Truesdale Lake  

by Scot Evans

Our 230 foot-long dam is now 117 years old and has deteriorated somewhat over the years, but remains strong with the two-foot-wide core wall intact. It’s most important for everyone to know that if we don’t maintain a strong dam, we will not have a lake. It is therefore in the interest of all residents around and near the lake to contribute equally to maintaining the dam.

The fire department’s water intake to fill its tanker (shown in the purple rectangle in the photo below) was lengthened to be submerged during winter drawdowns. 

The sluice gate location (green arrow), auxiliary overflow spillway (yellow oval), and primary service spillway no longer meet the current State Department of Environmental Conservation (NYSDEC) requirements. Some repairs may be able to be “grandfathered” at a lower expense than to replace them to current requirements at higher expense. 

The low-level outlet under the dam (red arrow), used to lower the lake’s level during winter and ahead of major storms, is no longer functional. This is the reason we have to rely on siphons (100 foot-long white tubes over the spillway on the right side of the photo above, and discharge ends shown in photo below) to draw down the lake during the winter months every two to three years to cold shock and kill weed tubers.

Full rehabilitation will take years to complete and a Special District will have to be established to pay for the most expensive projects. Grant money is not currently available, because we are classified as a minimum “Code A: Low Hazard” dam. We have separated these projects into five phases — listed in order of expense and safety priority — to be described at the end of this article. 

The Dam Rehabilitation Committee (DRC) consists of 14 neighbors from the two associations— the TLPOA and the TEA (listed in alphabetical order): Jennifer Bruch, Howard Citron, Robert Cummings (TEA President 2025-26 term), Susan Enos, Scot Evans (DRC Chairman), Alex Grigor, John Gusmano, Janet Harckham, Tianle He, Dieter Luelsdorf, Lucille Munz, Clare Panno, Ira Sanchick, Allison Settineri (TLPOA President)

Brief history of the lake and dam:

• Theodore Langdon Van Norden was the 13th minister of the South Salem Presbyterian Church and arrived in 1894. He purchased all the farmland
  under our lake, became a prominent farmer, and built a small dam in July of 1908 to turn the pond below the Boway Stream on his property into a small lake (around 40 acres).
• 18 years later on 10 APR 1926, the newly formed Truesdale Lake Corporation purchased the farmland, small lake and dam, and the land north of the dam from him. Van Norden then became one of nine Directors in the Corporation.
• The Corporation widened, reinforced, and built up the dam to its current height while installing a control tower over a low level outlet to drain the lake as needed. This second phase construction increased the size of the lake to its current 83 acres.

• The TLPOA now owns the dam and undeveloped property north of the dam. The embankment and property northeast of the spillway plunge pool has been cleaned up with invasive shrubs removed and grass planted by the abutting property owner, Marianne Shoecraft, at 25 Indian Lane at no expense to the TLPOA. We are grateful to Marianne for her maintenance of and beautiful work done to this area of the dam. The TLPOA performs regular maintenance on the embankment northwest of the spillway and plunge pool.

• The TEA owns and pays taxes on the 83-acre lakebed and the islands.

• The Lewisboro Highway Department has Right of Passage over the dam and maintains the asphalt road, guardrails, and bridge over the spillway. An engineering inspection will be necessary to determine if the guardrail posts that were driven into the dam damaged the embankments and/or allowed water infiltration to weaken the embankments. Lucille Munz recently inquired if the Town engineer had evaluated the dam prior to guardrail installation and found that he had not.
• The last overtopping of the road by the lake (at the 511 foot AMSL elevation) occurred with Hurricane IDA on 1 SEP 2021 as a “100-year storm.” (A 100-year storm event is defined as 9″ rain within 24 hours with 1,500 cubic feet of water inflow from the watershed within the first 12 hours of the storm.) This part of the road has been used as our “auxiliary spillway,” though, it is no longer authorized by the DEC to be used for that purpose. See https://truesdalelake.com/2024/02/truesdale-dam-overtopping-events-since-1999/

For a comprehensive and beautifully-written history of Truesdale Lake, see neighbor and historian Priscilla Luckow’s https://truesdalelake.com/history/

Engineering Inspections of the dam:

• HTE Northeast, Inc. conducted an engineering inspection and dam rehabilitation proposal in February of 2004.

• The most recent NYSDEC inspection of our dam (assigned ID #231-5160) was conducted in June of 2009.
• A dam engineering study by Kathryn Serra, P.E. of CT Male was conducted in February of 2024. In summary, she found that:
• The two-foot-wide concrete vertical core wall through the middle longitudinal length of the dam seems to be in good shape. This means that we are not in imminent danger of a breach during 100-year storm events, which are occurring more frequently.
• Our lowest elevation in the road over the dam is 511.3 feet located between the flooded valve vault and NYSEG pole #7367 and currently serves as our “Auxiliary Spillway” during rainfall overtopping events. Erosion of the north embankment occurs during these events. This low area of the road is not an authorized auxiliary spillway.
• A combination “primary service” and “auxiliary overflow” spillway will need to be designed and constructed so that the lake level can be reduced 75% within seven days between the combined spillway crests. The usage of our current removable Weir Boards in the new spillway is no longer authorized by the DEC. 
• A new low level outlet conduit must be constructed transversely through the dam, with the valve vault/control tower (currently flooded and non-functional shown in the photo below) relocated to the upstream side of the dam – along the south embankment or in the water directly over the intake south of the south embankment.

DAM REHABILITATION will be completed in five phases: 

Phase 1: North embankment reinforcement, grading and erosion control with replacement of road-to-river curtain drains.

• Lewisboro Superintendent of Highways, John Winter, looked at the project in February of 2024 and said that he would be able to help with the corrugated curtain drain replacement and providing soil and materials to regrade the north embankment once we receive Town Board approval, an engineer’s plan, and the required permits.
• Lucille Munz is developing an engineer’s plan to reinforce and regrade the north embankment.
• John Gusmano will work with James Gorman of Pond & Lake Connection regarding lake’s wetland status and with NYSDEC and NYCDEP in their portions of work permits.

Phase 2: Replacement of Low Level Outlet Conduit and Relocation of Valve Vault/Sluice Gate Control Tower to the upstream side of south embankment. 

• In March of 2021, Scot Evans offered to go into the flooded valve vault with SCUBA gear to inspect the submerged cavern and turn the submerged control wheel to open the low level outlet; the TLPOA president at that time, Nick Fiegoli, feared that if it opened and drained the lake successfully, it may not close properly to allow the lake to refill, so this plan was rightfully deferred. 

• This phase will be a major construction project and Lucille Munz estimates that approximately $250k would have to be raised for the actual construction and an additional $50k to $75k for engineering soft costs and permitting.
• Howard Citron is currently working with engineering contractors to see if the low level outlet can be repaired at a reasonable expense and permitted with NYSDEC “grandfathering” the project.

Phase 3: Spillway, Training Walls, Discharge Ramp and Auxiliary Spillway upgrades. 

• This is a major construction project with costs greater than the phase 2 project above. 

Phase 4: Bridge Replacement and load tested with Load Limit posted and No Fishing signs posted on each end of the dam. 

• This is an intermediate construction project to be performed in tandem with Phase 3.

Phase 5: Replacement of potable water and installation of sewer pipes along and apart from the south embankment, and replacement of road over dam. 

• This is a major construction project and the final rehabilitation initiative.

Funding options for the dam’s rehabilitation:

• Our low hazard classification means that we are out of the running for grant money.
• The Congressionally Directed Funding application that Scot Evans and Lucille Munz submitted was not granted – in favor of a competing drinking water project in another district.
• Therefore, all owners within the lake community would have to share the cost of dam rehab and maintenance via an ad valorem tax district program to insure that all affected households contribute.
• Special tax districts allow for bonding and loans when necessary to get the projects completed more quickly. 

• Rob Cummings provided links for the work done on the Truesdale Lake Improvement tax district initiative from 2005-2007: https://truesdalelake.com/projects/tax-district/tax-district-faqs/ and https://truesdalelake.com/projects/tax-district/tax-district-draft-bill/tax-district-proposed-bill-cliff-notes/. These essential links will help a volunteer (TBD) generate a checklist and take all the necessary steps to create a Special District for the dam.