Lake Sunapee Outlet and Dam

The only outlet of Lake Sunapee and the head of the Sugar River is in Sunapee Harbor. The Sugar River flows from the Lake through the screens on one side of the road and over a dam on the other side. Water level is controlled now by the State of NH but control began in 1820 when a private corporation of down-river industries built the first dam and controlled the flow.

In 1820 the NH legislature granted the rights to control the water levels of Lake Sunapee to a newly formed Sunapee Dam Corporation. The Corporation initially consisted of mill owners from Newport and Claremont who depended on the river to operate their water-powered businesses. The Corporation built the first lake dam in 1821, hired a dam-keeper, and built a secure building around the dam so others could not adjust its gates. Over time, industry depended less on the river for power but still needed to regulate the flow of water to carry their waste products away. Public health issues emerged with a surge in typhoid fever during the 1880s, when drought caused the Dam Corporation to maintain high lake water levels and shut down flow to the river. Raw sewage, previously diluted by river flow, collected in stagnant river pools.

In 1890 citizens petitioned the Board of Fish and Game to require the Dam Corporation to install a ladder for fish migration, but the Corporation refused. In 1898 lake shore owners and others with interests in the lake steamboat company formed the Lake Sunapee Protective Association (LSPA) to protect the rights of property owners in the fight to control lake levels. In 1904 an agreement was finally reached that established high and low water levels.

In 1927 as part of a new municipal water system, the lake dam was replaced, the old dam house was removed, and a pedestrian walk was built on the new dam screen. Finally, in 1961 the State Water Resources Board took control of the Lake Sunapee dam from the Dam Corporation and retained Artie Osborne as the last dam-keeper. Today, lake levels are maintained between 9-feet and 11.4-feet as measured at the harbor gauge in accordance with the agreement reached in 1904.

Barbara Bache Chalmers, Sunapee's Historic Buildings & Places Vol. 1 (Sunapee Historical Society, 1918 & 1919).