ITHACA, N.Y.—Ice jams, an annual flood risk for the City of Ithaca, are made with a careful recipe by mother nature.
First a deep freeze must set in, slowing the flow of the city’s four creeks until they ice over. Then comes the warmth of a “Fool’s Spring,” sunny days and temperatures of around 50 degrees Fahrenheit. The last ingredient is rain, which warms and fractures the sheets of ice atop Ithaca’s creeks, sending them adrift on water levels swollen with rain, added snow and ice melt.
In narrow parts of the channels, the ice chunks can clog up and form jams, disrupting the natural flow of water, and setting the stage for the creeks to break their banks. Most recently, ice jams formed in Ithaca on Feb. 17 and Feb. 18.
Rising water levels can raise blood pressure for the Ithacans that make their homes in the flood-prone areas of the city, but work is underway to expand the tools and techniques that the city has to unjam the ice, particularly around the use of “warm water effluent” from the Ithaca Area Waste Water Treatment Plant.
Effluent is treated and chlorinated wastewater. It’s normally pumped deep into Cayuga Lake, reintroducing it into the local water cycle. The warm water, though, becomes a valuable tool for breaking up piled ice slabs.
Scott Gibson, Acting Superintendent of Water & Sewer, said that in the instance of an ice jam, workers are able to run the effluent out of pipes near the Sciencecenter using a fire hose. Effluent can be poured into Cascadilla Creek up to the areas between Hancock and Adams Street.
Gibson said the technique is effective but he added, “what we don’t have covered is Fall Creek.”
The City’s plan is to expand piping from the Ithaca Area Waste Water Treatment Facility to carry warm effluent to Fall Creek, and further up along Cascadilla Creek.
The City of Ithaca’s Superintendent of Public Works Mike Thorne said there are ways of moving warm effluent water into the creeks that don’t involve adding new piping, but those methods are inconvenient and more costly. Thorne added that having the piping in place would reduce the time it takes to deal with an ice jam too.
“The cost to taxpayers in Ithaca pales in comparison to the damage flooding can do to homes,” Gibson said.
At the moment there is no set date for when this project will be completed. The piping is being installed by workers within the Department of Public Works, which Thorne said often get moved around as different projects arise and shift priorities.
“We work on it when we have time,” said Thorne, “I mean, we would love to have it in place now. But we only have so many people that can do the work.”
The City of Ithaca is not permitted by the New York State Department of Environmental Conservation (DEC) to discharge warm water effluent into its creek at its own discretion. The City can apply for emergency authorization from the DEC to discharge warm water effluent into its creeks, which it received on Feb. 17.
The DEC is currently reviewing the city’s proposal to expand the Ithaca Area Waste Water Treatment Facility’s State Pollutant Discharge Elimination System (SPDES) Permit. The permit only allows the facility to discharge treated wastewater into Cayuga Lake.
According to Gibson and Thorne, Ithaca does have a decades-long history of using effluent to combat ice jams in emergencies. The technique likely fell out of fashion as institutional knowledge was lost from staff turnover over the years, Gibson explained.
“Back in the ‘70s they used to use dynamite to clear the creeks,” said Gibson, laughing. “I don’t think they’d let us get away with that now.”
Thorne entered his position as superintendent in 2014, when that year’s spring melt brought a notorious slew of ice jams. It was then that the City moved to invest in and expand the use of warm water effluent.
Dealing with ice jams in Six Mile Creek, which poses a flood risk to Ithaca’s Southside neighborhood, is a more complex and costly issue for the city.
Thorne said that running piping from the wastewater treatment facility to the areas where ice jams occur in Six Mile Creek is not feasible. The flood control measure that the City has in mind is putting in backflow preventers on the storm drain system. Thorne said that the City of Ithaca is applying for grants to pull this project off.
In certain cases, the city will use a long arm excavator to smash and break up the ice, although Thorne said that these are limited in the locations they can be used along Six Mile Creek in particular.
The efforts to reduce Ithaca’s susceptibility to flooding are couched within the 2022 Preliminary FEMA Flood Zone Boundaries, which will likely raise the cost of flood insurance or even result in mandatory flood insurance being imposed on some properties by financial institutions serving as mortgage lenders.
Thorne said that the preliminary FEMA Flood Zone maps are “much more extensive than the old maps, but they don’t surprise us.”
Ithaca hired the consulting firm, Barton & Loguidice to prepare a Local Flood Hazard Analysis in preparation for the updated FEMA maps. The analysis was completed in 2020, and Thorne said that is the basis of Ithaca’s roadmap for reducing flood risk.
“There is a solution here,” said Thorne. “It just requires time and money.”