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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Proximity of farms to streams and rivers poses a challenge to keep nutrients from reaching the water. © Robert Queen
Proximity of farms to streams and rivers poses a challenge to keep nutrients from reaching the water.

© Robert Queen

December 2006

a better solution

Healthy farms, water protectors and communities are shaping better ways to manage manure.

DNR environmental communicators

A flowing health issue
A matter of timing
Attending to larger farms first

It should have been just another sweet day on the Sugar River.

Steve Haak and about a half dozen other members of the Upper Sugar River Watershed Association and the Deer Creek Sportsmen's Club had sharpened their pruning shears for a Saturday workout cutting back box elder and willow sprouts along the riverbanks. Five years, nearly $1 million and thousands of hours by volunteer groups had been spent cleaning up the west branch of the river that runs between Mount Vernon and Belleville in southern Dane County. The streambanks were riprapped, shoreline seeded, banks fenced and more than 1,000 fish habitat structures placed in a six-mile stretch of the west branch. This river reach had been hailed as a success story and celebrated as a place where clean water and dimpling trout again sparkled in the winter light. In February, the river should have flowed with about four to five feet of clear water.

But that wasn't the case.

"The water looked terrible," Haak recalled. "Gray, with about six inches of visibility and it smelled like manure. We trimmed brush on about a three-quarter mile segment and even in that murky water, we found eight dead trout in about two hours."

Later investigation showed that six miles upstream of where Haak and company were working, liquid manure spread on farmland had washed across frozen ground unimpeded into the waterway.

"It was bad. Even several miles downstream you could smell the manure 100 to 200 yards or more away from the water," Haak said.

As president of the watershed association and a farmer himself, Haak and Watershed Director Frank Fetter joined DNR fisheries crews the next morning to track upstream for signs of a fish kill. The pollution was still easy to see and smell. In a 1.5-mile stretch, they picked up 98 dead trout.

Once they found the spill site, the fisheries crews called for some heavy equipment and put in two earthen berms that dammed up the pooling liquid manure to keep it from reaching the water. The manure ponded up in ditches and was subsequently pumped out.

"The fisheries people checked for several more days, then did some live shocking to see what was still left alive after such a large amount of manure ran through the area," Haak recalled. The spill killed off the fish in the restored waters. A manure pumper had been working throughout the area the previous week spreading liquid manure on sloping frozen land in the Town of Blue Mounds south of Mount Horeb. Unfortunately in this location, the manure flowed right into the water.

A flowing health issue

Seepage from manure spreading on land has been linked to drinking water contamination and other health concerns. Runoff can flow into abandoned or improperly sealed wells or through fissures directly into groundwater. In areas where manure is spread over fractured bedrock, the soil does not have enough time or capacity to filter out bacteria before they reach groundwater and drinking water supplies. That scenario is one possible explanation for bacterial contamination of private wells last winter in the Town of Morrison in southern Brown County southeast of Green Bay. Seventy-eight wells in the community of Wayside tested unsafe and some residents reported their water smelled like manure.

In searching for a source of contamination at Wayside, health and environmental officials investigated leaks from a manure transfer line break and at a local dairy, but determined that probably wasn't the cause. That is not unusual in a region with fractured bedrock and many potential sources. Notices were posted advising residents in the surrounding area to boil water. More than 100 families received free bottled water for six months following the discovery, as allowed by state law, and 16 families so far have had their wells replaced with deeper wells under a special appropriation from state legislators to DNR's well compensation program.

The recent spinach scare in California's Salinas Valley may also be attributed to similar widespread runoff pollution. That health concern "marked the 20th time since 1995 that the dangerous E. coli strain has been linked to lettuce or spinach," according to the Los Angeles Times. The low-lying vegetable region is surrounded by intensive upland cattle raising and surface water contamination from upland areas is under investigation as a potential source of that E. coli contamination.

A matter of timing

Unless manure spreading causes an immediate health concern or a fish kill, it's unlikely that communities can accurately say how and where landspread manure threatens streams, groundwater and drinking water. Only a small fraction of contamination cases are noticed by the public and subsequently reported to environmental and health officials, says Gordon Stevenson, chief of DNR's Runoff Management Section. Stevenson mentioned that trends are apparent in the cases that are investigated, and that there are many more problems where manure is spread on sloping lands when the ground is snow-covered or frozen. Rain and melting snow carry both the nutrients and contaminants in manure a lot farther in winter.

"We need to better control manure runoff to protect human health and environmental health," said Stevenson. He noted that between July 2004-June 2005, 52 manure spills had been documented statewide that contaminated drinking water, caused fish kills or polluted lakes and streams.

Stevenson believes that number may reflect a better awareness among the general public of manure-related problems and a willingness to report them. But he also thinks the number reflects an increase in manure-related problems that can be traced to weather patterns and changes in farming practices.

Stevenson says weather patterns in recent years have brought mild winter weather with periodic warm ups and rain that have increased the risk of manure applied to frozen fields running off into lakes and rivers. More farmers are managing manure as a liquid rather than a solid without building the storage they need to avoid applying manure to fields during times of the year when the risk of runoff is high. The liquid form more easily runs off into state waters.

Even changes in the cows' diets may play a role in making manure spills or manure-related incidents a bigger threat to human health. Greater reliance on grain diets allows better survival of the virulent O157:H7 strain of E. coli in cows and in their manure.

Animal feed, genetics and manure handling have made technological advances in recent decades, while disposing of the manure has not. New technologies are needed, Stevenson says.

Landspreading manure can remain a practical and beneficial way to use the nutrients that animals don't turn into milk and meat, he says. Applying the phosphorus and nitrogen from manure on fields in appropriate amounts can build both soil fertility and tilth, but there's an art and a science to doing it well.

Manure on the land is a fertilizer; in water, it's a pollutant. These days "nutrient management" on farms of any size takes a more scientific approach that includes identifying the manure's nutrient content, levels of nutrients in the soil, and the needs of the crops to determine application rates. Timing and location of applications are also critical: when manure should be applied to soils, how often a given field can be treated and how close it is to water are key decisions for growing crops while minimizing environmental risks to groundwater, wells and streams.

"We all want clean streams, safe drinking water, good fishing and prosperous farms," Stevenson says. "Providing that protection gets more challenging when managing the manure from larger farms."

Attending to larger farms first

One way to judge the relative size of farming operations is to measure the number of "animal units" on a given farm. When it comes to manure, all animals are not created equal. Cows, pigs and poultry produce varying amounts of manure with varying amounts of phosphorus and nitrogen that can potentially pollute Wisconsin waters. The concept of "animal units" provides a way to equalize and compare manure production. For instance, the output of 1,000 beef cattle is roughly equivalent to that from 700 dairy cows, 2,500 pigs, 55,000 turkeys, 100,000 laying hens or 200,000 broiler chickens.

Concentrated sources of manure are among the most serious potential pollution problems in Wisconsin. Recently proposed rules revising manure management focus on the small number of larger farms where at least 1,000 animal units of cattle, dairy cows, pigs and or poultry are housed. These operations, also called Concentrated Animal Feeding Operations (CAFOs), represent half of one percent of Wisconsin's 30,000 livestock operations, but the sheer amount of manure from these large farms could threaten public health and the environment if it is not managed properly, Stevenson says. Animals at each of these large farms produce at least 6.5 million gallons of manure a year, as much organic pollution potential as people in a city of 18,000 would generate. Unlike a city, the livestock operations can spread their manure on land with no treatment required.

Proposed rules would limit manure spreading on frozen ground. © NRCS – Natural Resources Conservation Service
Proposed rules would limit manure spreading on frozen ground.

© NRCS – Natural Resources Conservation Service

Federal and Wisconsin environmental laws require that CAFOs must apply for Wisconsin Pollutant Discharge Elimination System (WPDES) permits to protect water quality from both manure and "process" wastewater – which includes wastewater from cleaning milking parlors, egg wash water, leachates from stored feed, and the like. The WPDES permit program does not have authority to address other concerns the public has raised about large-scale farms, including dust, odors, traffic and noise.

In response to changes in federal regulations, Wisconsin initiated revisions to Wisconsin's CAFO rule, ch. NR 243. From summer 2003 through 2005, an internal workgroup as well as an external Technical Advisory Committee worked on the issue. The external group included representatives of farm organizations, land conservation officials, environmental groups, manure haulers, angling and water resources. A round of public hearings and other opportunities to comment followed.

Based on the advisory group feedback and public hearings comments, DNR staff proposed changes to its CAFO rules that would:

  • Require all CAFO operators to have six months of storage for liquid manure so they would have the flexibility to avoid spreading on days when runoff is more likely. Ninety percent of CAFOsS already have that capacity.
  • Ban spreading solid manure on frozen or snow-covered ground during February and Marchthe winter unless it was is immediately worked into the ground. Research has shown that the risk of runoff to groundwater, streams and lakes in Wisconsin is greatest in February and March from manure applied to frozen fields.
  • Require that manure spread on land meet minimum distances from private and public drinking water wells, sinkholes and fractured bedrock. Additional restrictions would apply to manure and process wastewater spread on areas with shallow soils.
  • Require farms to follow nutrient management plans to assure they are only applying the right amount of phosphorus to the soil. This nutrient decreases water quality and fuels algae growth when it flows into streams, rivers and lakes.
  • Require farms applying manure near lakes and streams to limit spreading amounts and leave crop residue or create vegetated buffers between fields and surface waters. The provision aims to reduce the likelihood that manure and associated nutrients might reach waterways.
  • Require CAFOs to develop emergency response plans to address manure spills or discharges.

Following a public hearing in August, the Senate and Assembly agriculture committees sent the rule package back to the Department of Natural Resources seeking more changes. The earliest any revisions could go into effect would be late winter or early spring 2007.

Among the more contentious aspects, some farmers testifying before the legislators felt provisions that would prohibit spreading based on weather forecasts made it too difficult to plan manure applications. Spreading would be prohibited when forecasts called for at least a 50 percent chance of a quarter-inch of rain during winter months and a 70 percent chance of a half-inch of rain the rest of the year. Others objected to the six-month storage requirement. The most contentious issue was the provision that would prohibit spreading based on weather forecasts.

Laurie Fischer, executive director of the Dairy Business Association, asked for modifications. Her organization supports the rule, but felt that manure could be safely spread on some winter days. She also noted that six months of storage would leave a very short window of time in April to apply manure after the spring thaw but before the time that crops must be planted.

Environmental and conservation groups counter that storage and winter spreading restrictions are critical for preventing water quality problems. "Frankly, it is our position that the DNR may have gone too far in drafting these rules to meet the request of the agricultural community," George Meyer, executive director of the Wisconsin Wildlife Federation said in testimony to lawmakers. But WWF went on record supporting the "rapid" adoption of the changes, saying that the absence of the regulations "are jeopardizing citizen health and valuable public natural resources."

Whatever emerges as the manure handling requirements are formed, farmers, other rural residents, stream users, health professionals, agribusiness and Wisconsin citizens want practical regulations that keep the farm economy, communities and the land and water healthy.

Communicators from DNR's Education, Information and Water programs contributed to this piece.