The city is starting long-proposed dredging work in Flushing Bay this month, beginning what will likely be a decades-long process to clean the fetid inlet and rid it of what neighbors have described as a rotten-egg smell. The bay, near Citi Field, between LaGuardia Airport and the neighborhood of College Point, is lined with 10 combined sewer outflows, part of the city's outdated sewer system, which connects sewage lines with the flow from storm drains during heavy rains, sending raw sewage spewing into area waterways.

During wet weather, scientists have recorded fecal bacteria in Flushing Bay at levels 3-30 times what the federal government says is safe for recreational waters. Over the course of a year, city researchers have found, 1.45 billion gallons of sewage are discharged into the bay, plus copious amounts of highway and airport runoff. Boaters who frequent the bay have recounted paddling past turds, condoms, and a dead rat.

The initial work, announced today by the Department of Environmental Protection, is slated to cost $34 million and include dredging in the area near the World's Fair Marina, as well as the removal of a rotten old pier and timber pilings. The agency also plans to create three acres of mudflats and marsh to filter the water.

In the first phase of the cleanup, the DEP plans to decommission three of the combined sewer outflows along Flushing Bay. During the process, which is supposed to conclude by the end of this year, excavators are supposed to work around the clock, seven days a week, behind a "turbidity curtain," designed to keep the muck kicked up by the process contained.

In the long-term, the agency plans to throttle the flow of sewage into the bay by building a sewage storage tunnel, designed to divert the putrid rainstorm surge from two of the remaining combined sewer outflows and send it to be processed it at a new pumping station.

The process of building a 2 1/2-mile tunnel and "dewatering" station, among other measures, is anticipated to cost $5.7 billion and take till 2042, according to a DEP plan published in December. The state still has to approve the plan.

The cleanup is part of the contentious 2012 agreement between the city and the state to reduce the use of combined sewer outflows and clean the city's waterways so that they can one day be swimmable and fishable, or as near to it as possible, in accordance with the federal Clean Water Act. The city has sued the state for declining to approve its cleanup plan for Alley Creek, in Little Neck, and other scrubs, including Flushing Bay's, are behind schedule—the long-term plan for Flushing Bay was supposed to come last June.

A previous version of this story referred to the DEP as a state agency. It's a city one.