WILLMAR -- Eternal vigilance is the price of liberty, and the same can be said when it comes to protecting water quality when roads are built.
To protect water quality, the Minnesota Department of Transportation invested between $4 million to $4.5 million on erosion-control measures during the construction of state Highway 23 from the Eagle Lake "Y" to the north edge of New London, according to Bruce Gilbertson, Spicer area fishery supervisor with the Minnesota Department of Natural Resources.
It took more than money to protect water quality along the 12.5-mile construction path, according to Gilbertson and Skip Wright, area hydrologist with the DNR. They told an audience Thursday at the third annual shallow lakes conference in Willmar on that it required full-time vigilance during the three-year project to protect against a myriad of issues that developed.
Project contractor Duininck Bros. of Prinsburg employed a full-time erosion-control supervisor during the project. The contractor built 40 or more storm-water ponds to protect water quality, according to Gilbertson.
Through it all, the $60 million road construction project saw only one major setback. A 3-inch rain on June 23, 2003, came at the height of roadwork in Spicer and flushed muddied water directly into Green Lake.
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In hindsight, Gilbertson said the roadwork in closest proximity to Green Lake should have been scheduled for later in the summer when the risk of heavy rain decreases.
"It very probably could have been avoided'' if the scheduling had been changed, he said.
Otherwise, both Gilbertson and Wright said that the project largely succeeded in its goal of causing no net increase in the amount of nutrients reaching local waters.
It essentially meant applying the same standards as would be used for protecting trout stream waters, Wright told the audience.
The project itself required moving more than 1 million cubic yards of material, along with replacing a bridge and constructing four lanes of highway in place of two.
The four-lane route makes its way through some of Kandiyohi County's most coveted waters. Green Lake was the focal point for protection efforts, and for obvious reasons, according to Wright. Its waters are exceptional for their quality: Phosphorus levels in the lake range from between 12 and 15 parts per billion to 18 parts per billion, or considerably below the concentration needed to support algae blooms.
Three other deep-water lakes -- Nest, Elkhorn and Eagle -- also needed to be protected. There were also three shallow lakes -- Rice Pond, Woodcock Lake and the Alvig Slough -- to protect, as well as smaller wetlands.
It was as important to protect the shallow lakes as the deep lakes, according to Wright. The shallow waters are very sensitive and, in most cases, are also connected to the larger water bodies. "They share a common fate.''
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Each of the shallow lakes presented its own challenges, said Wright. Rice Pond is a pristine water body, while Alvig Slough holds turbid and carp-filled waters.
Woodcock Lake was once the site for the Spicer wastewater treatment plant. Its waters are nutrient-rich with 1,500 parts per billion of phosphorus measured there. A retention pond capable of holding water from a 100-year rain event was constructed to prevent a sudden infusion of its nutrient-heavy waters into Green Lake.
Along with protecting the water bodies, Gilbertson noted that there were 3.5 miles of shoreline district to watch over. Standards of urban highway design were used for the Nest Lake bridge. Retaining walls were used to reduce the amount of fill that would have otherwise been poured into the lake. The bridge removal was undertaken in the winter months to minimize the impact.
The construction project was completed late last year, but the effort to monitor and protect water quality continues. Gilbertson reported that the experience showed that no matter the amount of planning or attention, there is always more to learn. Unexpected problems still being addressed include beavers that block the flow from one pond and carp that have infiltrated another. The carp keep the waters turbid.
