Lake Adirondack Dam Improvements

The low-level outlet was unable to drain 90% of stored water in 14 days, deeming it inoperable. Other issues included seepage into the left embankment and cracking within the concrete core. The tailrace stone walls and concrete face of the spillway needed repairs, training wall sizes and orientation were inadequate, vegetation was limited on the embankment, and the spillway required a detailed survey and hydrological and hydraulic analyses.

These deficiencies not only concerned the Town and NYSDEC, but also posed a risk to the surrounding community. Classified by NYSDEC as a Class C “High Hazard” dam, its failure could result in the loss of human life and cause substantial damage to homes, industrial or commercial buildings, important public utilities, main highways, or railroads, leading to significant economic losses. Lake Adirondack would also face increased erosion and declining water quality—factors that greatly impact wildlife habitats and water ecosystems.

The dam’s deficiencies, notably issues with the spillway and embankment, threatened the lake’s water quality. Improvements to these areas will reduce erosion and limit related impacts on water quality, helping to preserve the lake’s environmental health.

Prior to design and construction, LaBella performed environmental due diligence of the dam and its deficiencies.

When project plans reached 30-60% completion, plans and compiled reports were reviewed carefully to determine if additional environmental permits (beyond the existing permit with NYSDEC) were necessary.

Situated directly off New York State Route 28, the Lake Adirondack Dam Improvement project was highly visible to the public. Work Zone Traffic Control measures maintained a safe but uninterrupted flow of traffic.

Residents were concerned water levels would drop significantly during construction. A sheet pile cofferdam was used to limit the drawdown of lake water to no more than six inches. Town officials and contractors on site were responsive to these and other questions and concerns from residents.

The proposed work was put out to bid and awarded to C.D. Perry as the prime contractor. Construction began in August 2024, with C.D. Perry substantially completing the dam structure improvements in December 2024.

A new sluice gate vault was constructed within the lake using a sheet pile cofferdam, dewatering pumps, and a tremie pour for the vault’s foundation. In conjunction with a turbidity curtain, these construction techniques essentially allowed concrete to be poured and work to be performed “inside” of the lake with zero impacts to the lake’s water quality.

Concrete work on the face of the dam and spillway required a temporary lowering of the lake level. Multiple siphons were used to allow the contractor to control the lake’s water surface elevation and maintain lake usability for residents.

The long-term improvements to the dam include:

• The low-level outlet was rehabilitated with a new sluice gate on the lakeside of the dam, making it operational so the lake would drain adequately.
• The spillway was reshaped, and cracks were sealed off.
• The spillway and tailrace walls were resurfaced.
• New training walls were constructed.
• The embankment was regraded and vegetated.

The new low-level outlet with a new sluice gate ensures that Lake Adirondack can be adequately drained in the event of extreme weather, preventing flooding or other hazards that could jeopardize homes, roads, and other local infrastructure. The enhanced spillway and embankment will reduce erosion and improve water quality, strengthening the overall health of Lake Adirondack and preserving local wildlife habitats, water ecosystems, and the water-based recreation activities that draw residents and visitors to the Town of Indian Lake.