State officials have warned leaders of suburbs close to White Bear Lake that they may have to order homeowners to let their lawns wilt for lack of water.

"Imagine a sprinkling ban that lasts for years," said Julie Ekman, a water manager for the Minnesota Department of Natural Resources.

She and other DNR officials met Thursday with an advisory group of city officials and other stakeholders in the northeast metro area to update them on the run-up to what promises to be a landmark trial in district court.

The case will test whether suburban sprawl — with its heightened pumping of groundwater to slake the thirst of grass and gardens — is draining stricken White Bear Lake, harming swimmers, boaters and others.

A drought that set in after the turn of the century drained White Bear, one of the state's marquee lakes, to its lowest point in recorded history — 918.8 feet above sea level — by 2013.

The DNR is being sued by two groups, the White Bear Lake Restoration Association and the White Bear Lake Homeowners' Association. The plaintiffs point out that even plentiful rainfall in the past couple of years hasn't brought the lake up to average levels of the past or allowed for the reopening of a county-owned beach.

The DNR notes that, at 922.57 feet as of Thursday, the lake is just half a foot below its average level — a big jump in recent years that has water lapping again below marinas.

The litigation has prompted a wave of scientific work on what's actually going on underground. The results are beginning to come in, researchers said Thursday.

A notable discovery, said Jim Stark of the U.S. Geological Survey: "Many lakes in the area are leaky," losing water via their lakebeds into deeper reserves.

Massively complex simulations, taking networks of sophisticated computers hours to crunch, are being run to find out whether piping water into White Bear Lake, as activists urge, would truly help, Stark said.

"Would augmentation stabilize the lake, and if so, at what cost to lake ecology and government budgets?" he said. "If you bring in Mississippi River water, would lake levels be higher?"

Changing lake levels

The plaintiffs in the case got the state to agree to set a precise level — not yet determined — at which protective measures would kick in. That's what could lead, officials warned, to draconian bans on water use.

Most nearby cities lack the authority today to do that, Ekman said. Their ordinances contemplate mere "brief dry spells," not "long-term bans, year after year" that could threaten property values.

Depending on what the science shows, folks for miles around could be forced to shut off sprinklers as the surest way to cut use without threatening necessities like drinking water. The DNR is advising a few jurisdictions closest to the lake to consider strengthening their legal authority.

City officials say they are responding with conservation measures that are cutting into water usage in places like Shoreview, while also asking questions about the unique issues that may be affecting White Bear Lake.

Mark Maloney, Shoreview public works chief, said that "I just met yesterday with a group concerned about flooding in various water bodies," even as White Bear Lake levels lag.

Bryan Bear, Hugo's city administrator, noted that research shows low lake levels are "positive for lakes from time to time."

Indeed, the DNR argues that changing lake levels over time are part of nature's plan, and at Thursday's meeting it previewed for participants a slick video that makes that case. A narrator describes lakes as "complex dynamic ecosystems teeming with life and character" where dry periods promote shoreline plants that help feed fish and ducks.

Final findings from the U.S. Geological Survey research were due this month but have been delayed until winter, in advance of a court trial in March.

Meantime, the DNR is asking companies that could build piping and pumping systems what they would charge to do so. Figures produced by government entities, vs. lake-level activists, have varied by tens of millions of dollars. Activists fear that with lake levels rising, it will be tough politically to ask the state to foot too large a bill.