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A Minnesota Pollution Control Agency team conducting an assessment last summer on Hawk Creek reaches shore near a culvert. Due to extensive public and private drainage systems, water that would have evaporated, percolated into groundwater or stayed put in wetlands is now moved rapidly to waterways. (Tribune file photo)

In farm country, water quantity and quality inextricably linked

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From his home along Hawk Creek, Renville County environment and community development director Mark Erickson has watched its rushing waters swell to two separate crests in the last couple of weeks, bouncing back 32-inches overnight the second time.

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The second time, he also watched a four- to six-foot wide section of river bank collapse into the churning waters as well.

It's becoming an increasingly common occurrence on the waterway, and part of a bigger issue facing many of Minnesota's agricultural counties.

When it comes to water quality issues in Minnesota's agricultural counties, water quantity is as much the issue as are the non-point sources of pollution that vex so many.

Erickson was among county officials, landowners and staff with the Minnesota Department of Natural Resources and Renville County Soil and Water Conservation District who took on the issues Monday during a "Our Waters Our Choices'' program in Olivia.

"We're seeing more water getting discharged,'' said Todd Kolander with the DNR's ecological and water resources division.

In part, that's because we're seeing more precipitation. Weather records show an upward trend in annual precipitation.

But even accounting for the increasing precipitation, area waterways are transporting more water than would naturally have flowed in them, according to Kolander. Water that would otherwise have evaporated, percolated into aquifers, or stayed put in wetlands and lakes is now rushed to waterways through modern drainage systems.

The result is a "flashy'' hydrology that causes a host of problems.

The most obvious is what Erickson witnessed on Hawk Creek. Cory Netland, director of the Hawk Creek Watershed Project, said there are other areas along the creek where banks are sloughing and being lost. The channel is changing and widening in response to the increased flow and energy it represents.

Erosion from river banks is now responsible for 65 percent of the sediment carried by the Minnesota River to Lake Pepin today.

Due to the flashy hydrology, big rain events are also serving to undermine efforts to keep phosphorus and nitrogen from the river as well.

The rapid rise and fall of water levels takes a big toll on the habitat needed by fish and wildlife. Northern pike rely on flooded areas to spawn. When they are able to find areas to spawn, the young fish produced often become stranded. Due to a flashy hydrology, creeks that would have been used by the minnow-sized northern pike to reach rivers and lakes have gone down too fast, explained Rob Collett, DNR ecological services.

In Renville County, 98 percent of the wetlands have been drained away, and that includes many lakes that held water through the years, according to Tom Kalahar with the Renville County Soil and Water Conservation District. The city of Renville once sat aside a small lake where residents used to picnic and cool off on hot summer days, he noted.

Renville County has 851 miles of open drainage ditches, as compared to 711 miles of county roads or 957 miles of township roads, Kalahar pointed out. Most drainage ditches -- those in Renville County included -- were built for 1950's water loads.

They are increasingly becoming overloaded. Millions of feet of tile lines have been installed in farm fields to carry waters to those ditches, with one guiding principle. "We still manage water by putting in a bigger pipe,'' said Kalahar.

There are essentially no regulations overseeing how many feet of tile line are added in a watershed. No one really even keeps track of it, he said.

Of course, modern drainage is also what makes Renville County an "agricultural rock star,'' noted Kalahar.

He and other speakers said that the strategic restoration of key wetlands could go a long way toward improving water quantity and quality issues in the county without compromising farm productivity.

There are other steps that can be taken as well. The Hawk Creek Watershed Project has helped install bio-filters and alternative tile intakes. The bio-filters absorb nitrogen in tile systems. Rock-covered tile inlets allow sediment and nutrients a chance to settle before the water is carried away.

Netland said some areas of the country have also used managed drainage to control pollution and slow the waters.

Renville County is already leading the way in protecting its water by promoting conservation easements. It leads the state in the number of conservation easements enrolled by landowners, said Kalahar.

Some of the most beneficial easements are the conservation buffers placed alongside waterways. A 50-foot buffer will capture a majority of the nutrients and sediments washing from fields before they can reach the water, noted Collett.

He also urges many small steps -- such as allowing native vegetation to grow in place of manicured lawns on lakeshores -- as effective means to reduce the harm we can cause. "Little by little we nick away at this stuff, and little by little we can get it back,'' he said.

The Renville County SWCD is also hoping to lead the way in developing what are termed "productive conservation'' practices. Kalahar said the district is working to get state and federal support to make it possible to return erosion-prone crop lands to use as pasture land again. Promoting a grazing economy could expand opportunities for young people eager to enter agriculture, and benefit water quality at the same time, he said.

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Tom Cherveny
Tom Cherveny is a regional and outdoor reporter with the West Central Tribune in Willmar, MN.
(320) 214-4335
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