The pilots who steer big cargo ships carrying most of Alaska's consumer goods through the port of Anchorage are getting antsy about what lies beneath upper Cook Inlet's waters.

Their cause for concern is a shoal on the west side of the inlet -- roughly parallel to Point MacKenzie -- that has been creeping steadily into Knik Arm's navigation channel over the past decade.

"You don't want to go anywhere near it," said Frank Smith, a pilot for Totem Ocean Trailers Express Inc., or TOTE, one of the two big cargo lines that sails to Anchorage.

"With a $300 million ship, you don't want to run aground," Smith said.

Anchorage port officials are worried about the shoal, too. That's because most of the goods Alaskans consume enter the port on four to six sailings per week: groceries, clothing, vehicles and just about everything else sold in stores.

For now, Cook Inlet pilots say they are able to navigate around the Point MacKenzie Shoal. What bothers them is that the shoal is eroding their margin of safety in an already treacherous navigation channel. The inlet's dramatic tidal fluctuations require precise timing for cargo deliveries. Sometimes, the pilots said, winter ice, winds and swirling currents can make turning a big ship into the port a harrowing experience.

"We just want to keep a safe, navigable waterway," said George Lowery, Tacoma-based TOTE's Alaska director.

Pilots and other mariners have been discussing the shoal with Anchorage port officials for almost two years now but they are having a tough time getting anything done about it.

Port of Anchorage Director Bill Sheffield tried but failed this year to get a $1 million appropriation put into the $3 billion capital budget that the Legislature approved in mid-April. The money was targeted to help pay for a U.S. Army Corps of Engineers feasibility study needed before dredging or any other federal action involving the shoal can occur. Excavating even just a portion of the shoal could cost tens of millions of dollars.

Sheffield petitioned two Mat-Su Republican lawmakers -- Sen. Charlie Huggins and Rep. Bill Stoltze. Huggins rejected the request. Stoltze could not be reached for comment on whether or not he tried to get the money.

A Huggins staffer said recently that Mat-Su borough officials told the senator the study was unnecessary.

Anchorage port officials said they aren't giving up.

"It's just a matter of cobbling together the financing to make it happen," said Anchorage Port Deputy Director Steve Ribuffo.

THE SHOAL

Cook Inlet pilots said the Point MacKenzie Shoal's growth spurt began about 10 years ago.

Two years later, big ships had to begin detouring around the shoal to make their approach to the Port of Anchorage, said Smith, the TOTE pilot.

The shoal is cutting into the ships' safety margin by reducing the amount of space they have to turn. Big ships need a large amount of room, so for safety, mariners prefer to be on the west side of the shipping channel before turning toward the port, said Steve Honeycutt, president of the Southwest Alaska Pilots Association. But the shoal is growing on the west side of the shipping channel, forcing them to turn closer to the east side of the channel, he said.

"There's a delicate balance of avoiding the shoal and having enough room to turn" into the port, he said.

The association, which dispatches experienced pilots to the majority of the large ships that travel through Cook Inlet, and other mariners began warning Anchorage port officials about the shoal's growth in early 2008. At that point, the shoal was sticking out like a giant tongue into the channel.

"It's pushed the ships over a half-mile now," said Brad Kroon, a tugboat captain for Cook Inlet Tug & Barge Co.

Kroon and other mariners interviewed for this story said they are concerned about the future of the shoal and favor a Corps study.

The pilot association, TOTE and a second cargo shipper, Horizon Lines, have sent letters to the Corps of Engineers asking it to do something.

DEADLOCK

For now, the Corps of Engineers is tracking the shoal but says it can't do anything about it until a local entity -- most likely the state, Anchorage or Mat-Su -- pitches in on the cost.

The Corps is no stranger to Knik Arm's silt. Every year, it spends millions of dollars removing it from the Anchorage port.

But the MacKenzie Shoal is a different deal. Congress authorized the Corps to deepen the Upper Cook Inlet shipping lane in 2005. But before launching a dredging barge, the Corps must first study the problem, and funding for that study must be provided equally by the Corps and state or local entities. If the study concludes dredging is needed, the Corps will needs state or local officials to help fund that work, too.

This year, Anchorage port officials sent letters to Stoltze and Huggins requesting a $1 million state appropriation to the Mat-Su Borough toward a Corps study, estimated to cost $2 million.

Why go to Mat-Su legislators when some Anchorage lawmakers hold seats on the budget-writing finance committees? For one thing, Anchorage port officials and many Cook Inlet pilots suspect the construction that began about a decade ago on the Mat-Su Borough's Port MacKenzie triggered the shoal's growth.

Also, Sheffield, the Anchorage port director, said he thought it would easier for the Mat-Su lawmakers to get the money because Anchorage "always has so many projects in the budget."

His idea backfired. Mat-Su Borough officials disagree that their dock is to blame and they argue that the shoal is not a serious obstacle for ships.

Huggins' aide, Jody Simpson, said the Wasilla senator did not request funding for the Corps study after receiving a letter from John Duffy, the Mat-Su borough manager, stating that the ships "simply need to maneuver their vessels into deeper water."

In interviews, Mat-Su officials said that if it's true that the shoal is growing, it's probably because the Corps dumps the millions of cubic yards of sediment that it dredges at the Anchorage port and puts into the deep waters of the shipping lane.

The dumping "has a much higher potential for adding to the shoal than anything else out there," said Port MacKenzie director Marc Van Dongen.

A couple of pilots said they are skeptical of that claim because the Corps dumped dredge spoils in the shipping channel decades before the shoal became a problem.

Steve Boardman, the Corps' district chief for civil construction, said it's possible that both the Port MacKenzie dock and the dumping of dredge spoils are enlarging the shoal.

Another potential factor is glacial melt-off from Southcentral Alaska rivers that is unloading silt into Knik Arm, he said.

"The question should be what can and should we do to lessen those impacts and keep navigation safe," he said.

"To date, we don't have any local cost-sharing partner saying they'd like to participate," he said.

A SILTIER FUTURE?

It's no secret that siltation is a big headache for the Port of Anchorage -- dredging the silt is a never-ending battle against Mother Nature the Corps has waged for at least 40 years.

That battle has intensified in the last 10 to 15 years, Boardman said.

It's possible that, 50 to 100 years from now, that Cook Inlet siltation could get so severe that it could become too costly to maintain the ship channel in Upper Cook Inlet, he said.

In the past decade, the Corps's dredging at the port of Anchorage has increased significantly.

In the 1980s and 1990s, the average annual excavation at the port was between 250,000 and 500,000 cubic yards of sediment. Starting about a decade ago, the excavation shot up to 800,000 to 1.4 million cubic yards annually, Boardman said.

The dredging at the port now costs about $12 million per year, all paid with federal dollars because the port and navigation channel are used to support military operations.

Sheffield, the port director, said he doesn't have any druthers on whether the MacKenzie Shoal is removed or if it is dredged every year like the port of Anchorage.

"The shoal has got to be dredged. Either I'm going to pay for it or the Mat-Su and I might share it, or the Corps might have to do it all by themselves," he said.