The Online Lower Minnesota River Watershed District News, October 2004

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Scour hole at Nicols Fen
— man measuring depth


Another view of scour hole,
showing steep banks


Sibley Fen
— one of three in Ft. Snelling State Park


Red-tailed hawk in Sibley Fen

can nicols fen be whole again?


Click here to see a Nicols Fen mini photo album

Saunterers may know the dogleg-shaped patch of Nicol Fen in Eagan hard on Nicols Road where stormwater, until a couple of years ago, would come rushing down onto the fen.

Over the years, the rush of stormwater scoured a hole in the fen, at the upper end of the dogleg. The hole reached a depth of 20 feet, with standing rainwater at the bottom, presenting a hazard to the unwitting and unwary. Two years ago, the city of Eagan redirected the pipe into a water ponding area.

This winter, when the soil is firm enough for heavy equipment, the city will  regrade the scour hole so that it no longer poses a threat.

After that, the city may transfer title to the property to the state and Fort Snelling State Park , says water resources coordinator Eric Macbeth. If the park acquires the property, notes Mark Cleveland of the Minnesota DNR (Department of Natural Resources), "we would look at stabilizing the site and restoring it to native vegetation."

The three fens

Nicols Fen is one of three remnant fen complexes within the park:

  • Nicols Fen, the most greatly impaired fen, in Eagan

  • Sibley Fen (also known as Ft. Snelling Fen), the highest quality fen, just south of 494, also in Eagan

  • Quarry Island Fen, in Mendota Heights , just north of 494

In these calcareous fens, calcium-laden water seeps up from aquifers and nourishes peat and rare plant communities. (For a full feature story on Nicols Fen, see our online 2001 issue.

Fen and sedge meadow communities once ran continuously from the Mendota Bridge area to Savage and beyond, says Cleveland.

Fen threats

Altogether Minnesota has over 115 calcareous fens, comprising some 1800 acres. Savage Fen, at 64 acres, is the state's largest. Like Nicols, many of the fens are threatened by 

  • Non-native and invasive plant species

  • Development pressures and, especially,

  • Loss of ground water sources, on which the fen communities are dependent

In the case of Nicols Fen, “dewatering,” or drying out, occurred in part because farmers once installed drain tiles. The DNR is looking for such drain tiles now, says Cleveland , and will remove them. “Sure, the farmers at the time had no way of knowing. They simply wanted to drain the area and make it viable for planting.”  

So, where are we now? The city of Eagan will be regrading the scour hole. The state, one day soon, may be regarding how to remediate the fen and at what cost. And we, for our part, as saunterers and stewards of the land, are looking eagerly for how to keep the wild in our midst.