It's just a pile of gunk scooped up from the river bottoms. But the cost of dealing with it is threatening to run into the millions.

As the legislative session approaches, Scott County is signaling that a huge pile of sludge squatting beside the Minnesota River in Savage is growing as a lobbying priority.

It's been growing in height for years, and unless something is done, officials say, its life span is nearing an end.

The sand, silt and other material have been dredged from the bottoms to ensure a shipping channel for the vast quantities of grain and other commodities shipped out to the world via the Ports of Savage, one of the better-kept secrets in the south metro.

Within a very few years, according to a report completed last year, either someone needs to start subtracting from the pile or a new site needs to be found to start another one.

Either option would be pricey.

Civic leaders in Scott County are supporting a $4 million bonding request lodged by the agency responsible for it, known as the Lower Minnesota River Watershed District.

So far, however, Gov. Mark Dayton has shown little interest.

Former legislator and now Scott County lobbyist Claire Robling said most of the soil "was previously used for covering landfills." She added, "but the demand for this has decreased."

She has suggested a conversation with the Shakopee Mdewakanton Sioux Community, "to see if they could use some of this fine topsoil, which is apparently not considered contaminated, washed downriver from other parts of the state, and mix it with compost made at the tribal compost site."

Tribal Administrator Bill Rudnicki said the Shakopee tribe "has not been approached by the Lower Minnesota River Watershed District. However, the tribe is open to collaborating on projects that benefit the environment and people in our region."

Unlike some in the state, the port is actually a private enterprise, although the creation of a shipping channel is a public matter. That would raise the question of participation by companies such as Cargill that do shipping through the area. But a pair of Cargill spokesmen sounded unaware of the issue at all. In the end, company spokesman Mark Klein reported via e-mail:

"I'm not gathering that we're involved in [the] project."

Linda Loomis, administrator of the watershed district, said the agency is "planning to lobby the legislature for money to develop a dredge site, but a lot of things are up in the air right now."

The question of when capacity gets reached is "kind of an ongoing issue," she said, one that depends on a number of factors.

There was a meeting last week with the Army Corps of Engineers in St. Paul on how much sediment from upriver is landing in the lap of folks in the metro to have to deal with. "There was a discussion about, 'Are there other things we could do, are there other places where it would be beneficial to dredge to try to reduce the amount of sediment that's reaching Fort Snelling?' It's kind of up in the air until they get some more information," Loomis said.

Truth is, she added, "We know we're going to have to continue dredging. Shipping by barge is by far the most efficient way to transport goods that go out of those terminals. But do you continue to just fill up the dredge site until infinity? And the amount of material is increasing."

Could one scrape off some of that material and find other uses for it?

"We're working on it," she said.

She has spoken with the state transportation people, who are working on road projects in the area, but the material doesn't meet MnDOT specifications. Hennepin County is doing a road project nearby and will look at it. There have been informal, early feelers out to the tribe. "So we are looking at re-use and all the options. Everything is on the table."

Staff writer Susan Feyder contributed to this article.

David Peterson • 952-746-3285