About 75 percent of the Delaware River navigation channel is now at or deeper than 45 feet, and the dredging work that began in March 2010 should be completed in mid-2017, state and federal officials said Tuesday.

Gov. Wolf last week released an additional $18.6 million for deepening a 103-mile stretch from Philadelphia and Camden to the Atlantic Ocean from 40 to 45 feet to accommodate larger ships.

The state of Pennsylvania, as the local project partner, will contribute 35 percent of the cost of the $360 million multiyear deepening project. The state has so far spent $82 million.

With the latest $18.6 million, the state will have contributed $100.6 million, a Wolf spokesman said.

The federal government's share, to date, has been $209 million, including $62.5 million that will be used for rock blasting near Marcus Hook starting in December.

Bids will open for the rock blasting work Aug. 18 and a contract will be awarded by the end of September, said Lisa Magee, chief engineer for the Philadelphia Regional Port Authority, a state agency.

The final steps will be deepening roughly 24 miles in the upper Delaware Bay and a section between Chester and Wilmington.

The Army Corps of Engineers is building dunes and storm-damage protection at Broadkill Beach in Delaware north of the Broadkill River, said Ed Voigt, public affairs chief for the Army Corps' Philadelphia District.

A 62-mile stretch of the channel deepening has been completed, or is underway, Magee said.

An additional 18 miles of the river channel were naturally at, or exceeded, 45 feet and did not need to be deepened.

Last month, a 2.5-mile stretch between the Ben Franklin and Walt Whitman Bridges was completed.

About $33 million in additional federal funds will be needed to complete the project, Voigt said.

Steamship lines and port officials say the dredging will put more cargo on ships coming into the ports, and allow larger ships from Asia to sail the river when the Panama Canal expansion is completed by 2016.

Now, large ships have to be careful coming up the Delaware. Some transfer cargo onto smaller vessels, a process known as "lightering," before coming upriver. With deeper water, Philadelphia could be a ship's first port of call, instead of second or later.

Ships are getting bigger, and the largest U.S. ports already have deeper water: Baltimore; Norfolk, Va.; and Oakland, Calif., are dredged to 50 feet.

Charleston, S.C., is at 45 feet, and Savannah, Ga., at 42 feet. Los Angeles soon will be deepened to 53 feet and Long Beach, Calif., to 76 feet. The Port of New York and New Jersey is being deepened to 50 feet from 45.