Building the reservoir required manpower and the employment of an ancient construction practice: the use of beasts of burdens. Horses and mules, and possibly animals like oxen, helped carry huge loads across the river basin.
Below, we see a few laborers sitting on top of a cart pulled by a horse (or mule). The cart is presumably loaded with rocks and chunks of dirt to be hauled away. Two laborers on the far right of the photo hold shovels or pickaxes. Together, the human and animal laborers not only built the reservoir but built new roads and new bridges (like the one in the background).
This picture were taken from the West Boylston edition of the Images of America book series written by Frank Brown and Beverly Goodale for the West Boylston Historical Society. The book contains tons of amazing photographs from West Boylston’s past.