On June 22,1793, the General Court of Massachusetts granted a charter to the Proprietors of the Middlesex Canal. This new corporation was to be responsible for the construction and operation of a canal that would link the Merrimack River with Boston Harbor, improving transportation to the state's capital.
Trade was hindered in the city of Boston because no major river flowed into its port and the raw materials needed to fuel its economy were difficult to obtain. The few roads which did exist were in poor condition, making travel slow and costly. In addition, work had begun on a canal which would by-pass the Merrimack River's Pawtucket Falls. This was to be called the Pawtucket Canal and would allow boats to pass unhindered to Newburyport, potentially creating unwelcome competition with Boston's markets.
Not only did Boston need to be supplied with raw materials from inland New England, but it also needed a domestic market for the goods it produced. For 50 years the Middlesex Canal met these needs by providing the safe and economical transport of goods and passengers from the Charlestown Mill Pond to the Merrimack River.
The Middlesex Canal was an engineering marvel and its construction was an arduous task. First, England's William Weston was hired to survey the route of the canal, an event which was marked by the first use of an accurate leveling instrument in this country.
Next came the acquisition of land. A total of 142 parcels were acquired by gift, purchase, and the power of eminent domain. Prices for the parcels ranged from $25 to $150 per acre.
At the time of construction, the available labor pool was small. The area was thinly settled and most people were farmers, unable to leave their lands for extended periods of time. In many cases, landowners were hired to complete the section of canal that ran adjacent to their property. The average pay for common laborers was $8 per month. The cost of construction was close to $500,000 and was funded by the sale of stock and assessments levied on shareholders. The capital stock was divided into 1000 shares, 200 shares of which were retained while 800 shares were sold in 1793 for two dollars each.
The route of the canal transversed many types of terrain. Rock ledges had to be cut and low lying areas filled. More than half of the canal was built above the natural surface of the land. Despite the many difficulties encountered, the canal was completed within the ten year time frame put forth in the legislation.
The canal ran for 27 miles from Middlesex Village (a part of Chelmsford at the time and later, Lowell) to Charlestown. It was 30 and one half feet wide at the top and 20 feet wide at the bottom. The bottom and sides were covered in clay which had been tamped to a two foot thickness. The water depth was three feet and the depth of the banks was four and one half feet. A ten foot tow path ran along the west bank and a five foot berm on the east.
The main source of water in the canal was the Concord River. A dam crossed the river in Billerica, creating a mill pond which stored the water that fed the canal. Another engineering first was the floating towpath, developed to allow the canal to cross this large water body. The water in the canal flowed from the pond six miles in a northwesterly direction to the Merrimack River, dropping 27 feet through three locks on its journey. To the southeast, the canal flowed 22 miles and dropped 100 feet through 13 locks to the Charlestown Mill Pond at the Charles River. The canal was made up of eight different levels ranging from one to six miles in length.
In order that the canal would not be subject to flooding, care was taken that water from rivers and streams never mixed with canal water. Eight aqueducts were constructed to carry the canal over other bodies of water. The most impressive of these was the 35 foot Shawnsheen River Aqueduct in East Billerica, the ruins of which can still be seen today.
A branch canal was constructed in Boston so that boats, after crossing the Charles River, could travel all the way to the harbor. At the opposite end of the Middlesex Canal, locks were constructed along the Merrimack River, creating a totally navigable route between Boston, Massachusetts and Concord, New Hampshire by 1814.