Even as city officials work to restart the stalled Port of Anchorage improvement program -- a decade-long boondoggle that has so already cost hundreds of millions of dollars -- another, more persistent and immediate problem is being scraped away at the port's docks: a buildup of silt and mud. The ships that dock there each Tuesday and Sunday deliver up to 85 percent of the goods that come into Alaska. When loaded, the massive barges require a draft -- the depth of water needed to keep the ships afloat when loaded -- of about 28 feet. The port's operation plans call for the entire dockside to be kept at a minimum of 35 feet of water at mean low tide, also called zero tide.
But at times this winter, the buildup of silt and mud has seen the depth at the dock get as low as 26 feet. Now, dredge barges contracted by the U.S. Army Corps of Engineers are getting to work to scoop out the debris and restore the intended 35 feet of depth there. And they didn’t arrive a moment too soon.
The waters of Cook Inlet see monstrous tides, the second largest of any major port in the world, behind only Nova Scotia's Bay of Fundy. The tides can scour the seafloor, creating new channels and covering old ones. But the problem at the port is a function of the water there, not the tides. Cook Inlet is a silty body of water, and while some of that silt is picked up and suspended by the Inlet's tidal action, most comes in from surrounding glaciers and the rivers they feed. Silt, mud, and particulates are suspended in its waters throughout the year. When that suspended material settles near the Port of Anchorage, it builds up thicker and thicker until it threatens the loading and unloading operations of the container ships that are the state's lifeline to goods delivered from Outside. The dredging ships arrived this month, and immediately began to dig out the area next to the port, so that it can continue to handle the deep-drafting container ships.