Lobbying Congress for more money may be the only way for South Carolina boaters and business owners to keep the Intracoastal Waterway from becoming too shallow.

The survival of the waterway is open to question without additional funding to keep the channel at its proper depth, boaters and business owners said Wednesday at a hearing in Charleston.

TOM MURRAY/AP A Charleston-based tug pushes a barge down the Intracoastal Waterway south of Georgetown on Tuesday.

On Thursday, the U.S. Senate Appropriations Committee approved money to pay for a variety of water-related infrastructure and dredging projects in South Carolina, including some $1.43 million for maintenance of the waterway.

Maintenance of critical water-related infrastructure is essential for the state's commerce, recreation, tourism and military installations, U.S. Sen. Fritz Hollings, D-S.C., said in announcing the appropriations.

The Army Corps Engineers has said it needs $4.5 million a year to keep the South Carolina section of the waterway at its traditional 12-foot depth, said Rosemary Lynch, executive director of the Atlantic Intracoastal Waterway Association.

But federal funding for dredging and other maintenance on the waterway is shrinking as commercial traffic dwindles. The waterway, 70 miles of which are in South Carolina, is down to 7 feet in some places.

"This waterway won't stay open without federal funds," said Benjamin "Bos" Smith, operations manager for Yonge's Island-based Stevens Towing Co. Inc.

"If Congress doesn't hear anything from us, we won't have a waterway."

The Senate bill also would allocate $10.5 million for Charleston Harbor maintenance and entrance channel dredging and $5 million to deepen the harbor.

Among other funding, a total of $100,000 would go for a new study of beach erosion on Edisto, where recent storms have destroyed several homes and the northern part of the beach appears to be critically eroded with high tides flowing under many houses.

About $200,000 would go to prepare plans and specifications for future renourishment of Folly Beach.

The S.C. Department of Natural Resources would receive $3.85 million for future operations on Aiken's Lake Russell, and $350,000 would go to Lakes Marion and Moultrie.

The bill now goes to the full Senate for consideration.