Monday, May 24, 2010

Great Stone Dam, Lawrence

I have visited and talked about Lawrence before.  This time, my trip was specifically related to the Essex, or Great Stone Dam. 

Little background (or read a better writeup here courtesy of Enel, N.A.): The Essex Company, which was the driving force behind Lawrence, using a design attributed to Charles Storrow, began construction of the dam in 1845 and completed it by 1848.  The 900-foot-long dam was needed to turn a 5' drop in elevation into a 30' drop in elevation to provide a Lowell-like source of hydropower to the new city.  In fact, the new dam created a millpond going all the way upriver to Lowell.  For chronological comparison, this is the same time period in which Lowell was building the Northern Canal and Moody Street Feeder - and Lawrence was just getting started.  The dam, due to its height and row-after-row of granite blocks, was considered an engineering marvel of its day.  Although becoming less useful as the mills it powered shuttered, the strongly-built dam survived.

In the late 1970s, a hydroelectric plant generating nearly 17 MW (smaller than Lowell's 24 MW installation) was constructed on the south side of the dam - the company was still the Essex Company.    Enel bought the Essex Company a few years later and took control of the plant (like they did at Lowell).  In the last few years, the old pin-and-5' wooden flashboard system Lawrence, like us, had used for well over a century, was replaced with a bladder dam similar to the one proposed for Lowell.  The flow rate is currently fairly low and water is not going over the dam, so it's a good time to see what it really looks like.  I'll let the pictures speak.

Great Stone Dam

P.S.  Something Lawrence has that I thought was pretty cool that was also part of this trip: The Antiques Mall over on Canal Street.  Why does a city so interested in history like Lowell is not have much of an antique industry?


  1. I believe the primary Enel facility near the University Ave bridge in Lowell produces about 17 Mw, and there is another 7 Mw of capacity distributed in a few other sites along the canals that are owned by Enel for the total of 24 Mw in the city.