Minnesota farmers, through their organizations, such as the Minnesota Soybean Growers Association, Minnesota Corn Growers Association, Minnesota Farm Bureau and others, supported the Clean Water Legacy Act. We believed then — and still believe today — that the Act has great potential to mobilize public and private collaboration to protect our state’s 12,000 lakes and 69,000 miles of rivers and streams.
A Sustainable Farmer’s Perspective
Minnesota Soybean Research & Promotion Council and Minnesota Soybean Growers Association
Table of Contents
- Background on Clean Water legislation
- Minnesota farmers support clean water through practical and common senseenvironmentalism.
- Minnesota’s water quality challenge is complex, with turbidity coming from many sources.
- Many water quality impairments attributed to agriculture are due to natural sources and causes.
- Through ongoing study and farmer involvement a more accurate view is emerging regarding sediment in the Minnesota River.
- Voluntary farmer soil conservation practices in cooperation with state and federal incentives are having significant positive effect on Upper Mississippi River Basin water quality.
- Drainage is a best management practice that enhances crop production, protects water quality and decreases erosion.
- Minnesota farmers believe more research and collaboration are needed regarding sources of sediment.
- Turbidity can be managed positively, not eliminated, and agriculture is part of the solution.
- Definition of terms
- Active Minnesota TMDLs related to turbidity
- Further study recommendations
- Key points
BACKGROUND ON CLEAN WATER LEGISLATION
The Federal Clean Water Act directs states to:
- Establish designated uses for waters within their borders.
- Develop water quality standards to protect the designated use.
- Assess waters and identify those that are impaired for the designated use. Conduct Total Maximum Daily Load (TMDL) studies to set impairment load and waste-load allocations and impairment reduction goals.
- Implement corrective measures to restore impaired waters to meet water quality standards.
As of 2011, U.S. states have identified 41,288 waters as “impaired.” Some states, including Minnesota, are more active in identifying impaired waters than other states. Fourteen have each identified at least 1,000 impaired waters; these are Florida, Idaho, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, New Hampshire, North Carolina, Oregon, Pennsylvania, Virginia and Washington. Pennsylvania is the most active with nearly 7,000 impaired waters.
The majority of states, including Iowa, have identified fewer than 300 impaired waters while Minnesota has identified 3,049 impaired waters.
Minnesota Clean Water Legislation
Each state has authority to meet these federal requirements through its own programs. In Minnesota, the Clean Water Legacy Act of 2006 appropriated $25 million to standardize Minnesota’s clean water policy. As a result, impaired water identification and Total Maximum Daily Load (TMDL) studies and water restoration projects began.
The Minnesota Pollution Control Agency (MPCA) administers the program in Minnesota and is required to update its list of impaired waters in the state every two years. Minnesota has an excellent environmental record and according to MPCA estimates; approximately 60 percent of the Minnesota lakes, rivers and streams that have been assessed are designated as “clean waters,” meaning they met Minnesota water quality standards at the time of assessment.
MPCA, MBSWR, MDNR, MDA, Public Facilities Authority; Feb. 2007; Why impaired waters are a priority for Minnesota, MPCA: March 2007)
MINNESOTA FARMERS SUPPORT CLEAN WATER THROUGH
PRACTICAL AND COMMON SENSE ENVIRONMENTALISM
We believe farmers should be actively involved in the process of developing TMDL allocations that are scientifically sound and practical, and that balance both environmental, economic and societal objectives.
Minnesota farmers want to be part of the solution to the problem of impaired waters. Agricultural ecosystems are an important component of the environment because they supply food, fiber and renewable resources that are critical to the well being of mankind; and as a result, some soil erosion and nutrient losses are natural and unavoidable. Balanced stewardship and thoughtful management of land and water is a vital part of supporting the long-term well being of local rural populations as well as burgeoning urban and world populations.
To that end, farmers have been working for decades with state and federal soil and water conservation programs to protect the state’s natural resources and are devoted to preserving the productive and fertile topsoil that generations of rural and urban families have depended on for their sustenance and livelihood. They use the best conservation technologies available to protect streams, rivers and lakes from soil erosion and through innovative solutions have had a substantial positive impact on conservation of wildlife resources, including natural wetlands, grasslands and forested areas.
MINNESOTA’S WATER QUALITY CHALLENGE IS COMPLEX, WITH IMPAIRMENTS COMING FROM MANY SOURCES
Turbidity is one of the primary water impairments that is blamed on agriculture, and many of the state’s TMDL studies are focused on turbidity. Turbidity is caused by particles suspended in water. These are from clay, silt, fine organic and inorganic matter, soluble colored organic compounds, tannic acids from peat and bog areas, microscopic organisms and algae.
Phosphorus enrichment is another water quality impairment that is measured. There are three types of phosphorus in surface waters: soluble (bio-available), organic-bound, and mineral soil-bound. Soluble phosphorus is directly available and causes algae and other aquatic plants to flourish while phosphorus in organic materials becomes available when it is leached out of dead plant materials, and soil mineral-bound phosphorus has very low availability for aquatic plants.
Nitrogen enrichment from field runoff to lakes, rivers and streams is a problem agriculture is facing. Farmers do not want to lose valuable and expensive nutrients to the environment or contribute to algae bloom or eutrophication downstream. Nitrogen is an essential plant nutrient that contributes greatly to the world’s economy and food supply. Modern agriculture relies on synthetic fertilizer (the Haber Process) and it is important today because the fertilizer generated from this process is responsible for creating half the world’s protein. It is difficult to distinguish between natural and synthetic nitrogen in rivers and streams, but farmers realize they contribute to the problem and are working hard to ameliorate its effects. The price of nitrogen fertilizer, manufactured from natural gas, is volatile and in 2011 averaged $70 per acre of corn and some predict may go as high as $120 per acre of corn in 2012. There is no incentive for farmers to over-apply this expensive nutrient to their fields.
Here are a few things farmers do to optimize economic returns and minimize environmental risks from fertilizers:
- Use Best Management Practices (BMP) developed by the University Minnesota for their region. BMPs for use of nitrogen fertilizer in Minnesota are diverse depending on soil types, precipitation and evapotranspiration. There are five BMP regions in Minnesota. BMPs cover nitrogen rates and sources, application methods and timing, and the use of nitrification inhibitors.
- Conduct soil tests for existing nutrients and select an appropriate nitrogen rate to meet crop needs using U of M guidelines.
- Use natural fertilizer responsibly whenever possible.
- Rotate crops. Soybeans naturally fix nitrogen.
- Tile farmland so nitrogen will not runoff the top and will be absorbed more efficiently by the crop.
- Use minimum tillage techniques to reduce runoff and preserve nutrients in the soil.
- Install bioreactors and holding ponds to filter excess nitrogen.
- Plant riparian buffer zones and cover crops to improve soil quality.
- Use precision farming techniques to target applications and improve efficiency.
- Inject fertilizer to reduce nitrogen losses from volatilization.
A 2010 survey provides the most comprehensive set of data on nitrogen fertilizer use on corn in Minnesota and will be used to target research and education programs to improve management. An important conclusion from the survey is that fertilizer use by Minnesota corn farmers is generally consistent with University of Minnesota Extension management guidelines and that 84 percent of Minnesota farmers regularly test their soil for excess nutrients.
Sediment and nutrients that impair waters come from many sources in a watershed and include erosion from stream banks, river bluffs, construction sites, farm fields, storm-water runoff from impervious surfaces in urban and industrial areas, discharge from wastewater treatment plants and ineffective sewer systems,
decomposition of organisms, such as leaves, grass, and animals, the natural movements of the stream channel itself, and irresponsible river and lakeshore development.
MANY WATER QUALITY IMPAIRMENTS ATTRIBUTED TO AGRICULTURE ARE DUE TO NATURAL SOURCES AND CAUSES.
Water quality impairments due to natural factors are considered “natural background.” All TMDLs must quantify natural background, as well as account for seasonal variations. Natural background, as defined in the Clean Water Legacy Act, means characteristics of the water body resulting from the multiplicity of factors in nature, including climate and ecosystem dynamics, that affect the physical, chemical, or biological conditions in a water body, but does not include measurable and distinguishable pollution that is attributable to human activity or influence.
Most water quality impairments have some level of natural background contribution that include turbidity, nutrients (phosphorus and nitrogen), bacteria, low dissolved oxygen, metals, and other natural elements that get into water through natural processes, such as erosion, decomposition, rainfall and wind.
Water quality standards cannot be more restrictive than natural background conditions. Consequently, there are some waters that can never meet the fishable and swimmable designated use because of the way they have naturally evolved over millennia.
It is unfair and unproven to cite agriculture as the major source of impairments to Minnesota water; and consistent with state law a TMDL should not make agriculture accountable for water quality impairments caused by natural background loadings and loadings that are natural should be separately identified, quantified and properly considered in the TMDL process.
THROUGH ONGOING STUDY A MORE ACCURATE VIEW IS EMERGING REGARDING TURBIDITY IN THE MINNESOTA RIVER
Significant attention has been focused on turbidity in the Minnesota River, which drains into the Mississippi River and forms Lake Pepin as the widest naturally occurring part of the Mississippi. This is the largest and most complex watershed in Minnesota, and understandably the one with the most diverse sources of sediment and phosphorus. Between 70 percent and 80 percent of the sediment that is settling in Lake Pepin comes from the Minnesota River. University of Minnesota soil scientists say this has been the case for a long time and the evidence is inconclusive as to what part agriculture plays in this scenario.
In addition, dramatic and destructive precipitation events have been increasing over the past 80 years in the Minnesota River Basin. Precipitation has increased, not only in overall volume, but in one-time and seasonal events that have changed the overall hydrology of the system.
A 2011 study by the Minnesota Pollution Control Agency (MPCA) using a lake bottom core analysis concludes that sediment load in Lake Pepin has increased dramatically in the past century and that agricultural runoff from the Minnesota River basin is the main culprit.
According to the MPCA report, the Minnesota River contributes 74 percent of the sediment to the South Metro Mississippi and Lake Pepin, with 65 percent coming from eroding stream bluffs, stream banks and ravines and 35 percent coming from farm fields. The report suggests that agricultural drainage tile (storm water runoff from farm fields) is a significant cause for increased riverbank erosion.
Though there may be recent agreement on the source of the sediment, the extent of agriculture’s role, and specifically drainage tiling’s effect, is unknown. Further study is required before costly and ineffective remedies are mandated. Honest investigators, including MPCA, have come to different conclusions over the years as our understanding of the problem evolves.
- In 2004, the MPCA stated: “More than 80 percent of sediment pollution in the Minnesota River is due to soil erosion from farm fields.”
- By 2008, MPCA was stating: “Sediment pollution is divided approximately equally between streambanks, ravines, and farm fields.”
- In 2009, radioisotope-fingerprinting studies confirmed that sediment from upland surfaces in the Blue Earth and LeSueur River watersheds, the highest contributing watersheds on a per-acre basis within the Minnesota River Basin accounted for only 7 percent to 18 percent of total sediment.
- Consequently, in 2010 MPCA stated: “In the LeSueur and Blue Earth River watersheds, sediment inputs from ravines and streambanks are in the range of 82 percent to 93 percent.”
- At a TMDL public input meeting in New Ulm on July 1, 2010, an MPCA official estimated the sources of the sediment load in the Minnesota River as follows:
o Bluffs: 40 percent
o Streambanks and ravines: 35 percent
o Agriculture: 25 percent
o Urban: <2 percent
University of Minnesota
Published research by the University of Minnesota indicates that erosion from stream banks, bluffs and other natural sources accounts for most of the sediment in the Minnesota River. There is evidence that sediment loads were as high in the 19th and early 20th centuries as they are today, however MPCA suggests a simple relationship between sediment load in Lake Pepin and modern agricultural drainage practices. In addition, the popular press has echoed similar concerns despite the reservations of respected soil and water scientists.
Many in the scientific and agriculture community would disagree with the MPCA’s assessment, and contend that increased sedimentation rates in Lake Pepin are primarily the result of straightening, widening and deepening of the channel between Chaska and Fort Snelling; building of levees near Mankato and Henderson on the main channel and along the Blue Earth River; a trend of increased precipitation starting around 1940; the natural erosion of the loose soil of the Minnesota River Basin and the natural southerly movement of the Mississippi River delta; along with additional impervious surfaces due to urbanization.
VOLUNTARY FARMER SOIL CONSERVATION PRACTICES IN COOPERATION WITH STATE AND FEDERAL INCENTIVES ARE HAVING SIGNIFICANT POSITIVE EFFECT ON UPPER MISSISSIPPI RIVER BASIN WATER QUALITY.
Sediment-sourcing studies indicate little relation between field erosion and downstream turbidity and farmers know that keeping rainfall as close as possible to where it falls is a centerpiece of sustainable agriculture. With land values and costs of agricultural inputs at record highs, farmers understand the economics of preserving their valuable soil and soil fertility. For decades, Minnesota farmers have been using state and federal voluntary conservation programs to reduce runoff from cropland. Conservation measures such asreduced tillage, crop rotation, grass waterways, terraces, grassed buffers at the field edge, and sediment control basins reduce the amount of soil that erodes from fields. There is no self-interest in a farmer flushing valuable soil and nutrients to the Gulf of Mexico.
By working with federal and state programs of the USDA Natural Resources Conservation Service (NRCS), Minnesota Board of Water and Soil Resources and the Minnesota Department of Agriculture, Minnesota farmers are national leaders in protecting the state’s soil, water and wildlife resources. The following examples provide the proof:
- According to NRCS, Minnesota farmers are using some form of conservation tillage on 1.4 million acres.
- In 2010, Minnesota was sixth in the U.S. in acres enrolled in the Conservation Reserve Program (CRP) with 1.64 million acres, and third in number of farms enrolled in the program with 32,956.
- In 2010, landowners and operators in Minnesota had contracts obligated in excess of $72 million for conservation efforts.
- Minnesota farmers constructed nearly 2,000 sediment control basins in 2010.
- In 2010, NRCS provided $21.4 million in support to environmentally friendly water quality practices, including nutrient management, stream bank erosion control, buffer strips, wastewater, and feedlot runoff management. Minnesota has enrolled more than 915,000 acres in this innovative program that links conservation payments to environmental performance.
- NRCS reports that Minnesota farmers implemented $4.6 million in erosion control practices in 2010, including crop residue management, grass waterways, diversions and terraces.
- In 2010, Minnesota had 3,900 acres in the Grassland Reserve Program.
- Nearly 1,200 landowners participated in USDA Environmental Quality Incentive Programs (EQIP) in 2010, and spent over $28 million dollars implementing programs such as ring dikes that protect overland flooding from carrying farm chemicals, hydrocarbons and animal waste into surface waters.
- The Minnesota Board of Water and Soil Resources allocated $14 million to farmers participating in its Wetlands Reserve Program. This is the largest private landowner focused aspect of the Clean Water, Land and Legacy Sales Tax Amendment.
DRAINAGE IS A BEST MANAGEMENT PRACTICE THAT ENHANCES CROP PRODUCTION AND PROTECTS WATER QUALITY
Both MSGA and ASA believe farmers must have flexibility in improving and maintaining drainage for production purposes and discourage unproven and costly regulations that limit the most beneficial use of agricultural land. Modern tile drainage benefits all Minnesotans for many reasons:
- The residue that farmers leave on the field after harvest for conservation of soil and energy causes soils to be wetter and cooler in the spring. In certain areas of the state, tile drainage is needed to enable timely spring planting and to protect plants from being damaged by excess moisture in the soil.
- Tiling allows reduced and no-till farming practices on land that would otherwise need moldboard plowing in order to maintain production. Minimum and no-till practices leave more residues on the land and reduce erosion and runoff producing healthier crops that use less herbicides and pesticides.
- Tiling improves agriculture’s productivity and helps feed the world. Tiling normally increases corn and soybean yields 15 percent to 20 percent immediately.
- The NRCS Universal Soil Loss Equation predicts a 40 percent reduction in water runoff from fields when tile are installed.
- Tile drainage mediates heavy seasonal precipitation events by slowly drying the soil and enabling it to act as a sponge. This reduces runoff and topsoil erosion in comparison to land that is not tiled. Research shows a 40 percent to 50 percent reduction in erosion after the land has been tiled.
- Since 1985, federal farm legislation has made it illegal to drain natural wetlands and Minnesota farmers install tile drainage on cropland only. They do not drain wetlands.
- Tiling improves water quality and allows water to infiltrate the soil taking advantage of the soils natural filtering powers before it is discharged into streams. Water coming from tile is clean and clear.
- Tiling reduces flooding. If land is tiled, the water table is normally lowered 3 or 4 feet. Soil can then hold a huge amount of water when a rain comes. Studies show a 15 to 30 percent reduction in peak flows off tiled land.
Today’s higher yielding crops use more water, so less water flows from farm fields.
- New research by the University of Minnesota shows that the best way to keep nutrients from leaving the field through tile drainage is with an optimal fertilizer program that enables the crop to use nitrogen more efficiently.
- Tiling helps plants use water more efficiently; keeping water available for the crop rather than having it leave the field.
MINNESOTA FARMERS BELIEVE MORE RESEARCH AND COLLABORATION IS NEEDED REGARDING SOURCES OF WATER QUALITY IMPAIRMENTS
Because research on the sources of water quality impairment is complex and findings have been inconclusive, Minnesota farmers believe more studies are needed to make good decisions. The worst thing that could happen is that incomplete research would bring unnecessary regulation on Minnesota farmers who are working to feed the world when there is no conclusive proof that agriculture is the major source of the problem.
The evidence so far shows that such regulation might not improve water quality in many areas because of the significant contributions from other sources, including natural background. Costly and experimental regulation of farming would have an impact on Minnesota’s agricultural industry and its ability to produce safe, affordable food for people here and around the world.
Voluntary incentive programs and innovative conservation efforts by individual farmers are contributing to improved strategies for protecting soil and water quality. Everyone has a role to play, and Minnesota farmers will continue to be part of the solution. Through check off programs, farmers are currently funding University research on best management practices for multiple aspects of agriculture’s effect on water quality.
- River Bank Sediment as a Carrier and Source of Available Phosphorus
- Developing Optimum Drainage Design Guidelines for Minnesota
- Evaluation of Drainage and Surface Water Quality on Diverse Crop and Livestock Production Systems
- Extension Agricultural Drainage Education and Applied Research
- The Impact of Stream Alteration and Streambank Erosion on Sediment and Phosphorus Loan to the Minnesota River
- Sediment Fingerprinting for Sources and Transport Pathways in the Root River
- Integrated Water Management Systems to Achieve Optimum Corn Production
Minnesota Soybean and Minnesota Corn have organized and funded the
to improve communication between farmers and various stakeholders in water quality. We are dedicated to improving communication among the agricultural community, consumers, researchers and policy-makers regarding the economic and environmental effects of agricultural practices employed on Minnesota farms. We are educating and engaging farmers in innovative water quality programs and building relationships with watershed organizations, river and lake advocacy groups and local soil and water conservation districts.
TURBIDITY CAN BE POSITIVELY MANAGED, NOT ELIMINATED. AGRICULTURE IS PART OF THE SOLUTION.
Turbidity caused by sedimentation is a situation our government agencies and public and private landowners can manage by working together. However, it can never be completely eliminated because it has been occurring for centuries.
Most sedimentation is from natural background, such as river bluffs, stream banks and other natural sources. The Minnesota River and its tributaries are located at the outer edge of the last ice age and the soil is softer and more erodible than soil to the north. The Blue Earth River flows north and is naturally erodible. For the portion of turbidity that is man-made, we need to use the best practices available to us and continue to develop new ones. We are committed to collaboration with MPCA and other agencies working to protect Minnesota waters. They belong to all Minnesotans.
We strongly support voluntary, scientific solutions to water quality improvement and are committed to sharing our financial resources with Universities and other scientists to continue adding to the base of knowledge about water quality and how it can be managed in the best interests of all Minnesotans. It’s not a case of “our science,” vs. “their science,” but rather a balanced and common sense approach to a modern problem.
Minnesota farmers are part of the solution to improve our valuable waterways. There is no way to go back to the 19th century and there are no simple solutions. Like all Minnesotans, farm families appreciate our state’s rich legacy of land and water and want to steward and improve these assets scientifically and sustainably for the benefit of all Minnesota families today and into the future.
DEFINITION OF TERMS
Lakes, rivers and streams that do not meet state water-quality standards for basic pollutants, such as sediment, bacteria, nutrients and mercury
Monitoring and Assessment
Water quality data is collected by state, local and federal agencies, and the public and then assessed to determine what water bodies meet water-quality standards. Only a small percentage of Minnesota’s rivers and lakes have been assessed. About 40 percent of waters assessed are impaired, a rate comparable to other states.
According to the Minnesota Clean Water Legacy Act, natural background is “characteristic of the water body resulting from multiplicity of factors in nature including climate and ecosystem dynamics that affect the physical, but does include measureable and distinguishable pollution that is attributable human activity or influence.”
Phosphorus that is directly available from dead plant materials and causes aquatic plants to grow
Phosphorus in organic materials that becomes available when it is leached out of dead plant materials
Phosphorus that is bound to minerals and has very low availability for aquatic plants
Total Maximum Daily Load. For each impaired water on the list federal law requires that a TMDL be established, which is a calculation of the maximum amount of a pollutant the water body can receive and still meet water quality standards. In Minnesota, all TMDLs must be approved by the Minnesota Pollution Control Agency
For each impaired water on the state’s list, a Total Maximum Daily Loan study must be prepared. The TMDL results in a calculation of the maximum amount of a pollutant the water body can receive and still meet water quality standards. The process typically involves two to four years of technical study and intensive stakeholder and public input. All TMDLs must be approved by the U.S. EPA.
Following approval of a TMDL, a detailed implementation plan is developed to outline the restoration activities needed to meet the TMDL’s pollutant load allocation. Restoration activities range from improvements of wastewater treatment plants and urban stormwater systems to upgrades of failing septic systems and adoption of best management practices on agricultural and urban land.
If restoration is successful and follow-up assessment verifies that water quality standards are being met, impaired water is removed from the impaired waters list.
Waters not listed as impaired. About 60 percent of Minnesota lakes and streams are found to be meeting standards at the time of assessment.
Tiered Aquatic Life Uses (TALU)
States are required to designate beneficial uses for its waters and develop quality standards to protect each use. Minnesota adopted a beneficial use framework that includes uses for drinking water, aquatic life and recreation, industry, agriculture, wildlife, aesthetic enjoyment and navigation. In Minnesota, all waters are considered fishable and swimmable with the exception of waters designated as limited resource value waters, which are protected for secondary body contact only.
A measure of how cloudy or murky water is. It is caused by particles suspended or dissolved in water that scatter light making the water appear cloudy or murky. Particulate matter can include sediment, fine organic and inorganic matter, soluble colored organic compounds, algae and other microscopic organisms.
These are divided into “natural background,” and “human-induced,” sources. Natural sources can include erosion from upland, riparian, stream bank and stream channel areas.
Phosphorus and nitrogen are the primary nutrients that in excessive amounts pollute water. Nitrate, a compound containing nitrogen, can exist in the atmosphere or as a dissolved gas in water. At elevated levels, it can have harmful effects on humans and animals. Common sources of excess nitrate reaching lakes and streams include septic systems, animal feedlots, fertilizer, manure, industrial wastewater, sanitary landfills and garbage dumps. Phosphorus can cause water pollution by promoting excessive algae growth. Most phosphorus load to lakes and rivers comes from nonpoint sources such as cropland, pastureland, urban storm water runoff, and seepage from industrial swage treatment systems.
Total Suspended Solids (TSS)
MPCA uses TSS and transparency values to predict turbidity. The TSS values used are 58 and 66 milligrams per liter in the Western Corn Belt Plains and North Glaciated Plains ecoregions, respectively.
Riparian (stream bank, lakeshore) buffers, stream bank stabilization, water storage, surface tile intake buffers, crop residue management, conservation tillage, crop rotations, crop nutrient management plans, improvement in private and public wastewater treatment systems
ACTIVE MINNESOTA TMDLS RELATED TO TURBIDITY (PARTIAL LIST)
Lake Pepin Watershed
Minnesota River Basin
Blue Earth River
Lake Crystal Cottonwood River
Little Cottonwood River
Lac qui Parle River
Pomme de Terre River Watershed
Seven Mile Creek
Lower Vermillion River
Zumbro River Watershed
West Fork Des Moines River Watershed
Red River Basin
Lower Cannon River
Long Prairie River
Lower Mississippi River
Lower Otter Tail River
Pomme de Terre River
South Branch Yellow Medicine River
- Water is very important to Minnesota farmers. We are striving to work closely with state and local officials to clarify agriculture’s role as a source of sediment so that measures to protect water quality are effective for our environment and balanced and fair to farmers.
- Increased sedimentation rates in Lake Pepin are primarily the result of straightening, widening and deepening of the channel between Chaska and Fort Snelling; building of levees near Mankato and Henderson on the main channel and along the Blue Earth River; a trend of increased precipitation starting around 1940; the natural erosion of the loose soil of the Minnesota River Basin and the natural southerly movement of the Mississippi delta; along with additional impervious surfaces due to urbanization.
- The Blue Earth River and the LeSeur River contribute most of the sediment to Lake Pepin through the Minnesota River and that sediment comes from natural erosion of the banks. Lake Pepin is a natural delta that has been filling in since the last ice age.
- Dramatic and destructive precipitation events have been increasing over the past 80 years in the Minnesota River Basin. Precipitation has increased, not only in overall volume, but in one-time and seasonal events that have changed the overall hydrology of the system.
- Tiling is a best practice, and a tried and true conservation tool that reduces erosion, saves topsoil, increases productivity, reduces chemical application, and slows rapid and erosive runoff from fields. Tiled land that has been drained properly acts as a sponge for a dramatic precipitation event.
- It would be a mistake to mandate artificial, one-size fits all regulations on a problem that’s been evolving for centuries without first being sure of the science. Voluntary best management practices should be tailored for different regions and soil characteristics.
- A 2011 University of Minnesota study shows nitrogen fertilizer application by Minnesota farmers was generally consistent with University Extension guidelines and that 84 percent of farmers tested their soil for excess nutrients.
- Minnesota farmers are part of the solution to improve our valuable waterways. Like all Minnesotans, farm families appreciate and cherish our rich legacy of land and water and want to steward and improve these assets scientifically and sustainably for all Minnesota families today and into the future.
SUGGESTED FURTHER STUDY
The University of Minnesota Soil and Water Department has much excellent research. Footnote six below will access some of the work of Dr. Satish Gupta. There are a series of must see videos at the bottom of the Minnesota Agricultural Water Resources Coalition web page, http://mawrc.org/. A 2011 precipitation and sediment seminar is also here at footnote seven. The 2011 MPCA report is footnote five below.
http://www.mn.nrcs.usda.gov/partnerships/mstc/2010_sep29/Minnesota NRCS Conservation Program Update final.pdf