It's easy to spot kayaks and shorebirds along the Petaluma River's 16-mile path to San Pablo Bay.

You still can see barges hauling sand, rock and other cargo, too. But commercial traffic is declining because silt is making the river harder to navigate. It also could cut into recreational use of the river, which is actually a tidal slough.

At one time, this bucolic stream carried more cargo than any other river in the state. That's now a fact for the history books, but the Petaluma River can still be a major economic artery for the North Bay.

For that to happen, the river must be dredged.

Aside from some emergency work after a major storm in late 2005, it has been 10 years since the U.S. Army Corps of Engineers last cleared sediment from the riverbed. As tides and storm runoff built layers of silt, it's become increasingly difficult for larger boats to traverse the river.

Commercial haulers carried more than a million tons of cargo on the river as recently as 2007, but they say tonnage has declined 15 percent in recent years — and warn that it will drop another 25 percent if the channel isn't dredged soon. If the river gets too shallow, the cargo business will be sunk.

Cargo hauling isn't the only economic asset at risk.

The river is a major source of tourism for Petaluma. More than 460 boats spent at least one night in town last year, providing a $1.3 million boost to the local economy, according to the Petaluma Downtown Association. But concerns about getting stuck on a sand bar may cause some boaters to look for other designations.

Other benefits of regular dredging include Petaluma's popular Shollenberger Park, which was sculpted with silt and mud from the river.

Dredging used to take place every four years. But federal budget cuts have left Petaluma competing with other communities for scarce dollars.

Rep. Jared Huffman, D-San Rafael, is skippering a renewed effort to secure funding to dredge the river. The estimated cost of dredging the full length of the river is $7 million.

Huffman's effort suffered a setback in June when the Senate scrapped an increase in maintenance money in a funding bill for the Corps of Engineers. There isn't any extra money in the House funding bill, either.

So in all likelihood, it will be 2014 before there's a chance to get federal funding to dredge the river.

In the meantime, Huffman told a gathering of dredging advocates, "We're going to have to keep working on this, keep pushing the Corps."

Otherwise, the working days of the Petaluma River may end prematurely.