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7 Questions to Ask Before Drilling an Irrigation Well

December 7, 2013
By: Nate Birt, Top Producer Deputy Managing Editor google + 
 
 

Plan well-drilling activities ahead of time to get irrigation water aboveground

Much like the engine that powers your tractor, farmland drives your operation forward by providing the fuel your crops need to survive.

Well Column

Before installing a well, hire a professional to drill a test hole to better understand local geology and availability of water.


That’s particularly true if you use underground water to irrigate your corn and soybeans. And like an engine in need of an oil change, farmland that can’t handle a well will give you warning signs.
The best solution is to evaluate available resources, work with experts who know geology and drilling, and keep good records. Wells are a significant financial investment, so a good plan will also help you spend your money wisely.

"It adds up pretty fast, and every situation’s a little different," says Robert Albrecht, owner of Albrecht Well Drilling in Ohio, Ill.

Here are seven questions to ask when deciding whether to drill a new irrigation well.

Will my water supply support a new well? First, do some research. "Study the area, other well logs and what’s known about the existing aquifer," Albrecht says.

Second, identify a professional well-driller who can help you gather additional information. It might be your pivot dealer or a contractor. Get recommendations and work with someone who knows local geology and has access to state records.

Third, have your well-drilling professional drill a test hole. This will provide clues as to the soil composition at various depths and the quality of the aquifer.

Otherwise, "they can end up with what we call a sand pumper," says Aaron Schrader, owner of Schrader Well Drilling in Carbon, Ind. "It’s where a test well wasn’t put in to find out what the size of the gravel formation is."

In Nebraska, which has nearly 95,000 active irrigation wells, drillers are looking for several factors, says Bill Kranz, associate professor of biological systems engineering at the University of Nebraska. Among them are a sizeable layer of sand, gravel or other water-bearing formation.
Based on what the driller finds, it would be prudent to take the results to a geologist to determine whether the rock formation will sustain a well.

Water volume is also important to know. In Nebraska, wells generally need to sustain a pumping rate of at least 6 gal. per minute per acre for a full quarter-section center pivot. Get as good an estimate as possible of the rate that will be achieved once a pump is installed, Kranz notes.

"Since they’re now $85 to $95 a foot to put an irrigation well in, you don’t want to put one in and not be able to pump water out of it," he says.

Am I legally entitled to drill a well? Most states require a permit to drill a well. Your contractor can help you complete the necessary paperwork with your state’s department of natural resources, Kranz says.

The form details the diameter of the well bore, geological formations encoun­tered, well column size and material, location of the well screen in the well bore, GPS coordinates and the site’s legal description.

Some states place limits called allocations on the volume of water that can be pumped from a well over time.

States often stipulate how well-drilling is done, as well. "They drill a hole that’s much larger in diameter than what the well’s column is," Kranz explains. "Then they backfill with gravel in the annular spaces between the well and the outside of the well bore. The well-driller will size the sand and gravel according to the formation that the screen is in. Other rules can come into play once you get closer to the soil surface in terms of sealing off the top to keep surface water from going into that sand and gravel."

How much time do I need to get a well installed? Farmers generally begin making calls about new wells after harvest, Albrecht says. Anticipate two months from the time you begin planning your well until the time it is drilled and ready to provide irrigation. Plan to have your well ready to go by May 1 so it can irrigate newly planted crops.

Will my well interfere with other property owners? Think about the land surrounding the well that you are planning, Schrader says. Because significant drawdown of water will occur over the years, it’s a good idea to stay away from neighboring homes or other residential areas to avoid interfering with their water supply.

How much will it cost? Cost depends on a variety of factors, including the depth of the well. In northwestern Illinois, Albrecht says sand-and-gravel wells generally run 100' to 300' deep, though some deep bedrock wells can run from 500' to 1,500' belowground. In Nebraska, the average pumping level ranges from 125' to 150' below the surface, Kranz adds.

Many wells fall in the $50,000 to $75,000 range, which normally includes the pump, Albrecht says. Deeper wells might cost in excess of $100,000. Power supply such as diesel engines or electric motors add to the overall cost.

To avoid surprises, factor the cost of a well into your overall irrigation budget, Schrader adds. Stainless steel screens are a good idea for filtering debris but might be more expensive than other materials.

When does it needs maintenance? That initial depth is known as static water level, and it acts as a baseline for determining how quickly an underground water source is being depleted. Know your depletion rate to help determine whether your well needs maintenance because of encrustation or because water is being used faster than the well can recharge. 

"Year to year, that drawdown level will decrease as the screen starts to plug up," Schrader says. "As it goes down significantly, that’s when they need to get somebody to clean the well."

A water-sample analysis conducted before well-drilling can be another valuable piece of the puzzle.
Some formations high in calcium and magnesium will have mineral buildup on the well screen. "Eventually, the slots the water comes in get blocked off, and it can affect the sand and gravel on the outside, too. Screen selection would be important if you’ve got that scenario," Kranz says.
Well screens can often be cleaned with an acid treatment to dissolve the calcium, magnesium and other minerals that plug them.

How long will my well last? Wells can last decades if properly maintained, Albrecht says. Many wells drilled 30 to  40 years ago still work great.

Farmers often ask if they are pumping sustainably, but it depends on the location of the pump, Albrecht says. Wells not under allocations are fed by off-season rains. "You pump hard for three months, but there are nine months to recharge," he says. 

You can e-mail Nate Birt at nbirt@farmjournal.com.

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FEATURED IN: Farm Journal - December 2013
RELATED TOPICS: Corn, Soybeans, Crops, Irrigation, Production

 
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