With the completion of dredging last month of a 14-mile stretch of the Delaware River, the deepening of the river's main navigation channel to attract bigger ships and commerce is now about 60 percent complete, Philadelphia port officials said Wednesday.

Since the project began in March 2010 between Camden and the Atlantic Ocean, 42 miles of the Delaware has been dredged to 45 feet, from 40 feet. Roughly 35 miles of channel is at, or below, 45 feet naturally, leaving about 25 miles of the 102-mile river channel to go, said Lisa Magee, engineer and director of special projects at Philadelphia Regional Port Authority (PRPA).

Pennsylvania and the PRPA, as local sponsor, have spent $50.8 million toward the project, and the federal government and U.S. Army Corps of Engineers $70.5 million.

The next stretch, starting in September, will be in the Delaware Bay. After that, contract bids will go out for dredging between the Walt Whitman Bridge and Beckett Street Terminal in Camden.

The entire $300 million deepening, which has been debated since 1983 when Congress directed the Army Corp to investigate the feasibility of channel deepening, is expected to be completed by 2017.

"Some of the toughest parts still remain to be done," said Army Corps spokesman Richard Pearsall. "The area around Marcus Hook, which is rock, while that might be a small area in linear feet - mileage-wise - it's a big, costly and tough job.

"And the lower Delaware Bay is still to be done. That is also somewhat more problematic because it's open water, so there are more currents and more distances. It's not a big problem because it's a fairly sandy bottom."

"Then, after that, we have the area between the Walt Whitman and Ben Franklin Bridges," Pearsall said. "If you look at the map [you would] say, 'Wow, that's a lot of area covered.' And it is, but there are still some spots there that are going to take time and money."

President Obama proposed $31 million in his 2013 fiscal budget for the Delaware River project. The government has appropriated $20 million and the balance, $11 million, is expected any day, Magee said.

The president's proposed 2014 federal budget includes an additional $20 million for the work.

"After years of discussions and hurdles, it's wonderful to finally see steady progress on this critical project," said PRPA chairman Charles G. Kopp. "A deeper shipping channel will allow us to welcome a wider variety of cargo vessels. Other ports are also deepening their channels, and it is so important that we do so as well."

Going to 45 feet would put ports on the Delaware in line with other major East Coast ports. The Port of New York is being deepened to 50 feet.

The federal government is supposed to pay 65 percent, and Pennsylvania, as local sponsor, 35 percent of the total tab.

Studies have estimated that a deeper shipping channel will create 8,000 to 12,000 direct jobs and spin off as many as 38,000 more through the region, Gov. Corbett said last summer, echoing support for the project that began with former Gov. Ed Rendell.

Across the river, Gov. Christie has been staunchly opposed, citing economic and environmental reasons.

Delaware, which originally sued to stop the deepening, now publicly supports it to accommodate larger ships and trade that is expected to come to the East Coast from Asia after the Panama Canal is expanded in 2015.

Contact staff writer Linda Loyd at 215-854-2831 or lloyd@phillynews.com.