Program

NYS Historic

Subject

Industry & Commerce, Site

Location

199 Mill St, Theresa, NY 13691, USA

Lat/Long

44.2170413, -75.7907229

Grant Recipient

Town of Theresa

In August 1903, a buttress dam was built on the Indian River in the town of Theresa in Jefferson County, New York. The dam was built to provide power for grist and saw mills, and replaced a timber dam already in place on the river. The dam was of a new design, patented by engineer, Nils F. Ambursen and built by his engineering firm Ambursen & Sayles of Watertown, New York. Ambursen’s July 28, 1903 patent on this new type of dam explained the benefits of the design, reading in part:

“The invention relates to certain improvements in the construction of dams, and has for its principal object to construct a gravity dam, weir, or reservoir composed of concrete and steel which may be used in place of dams of solid masonry at smaller expense, the cost of both materials and labor being materially reduced.

A further object of the invention is to provide a dam having flooring arranged at such an angle as to take advantage of the pressure of water to assist in holding the dam in place and prevent sliding movement from the horizontal thrust of the water, the flooring being inclined and slightly curved in such manner as to throw all the pressure of the water well within the lines of the dam supports, increase in the depth of the water proportionately increasing the weight on the dam and tending to more firmly hold the same in place.

A further object of the invention is to provide a construction of dam composed wholly of concrete strengthened by iron or steel and in which the metal is entirely embedded in the concrete and all danger of oxidation prevented, the dam requiring no attention whatever after the building operation is completed.”

The dam in Theresa was built of approximately 125 cubic yards of concrete, reinforced with steel rods and expanded metal. Built on a foundation of rock, the dam was 120 feet long and 11 feet high. It was constructed with a series of concrete buttresses that each spanned six feet and were anchored into the rock foundation with iron pins.

According to an article written by Ambursen & Sayles, published in the November 5, 1903 issue of Engineering News, the dam was completed in 18 working days by a crew of ten men, including three carpenters and seven laborers. In the article, Ambursen & Sayles stated:

“Several bids were received by the owners for timber and solid masonry dams. Our bid being but very little in excess of the cost of timber construction, we were awarded the contract and completed the work to the entire satisfaction of Messrs. Snell & Makepeace, and we add to our own, also.”

As of 2022, remains of the grist mill and a portion of the dam can be seen from the Mill Street bridge in Theresa.