Construction equipment dig new stream bed at Strait Creek.
Strait Creek Restoration In 2019, the Ohio Mitigation Program restored more than 2,600 linear feet of perennial stream at Strait Creek in southern Ohio. © Dana Ohman/TNC

Stories in Ohio

Restoring Streams and Wetlands Through the Ohio Mitigation Program (OMP)

For the last 10 years, the OMP team has worked to restore and protect streams and wetlands in Ohio.

It’s almost like a sixth sense kicks in when Dana Ohman is out in the field assessing stream health. Sure, there’s plenty of science involved. Boulders are counted. Pool depth is measured. Habitat for fish and bugs is evaluated. The list goes on. But then there’s the art of it all. The space within which decidedly unscientific things like senses and imagination come into play. With each visit to a potential mitigation site, the Ohio Mitigation Program (OMP) team embarks on a journey of understanding. They see beyond the surface, recognizing the cries for help from a habitat in distress.

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It’s a skill presumably acquired only by those who have long since lost track of the number of times they’ve walked in a creek bed. Ohman falls into that category. A stream and wetland mitigation specialist for The Nature Conservancy in Ohio, Ohman’s job is to help restore waterways and floodplains as part of our mitigation program. 

Where most people see only a degraded waterway, OMP staff see potential. “You have to read the land, and imagine it prior to European colonization,” Ohman says. “What the tree cover might have been like, how the stream would have moved through the valley, what plants would have existed along the banks.” From here, armed with a vision and plenty of stream quality data, Ohman’s job is to work with the OMP team to create a restoration plan.

Celebrating 10 Years of Ohio Mitigation Program

Since its initiation in 2014, the Ohio Mitigation Program has worked hard to restore stream and wetland habitat throughout the state.

  • Tree icon.


    Completed restoration projects

  • Cattail icon.


    Acres of wetlands restored

  • Stream icon.


    Miles of streams restored

  • Heron icon.


    Active restoration projects

Aerial view of Baker Swamp surrounded by woodland habitat and fields in distance.
Baker Swamp Mitigation Project The OMP helps protect and restore degraded streams and wetlands in ways that increase water quality while providing critical wildlife habitat. © Dana Ohman/TNC

Stream and Wetland Mitigation

In a state that’s lost 90 percent of its original wetlands, good mitigation is critical. TNC’s mitigation program is founded on federal and state laws that require developers to avoid and minimize harm to wetlands and streams. When regulators consider the impacts to be unavoidable, they must be mitigated by protecting or restoring nearby water resources. In the past, many of the projects undertaken by developers on their own were ecologically unsuccessful. Now regulators prefer that developers pay a fee to an approved mitigation provider like TNC to do the required environmental restoration work. The OMP consolidates money from many small, permitted impacts to streams and wetlands and uses these resources to design and implement high quality restoration projects. Through the OMP, TNC and its conservation partners conduct restoration and preservation activities in the same watersheds where wetland and stream disturbances have occurred.

Why We Need Streams and Wetlands in Ohio

Ohio's extensive network of streams and wetlands provide a myriad of benefits to both human and natural systems, serving as vital habitats for a diverse array of plant and animal species and providing flood control and water filtration services. These water bodies act as nurseries for fish and other aquatic organisms, providing breeding grounds and essential shelter for their early life stages. In fact, wetlands are regarded as some of the most biodiverse ecosystems on the planet.

Northern pike underwater.
Northern Pike Wildlife, like this northern pike, rely on high quality wetlands for spawning. © abadonian/Getty Images
Hand holds a spotted turtle in a wetland.
Spotted Turtle Threatened in Ohio, spotted turtles need quality wetlands for their survival. © Derrick Cooper/TNC
Northern Pike Wildlife, like this northern pike, rely on high quality wetlands for spawning. © abadonian/Getty Images
Spotted Turtle Threatened in Ohio, spotted turtles need quality wetlands for their survival. © Derrick Cooper/TNC

Streams and wetlands also serve as natural filters, purifying water by trapping sediments and pollutants and improving overall water quality. In a state that relies heavily on agriculture and industry, the presence of wetlands helps to mitigate the impact of runoff from fertilizers and pesticides, preventing contamination of larger water bodies, including Lake Erie. These ecosystems also contribute to flood control by absorbing excess water during periods of heavy rainfall, reducing the risk flooding and protecting downstream communities and infrastructure.

Enjoy Learning About Our Recent OMP Projects

Strait Creek

The Ohio Mitigation Program team restored 1.3 miles of stream and 1.7 acres of wetlands at Strait Creek.

Construction crews work to dig new stream bed near forest.
A newly dug stream bed winds through natural area in front of forest.
A newly dug stream bed winds through natural area in front of forest.
A winding stream bed cuts through green vegetation.

In the rugged foothills of the Appalachian Mountains, land suitable for agriculture has always been at a premium. Pushing streams toward the outer edges of a valley afforded settlers more space to grow crops and create infrastructure like roadways as populations expanded. In doing so, many streams like Strait Creek were straightened and channelized, resulting in issues with erosion, flooding and loss of both terrestrial and aquatic wildlife habitat.

Restoring Strait Creek involved dramatically changing the local ecology. In summer 2019, the OMP team worked to remove trash from the streambeds and transform the landscape from one dominated by straightened ditches and abandoned agricultural fields, to streams teeming with life that meander through abundant wetlands and riparian forest.

Today, Strait Creek is a far cry from the channelized and degraded streams that once flowed through the landscape. The team restored 1.3 miles of stream and 1.7 acres of wetlands at Strait Creek. By recontouring the streambed and restoring the stream’s riparian buffer, the project improved water quality, enhanced in-stream headwater habitat for a diversity of plants and animals, and reestablished habitat connectivity with existing natural areas.

Rialto Marsh

The Ohio Mitigation Program team worked to re-contour the stream at Rialto Marsh back to a natural flow state and dug shallow pools that will provide habitat for a diversity of wildlife.

Aerial view of newly dug stream beds in field nestled amongst industrial site.
Aerial view of newly created wetland with surrounded by bare ground.
Volunteer wearing work gloves works to plant tree in wet ground.
Tree tubes protect newly planted trees at Rialto Marsh.

Like much of Ohio, the Rialto Marsh property was once covered in wetlands. Being right on the banks of the Mill Creek, the property is part of the creek’s natural floodplain and would likely have been a forested wetland that provided habitat and improved water quality for hundreds of plants and animals.

When the greater Cincinnati area was taken by settlers, large swaths of land were cleared for agriculture, and farmers built up berms around the Mill Creek to prevent it from flooding their fields. The Rialto Marsh property was no exception, and every tree was logged until only one sycamore remained. The wetlands were then drained and separated from the Mill Creek with a berm, a fate seen by many of Ohio’s original wetlands. This has severely impacted the freshwater system upon which plants, animals and people depend.

Working with an engineering consultant, the OMP team began restoring the Rialto Marsh site in 2021. When TNC first saw the area, it was a large field of invasive plants divided by a narrow drainage ditch that emptied into the Mill Creek. Working around powerline easements, utility lines and the railroad tracks, TNC and the engineering consultant removed drainage tiles and invasive species from the property, recontoured the stream back to a natural flow, dug shallow pools that will provide important wetland habitat and planted nearly 12,000 native trees and shrubs, which will shade the stream corridor and provide important forest wetland habitat for wildlife in time. 

Restoration Benefits People

In the summer of 2022, TNC opened up the Rialto berm to allow floodwater to flow into the wetland. After a 3-day rainstorm began in Cincinnati, thousands of gallons of water safely flowed into the wetlands instead of into the homes and businesses of community members downstream, proving the projects worth to people and communities.

Turning Back Time

Learn more about the OMP's work to restore Rialto Marsh by visiting our StoryMap.

Visit the Rialto Marsh StoryMap

Jacoby Branch

Jacoby Branch was once a detriment to the Little Miami River, pouring sediment, pollution and excess nutrients into the watershed. But that’s changing thanks to the restoration work on 60 acres in Yellow Springs, Ohio.

In January 2023, the OMP completed the initial phase of restoration at Jacoby Branch in partnership with the Agraria Center for Regenerative Agriculture, an organization whose mission is to cultivate community resilience by modeling regenerative practices that restore ecosystem health and promote equitable food systems. The project recontoured and reconnected over a mile of degraded stream and created almost four acres of wetland to restore surface water hydrology to the floodplain. Allowing water to access the floodplain more frequently will help to create a cleaner, more diverse ecosystem that will serve as habitat for an abundance of freshwater species including fish, amphibians, and macroinvertebrates.

Aerial view of newly dug stream beds winding through patches of forest.
Jacoby Branch Aerial view of Jacoby Branch restoration site. © Dana Ohman/TNC
Aerial view of newly constructed stream bed winding through patches of forest.
Jacoby Branch Post Restoration Newly constructed stream beds wind through forest and field. © Amelia Harris/TNC
Jacoby Branch Aerial view of Jacoby Branch restoration site. © Dana Ohman/TNC
Jacoby Branch Post Restoration Newly constructed stream beds wind through forest and field. © Amelia Harris/TNC

After initial design and restoration work, the OMP team worked to seed the former fields with native seed mixes and plant nearly 30,000 tree and shrub seedlings. In time, the young forest will provide important habitat for wildlife while increasing the ability of the land to hold water by shading the streams and wetlands. The OMP will continue working with partners to help control aggressive non-native species such as bush honeysuckle and Canada thistle. A successful restoration project is a long-term effort, and the OMP will monitor this project for 10 years to support the continued stewardship of the restored stream and newly created wetlands.

Aerial view of construction equipment working to remove dam in river.
Brinkhaven Dam Removal Crews work to remove Brinkhaven Dam on the Mohican River. © Amelia Harris/TNC

Brinkhaven Dam

More than just an impediment to paddlers looking to enjoy the Mohican River’s recreational opportunities, the Brinkhaven dam had long disrupted the natural flow of water and created a barrier for fish and other aquatic wildlife that call the river home, including mussels, macroinvertebrates and hellbenders. That changed when TNC worked to remove the dam in late 2023.

"By restoring the river’s natural flow patterns and directly protecting nearly 3,000 linear feet of the river and its riparian buffer, removing the dam is a huge win-win for people and wildlife alike," says Amelia Harris, TNC restoration ecologist and member of the OMP team.

A Larger Vision

TNC’s stream and wetland restoration projects are part of The Nature Conservancy's larger goals to halt catastrophic climate change and biodiversity loss. What’s done between now and 2030 will determine whether warming is slowed to 1.5 degrees Celsius—the level scientists agree will avoid the worst impacts of climate change. Worldwide action will also determine whether enough land and water are conserved to slow the rapid acceleration of species loss. Doing both will safeguard people from the disastrous effects of these crises.