A new cost analysis study on the Tillson Lake dam places upgrades and repairs much lower than previously thought, opening up the possibility of repairing rather than removing the dam.
Around this time last year, the Palisades Interstate Park Commission (PIPC) planned to drain Tillson lake and demolish the dam that created it because they couldn’t obtain the funding to upgrade and repair the dam to its Class C classification.
The prospect of dam removal caused a public outcry, and pressure from concerned citizens, Friends of Tillson Lake, and county and state legislatures—including Senator John Bonacic, Assemblyman Kevin Cahill and New York State Senator Jen Metzger—forced the PIPC to reconsider. The PIPC commissioned a new cost study by Schnabel Engineering, which was released in June.
The study identifies four options for the dam. The first three involve repairing and upgrading the dam to modern standards in various ways and the fourth is to decommission the dam.
The first three options range in estimated price from $2.9 million to $3.8 million. The cost of decommissioning the dam is estimated to cost around $1.7 million.
The cost estimates for upgrade and repair of the dam is lower than previous cost estimates. In March 2018, letters were sent to homeowners near Tillson Lake by PIPC Executive Director James Hall which stated the cost of repairing and upgrading the dam could be as high as between $7 and $9 million. A 2017 preliminary construction cost estimate proposed by Malcom Pirnie estimates the dam upgrades would cost about $4.3 million.
Morey Gottesman, Friends of Tillson Lake President, said he hopes the lower cost will cause the PIPC and the New York State Office of Parks, Recreation and Historic Preservation to upgrade and repair the dam rather than remove it.
“We’re pretty happy with the new, most reasonable figure of far less than 7 to 9 million dollars,” Gottesman said.
Hall said the PIPC is waiting for comments from the New York State Department of Environmental Conservation (DEC) before they make any decisions.
“We have submitted the report to DEC to determine if they concur with the use of this model,” Hall said. “Before any decision is made on rehabilitation with a full understanding of projected costs, we will need to get comments from DEC in order for us determine if the methods and resulting cost analysis provided in this report is appropriate.”
Gottesman, who met with New York State Parks Commissioner Erik Kulleseid in April, said the PIPC and New York State Parks will meet to make their decision after they receive comments from the DEC. If the agencies decide to repair the dam, Gottesman said Friends of the Tillson Lake will help the agencies and lawmakers find funding.
“We’re hoping that that will be the ultimate decision, that they will decide to go ahead and fix the dam, at which point we will be working with Senator Metzger and Assemblyman Cahill to help them secure the funding,” Gottesman said.
If the agencies decide to remove the dam, Gottesman said Friends will continue to fight to save the dam and Tillson Lake.
“If the outcome is negative and they want to pursue alternative number four, we’ll have a battle on our hands,” Gottesman said.
The dam is a Class C “high hazard” dam, a classification assigned to dams with a certain amount of development downstream. A 2012 Engineering Assessment Report for Tillson Lake Dam stated the advanced deterioration in the spillway represents an “unsound” condition.
Hall said the classification of the dam requires more stringent standards. The PIPC has done basic maintenance on the dam, but it hasn’t had the funding to do more significant repairs and upgrades, and it wasn’t up to the standard of a class C dam when they acquired it.
Hall said the new report affirms the high hazard classification and most of the previously known issues with the dam. However, the consultant suggests the spillway does not need to be increased to meet passing flow requirements as previously thought, lowering project costs.
The 13-acre lake was dammed in 1929 and has been a popular swimming, fishing, boating and recreational spot for decades among Gardiner residents and neighboring communities. Tillson Lake was acquired by Minnewaska State Park in 2006 as a part of the Awosting Reserve, a 2,500-acre property bought by Open Space Institute and Trust for Public Land, and then turned over to the state.