The fate of White Bear Lake, including whether millions of dollars will be spent to replenish it after years of historic depletion, now rests with a Ramsey County district judge after a key ruling in a nearly two-year-old lawsuit.

Even as an array of plans to restore the lake ranging from $5 million to $620 million are being studied —such as piping water to the lake from the Mississippi River — both sides in the suit are now preparing for a court trial in March that could result in those remedies being ordered sooner rather than later.

The ruling last week by Judge Margaret Marrinan set up that trial when she rejected motions from all parties for summary judgment.

Her ruling also bluntly warned the state Department of Natural Resources (DNR), the main defendant, that there are flaws in its case so far.

The DNR asserts that not only is White Bear Lake unharmed by chronically low levels in recent years, but such fluctuations are normal and even beneficial to the lake's vegetation and fish habitat.

But the judge wrote that the lake's shrinkage has resulted in exposed lake bed hundreds of feet from the normal shoreline, created an environment ripe for noxious species like Eurasian milfoil. It has also made boating and fishing difficult.

"It has had an obviously deleterious effect not just upon habitat and recreation, but also upon the local businesses that depend on those activities," Marrinan wrote.

She added that the plaintiffs in the case — chiefly homeowners along the lake — made a compelling case that the DNR failed to protect the lake in two ways: by not considering the cumulative effect of letting nearby communities draw water from the main aquifers that supply the lake, and by not moving faster to protect the lake and aquifers when it became clear as far back as 1998 that those drawdowns were causing major problems.

Marrinan noted that it was only after the lawsuit was filed in November 2012 that the DNR and the Metropolitan Council began developing a groundwater management plan, "despite having had for a long time the green light from the Legislature. It is undisputed that, as a result, water-use planning did not take place in the White Bear Lake area."

The original lawsuit against the DNR was filed by the White Bear Lake Restoration Association. A second group, the White Bear Lake Homeowners' Association, has since joined as a plaintiff.

And both the city of White Bear Lake and White Bear Township have signed on as co-defendants with the DNR, after leaders decided they had a stake in the outcome and wanted a chance to argue their case. Other lake communities also considered joining but in the end chose not to.

White Bear Lake, one of the largest recreational lakes in the region, dropped 5 feet from 2003 to 2011 and lost an estimated one-fourth of its volume.

The lake's water level, typically about 925 feet above sea level, plummeted to an all-time recorded low in January 2013 with a surface elevation of just under 919 feet.

This year's heavy rains pushed levels higher before the water receded again.

The lawsuit is not seeking monetary damages but aims instead to compel the DNR and Met Council to take steps to get the lake back to its normal level and maintain it.

Katie Crosby Lehmann, one of the attorneys for the Restoration Association, said the group was encouraged by how Marrinan framed her ruling.

"It's clear she views our case as being a very strong case," Crosby Lehmann said.

The judge, she said, was not persuaded by the DNR's arguments denying that the agency had violated state standards in how it went about issuing groundwater permits, or by its assertion that there were no prudent options to address water depletion problems.

"It really gives the homeowners some hope," Crosby Lehmann said. "We want to help the lake and the aquifers in any way we can."

She added that it's clear the judge understands the harm caused by the lake level decline, despite the DNR's arguments that fluctuations are normal and beneficial.

"That's a breathtaking opinion, and the city of White Bear Lake has made similar arguments," Crosby Lehmann said. "It's ridiculous."

But DNR spokesman Chris Niskanen said that many significant scientific and legal questions remain about the levels of White Bear Lake. The connection between groundwater and surface water in general, and for this lake in particular, is a matter of debate and will be addressed at the trial.

Along with the Met Council, Niskanen said, the DNR has made water management a top priority.

"We've said all along that some of these issues are better addressed by the Legislature," he said. "That being said, we've defended our position ardently."

Niskanen said that the underground nature of groundwater makes it hard to know what's happening to it, and that the uncertain role of wet and dry weather conditions further complicates matters.

"In this case, it's really a science issue," he said. "What is really contributing to the lake's decline?"

Jim Anderson • 651-925-5039

Twitter: @StribJAnderson