Drainage Management Systems
Conservation drainage helps farmers increase yield, conserve water and reduce nutrient loss.
Most cost effective, most efficient, most economical – this is the end game for management consultants in their efforts to improve processes and save money in any business.
While drainage technology has been improving the productivity of farmland clear across the continent, the Cisne soils of south-central Illinois have stubbornly resisted progress. But the Wendte family has proven more persistent than even the land itself.Leon Wendte was armed with a degree in agricultural engineering and 33 years of experience when he retired from his position as New Hampshire’s state engineer for the Natural Resources Conservation Service and came home to the family farm. His brother, Roy, was growing more than 5,000 acres of corn and soybeans near Altamont, Ill., and surface draining the farm exactly the same way farmers have for centuries in that part of the state.Tile drainage is impossible in this area, thanks to glaciation and natural geology, says Wendte. First, there’s an impermeable clay pan layer about 18 inches below the soil surface and second, he says, there’s no more than one to three inches of slope for every 100 feet of land, which really offers water no place to go. “Where most farmers put in tile to lower the water table, we have to rely on evapotranspiration,” Leon explains. Their only other alternative is to grade surface ditches at the same slope most contractors would install a tile drain or lateral. But even the most experienced struggled to maintain margins of error less than a tenth of a foot, grading surface ditches with whatever machine might be available. In years past, farmers have used spade and shovel, mold board plow, and tractor-mounted blades, box scrapers, or small rotary ditchers. On the Wendte family farm, this meant approximately 500 acres remained improperly drained. So Wendte looked to precision implements for improvement.Equipped with a Wolverine rotary ditcher and laser controlled hydraulics, Wendte has installed three- to six-inch deep, five-foot wide, flat-bottomed, surface ditches on over 300 acres in the last three years. He says he slopes the banks on a 10:1 ratio, “so that you can drive a sprayer across it at 12 to 15 miles per hour and not even feel it,” and focuses on the worst fields first. But Wendte also accredits his brother Keith with providing a critical piece of their precision surface drainage system: the topographic maps he uses for planning.“All our tractors have autosteer and on our farm we’ve found it cost effective to install our own base station, so we generate our own RTK correction factor accurate to one inch or less,” Wendte explains. Using Case IH AFS desktop software, their ‘As Planted’ records, and aerial photos, Keith saved the family hundreds of dollars in survey costs, and it only took him a few days to pull everything together.” So for all 100 fields that we have, I have topographic maps accurate down to a two or three inch contour line just waiting to be used,” Wendte says.A lot of time goes into planning his drainage systems long before any earth is ever moved. Wendte follows natural drainage paths on the maps Keith made, taking into consideration wet areas identified during scouting, in field histories, on aerial photos and indicated on yield maps. He plans laterals from wet areas to the main ditches to carry water off the field. An AB guidance line is created on the maps for each surface ditch so that when installation begins the exact location and alignment of the channel is transferred from the maps to the field. All of which, he believes, a drainage contractor would find pretty instinctive.“Any tiling contractor can use the laser equipment and smarts that they already have to install a drain over the surface of the land, in addition to the tile that they install below the soil surface,” he says. He thinks that if more contractors combined surface drainage with subsurface work, everyone would save more money on their field drainage. “When you have a wet field, it is far more economical to drain whatever water you can off the surface with a surface drain than it is trying to install tile and let the water that’s ponded on the surface infiltrate through the soil and then out through the tile.”He knows some contractors realize this, but not all. In defense of those who never give much thought to surface drainage, Wendte admits that some fields will not lend themselves to be surface drained. Surface drainage wouldn’t work on prairie pothole soils, for example, where depressions can fill up to two feet deep. But he insists that his family is getting the same benefit from their surface drainage system that they would with systematic tiling at a fraction of the cost, and contractors who can learn to use precision techniques on the surface will, in his opinion, offer customers more bang for their buck.“The combination of surface drainage and subsurface drainage is by far the most cost-effective and best working system you can have on a wet field,” Wendte says. “Just let your tile work that much more effectively, remove more gallons of water off your field in a shorter period of time, and take the pressure off your tile.”
April 7, 2014, Longmont, CO – Officials are planning a controlled burn of a drainage system that runs through a golf course to clear dead and downed vegetation in the system, according to the Times-Call. | READ MORE
April 7, 2014, Ohio – State conservation engineers in Ohio are seeing the benefits of Drainage Water Management, an option from the USDA's Natural Resource Conservation Services, writes FarmersAdvance.com. | READ MORE 
Dec. 11, 2013, Algoma, ON – The Agricultural Tile Drainage and Storage Study for Algoma District has identified investment needs of approximately $6.5 million for agricultural infrastructure improvements, including land drainage, according to Wawa-news.com. | READ MORE
Nov. 21, 2013, Illinois – A farmer in Illinois turned to different strategies when traditional tile drainage methods didn't work for his soil, writes AgWeb.com. | READ MORE
Nov. 21, 2013, England – Clitheroe Golf Club in northern England has completed the drainage element of a substantial redevelopment program, which was delayed by bad weather last winter, according to GolfCourseArchitecture.com. | READ MORE
Sept. 13, 2013, United Kingdom – The North Wales Golf Club received an updated drainage system after last year's wet summer brought drainage problems to a head, writes PitchCare.com. | READ MORE
Sept. 9, 2013 – As Denis Rogerson, a drainage commissioner in Norfolk County, Ont., noted in the 1975 issue of Drainage Contractor, preventative maintenance is an important part of open-ditch drainage. Read more in this week's Forty-year flashback article.
May 16, 2013, Ireland – A farmer in Ireland has already seen the benefits of updating an outdated drainage system, writes the Irish Independent. | READ MORE
May 6, 2013, Ohio – An Ohio State University scientist has created a two-stage ditch design, earning him the Ohio Agricultural Research and Development Center's 2013 Innovator of the Year Award, according to Ag Answers. | READ MORE
The agricultural drainage lines that drain water away from individual farmland tile systems are being replaced in a carefully orchestrated program that is expected to take 10 to 15 years.  According to Tom Cummins, Montgomery County surveyor, “In a county like this, drainage is paramount because of the loamy and water-bearing soil. We have more than 200 regulated drains and somewhere between 360 to 400 miles of tile, and during the past five years this drainage infrastructure has just been falling apart.” Montgomery County, whose county seat, Crawfordsville, is 50 miles northeast of Indianapolis, has 505 square miles that is mostly farmland, mainly corn and soybeans.In Indiana and the Midwest, recognizing the need to drain the large numbers of watersheds dates to the late 1800s and early 1900s. Montgomery County landowners realized that it would be mutually beneficial to pool their money and construct common pipelines that would carry water away from their land. Now there are a combination of open ditches and subsurface drains that landowners pay taxes to maintain. It is not uncommon to have a large-diameter 18-, 24- or 30-inch clay or concrete tile or an open ditch that would be as long as three or four miles. Cummins has found that those clay and concrete tiles have outlived their useful life, have started to break down and collapse and today are being replaced with pipe made from high-density polyethylene (HDPE). “We started recognizing the problems that needed to be addressed,” he continued. “I spoke with all the contractors who are on my list for doing the repair work and got their feel for what was the best product out there. I had three or four who were actual tile installers, and got a lot of good information from them, what seems to be doing the best job and that led me to the HDPE pipe.”Mostly used in this county project is perforated, corrugated, smooth inner wall HDPE pipe made with virgin resin supplied by local manufacturer Fratco, Inc. (Francesville, Indiana). Pipe diameters range from 10 to 30 inches. The bidding contractor who was awarded the project selects the brand of pipe as long as it conforms to the specifications and any additional criteria set out by the surveyor’s office. “We have never had a problem with the Fratco HDPE pipe,” stated Cummins. “It meets AASHTO and ASTM specifications.”“Corrugated HDPE pipe is rugged because the material itself is rugged,” stated Tony Radoszewski, executive director of the Plastics Pipe Institute, Inc. (PPI), (Irving, Texas). “HDPE is abrasion resistant and will not corrode. Used since the mid-1960s for agricultural applications, the pipe is a flexible conduit for water that has continued to evolve to provide for the demands of an efficient farming operation and the environment of soil and water conditions.  Today we have pipe that is delivered to the field on mega-size coils of thousands of feet, and on some reels there’s nearly a mile of three-inch-diameter pipe. This enables a contractor to tile acres of land rapidly. The very design of the HDPE pipe that permits perforations, which allow water to enter the system and be drained away, is the key.” PPI is the major trade association representing all segments of the plastic pipe industry.Today, installing a system is vastly easier due to advances in machinery and the pipe. “I’m a fourth-generation drainage contractor,” said Bart Maxwell, Maxwell Farm Drainage (Crawfordsville, Indiana). “We started in 1910, and we’ve seen a lot of things happen over the years. We started with clay tiles and cement, and some of the first plastic tile was put in by my dad, Bart Maxwell, Sr.”According to PPI’s Radoszewski, “The concrete folks like to say that their 100-year product life cycle is proven, because some of it has been in the ground for 100 years. But now it’s not automatic to replace it with reinforced concrete pipe (RCP), which is heavy, difficult to work with, and some contractors report there could be as much as a 30 percent cost advantage of HDPE pipe in labor and materials verses RCP. Installation of HDPE pipe can be done with an excavator, chain digging machines or a trencher.”“We experience so many different soil types and conditions,” Maxwell commented. “We usually try to look at it from the standpoint of ‘if there wasn’t any tile, how would we tile this field?’ You can’t of course do it without factoring in the course of the old concrete or clay tile.“One factor is the grade we use installing the pipe . . . . It could be a tenth of a foot per 100 feet of fall, or five-tenths of a foot per 100 feet. The grade is based on each job,” Maxwell said. “We are very cognizant of the need to increase the size of the pipe based on the lack of grade. Using GPS, we survey the field and plot the topography, lay the main in the lowest parts of the field and keep at least two feet of cover over the pipe just because of the depth of some of the farming tools. Three feet would be great on a 24-inch tile. Sometimes we’re 12 feet deep to catch really low areas such as at the end of the tile run. When you’re doing gravity drainage, and you’re not able to pump, you have to have constant flow through that pipe.”Maxwell generally uses a trencher machine wherever possible instead of an excavator.  “A key factor is that we can cut the trench with a contoured bottom so the soil is not disturbed on the sides and putting some gravel backfill is the extra insurance and then the native soil.  There are some places you can’t use the trenching machine and have to use a bucket excavator and this means more stone has to be used.  Our trencher also grinds the soil finer than just excavating out.  So when you push it back in you don’t have large chunks.  We backfill with number 8 gravel or stone to bed the pipe.”  To allow the trencher to more easily follow the natural contour of the land, Maxwell fitted it with a shorter boot. To facilitate a safe installation with this shorter boot behind the trenching machine, he used shorter lengths of pipe – 13 or 14 feet, and as short as 8-1/2 feet.  Maxwell uses a 1971 Buckeye Super 7 Trencher. “Buckeye is building me a new one that will be delivered in October that will lay up to 36-inch-diameter pipe. The one we have now is slow by trenching standards, but as far as someone digging with an excavator or a backhoe goes, it’s very fast . . . about six feet a minute, that’s 36 inches wide, six to seven feet deep. In a day’s time, it’s no problem to do 2000 to 2500 feet, a half-mile of 24-inch or 30-inch-diameter drainage tile. We run Fratco XD Class II perforated pipe. On the farm field, we want perforated all the way around, which really drains the field.”“Once we install the new HDPE pipe,” continued Maxwell, “we go back and destroy the old tile, cut another trench on the opposite side of it to find any laterals coming in, so we can hook those in to the new system. It’s typical to lay about three trenches total to accomplish the job and we usually have a crew of seven to operate the trencher, feed the pipe and backfill.”Developing the planCummins and the five-member Montgomery County Drainage Board mapped out a program that included pinpointing the drains to be rehabilitated and a fair tax assessment plan. “It was a matter of going over what drains were taken care of during the past 20 years and seeing how much money came out of the assessments for these new ones,” he said.  “We don’t assess people so that as soon as the money comes in we can spend it and then be broke until the following year when the assessments come in again. In the process of examining the books, it became evident that we were spending money as fast as it was coming in. The county collected taxes over the years and at this point in time they figured out that we spent more in repairs and maintenance on fixing broken clay or concrete tile, than it was really worth. We changed the method. Now we identify the drains that are needing constant maintenance and are getting to the point of doing a reconstruction, and fixing it from top to bottom. With a new drain we can keep the landowner’s assessment at a lower rate because it will be decades before any maintenance is needed on that drain. The determining factor is the number of acres in the watershed. Let’s say we have a 200-acre watershed; one farmer might own 20 acres, another 150, and so they figure the percentage of the watershed that they own and that’s the percentage that they will pay on that project.“It’s been during the past four to five years that we have started going gung-ho on the drain reconstructions,” Cummins explained. “We’ve put in close to 50,000 feet. That’s anywhere from 10- to 12-inch all the way up to 30-inch diameter-pipe. We have averaged four to five reconstructions a year with the smallest, generally, about 2000 feet. The longest one we’ve done to date was 6000 feet, completed during the summer of 2012 up in Crawfordsville, which is the main city in Montgomery County.”  According to contractor Bart Maxwell, “A lot of people didn’t think anyone would spend money on these projects, they just wanted to patch up the bad areas. And then all of a sudden when progress was being made, people began showing up at the Drainage Board meetings, and were willing to spend the money to get new mains so they could expand their farm drainage system, and that turned this county around. Before, some people wouldn’t do a drainage system because they didn’t have a good outlet and they were never going to spend money on this tile even though it would help them grow more crops. Now at every meeting there are several landowners saying they have a problem and want the county to fix it because they see the success of the program and the way the tax assessment is handled.” For Maxwell, the past is truly prologue. “A customer of mine bought a farm the other day and he got a packet with information about the farm from the early 1800s,” he said. “There was also the original tile paperwork that showed it was my great-grandfather and his brother who had laid 18-inch tile across this farm. Tom Cummins plans showed that the tile is now coming up for reconstruction. It was installed in 1918 and now four generations later, I may very well be the guy who gets to redo my great-grandfather’s work.” 
Although drainage is usually meant to draw water away, Canadian researchers are successfully irrigating through tile drainage and are improving crop yields not only through increased water uptake but also by reclaiming lost fertilizer nutrients.At the Greenhouse and Processing Crops Research Centre in Woodslee, Ontario. Agriculture and Agri-Food Canada scientists have developed water management technology that combines tile drainage, reservoir and controlled drainage with sub-irrigation systems. Designed by Dr. Chin Tan, research scientist and water management specialist, the two facilities are fully automated, remotely monitored, and equipped with the most extensive and sophisticated water sampling capabilities.The first of the two systems, the Long-term Crop Rotation Water Quality site, was established in 1959 to demonstrate the benefits of crop rotations, whereas the Great Lakes Water Quality site was constructed in 1991 specifically to study controlled drainage and sub-irrigation, and water recycling. On the Great Lakes site, riser pipes that were installed on existing tile drainage systems control drainage. Both sites were upgraded in 2008, with the addition of four storage reservoirs to capture and recycle surface runoff and tile drainage water at the Great Lakes site. Additional “real-time” measuring equipment was issued to the long-term site. Using these instruments, Tan and his team can now measure surface runoff and sub-surface tile flow year round. “Water has to balance and if you do not measure, you do not know,” says Tan. “If you look at the entire water balance, then you know where you want to control and where you want to reduce nutrient loss.”Tan says that with his background in hydrology, it didn’t take long to establish that the prime conditions for nutrient runoff are when there’s residual nutrient left in the soil leading into the winter. With 70 percent of rainfall occurring outside of the cropping season in southern Ontario, it was easy to conclude that capturing and storing surface and tile drainage water during the non-cropping season would be the only means of intercepting sediments and nutrients. By pumping the same water back out of the reservoir during the next cropping season, all these nutrients, particularly phosphorus and nitrates, can be reused.  “In the summertime, you don’t have that much runoff so you want to encourage the crop to use water,” says Tan. “If the crop is using more water, it’s going to produce higher yields.”In tests conducted from 2000-2005 on a Conservation Authority demonstration farm, Tan and his team demonstrated yield increases of 50 percent in soybeans and nearly 90 percent in corn with the controlled drainage and sub-irrigation combination. In a commercial growers’ field, processing tomato yield also increased 40 percent. The increase in production and cost savings makes up for the cost of taking land out of production for water storage. “There’s no question about it from my point of view,” says Tan. “This is not only good for crops, it is good for the environment.” Water quality and environmental impactsSubsurface tile drains are installed to remove excess soil water from agricultural fields so that crop productivity isn’t compromised by wet soils during spring planting. In Ontario, tile drained farms account for 70 per- cent of land in agricultural production. But from an environmental perspective, tile drains also remove excess nitrate during the non-cropping season and this can impair water quality. Tan says phosphorus loss in tile drainage water, especially in the poorly structured clay soils he often works with, has increasingly become a concern. Protecting water quality becomes even more important to the team as more farmers adopt conservation tillage practices, says Tan. “There’s no question about it, conservation tillage has a lot of advantages besides reducing soil erosion; you improve soil structure and use less energy,” says Tan. “But the disadvantages include nutrients coming out, in particular if you have tile.”The improved storage of no-till soils promotes higher water in the upper levels of the soil profile, says Tan, which is a good thing during the cropping season but not during the non-cropping season. Dr. Dan Reynolds is one of the members of the research team who has been heavily involved in studying the relationship between tile drainage and nutrient loss. After conducting an experiment that followed N fertilizer and a chloride tracer in the fall and winter through five agricultural soils, Reynolds was surprised by how fast and deep these nutrients moved down the profiles. “We found, for all five soils, between 60-96 percent of the chloride tracer leached below the 60-centimetre depth over the fall, winter and spring,” says Reynolds. “So based on that, we’d have to say that the N leaching risk was high for all five soils, even though some of the soils had hydrologic soil group designations which suggested low leaching risk.”In Ontario soils are classified by the Nitrogen (N) Index, which rates the risk for contamination of surface and ground waters by nitrate leached out of the crop rooting zone. Reynolds says that in the States they’ve been using N indexing for 20 to 30 years in various forms and Ontario’s version is a hybrid of the two main tiers. But it’s still based on hydrologic soil group and his research is making him think the soil survey information these designations are based on might be lacking.“Water and nutrient movement are strongly affected by the cracks and worm holes making up the soil’s structure, not just the proportions of sand, silt and clay making up the soil’s texture,’’ says Reynolds. ‘‘But soil surveys tend to focus on texture as opposed to structure, because structure is hard to quantify numerically, while texture is relatively easy to quantify.”Reynolds says farmers and drainage contractors need to have a better feeling for just how permeable the soil is and suggests collecting more of the fundamental data, such as saturated soil hydraulic conductivity, and designing your drainage systems partially on that, as opposed to solely soil texture, topography or tradition. To address nutrient leaching, he thinks controlled drainage is worth considering in fairly flat areas and where precipitation can be erratic. “Controlled drainage will definitely decrease nutrient leaching losses, partially because it changes the hydrology of the field by slowing down the rate in which the water moves,” says Reynolds. So far, Tan says, the system they have designed can reduce total nitrate and phosphorus losses by up to 40 per cent. But he warns that controlled drainage with sub-irrigation still requires care in order to avoid making higher surface run-off problems worse.“Once you do sub-irrigation, the soil becomes moist and, with a heavy rainfall, you create more surface runoff,” says Tan. “But when you think about it, you really have a win-win situation in terms of improved nutrient management and increased crop productivity.”Expanding sub-irrigating technology beyond bordersTan says there is renewed interest in drainage management outside of Ontario and even Canada. He says that in much of the Lake Erie basin, the majority of corn production areas have tile drainage and that his research is earning him some new attention, particularly in dry years.“Our climate is changing to be drier but even if you only get 600-700 millimetres a year of rainfall, about 40 percent goes into the tile and surface runoff during the off season,” says Dr. Tan. “With that amount of water we collected in the storage reservoir, you can irrigate for two months, every day, without drying out.”  One of Tan’s colleagues in neighbouring Manitoba recently came to see the Ontario facility in operation. Bruce Shewfelt, a senior water and biosystems engineer, is developing parallel research and development activities on controlled drainage and sub-irrigation. He says addressing drainage management is becoming a hotter topic west of Ontario and to the south of him in the Dakota states.“There’s been a lot of interest and uptake in tile drainage in the last three to four years and the industry is growing very rapidly here,” says Shewfelt. “Dr. Tan’s experimental setup is second to none and provides a great deal of information in a very controlled environment.”Shewfelt says that in their own trials, they address the technical differences between the clayey soils Tan has worked with in Ontario and the fine sands of Manitoba’s special crops areas. Seasonal rainfall variations make drainage in the spring extremely important but in those same locations there is often a need for water by July and August. Manitoba growers of high-value crops could be particularly interested in sub-irrigation and controlled drainage says Shewfelt, if the large-scale studies he is conducting continue to support and build on Tan’s findings.“In a year like this year when we didn’t really get much for spring moisture, if you’re considering means of adding water to the soil and you don’t have overhead irrigation, sub-irrigation might be a method to supplement water available to the crop,” says Shewfelt. “Our contractors and producers are certainly watching what we’re doing and waiting to see what the advantages or disadvantages might be.”
On Jan. 19 a large and interested group heard Larry Brown of Ohio State University discuss “Drainage Water Management for Water Quality and Crop Yield” at the Land Improvement Contractors of Ontario conference in London, Ont. Brown sought to stimulate some new thinking about drainage strategies by presenting photos and discussion of several farms he has toured as part of his work with academic groups from several colleges.Brown started by laying out the problem he and his fellow academicians are seeking to alleviate: worrying levels of nitrates and phosphates that are draining into major water systems from cropland and causing drops in water quality and deadly algae blooms. He noted that agriculture was a major source of nitrates, but not the only source, and that the problem stems mainly from the Midwestern U.S. farm belt and subsurface drainage. Runoff from agricultural lands is causing problems in the Gulf of Mexico and the Great Lakes.In a nutshell, Brown described the solution as better management of drainage, shallower drains, bioreactors, and more use of wetlands as filters for nitrates. He pointed to the NRCS standards 554 and 587 for controlling drainage from a field and noted that of the three kinds of drainage – conventional, controlled and subirrigation – he would primarily be discussing controlled. While controlled drainage has been around since the 1950s to control subsidence on organic soils, groups like Brown’s from across the Cornbelt have met resistance since they started promoting it as a general drainage tool in the 1990s. Contrary to the fears of many landowners, Brown says his studies have found that nitrate concentrations in soil do not fall measurably with controlled drainage whereas water outflows decrease dramatically. He admitted that we do not fully understand where the water and nitrates go. Scientists speculate that because controlled drainage leaves the water table higher, nitrogen may get reintroduced into the soil after the surface water is drained off. His group has measured up to a 50 percent reduction in nitrogen loads in corn and soybeans in controlled drainage operations with subsurface flow reduced by a similar amount. The group does not yet have enough research to say definitively if controlled drainage will increase crop yields. Brown said concerns about using controlled drainage in the winter are mostly due to misunderstandings about the technology. Blocking drains is not an aspect of a controlled drainage management system; instead, the group is adjusting the outlet “elevation” at which water can leave the field. Local practices would have to be adapted to regional climate variations, but he said that controlled drainage has been demonstrated to work as far north as Minnesota and as far south as North Carolina and Louisiana. The practice involves installing water table control structures at drainage outlets.Brown showed an example from a farm that had been converted from beef production to grains. The new drainage system used an existing wetland to take the overflow, and this excess water was used in a lower portion of the field that was under controlled drainage. He pointed out that controlled systems can be retrofitted onto existing drains. Brown said it was true that controlled drainage was not the perfect solution in all situations, but that systems should be designed for the particular cropping system and soils the farmer manages.Brown then moved on to offer some general guidelines for controlled drainage systems. He said the best results are achieved when the water table control structure is installed on solid ground without gravel. Contractors should use an anti-seep collar and hand backfill around the structure after retrofitting. He said it is important to use the manufacturer’s recommended fittings, pipe and watertight joints, and use non-perforated pipe on either side of the structure for a distance of about 20 feet, or half the drain spacing.For good system management, Brown recommends adjusting the outlet elevation in the fall and reducing the drainage outflow until early spring the next year. The outlet elevation should be adjusted again after planting, and unless there is rainfall, allow the crop to slowly lower the water table. The next step on appropriate crop fields is to couple controlled drainage with subirrigation systems, where remarkable increases in crop yield may be achieved, according to Brown’s studies. Forty- to 50-bushel increases in corn production were seen in some instances, with 10-bushel increases in bean production.  Brown faced a number of skeptical questions from the Canadian audience about how such a system would work in the harsh winters. He allowed that more demonstration in northern climates was probably needed.
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