Farm Progress

Think Different Open tile intakes in Midwest farm fields, “is a practice that should be ended,” says Gary Feyereisen, a USDA drainage expert in Minnesota.He notes that open tile intakes allow debris, sediment and pollutants, such as nitrogen and phosphorus, to enter surface waterways and block underground pipes.Most farmers would love to get rid of open surface tile intakes, adds Gary Sands, University of Minnesota Extension ag engineer, “provided they can maintain adequate drainage flow. Alternatives to open inlets, such as inlet risers, rock inlets, or intensive tiling, are “a win-win” for both farmers and the environment.”

Liz Morrison 1

December 19, 2012

7 Min Read
<p> The Quick Drain from Ag Solutions has slots on the undersides of a stepped funnel or a riser pipe to reduce plugging. Cost ranges from about $27 to $40, depending on size and model.</p>

Gary and Steve Glazik were sick of slogging through standing water in their farm fields to unclog surface tile inlets. Their Paxton, Ill., fields are pocked with low spots where water ponds, and their perforated risers were forever plugging up with residue. “We’d have to go out in hip boots and clean them out,” Gary says.

The Glazik brothers, who grow 6,000 acres of corn and soybeans, also own a plastics injection molding company, so they developed a low-rise, funnel-shaped inlet that’s designed to avoid plugging. The Quick Drain from Ag Solutions has intake slots on the undersides of a 17-in.-high stepped cone. The company also makes a riser-style inlet with underside slots. Water enters the Quick Drain from below, shedding trash as it moves over a lip, “so we don’t get debris stuck in the holes,” Gary says.

There’s more area for water to enter the intake, too, which reduces the sucking force that pulls in debris and sediment, he explains, and underside slots keep spray drift out of the drainage system. “We put them out in all our fields and they worked great. We don’t have the clogging problem anymore.”


More inlet versions

Ag Solutions’ Quick Drain is one of several new tile inlet alternatives to open surface intakes. These innovations are designed to be convenient for farmers and safer for the environment, while still maintaining drainage capacity.

Standard perforated risers, such as the familiar orange Hickenbottom, slow water discharge, allowing some soil particles and pollutants to settle out, says Richard Cooke, a drainage engineer at the University of Illinois, who is testing the performance of several new tile intake designs.

Like any inlet, they can become blocked with debris, and farmers dislike working around them, says Phil Algreen, technical support manager for AgriDrain, a drainage equipment company in Adair, Iowa. “With today’s big implements, it can be difficult for farmers to maneuver equipment around the inlets.”

AgriDrain recently introduced an inlet that farmers don’t have to plant around. The Water Quality Inlet consists of bundles of 5/8-in. slotted polyethylene tubes, or wicks, that snap into single-wall, corrugated plastic pipe, Hickenbottom or Precision underground sections. Drainage velocity is slower than with standard perforated risers, says Algreen, which “gives sediment more time to settle out.” The inlets can also be deployed underground.

Drainage contractor Charles Adams, A.J. Adams and Sons, Kansas, Ill., has installed AgriDrain’s Water Quality Inlets both above and below ground. Placed above ground, the flexible inlets take less maintenance than coated-steel “bird cage” inlets, he says, and they don’t snag field equipment.

For rock or blind inlets, Adams inserts a 36-in.-tall bundle of wicks vertically into the tile line T, then covers the inlet with about 3 ft. of 1-in. gravel. “No-tillers love them,” he says. “They don’t have to farm around the drain and it absorbs water faster than a regular field drain because the intake is closer to the surface and there’s a larger area for water to enter.”

In tilled fields, drainage contractor Doug Wulf, Wulf Tiling, Morris, Minn., suggests replacing open tile intakes with bird-seed sand French drains, another variation of a rock inlet. The T is laid horizontally in a 30-ft. trench, which is filled with about 18 yards of washed, 1/8-1/4-in. aggregate. The trench is mounded so soil doesn’t fan over the drain when the planter or disk ripper goes through.

Surface water flows easily through the birdseed sand, and the smaller aggregate is less likely to get plugged with soil particles than larger gravel or rocks, which extends the life of the drain, notes Wulf. “It works best with pattern tiling, providing the same drainage capacity as a 6-in. open drain, with fewer environmental hazards. We’re really excited about these drains.”


Alternatives to inlets

Gary Feyereisen, an agricultural engineer with the USDA-ARS, St. Paul, Minn., is evaluating the water quality effects of French drains in two quarter-section tiled fields in west-central Minnesota. The corn silage fields, which receive annual manure applications, had 48 open surface-tile inlets. All but two were replaced with birdseed sand French drains. “In the three years with the new intakes, average concentrations of sediment in the drainage water have gone down,” Freyereisen reports.

Another inlet alternative is intensive tiling of field potholes, says Gary Sands, University of Minnesota Extension agricultural engineer. Narrowly spaced tile pipes are installed in a shallow grid or coil in the middle of a wet spot. “In new tile systems, contractors have been putting a lot of these in.”

Sands says all these alternative inlets protect water quality better than open inlets, while still providing adequate drainage.

At the University of Illinois, graduate student Stephanie Herbstritt designs and tests filters that can be retrofitted to existing tile inlets or outlets. The goal is to keep out pollutants such as spilled anhydrous ammonia or phosphorus, without lowering drainage capacity.

“There is a need for these innovations,” she says. If regulations on drainage water quality tighten, as they are expected to do, “farmers will need economical solutions.”




Field tests compare tile inlet designs

University of Illinois Agricultural Engineer Richard Cooke and graduate student Tim Rendall compared the performance of four surface tile inlet designs at the University’s indoor drainage testing facility in Urbana. The following inlets were evaluated for sediment transport and drainage water flow with and without crop debris in the water:

     •6-in. Hickenbottom riser

     •6-in. funnel-style Quick Drain from Ag Solutions

     •6-in. riser-style Quick Drain from Ag Solutions

     •6-in. Water Quality Inlet from AgriDrain

Below are some preliminary findings.

The funnel-style Quick Drain from Ag Solutions had the greatest capacity to drain water when there was no crop residue or debris in the drainage water, and when there was heavy debris (wheat trash) in the drainage water.

The Water Quality Inlet from AgriDrain had the lowest drainage capacity, but preliminary results show that the AgriDrain inlet transports much less sediment, says Cooke.

With heavy debris, the drainage capacity of the riser-style Quick Drain from Ag Solutions was about the same as the Hickenbottom riser.

The drainage capacity of the Hickenbottom riser was not significantly affected by the presence of debris.



Inspect drainage systems yearly

Early spring is a good time to make an annual inspection of your drainage system and ensure it’s working properly, says drainage contractor Charles Adams, A.J. Adams and Sons, Kansas, Ill. Pay special attention to outlets, which are the most neglected part of farm drainage systems, Adams says. “The ditch or creek will grow up in trees and the roots will get into the tile pipes, or beavers will chew on the outlet, or the pipe will break or be crushed by ice. There are a lot of things that can happen to outlets, and without an outlet, the system doesn’t have a chance of working.”

Here are some spring inspection tips from Midwest drainage experts:


  • Clear trash around outlets and remove other debris or tree roots.

  • Check that rodent guards are in place.

  • Look for erosion, gullies or silting at the outlet pipe and receiving ditch. Also check for water draining from underneath the outlet pipe.

  • Make sure subsurface drain outlets are stable and properly protected with vegetation and riprap.

  • Repair any eroded side inlets or gullies where surface water enters a ditch.

  • Remove water-loving trees growing within 100 ft. of the drain.

  • Monitor outlet ditches and remove sediment, trees, brush, or debris that could slow water flow and submerge tile outlets.


  • Remove residue and debris from around inlets in the spring and fall, and after heavy rainstorms. If soil has built up around the inlet riser, reshape the basin so water drains to the inlet.

  • Clean catch basin sumps.

In fields

  • Fix blowout holes and sink holes over subsurface drains. They indicate broken or severed tile, or drains under pressure.

  • Identify wet spots in the field that used to drain well. These indicate broken or crushed tile.


For more information see the University of Wisconsin’s “Maintaining Tile Drainage Systems” (


Sources: Gary Brenneman, Iowa State University; Gary Sands, University of Minnesota; Richard Cooke, University of Illinois; John Panuska, University of Wisconsin; Phil Algreen, AgriDrain; Charles Adams, A.J. Adams and Sons, Kansas, Ill.; Doug Wulf, Wulf Tiling, Morris, Minn.


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