Project 47164: Conklingville Dam Remediation, Hadley

This project entails the repair and improvement to the dam's concrete spillway and training walls, removal and replacement of the dam's three existing eight-foot diameter valves, installation of a relief well system to mitigate pore water pressure buildup within the dam's earthen embankment, and installation of a graded filter system within a large scour hole located downstream of the dam's tailrace.

• Estimated Cost: Between $50.5 million and $61 million
• Project Location: Conklingville Dam, Hadley, NY
• Design & Construction Region: Region 5 – North Country
• Plans and Specs Available: Summer 2026
• Bids to be Received: September 17, 2026

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The Conklingville Dam, located in Hadley, New York, is one of the most important dams in the state. Completed in 1930, it created the Great Sacandaga Lake, one of New York’s largest lakes. Today, the dam helps protect communities from flooding, generates clean hydroelectric power, and provides a popular destination for boating, fishing, and other outdoor recreation.

A Landscape Shaped by Glaciers

Thousands of years ago, during the last Ice Age, glaciers shaped the landscape of the Sacandaga Valley. As the glaciers melted, they left behind piles of rock and soil called moraines that blocked the Sacandaga River, forming a large natural lake known as Glacial Lake Sacandaga.

Eventually, the water found a new path through a low area near present-day Conklingville. Over time, the rushing water carved away the land, draining the ancient lake. Engineers later realized that building a dam at this same location could once again hold back the river and create a large reservoir.

For many years, the Sacandaga River flooded during heavy rains and spring snowmelt. These floods caused major damage to towns along the Hudson River. The devastating flood of 1913 was one of the worst in New York’s history. It caused widespread destruction in communities including Albany, Troy, Rensselaer, Watervliet, and Green Island. After this disaster, New York State decided action was needed to better control flooding.

Constructing the Dam

In 1922, the state created the Hudson River Regulating District (now the Hudson River–Black River Regulating District) to manage the flow of the Hudson and Sacandaga Rivers and help protect people, homes, and businesses.

The Conklingville Dam was designed by engineer Edward Haynes Sargent. Construction began in 1927, but the project faced several challenges, including flooding. These delays pushed the completion date to March 27, 1930.

The dam cost approximately $12 million, a huge investment at the time. Standing 95 feet tall, it created the Great Sacandaga Lake, which covers about 42 square miles and has 129 miles of shoreline.

When the dam was completed in 1930, the waters of the Sacandaga River filled the valley, creating the Great Sacandaga Lake. What was once farmland and small communities became one of New York’s most popular lakes. Today, the lake attracts thousands of visitors every year who enjoy boating, fishing, swimming, camping, and other outdoor activities.

More than 95 years after its construction, the Conklingville Dam continues to serve the people of New York.

The Dam Today

The Conklingville Dam is undergoing rehabilitation to ensure it continues operating safely and reliably for future generations. These improvements will help preserve this remarkable engineering achievement while continuing its important mission of protecting communities, producing renewable energy, and supporting recreation across the Great Sacandaga region.

The dam provides:

• Flood Control: Carefully manages water levels to reduce flooding along the Sacandaga and Hudson Rivers.
• Clean Energy: Dam reservoir generates electricity through hydropower.
• Recreation: The Great Sacandaga Lake supports tourism, outdoor recreation, and local businesses throughout the region.