: Chief engineer Loammi Baldwin
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