Places We Protect

Mackinaw River Watershed


Corn crop at the Franklin Family farm under a pastel blue sky.
Corn Crop Corn crop at the Franklin demonstration farm in the Mackinaw River watershed, Lexington, Illinois. © Timothy T. Lindenbaum

The Mackinaw River represents one of the finest examples of a restorable watershed in Illinois.



While the development and use of the lands near the Mackinaw River have taken a toll on water quality and wildlife habitat, the Mackinaw River still represents one of the state’s finest examples of a restorable watershed. 

The Franklin Research and Demonstration Farm was established in 2004 to allow research on agricultural practices that benefit both farmers and conservation efforts. Through a 15+-year cooperative agreement between TNC and the Franklin family, 140 acres of their farm were transformed into a place where farmers and others can learn firsthand about cutting-edge agricultural practices that benefit nature.

With the help of other partners at the University of Illinois Champaign-Urbana (UIUC), the McLean County Soil and Water Conservation District (SWCD) and the McLean County Natural Resources Conservation Service (NRCS), the Franklin Research and Demonstration Farm now serves as a model for sustainable agriculture, innovative research and successful partnerships. It demonstrates firsthand how nature and agriculture can coexist to produce benefits for crop production, water quality and habitat preservation.



The Mackinaw River Watershed is located in Lexington, Illinois.


140 acres

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Protecting the Mackinaw River (3:33) The Nature Conservancy is working with farmers and landowners in Illinois to construct wetlands that help keep valuable nutrients out of the Mackinaw River.

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Why TNC Selected This Site

TNC's Illinois Chapter has a long history of working collaboratively to advance conservation efforts in the Mackinaw River watershed, which was identified in the early 1990s as one of the few remaining high-quality, ecologically biodiverse riverine ecosystems in Illinois. The Mackinaw River is a major tributary to the Illinois River that drains into the Mississippi River. This 3,000-square-kilometer watershed contains some of the most productive agricultural lands in the nation and plays a key role in the livelihoods of farmers and the Illinois economy.

The Mackinaw River was selected as a priority site by TNC more than 25 years ago because of its status as a high-quality river that sustains some of the highest-quality stream segments in Illinois and provides habitat for 60-70 native fish species and 25-30 mussel species. Yet, urban development and intensive tile-drained row-crop agriculture have stressed freshwater resources, leading to habitat loss and reduced water quality.

Our Conservation Work

At the site, researchers from TNC and the University of Illinois at Champaign-Urbana have tested a variety of conservation methods, including implementing cover crops, restoring habitats and constructing wetlands to reduce agricultural runoff and improve local water quality.

A combine harvesting on The Franklin family farm.
Harvesting A combine harvesting on The Franklin family farm, located near Lexington, Illinois, on the banks of the Mackinaw River. © Timothy T. Lindenbaum

Cover Crops

Cover crop research began at the farm in 2011, funded in part by an Illinois NRCS Conservation Innovation Grant to monitor the effectiveness of cover crops in sequestering nutrients and reducing tile nutrient runoff. This research helps to increase our understanding of the effectiveness of cover crops for sequestering nutrients as a single practice, as well as how effectiveness might be increased by stacking cover crop practices with constructed wetlands.

Farmers are increasingly realizing the benefits of cover crops, typically oats, radish and cereal rye, which in addition to improving the health of the farmer’s soil also help keep soil and nutrients in the field and out of nearby freshwater resources. Typically planted in the late summer or early fall, they germinate and grow through to the first frost and in many cases reemerge the following spring, stabilizing soil with their roots during the winter and early spring months—but that’s not all. They also replenish important nutrients, and they can help control pests and weeds. As the cover crops decompose in the field, they also add beneficial organic matter to the land that further increases soil health.

An overhead photo of the farm's constructed wetlands.
Franklin Farm's Wetlands Three wetland complexes, East, West & Gully, were constructed on the Franklin Farm between 2004 and 2006, each consisting of three wetland cells separated by berms. © Tim Lindenbaum

Constructed Wetlands

Wetlands function as nature’s kidneys, removing nutrients and sediment as well as slowing down the flow of water before it reaches creeks, streams and rivers. When placed near agricultural lands, constructed wetlands can catch and absorb nutrients from farm fields. 

In 2003, wetlands were constructed in the cropland area of the Franklin Farm, along with seven acres of floodplain and upland wetland habitat near Turkey Creek, totaling 13.3 acres. A long-term study on these wetlands has helped researchers and farmers understand how effective constructed wetlands can be, and specifically the size and amount needed to help clean nutrients from water that passes through tile drain systems. The wetlands have proven to be very effective at reducing nitrate-nitrogen and dissolved phosphorus export from agricultural tiles that would otherwise be entering directly into the Mackinaw River. Since 2005, many wetland plants have also emerged voluntarily, including blue lobelia, broadleaf arrowhead, smartweed and water plantain.

Closeup of milkweed growing on the Franklin Farm.
Milkweed on the Farm Common milkweed at the Franklin demonstration farm in the Mackinaw River watershed, Lexington, Illinois. © Timothy T. Lindenbaum/TNC

Habitat Restoration

Prairies, savannas and floodplains are all habitats that were once prevalent throughout Illinois before their acreage was reduced to make way for agriculture and development. The team at the Franklin Demonstration Farm has worked hard to restore these natural areas to the benefit of local birds, plants and wildlife. Habitat restoration at the farm includes a 14-acre native prairie planted and tended by the farm operator, Tim Lindenbaum, and underbrush removal within a remnant oak-hickory savanna conducted by students from Illinois State University under the guidance of TNC’s Krista Kirkham. 

In addition to research, outreach is an important part of the work that happens at the Franklin Demonstration Farm. Farmers and landowners are interested in seeing how conservation practices are implemented and how they work on the ground without negatively impacting their bottom lines. Tours of the Franklin Demonstration Farm help these and other members of the agricultural community see firsthand how conservation practices such as restored wetlands and grassed waterways function on working farms and how they can be economically feasible.

About the Franklin Family

The Franklin Family has lived and worked their farm alongside the Mackinaw River in Lexington, Illinois for six generations. Along with his childhood friend and local farmer Tim Lindenbaum, John Franklin serves as a leader at the demonstration farm, where other farmers and scientists can see firsthand how nature and agriculture can work together to keep our water clean.

A vintage black-and-white photo of the Franklin family from 1932.
Franklin Family in 1932 Noah Franklin (second row, seated in black suit) on his 100th birthday in 1932 surrounded by third- and fourth-generation family. © Franklin Family
A photo of the Franklin family in 2012.
Franklin Family Today Franklin family members at an Open House event in 2012. © Tim Lindenbaum

For the first 100 years, the farm was primarily a cattle operation, managed by Noah Franklin. Noah is credited for building up the property, raising shorthorn and then Angus beef cattle, and was represented at the Chicago stockyards for 78 consecutive years. During the 1960s, the Franklin family farm went through a transition, converting several acres of the property to row-crop agriculture; those fields have been in a corn and soybean rotation for the past 50 years.

Over the past 15+ years, the farm has served as a model for sustainable agriculture, innovative research and successful partnerships. Today, the Franklin Research and Demonstration Farm has been toured by hundreds of visitors and has been utilized by several agencies and universities for educational purposes, including work published in scientific journals.

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