Cascadilla Creek Dredging Project Begins to Take Shape

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Posted January 22, 2019

During the winter months, Cascadilla Creek has created problems with ice jams at the Route 13 bridge. To alleviate this frequent issue, the City of Ithaca is working to dredge the creek from Route 13 to its mouth, where it empties into the Cayuga Inlet. Even though this project has been in the works for some time now, it still has quite a way to go before the actual dredging begins.

For now, Department of Public Works Superintendent Mike Thorne is confident that the work will begin by the end of this year and continue into early 2020. Around 18,000 cubic yards are being dredged from the creek, in addition to a sediment trap being installed. A recent survey of the creek has discovered just what work needs to be done to keep ice jams from reoccurring.

“We’ve talked to the DEC and let them know what we are planning on doing,” Thorne said. “The U.S.G.S. [United States Geographic Survey] has done a recent bathymetric survey so we know what the bottom of the creek looks like geometrically. We have a consultant that has designed a proposed dredging prism, which is what the shape of the bottom of the channel will look like when we’re done. Based on that, we have come up with a volume of sediment we’re going to be removing from the creek. We’re working with the adjacent property owner to see if we can use their property to store the sediments until they’re dried out enough to be put into trucks and taken off site. Again, a lot of the little details still need to be worked out but we are still planning on dredging a year from now.”

Agreements from the neighboring property owners are still in the works, the search for a location to dispose of the sediment continues, and the determination of where to put the sediment trap still has to be found.

Thorne said that once the sediment has been completely dried out, it will probably be taken to either an abandoned mine or an abandoned quarry. For several years now, this project has been a necessity to conclude the lengthy history of ice jams that form at the mouth of Cascadilla Creek. According to Thorne, some of the gravel bars that have developed have been there for several years.

“If you look at Cascadilla Creek when the lake is low, you’ll see a lot of gravel bars that actually stick up in the mouth of Cascadilla Creek, so we want to remove those,” said Thorne. “In the past when we’ve had ice jam problems, the ice will flow down Cascadilla Creek and will get caught on these gravel bars and start building up an ice jam from that point. Those gravel bars have been there for a number of years, at least five years, but probably a lot longer. Navigation along Cascadilla Creek has also been impacted. We’ve been getting reports from marina owners, in the past year or so, that boats are starting to bottom out.”

Lisa Nicholas, deputy director of Planning and Economic Development, said that acquiring the necessary $2 million of funding was not a difficult part of this elaborate process.

“We got money through the Capital Assistance Program, which is a state grant, and we got it through Barbara Lifton,” Nicholas said. “And we got the allocation to advance dredging, but it took a while to determine what was the best use for it given the other dredging projects so it became apparent that we could use it for this. [...] We will be doing the dredging this fall into early next year. We don’t want to interrupt the boating season. They want to keep Johnson’s Marina open or those docks at the end of Cascadilla Creek. Then, at the end of the summer, we can come in and do the dredging.”

Source: Ithaca Times