Mozingo Lake supplies water for the city of Maryville and rural Nodaway County. Elevated levels of nitrates and phosphorus, likely caused by runoff and erosion, have resulted in large blooms of blue-green algae. Water-treatment officials are working with area farmers to help curb the problem. They are also experimenting with floating, solar-powered, ultrasonic algae controllers, placed near the intake pipe. The ultrasonic sound keeps algae from moving upward and absorbing enough sunlight and nutrients. They sink to the bottom and decompose.
At the water treatment plant in Maryville, Mo., Jerry Riley, left, and George Hulet, center, of contract operations company PeopleService Inc., discuss the complex surface-water filtration process with Missouri Rural WaterAssociation’s Eric Fuchs. The facility has been battling algae in the water supply, which creates an unpleasant taste and odor and can become toxic if levels get too high.
Dennis Shoup, left, Clark County water treatment plant manager, and Dan Dover, center, district manager, explain the filtration process to Adam Jones, MFA natural resources conservation specialist. Pulled from underground aquifers, Clark County’s water supply has historically been so clean it only needs to be filtered for sediment and minerals and treated with chlorine. Increasing nitrate levels in one of the wells may complicate the process.
This jar contains a sample of the proprietary layers of materials used in the high-volume pressure filters, which operate like a swimming pool filter—just on a much larger scale. Each filter is rated at 300 gallons per minute.
The Maryville plant uses activated carbon and cartridges made up of these fibrous membranes as part of the water treatment process. After nine years of use, the old cartridges were replaced by new ones this past summer—a cost of $2 million. It takes more than 700 cartridges to equip the filtration modules that the water flows through.
Jeff Arnold raises continuous corn on irrigated ground near the Clark County well with nitrate contamination. To help mitigate the problem, Arnold is collaborating with the water district to raise cover crops behind his corn and manage nitrogen more precisely. Both practices have been shown to reduce nitrate leaching into ground water.
Dover, left, gives Arnold a bottle to collect a sample of irrigation water from the center pivot on this corn field where cover crops will be grown. The well in question is about three-fourths of a mile from here. At one point, tests showed nitrate levels of 14 parts per million from the well; 10 parts per million is the limit for drinking water.
Gary Brown, technician with PeopleService Inc., in Maryville, performs a series of tests on the treated water every few hours. He measures, analyzes and records such factors as turbidity (cloudiness of the water), pH, and levels of chlorine, fluoride, manganese, hardness and more.
FIRST IN THE STATE. It’s not a distinction that officials with the Clark County Water District in Kahoka, Mo., want to hold.
Two years ago, one of the three wells that provides water to the district’s service area in northeast Missouri began showing levels of nitrates above the allowable limit. Although a necessary nutrient for plants, high nitrate levels can be harmful to humans, especially infants.
The water in the Clark County district is sourced from the Des Moines River alluvial aquifer, pulled deep from the ground. The water is usually so clean that only minimal filtration and chlorine treatment is needed before it is pumped to homes and businesses.
“When our newest well was drilled in 2008, the nitrates were slightly higher than the other two, but they weren’t at levels that concerned us,” said Dan Dover, Clark County Water District manager. “For several years, they continued to steadily increase, but only about half a part per million every year. Then two years ago, they just skyrocketed.”
Until now, nitrates in ground water have never been a problem—in Clark County or anywhere else in Missouri, said Eric Fuchs, source water specialist for the Missouri Rural Water Association, a nonprofit organization that provides services, support and representation for the state’s water and wastewater utilities. In the Show-Me State, 33% of the population depends on ground water, while the remaining 67% gets its drinking water from surface water pumped out of lakes, rivers and streams.
“The Clark County situation is unique for us,” said Fuchs. “This is our first real case of nitrates in Missouri. In other states, like Kansas, Minnesota and Nebraska, nitrates are a huge problem. But here, our soil profile typically isn’t leachable enough to allow them to get all the way down into the ground water.”
The Clark County Water District serves about 10,000 people through nearly 2,000 miles of water line. Water from the three wells is currently blended to lower the nitrate levels under the threshold, a process that slows capacity. If nitrate numbers continue to climb, additional equipment and considerable extra expense will be needed to treat the water—costs that will have to be passed on to customers, Dover said.
“We were actually in the process of expanding our plant when the nitrate problem came up, and we had to put those plans on hold because we really don’t know what kind of treatment process we’re going to have to go with,” he said. “It all depends on whether we can get the nitrates under control. We’ve looked at some reverse-osmosis systems; they run about $2 million. We could possibly go with an ion-exchange system, which is like a giant water softener, but it’s still about $1 million. Either one will increase our end-user cost, which we’re trying to avoid.”
Beneath the surface
A few counties west, the city of Maryville is also having quality issues with its water source, Mozingo Lake, a 1,000-acre reservoir built in the mid- 1990s for both drinking water and recreational purposes. Nitrates and phosphorus are the issue here. These nutrients encourage algae blooms, which, in turn, create an unpleasant taste and odor in the water that is pumped from the lake to the Maryville Water Treatment facility and eventually into homes and businesses.
“Last winter, we had the highest algae counts we’ve ever had,” said George Hulet, region manager for PeopleService Inc., the contract company that operates the Maryville Water Treatment facility. “The problem was blue-green algae, which is the primary type we have in our lake. Tests showed numbers around 200,000 cells per milliliter, and the Department of Natural Resources starts getting concerned at 100,000.”
In January 2020, the elevated algae levels prompted a “Do Not Use” warning for recreational activities on the lake. The water remained free of toxins, so it was still considered safe to drink. However, the incident caused a flurry of negative media attention and complaints from residents about the water quality.
“I’ve been in this job for about six years, and I’ve never seen so much attention drawn to a place so quick,” Fuchs said. “The biggest reason is that Maryville’s water plant serves about 30,000 people—not just the city but also rural Nodaway County and the college [Northwest Missouri State University]—and there’s no backup supply. If they did get a toxic algae bloom, we’d have a huge problem.”
Unlike ground water, which typically maintains the same quality, surface water is at the mercy of Mother Nature and many other outside forces. That means the treatment process is significantly more complex than the simple filtration system of the Clark County facility.
“For us, quality is a moving target,” said Jerry Riley, lead operator at the Maryville water treatment plant. “It’s always changing. We’re continually monitoring and testing samples throughout the day and adjusting our processes and chemicals accordingly. We want to provide water that people enjoy drinking. We don’t want to send out water that tastes bad and smells bad.”
While Clark County’s ground water treatment facility and Maryville’s surface water system are vastly different, their quality problems appear to have a common denominator—excessive nutrient leaching and runoff.
In Kahoka, testing points to nitrogen-based fertilizers as the likely
culprit of the well’s contamination, rather than other potential nitrate sources such as sewage, animal waste or industrial drainage. In Maryville, the nitrates and phosphorus that feed the algae are coming from runoff and erosion. A majority of the acreage surrounding the lake is farmland.
However, rather than pointing fingers or assigning blame, officials with both districts are working closely with the agricultural community to help solve the current problems and ensure water quality in the future. Efforts include local outreach, producer meetings and government funding to identify and implement effective land-use strategies.
“I want people to realize there are water-quality issues out there,” Fuchs said. “They’re not getting better; in fact, they’re getting worse. If we can admit we have problems, then we can tackle them head on. Don’t worry about whose fault it is. Just fix them. A huge part of this process is education, and farmers have been willing to listen.”
Flow of ideas
After the nitrate issue was discovered in Clark County, the Consolidated Public Water Supply District board held several meetings with farmers and landowners in the area around the compromised well. Fuchs was also on hand to help explain the problem and talk about solutions. Putting some common conservation practices in place is the first step, he said.
“This is all low-hanging fruit,” Fuchs said. “No. 1: Manage your nitrogen. No. 2: Get some cover on those fields to scavenge the nitrogen left over from your cash crop. No. 3: Get on a good soil health program that includes no-till among other things.”
Although Dover said there was some tension at first, the message was ultimately well received. At the last producer meeting held in August, one of the farmers stood up and said, “I’ve got 40 acres we can work with. Why don’t we try some cover crops on that?”
That farmer was Jeff Arnold, who raises corn and soybeans with his brother, Lance, on fields adjacent to the Clark County well in question. The water district agreed to fund the cover crop inputs, and within a few days, the seed was flown into the field’s standing corn. Fuchs said the goal is to expand the practice to about 1,000 acres in the area.
“They’ve got a situation here with this well, and everyone in the neighborhood is going to have to do something to help,” Arnold said. “The cover crop thing has been the easiest, simplest thing to try. If we can get some data and some information on what this can do, then we can get other people involved.”
Dover explained that the soil profile is the biggest difference between the district’s three wells, even though they’re all less than a mile apart. Where the newest well was dug—and where Arnold farms—the soil is sandy and more susceptible to leaching than the denser clay soils in the location of the other two wells.
“Looking at the last 10 to 15 years of farming history in the area, a bunch of center pivots have gone in, which has allowed more corn-on-corn production,” Fuchs explained. “Irrigation is constantly pulling that water from different directions out of the ground, and a lot more nitrogen fertilizer is being applied.”
The cover crop Arnold planted is a five-way mix of barley, vetch, crimson clover, radishes and turnips. He, too, has installed several irrigation systems in recent years and plants continuous corn in the fields surrounding the Clark County Water District well.
“The field we’re dealing with is about three-quarters of a mile from the well, so we know the pivot is pulling from the same aquifer,” Arnold said. “We’re going to take this 40-acre field, grow the cover crops, cut back on our nitrogen use next year, and then do a comparison with a field across the road, with all things being equal, to see how it turns out.”
In Maryville, producer outreach has been more individualized. Just as public meetings were being planned last spring in the aftermath of the highly publicized algae bloom, COVID-19 concerns curtailed plans for in-person gatherings. Still, there’s been a positive, proactive response from farmers in the Mozingo Lake watershed, Fuchs said.
“We’re targeting somewhere in the neighborhood of 7,500 acres,” he said. “I imagine 50 producers would probably cover most of the land. We’ve had a lot of interest and haven’t even had an official farmer meeting yet. People are coming forward saying, ‘Hey, we want to help with the problem,’ and we’ve already got $400,000 on the ground for cover crops and other conservation practices.”
Those funds have come from NRCS, the Missouri Soil and Water Conservation Program and Department of Natural Resources’ Section 319 Nonpoint Source Program, which is part of the national Clean Water Act. Nonpoint source is defined as pollution that can’t be traced to a single source but is likely from multiple activities such as stormwater runoff, agricultural practices and land development.
“There’s a lot of room for improvement in the watershed,” Fuchs said. “We’re talking to farmers about managing nitrogen, phosphorus and sediments. I have no doubt there are solutions out there that are cost-effective and will actually help them be more profitable in the long run.”
Adam Jones, MFA natural resources conservation specialist, is working with Missouri Rural Water Association to help identify some of those solutions. MFA’s precision agriculture program offers many conservation practices needed to help improve water quality, such as nitrogen modeling and variable-rate fertilizer applications based on intensive soil sampling.
Simply put, Jones added, much progress can be made if farmers follow the 4Rs of Nutrient Stewardship—right source at the right rate, at the right time and in the right place.
“Managing your nutrient applications more precisely helps keep excess from being lost,” Jones said. “That’s the biggest thing. In a heavily tilled system without any cover, any residual nitrogen in your soil won’t be there for long. It’s going down into the ground or washing away with the next big rainfall. No-till and cover crops will help keep that nitrogen in the soil profile where it can be used the following year.”
Additionally, cover crops along with practices such as rotational grazing in pastures, grass waterways in crop fields and reduced tillage are all ways to help curb erosion, one of the main concerns around Mozingo Lake.
“Typically, phosphorus is tied to the soil particle, so it’s most likely entering the lake through sediment eroded away from the fields,” Jones explained. “If you stop erosion, you stop the phosphorus.”
When the government money dries up, Fuchs said he hopes the conservation practices it funded will become permanent. Water quality improvements are a long-term strategy with no quick fixes.
“Too many times, you see an all-hands-on-deck response to a problem, and everybody does good for a while, but then everything goes right back to how it was before,” he said. “We can’t afford to let that happen. We want to change the mindset, change the management styles and even change the legacy.”
The implications go far beyond any specific situation, Fuchs added. Government scrutiny of agriculture and water quality is becoming more and more stringent, threatening farmers and rural communities with costly and burdensome regulations. Showing success with a grassroots approach could go a long way toward keeping such restrictions at bay, he said.
“We are on the cusp of more and more regulations coming down the pike,” Fuchs said. “The goal is to turn this into a positive situation, to show the federal government that we can all work together—the cities, the water districts, conservation agencies and farmers—to solve the problem. We need these wins in Clark County and Maryville. We want to be able to tell EPA to go away. Missouri’s got this.”
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From source to tap
Learn more about the process of getting water to your home, farm and business
Turning on the tap for a flow of water is something many of us take for granted. If you rely on a municipal supplier for that water, do you know what goes on beyond the faucet to get it to your home, farm or business?
About 10% to 12% of American households rely on private groundwater wells for drinking water—either by choice or because the town they live in does not have a municipal water source, often the case in rural settings.
Everyone else gets their water from the nation’s 150,000 public water systems, which draw from both surface water and groundwater sources. In the U.S, about 70% comes from surface water, replenished by rain and snow that run off into rivers, streams, and lakes. For example, the water source for Maryville, Mo., is Mozingo Lake, which is about five miles away from the city’s water treatment facility.
The rest of the nation’s fresh water comes from groundwater, which originates from rain and snow that seeps into the soil. It’s stored in aquifers, natural formations of soil, rocks, and sand beneath the ground. Groundwater is accessed from natural springs or pumped out of the ground from a well and is mainly used as drinking and irrigation water. The Clark County Water District in northeast Missouri provides water to its customers from the Des Moines River alluvial aquifer.
No matter the source, public water supplies must undergo regular tests to verify they meet the U.S. Environmental Protection Agency’s Safe Drinking Water Standards. Groundwater sources usually require less treatment than surface water. Though levels of treatment vary, depending on the source, the most common steps are:
A series of pumps and pipes connect a water source to a treatment plant. Most treatment plants use gravity as much as possible to move the water.
When the water reaches the treatment area, a large metal screen traps large debris, such as plants, trees, trash, and fish, to keep them out.
Coagulation and Flocculation
Chemicals with a positive charge, called coagulants, are added to the water. The coagulants bind with negatively charged dirt particles, and together they form larger gelatinous particles called floc. Floc is separated from the water and pumped to a sedimentation pond. Meanwhile, the water is sent on for further treatment.
In some systems, ozone is added to the water. Ozone consists of three molecules of oxygen bound together and is made by applying electricity to liquid oxygen. When it’s pumped through water, it kills bacteria, viruses, and protozoans and reduces the concentration of iron, manganese, and sulfur. It also degrades pesticides and helps correct bad odors and tastes.
Next, gravity pulls water through filters, which are usually made from sand, gravel, granular activated charcoal, or another medium. The filters remove particles from the water.
Chlorine is added to the water to kill or inactivate microorganisms. Sometimes, fluoride is also added to the water for dental health.
After drinking water is treated and meets the U.S. Environmental Protection Agency’s Safe Drinking Water Standards, it's transported to storage facilities where homes and businesses can access safe, clean drinking water straight from their taps. American water distribution systems span nearly 1 million miles and are mostly underground. The infrastructure includes pipes, control valves, pumps, meters, storage tanks and hydrants.
Do you know where your water comes from? Check out this interactive map from EPA: https://geopub.epa.gov/DWWidgetApp/
Solutions for the sources
When nitrogen and phosphorus are not fully utilized by growing plants, they can be lost from farm fields and negatively impact water quality. Excess N and P can be washed into waterways during rain events and when snow melts and can also leach through the soil and into groundwater over time. There are many ways that farmers can reduce nutrient losses from their operations, including, but not limited to:
- Adopting Nutrient Management Techniques: Farmers can improve nutrient management practices by following the 4Rs of nutrient management: applying fertilizer and manure in the right amount, at the right time, with the right method and with the right placement.
- Using Conservation Drainage Practices: Subsurface tile drainage is an important practice to manage water movement on and through many soils, typically in the Midwest. Drainage water can carry soluble forms of nitrogen and phosphorus, so strategies are needed to reduce nutrient loads while maintaining adequate drainage for crop production.
- Ensuring Year-Round Ground Cover: Farmers can plant cover crops or perennial species to prevent periods of bare ground on farm fields when the soil is most susceptible to erosion and loss into waterways.
- Planting Field Buffers: Farmers can plant trees, shrubs and grasses along the edges of fields; this is especially important for a field that borders water bodies. Planted buffers can help prevent nutrient loss from fields by absorbing or filtering out nutrients before they reach a water body.
- Implementing Conservation Tillage: Farmers can reduce how often and how intensely the fields are tilled. Doing so can help to improve soil health, and reduce erosion, runoff and soil compaction, and therefore the chance of nutrients reaching waterways through runoff.
- Managing Livestock Access to Streams: Farmers and ranchers can install fence along streams, rivers and lakes to block access from animals to help restore stream banks and prevent excess nutrients from entering the water.
- Engaging in Watershed Efforts: The collaboration of a wide range of people, stakeholders and organizations across an entire watershed is vital to reducing nutrient pollution to our water and air. Farmers can play an important leadership role in these efforts when they get involved.
Did you know ...
...that although 70% of Earth’s surface is water, 97% of that is in oceans and estuaries and not available for drinking or irrigating? And that much of the remaining 3% is trapped in glacial ice?
...that the volume of water on Earth stays the same, but the form—liquid, gas, or solid—changes constantly?
...that per-capita daily water use in the United States is about 1,400 gallons (all uses, including irrigating, mining, and manufacturing, as well as domestic use)?
...that soil quality is a key determinant of water quality because soils regulate and partition water flow and buffer against human use and environmental changes?
...that many of the contaminants that people introduce into water—such as nitrate—also occur naturally?
...and that 3 out of 4 farmers have changed their farming practices to help reduce water pollution?