The loss of water flow from the Farmland plant might cause a significant oxygen level depreciation in Albert Lea Lake while the lake is frozen over, the Freeborn County Environmental Services predicts.

Saturday, December 08, 2001

The loss of water flow from the Farmland plant might cause a significant oxygen level depreciation in Albert Lea Lake while the lake is frozen over, the Freeborn County Environmental Services predicts.

To make up for the reduction, the county is considering installing an aerator in channel. But the Minnesota Department of Natural Resources thinks the aeration is not necessary and could even be dangerous.

Before the July 8 fire, Farmland constantly drained some water into the channel. The non-hazardous water was either from rainfall and thaw or a cleanup of the facility, according to the county.

&uot;The discharge stirred the water in the channel and oxygenated it,&uot; Environmental Services Director Randy Tuchtenhagen said. &uot;The drain created an open water that also helped the oxygenation process.&uot;

The low oxygen level while the lake is frozen over, particularly in late February, is a major cause of fish kill in Albert Lea Lake.

When ice and snow cover the lake’s surface, the supply of oxygen comes mainly from the channel stream. If the water level of Fountain Lake is low and there is no water flowing into the channel over the dam, then the Farmland discharge becomes a crucial oxygen source for Albert Lea Lake, Tuchtenhagen said.

Andrew Henschel, the county watershed field technician, explained that game fish will start dying when the oxygen level goes below four to five milligrams per liter while rough fish can survive in two milligrams level.

Henschel believes the aeration will increase the fish survival rate significantly. &uot;The lower reaches of the Channel has a 12.5- to 13-foot depth, which is the deepest point of the lake. Many fish congregate there to pass the winter,&uot; he said.

The state is against the idea.

While the DNR issued a permit to aerate the channel in case that extreme low oxygen level was observed last season, a renewal application by the county was rejected.

The county installed two aeration units in the lake near the Interstate-35 bridge on November. The DNR maintains no more aerators are necessary for the lake.

The agency also doubts the effect of the drained water.

&uot;We conducted visual observations in last season, but we did not see the water from the Farmland plant was contributing to making a current in the channel,&uot; Jim Wagner of the DNR Lanesboro Fisheries Office said.

According to Wagner, even without the discharge, channel water was fairly open by the flow from the dam.

The other concern of DNR is safety.

The area attracts a lot of people for winter recreation. &uot;An excess of the open water could endanger the people come to the lake for ice fishing or riding snowmobile,&uot; Wagner said. &uot;We need to take care of different purposes of lake use.&uot;

Henschel recognizes the safety concern, but emphasized some type of aerators would not generate much open water space.

The county will gather relevant data about the past discharge from the Farmland factory so it can estimate the lake oxygen level this winter without the plant.